aboutsummaryrefslogtreecommitdiff
path: root/clang/lib/Sema/SemaExprCXX.cpp
blob: 7961e794181304161cb7b6be48d5d8c654b70aad (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
8231
8232
8233
8234
8235
8236
8237
8238
8239
8240
8241
8242
8243
8244
8245
8246
8247
8248
8249
8250
8251
8252
8253
8254
8255
8256
8257
8258
8259
8260
8261
8262
8263
8264
8265
8266
8267
8268
8269
8270
8271
8272
8273
8274
8275
8276
8277
8278
8279
8280
8281
8282
8283
8284
8285
8286
8287
8288
8289
8290
8291
8292
8293
8294
8295
8296
8297
8298
8299
8300
8301
8302
8303
8304
8305
8306
8307
8308
8309
8310
8311
8312
8313
8314
8315
8316
8317
8318
8319
8320
8321
8322
8323
8324
8325
8326
8327
8328
8329
8330
8331
8332
8333
8334
8335
8336
8337
8338
8339
8340
8341
8342
8343
8344
8345
8346
8347
8348
8349
8350
8351
8352
8353
8354
8355
8356
8357
8358
8359
8360
8361
8362
8363
8364
8365
8366
8367
8368
8369
8370
8371
8372
8373
8374
8375
8376
8377
8378
8379
8380
8381
8382
8383
8384
8385
8386
8387
8388
8389
8390
8391
8392
8393
8394
8395
8396
8397
8398
8399
8400
8401
8402
8403
8404
8405
8406
8407
8408
8409
8410
8411
8412
8413
8414
8415
8416
8417
8418
8419
8420
8421
8422
8423
8424
8425
8426
8427
8428
8429
8430
8431
8432
8433
8434
8435
8436
8437
8438
8439
8440
8441
8442
8443
8444
8445
8446
8447
8448
8449
8450
8451
8452
8453
8454
8455
8456
8457
8458
8459
8460
8461
8462
8463
8464
8465
8466
8467
8468
8469
8470
8471
8472
8473
8474
8475
8476
8477
8478
8479
8480
8481
8482
8483
8484
8485
8486
8487
8488
8489
8490
8491
8492
8493
8494
8495
8496
8497
8498
8499
8500
8501
8502
8503
8504
8505
8506
8507
8508
8509
8510
8511
8512
8513
8514
8515
8516
8517
8518
8519
8520
8521
8522
8523
8524
8525
8526
8527
8528
8529
8530
8531
8532
8533
8534
8535
8536
8537
8538
8539
8540
8541
8542
8543
8544
8545
8546
8547
8548
8549
8550
8551
8552
8553
8554
8555
8556
8557
8558
8559
8560
8561
8562
8563
8564
8565
8566
8567
8568
8569
8570
8571
8572
8573
8574
8575
8576
8577
8578
8579
8580
8581
8582
8583
8584
8585
8586
8587
8588
8589
8590
8591
8592
8593
8594
8595
8596
8597
8598
8599
8600
8601
8602
8603
8604
8605
8606
8607
8608
8609
8610
8611
8612
8613
8614
8615
8616
8617
8618
8619
8620
8621
8622
8623
8624
8625
8626
8627
8628
8629
8630
8631
8632
8633
8634
8635
8636
8637
8638
8639
8640
8641
8642
8643
8644
8645
8646
8647
8648
8649
8650
8651
8652
8653
8654
8655
8656
8657
8658
8659
8660
8661
8662
8663
8664
8665
8666
8667
8668
8669
8670
8671
8672
8673
8674
8675
8676
8677
8678
8679
8680
8681
8682
8683
8684
8685
8686
8687
8688
8689
8690
8691
8692
8693
8694
8695
8696
8697
8698
8699
8700
8701
8702
8703
8704
8705
8706
8707
8708
8709
8710
8711
8712
8713
8714
8715
8716
8717
8718
8719
8720
8721
8722
8723
8724
8725
8726
8727
8728
8729
8730
8731
8732
8733
8734
8735
8736
8737
8738
8739
8740
8741
8742
8743
8744
8745
8746
8747
8748
8749
8750
8751
8752
8753
8754
8755
8756
8757
8758
8759
8760
8761
8762
8763
8764
8765
8766
8767
8768
8769
8770
8771
8772
8773
8774
8775
8776
8777
8778
8779
8780
8781
8782
8783
8784
8785
8786
8787
8788
8789
8790
8791
8792
8793
8794
8795
8796
8797
8798
8799
8800
8801
8802
8803
8804
8805
8806
8807
8808
8809
8810
8811
8812
8813
8814
8815
8816
8817
8818
8819
8820
8821
8822
8823
8824
8825
8826
8827
8828
8829
8830
8831
8832
8833
8834
8835
8836
8837
8838
8839
8840
8841
8842
8843
8844
8845
8846
8847
8848
8849
8850
8851
8852
8853
8854
8855
8856
8857
8858
8859
//===--- SemaExprCXX.cpp - Semantic Analysis for Expressions --------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Implements semantic analysis for C++ expressions.
///
//===----------------------------------------------------------------------===//

#include "clang/Sema/Template.h"
#include "clang/Sema/SemaInternal.h"
#include "TreeTransform.h"
#include "TypeLocBuilder.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/AlignedAllocation.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ParsedTemplate.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Sema/SemaLambda.h"
#include "clang/Sema/TemplateDeduction.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/ErrorHandling.h"
using namespace clang;
using namespace sema;

/// Handle the result of the special case name lookup for inheriting
/// constructor declarations. 'NS::X::X' and 'NS::X<...>::X' are treated as
/// constructor names in member using declarations, even if 'X' is not the
/// name of the corresponding type.
ParsedType Sema::getInheritingConstructorName(CXXScopeSpec &SS,
                                              SourceLocation NameLoc,
                                              IdentifierInfo &Name) {
  NestedNameSpecifier *NNS = SS.getScopeRep();

  // Convert the nested-name-specifier into a type.
  QualType Type;
  switch (NNS->getKind()) {
  case NestedNameSpecifier::TypeSpec:
  case NestedNameSpecifier::TypeSpecWithTemplate:
    Type = QualType(NNS->getAsType(), 0);
    break;

  case NestedNameSpecifier::Identifier:
    // Strip off the last layer of the nested-name-specifier and build a
    // typename type for it.
    assert(NNS->getAsIdentifier() == &Name && "not a constructor name");
    Type = Context.getDependentNameType(ETK_None, NNS->getPrefix(),
                                        NNS->getAsIdentifier());
    break;

  case NestedNameSpecifier::Global:
  case NestedNameSpecifier::Super:
  case NestedNameSpecifier::Namespace:
  case NestedNameSpecifier::NamespaceAlias:
    llvm_unreachable("Nested name specifier is not a type for inheriting ctor");
  }

  // This reference to the type is located entirely at the location of the
  // final identifier in the qualified-id.
  return CreateParsedType(Type,
                          Context.getTrivialTypeSourceInfo(Type, NameLoc));
}

ParsedType Sema::getConstructorName(IdentifierInfo &II,
                                    SourceLocation NameLoc,
                                    Scope *S, CXXScopeSpec &SS,
                                    bool EnteringContext) {
  CXXRecordDecl *CurClass = getCurrentClass(S, &SS);
  assert(CurClass && &II == CurClass->getIdentifier() &&
         "not a constructor name");

  // When naming a constructor as a member of a dependent context (eg, in a
  // friend declaration or an inherited constructor declaration), form an
  // unresolved "typename" type.
  if (CurClass->isDependentContext() && !EnteringContext && SS.getScopeRep()) {
    QualType T = Context.getDependentNameType(ETK_None, SS.getScopeRep(), &II);
    return ParsedType::make(T);
  }

  if (SS.isNotEmpty() && RequireCompleteDeclContext(SS, CurClass))
    return ParsedType();

  // Find the injected-class-name declaration. Note that we make no attempt to
  // diagnose cases where the injected-class-name is shadowed: the only
  // declaration that can validly shadow the injected-class-name is a
  // non-static data member, and if the class contains both a non-static data
  // member and a constructor then it is ill-formed (we check that in
  // CheckCompletedCXXClass).
  CXXRecordDecl *InjectedClassName = nullptr;
  for (NamedDecl *ND : CurClass->lookup(&II)) {
    auto *RD = dyn_cast<CXXRecordDecl>(ND);
    if (RD && RD->isInjectedClassName()) {
      InjectedClassName = RD;
      break;
    }
  }
  if (!InjectedClassName) {
    if (!CurClass->isInvalidDecl()) {
      // FIXME: RequireCompleteDeclContext doesn't check dependent contexts
      // properly. Work around it here for now.
      Diag(SS.getLastQualifierNameLoc(),
           diag::err_incomplete_nested_name_spec) << CurClass << SS.getRange();
    }
    return ParsedType();
  }

  QualType T = Context.getTypeDeclType(InjectedClassName);
  DiagnoseUseOfDecl(InjectedClassName, NameLoc);
  MarkAnyDeclReferenced(NameLoc, InjectedClassName, /*OdrUse=*/false);

  return ParsedType::make(T);
}

ParsedType Sema::getDestructorName(SourceLocation TildeLoc,
                                   IdentifierInfo &II,
                                   SourceLocation NameLoc,
                                   Scope *S, CXXScopeSpec &SS,
                                   ParsedType ObjectTypePtr,
                                   bool EnteringContext) {
  // Determine where to perform name lookup.

  // FIXME: This area of the standard is very messy, and the current
  // wording is rather unclear about which scopes we search for the
  // destructor name; see core issues 399 and 555. Issue 399 in
  // particular shows where the current description of destructor name
  // lookup is completely out of line with existing practice, e.g.,
  // this appears to be ill-formed:
  //
  //   namespace N {
  //     template <typename T> struct S {
  //       ~S();
  //     };
  //   }
  //
  //   void f(N::S<int>* s) {
  //     s->N::S<int>::~S();
  //   }
  //
  // See also PR6358 and PR6359.
  //
  // For now, we accept all the cases in which the name given could plausibly
  // be interpreted as a correct destructor name, issuing off-by-default
  // extension diagnostics on the cases that don't strictly conform to the
  // C++20 rules. This basically means we always consider looking in the
  // nested-name-specifier prefix, the complete nested-name-specifier, and
  // the scope, and accept if we find the expected type in any of the three
  // places.

  if (SS.isInvalid())
    return nullptr;

  // Whether we've failed with a diagnostic already.
  bool Failed = false;

  llvm::SmallVector<NamedDecl*, 8> FoundDecls;
  llvm::SmallPtrSet<CanonicalDeclPtr<Decl>, 8> FoundDeclSet;

  // If we have an object type, it's because we are in a
  // pseudo-destructor-expression or a member access expression, and
  // we know what type we're looking for.
  QualType SearchType =
      ObjectTypePtr ? GetTypeFromParser(ObjectTypePtr) : QualType();

  auto CheckLookupResult = [&](LookupResult &Found) -> ParsedType {
    auto IsAcceptableResult = [&](NamedDecl *D) -> bool {
      auto *Type = dyn_cast<TypeDecl>(D->getUnderlyingDecl());
      if (!Type)
        return false;

      if (SearchType.isNull() || SearchType->isDependentType())
        return true;

      QualType T = Context.getTypeDeclType(Type);
      return Context.hasSameUnqualifiedType(T, SearchType);
    };

    unsigned NumAcceptableResults = 0;
    for (NamedDecl *D : Found) {
      if (IsAcceptableResult(D))
        ++NumAcceptableResults;

      // Don't list a class twice in the lookup failure diagnostic if it's
      // found by both its injected-class-name and by the name in the enclosing
      // scope.
      if (auto *RD = dyn_cast<CXXRecordDecl>(D))
        if (RD->isInjectedClassName())
          D = cast<NamedDecl>(RD->getParent());

      if (FoundDeclSet.insert(D).second)
        FoundDecls.push_back(D);
    }

    // As an extension, attempt to "fix" an ambiguity by erasing all non-type
    // results, and all non-matching results if we have a search type. It's not
    // clear what the right behavior is if destructor lookup hits an ambiguity,
    // but other compilers do generally accept at least some kinds of
    // ambiguity.
    if (Found.isAmbiguous() && NumAcceptableResults == 1) {
      Diag(NameLoc, diag::ext_dtor_name_ambiguous);
      LookupResult::Filter F = Found.makeFilter();
      while (F.hasNext()) {
        NamedDecl *D = F.next();
        if (auto *TD = dyn_cast<TypeDecl>(D->getUnderlyingDecl()))
          Diag(D->getLocation(), diag::note_destructor_type_here)
              << Context.getTypeDeclType(TD);
        else
          Diag(D->getLocation(), diag::note_destructor_nontype_here);

        if (!IsAcceptableResult(D))
          F.erase();
      }
      F.done();
    }

    if (Found.isAmbiguous())
      Failed = true;

    if (TypeDecl *Type = Found.getAsSingle<TypeDecl>()) {
      if (IsAcceptableResult(Type)) {
        QualType T = Context.getTypeDeclType(Type);
        MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
        return CreateParsedType(T,
                                Context.getTrivialTypeSourceInfo(T, NameLoc));
      }
    }

    return nullptr;
  };

  bool IsDependent = false;

  auto LookupInObjectType = [&]() -> ParsedType {
    if (Failed || SearchType.isNull())
      return nullptr;

    IsDependent |= SearchType->isDependentType();

    LookupResult Found(*this, &II, NameLoc, LookupDestructorName);
    DeclContext *LookupCtx = computeDeclContext(SearchType);
    if (!LookupCtx)
      return nullptr;
    LookupQualifiedName(Found, LookupCtx);
    return CheckLookupResult(Found);
  };

  auto LookupInNestedNameSpec = [&](CXXScopeSpec &LookupSS) -> ParsedType {
    if (Failed)
      return nullptr;

    IsDependent |= isDependentScopeSpecifier(LookupSS);
    DeclContext *LookupCtx = computeDeclContext(LookupSS, EnteringContext);
    if (!LookupCtx)
      return nullptr;

    LookupResult Found(*this, &II, NameLoc, LookupDestructorName);
    if (RequireCompleteDeclContext(LookupSS, LookupCtx)) {
      Failed = true;
      return nullptr;
    }
    LookupQualifiedName(Found, LookupCtx);
    return CheckLookupResult(Found);
  };

  auto LookupInScope = [&]() -> ParsedType {
    if (Failed || !S)
      return nullptr;

    LookupResult Found(*this, &II, NameLoc, LookupDestructorName);
    LookupName(Found, S);
    return CheckLookupResult(Found);
  };

  // C++2a [basic.lookup.qual]p6:
  //   In a qualified-id of the form
  //
  //     nested-name-specifier[opt] type-name :: ~ type-name
  //
  //   the second type-name is looked up in the same scope as the first.
  //
  // We interpret this as meaning that if you do a dual-scope lookup for the
  // first name, you also do a dual-scope lookup for the second name, per
  // C++ [basic.lookup.classref]p4:
  //
  //   If the id-expression in a class member access is a qualified-id of the
  //   form
  //
  //     class-name-or-namespace-name :: ...
  //
  //   the class-name-or-namespace-name following the . or -> is first looked
  //   up in the class of the object expression and the name, if found, is used.
  //   Otherwise, it is looked up in the context of the entire
  //   postfix-expression.
  //
  // This looks in the same scopes as for an unqualified destructor name:
  //
  // C++ [basic.lookup.classref]p3:
  //   If the unqualified-id is ~ type-name, the type-name is looked up
  //   in the context of the entire postfix-expression. If the type T
  //   of the object expression is of a class type C, the type-name is
  //   also looked up in the scope of class C. At least one of the
  //   lookups shall find a name that refers to cv T.
  //
  // FIXME: The intent is unclear here. Should type-name::~type-name look in
  // the scope anyway if it finds a non-matching name declared in the class?
  // If both lookups succeed and find a dependent result, which result should
  // we retain? (Same question for p->~type-name().)

  if (NestedNameSpecifier *Prefix =
      SS.isSet() ? SS.getScopeRep()->getPrefix() : nullptr) {
    // This is
    //
    //   nested-name-specifier type-name :: ~ type-name
    //
    // Look for the second type-name in the nested-name-specifier.
    CXXScopeSpec PrefixSS;
    PrefixSS.Adopt(NestedNameSpecifierLoc(Prefix, SS.location_data()));
    if (ParsedType T = LookupInNestedNameSpec(PrefixSS))
      return T;
  } else {
    // This is one of
    //
    //   type-name :: ~ type-name
    //   ~ type-name
    //
    // Look in the scope and (if any) the object type.
    if (ParsedType T = LookupInScope())
      return T;
    if (ParsedType T = LookupInObjectType())
      return T;
  }

  if (Failed)
    return nullptr;

  if (IsDependent) {
    // We didn't find our type, but that's OK: it's dependent anyway.

    // FIXME: What if we have no nested-name-specifier?
    QualType T = CheckTypenameType(ETK_None, SourceLocation(),
                                   SS.getWithLocInContext(Context),
                                   II, NameLoc);
    return ParsedType::make(T);
  }

  // The remaining cases are all non-standard extensions imitating the behavior
  // of various other compilers.
  unsigned NumNonExtensionDecls = FoundDecls.size();

  if (SS.isSet()) {
    // For compatibility with older broken C++ rules and existing code,
    //
    //   nested-name-specifier :: ~ type-name
    //
    // also looks for type-name within the nested-name-specifier.
    if (ParsedType T = LookupInNestedNameSpec(SS)) {
      Diag(SS.getEndLoc(), diag::ext_dtor_named_in_wrong_scope)
          << SS.getRange()
          << FixItHint::CreateInsertion(SS.getEndLoc(),
                                        ("::" + II.getName()).str());
      return T;
    }

    // For compatibility with other compilers and older versions of Clang,
    //
    //   nested-name-specifier type-name :: ~ type-name
    //
    // also looks for type-name in the scope. Unfortunately, we can't
    // reasonably apply this fallback for dependent nested-name-specifiers.
    if (SS.getScopeRep()->getPrefix()) {
      if (ParsedType T = LookupInScope()) {
        Diag(SS.getEndLoc(), diag::ext_qualified_dtor_named_in_lexical_scope)
            << FixItHint::CreateRemoval(SS.getRange());
        Diag(FoundDecls.back()->getLocation(), diag::note_destructor_type_here)
            << GetTypeFromParser(T);
        return T;
      }
    }
  }

  // We didn't find anything matching; tell the user what we did find (if
  // anything).

  // Don't tell the user about declarations we shouldn't have found.
  FoundDecls.resize(NumNonExtensionDecls);

  // List types before non-types.
  std::stable_sort(FoundDecls.begin(), FoundDecls.end(),
                   [](NamedDecl *A, NamedDecl *B) {
                     return isa<TypeDecl>(A->getUnderlyingDecl()) >
                            isa<TypeDecl>(B->getUnderlyingDecl());
                   });

  // Suggest a fixit to properly name the destroyed type.
  auto MakeFixItHint = [&]{
    const CXXRecordDecl *Destroyed = nullptr;
    // FIXME: If we have a scope specifier, suggest its last component?
    if (!SearchType.isNull())
      Destroyed = SearchType->getAsCXXRecordDecl();
    else if (S)
      Destroyed = dyn_cast_or_null<CXXRecordDecl>(S->getEntity());
    if (Destroyed)
      return FixItHint::CreateReplacement(SourceRange(NameLoc),
                                          Destroyed->getNameAsString());
    return FixItHint();
  };

  if (FoundDecls.empty()) {
    // FIXME: Attempt typo-correction?
    Diag(NameLoc, diag::err_undeclared_destructor_name)
      << &II << MakeFixItHint();
  } else if (!SearchType.isNull() && FoundDecls.size() == 1) {
    if (auto *TD = dyn_cast<TypeDecl>(FoundDecls[0]->getUnderlyingDecl())) {
      assert(!SearchType.isNull() &&
             "should only reject a type result if we have a search type");
      QualType T = Context.getTypeDeclType(TD);
      Diag(NameLoc, diag::err_destructor_expr_type_mismatch)
          << T << SearchType << MakeFixItHint();
    } else {
      Diag(NameLoc, diag::err_destructor_expr_nontype)
          << &II << MakeFixItHint();
    }
  } else {
    Diag(NameLoc, SearchType.isNull() ? diag::err_destructor_name_nontype
                                      : diag::err_destructor_expr_mismatch)
        << &II << SearchType << MakeFixItHint();
  }

  for (NamedDecl *FoundD : FoundDecls) {
    if (auto *TD = dyn_cast<TypeDecl>(FoundD->getUnderlyingDecl()))
      Diag(FoundD->getLocation(), diag::note_destructor_type_here)
          << Context.getTypeDeclType(TD);
    else
      Diag(FoundD->getLocation(), diag::note_destructor_nontype_here)
          << FoundD;
  }

  return nullptr;
}

ParsedType Sema::getDestructorTypeForDecltype(const DeclSpec &DS,
                                              ParsedType ObjectType) {
  if (DS.getTypeSpecType() == DeclSpec::TST_error)
    return nullptr;

  if (DS.getTypeSpecType() == DeclSpec::TST_decltype_auto) {
    Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
    return nullptr;
  }

  assert(DS.getTypeSpecType() == DeclSpec::TST_decltype &&
         "unexpected type in getDestructorType");
  QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());

  // If we know the type of the object, check that the correct destructor
  // type was named now; we can give better diagnostics this way.
  QualType SearchType = GetTypeFromParser(ObjectType);
  if (!SearchType.isNull() && !SearchType->isDependentType() &&
      !Context.hasSameUnqualifiedType(T, SearchType)) {
    Diag(DS.getTypeSpecTypeLoc(), diag::err_destructor_expr_type_mismatch)
      << T << SearchType;
    return nullptr;
  }

  return ParsedType::make(T);
}

bool Sema::checkLiteralOperatorId(const CXXScopeSpec &SS,
                                  const UnqualifiedId &Name, bool IsUDSuffix) {
  assert(Name.getKind() == UnqualifiedIdKind::IK_LiteralOperatorId);
  if (!IsUDSuffix) {
    // [over.literal] p8
    //
    // double operator""_Bq(long double);  // OK: not a reserved identifier
    // double operator"" _Bq(long double); // ill-formed, no diagnostic required
    IdentifierInfo *II = Name.Identifier;
    ReservedIdentifierStatus Status = II->isReserved(PP.getLangOpts());
    SourceLocation Loc = Name.getEndLoc();
    if (Status != ReservedIdentifierStatus::NotReserved &&
        !PP.getSourceManager().isInSystemHeader(Loc)) {
      Diag(Loc, diag::warn_reserved_extern_symbol)
          << II << static_cast<int>(Status)
          << FixItHint::CreateReplacement(
                 Name.getSourceRange(),
                 (StringRef("operator\"\"") + II->getName()).str());
    }
  }

  if (!SS.isValid())
    return false;

  switch (SS.getScopeRep()->getKind()) {
  case NestedNameSpecifier::Identifier:
  case NestedNameSpecifier::TypeSpec:
  case NestedNameSpecifier::TypeSpecWithTemplate:
    // Per C++11 [over.literal]p2, literal operators can only be declared at
    // namespace scope. Therefore, this unqualified-id cannot name anything.
    // Reject it early, because we have no AST representation for this in the
    // case where the scope is dependent.
    Diag(Name.getBeginLoc(), diag::err_literal_operator_id_outside_namespace)
        << SS.getScopeRep();
    return true;

  case NestedNameSpecifier::Global:
  case NestedNameSpecifier::Super:
  case NestedNameSpecifier::Namespace:
  case NestedNameSpecifier::NamespaceAlias:
    return false;
  }

  llvm_unreachable("unknown nested name specifier kind");
}

/// Build a C++ typeid expression with a type operand.
ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
                                SourceLocation TypeidLoc,
                                TypeSourceInfo *Operand,
                                SourceLocation RParenLoc) {
  // C++ [expr.typeid]p4:
  //   The top-level cv-qualifiers of the lvalue expression or the type-id
  //   that is the operand of typeid are always ignored.
  //   If the type of the type-id is a class type or a reference to a class
  //   type, the class shall be completely-defined.
  Qualifiers Quals;
  QualType T
    = Context.getUnqualifiedArrayType(Operand->getType().getNonReferenceType(),
                                      Quals);
  if (T->getAs<RecordType>() &&
      RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
    return ExprError();

  if (T->isVariablyModifiedType())
    return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid) << T);

  if (CheckQualifiedFunctionForTypeId(T, TypeidLoc))
    return ExprError();

  return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), Operand,
                                     SourceRange(TypeidLoc, RParenLoc));
}

/// Build a C++ typeid expression with an expression operand.
ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
                                SourceLocation TypeidLoc,
                                Expr *E,
                                SourceLocation RParenLoc) {
  bool WasEvaluated = false;
  if (E && !E->isTypeDependent()) {
    if (E->getType()->isPlaceholderType()) {
      ExprResult result = CheckPlaceholderExpr(E);
      if (result.isInvalid()) return ExprError();
      E = result.get();
    }

    QualType T = E->getType();
    if (const RecordType *RecordT = T->getAs<RecordType>()) {
      CXXRecordDecl *RecordD = cast<CXXRecordDecl>(RecordT->getDecl());
      // C++ [expr.typeid]p3:
      //   [...] If the type of the expression is a class type, the class
      //   shall be completely-defined.
      if (RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
        return ExprError();

      // C++ [expr.typeid]p3:
      //   When typeid is applied to an expression other than an glvalue of a
      //   polymorphic class type [...] [the] expression is an unevaluated
      //   operand. [...]
      if (RecordD->isPolymorphic() && E->isGLValue()) {
        if (isUnevaluatedContext()) {
          // The operand was processed in unevaluated context, switch the
          // context and recheck the subexpression.
          ExprResult Result = TransformToPotentiallyEvaluated(E);
          if (Result.isInvalid())
            return ExprError();
          E = Result.get();
        }

        // We require a vtable to query the type at run time.
        MarkVTableUsed(TypeidLoc, RecordD);
        WasEvaluated = true;
      }
    }

    ExprResult Result = CheckUnevaluatedOperand(E);
    if (Result.isInvalid())
      return ExprError();
    E = Result.get();

    // C++ [expr.typeid]p4:
    //   [...] If the type of the type-id is a reference to a possibly
    //   cv-qualified type, the result of the typeid expression refers to a
    //   std::type_info object representing the cv-unqualified referenced
    //   type.
    Qualifiers Quals;
    QualType UnqualT = Context.getUnqualifiedArrayType(T, Quals);
    if (!Context.hasSameType(T, UnqualT)) {
      T = UnqualT;
      E = ImpCastExprToType(E, UnqualT, CK_NoOp, E->getValueKind()).get();
    }
  }

  if (E->getType()->isVariablyModifiedType())
    return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid)
                     << E->getType());
  else if (!inTemplateInstantiation() &&
           E->HasSideEffects(Context, WasEvaluated)) {
    // The expression operand for typeid is in an unevaluated expression
    // context, so side effects could result in unintended consequences.
    Diag(E->getExprLoc(), WasEvaluated
                              ? diag::warn_side_effects_typeid
                              : diag::warn_side_effects_unevaluated_context);
  }

  return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), E,
                                     SourceRange(TypeidLoc, RParenLoc));
}

/// ActOnCXXTypeidOfType - Parse typeid( type-id ) or typeid (expression);
ExprResult
Sema::ActOnCXXTypeid(SourceLocation OpLoc, SourceLocation LParenLoc,
                     bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
  // typeid is not supported in OpenCL.
  if (getLangOpts().OpenCLCPlusPlus) {
    return ExprError(Diag(OpLoc, diag::err_openclcxx_not_supported)
                     << "typeid");
  }

  // Find the std::type_info type.
  if (!getStdNamespace())
    return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));

  if (!CXXTypeInfoDecl) {
    IdentifierInfo *TypeInfoII = &PP.getIdentifierTable().get("type_info");
    LookupResult R(*this, TypeInfoII, SourceLocation(), LookupTagName);
    LookupQualifiedName(R, getStdNamespace());
    CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
    // Microsoft's typeinfo doesn't have type_info in std but in the global
    // namespace if _HAS_EXCEPTIONS is defined to 0. See PR13153.
    if (!CXXTypeInfoDecl && LangOpts.MSVCCompat) {
      LookupQualifiedName(R, Context.getTranslationUnitDecl());
      CXXTypeInfoDecl = R.getAsSingle<RecordDecl>();
    }
    if (!CXXTypeInfoDecl)
      return ExprError(Diag(OpLoc, diag::err_need_header_before_typeid));
  }

  if (!getLangOpts().RTTI) {
    return ExprError(Diag(OpLoc, diag::err_no_typeid_with_fno_rtti));
  }

  QualType TypeInfoType = Context.getTypeDeclType(CXXTypeInfoDecl);

  if (isType) {
    // The operand is a type; handle it as such.
    TypeSourceInfo *TInfo = nullptr;
    QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
                                   &TInfo);
    if (T.isNull())
      return ExprError();

    if (!TInfo)
      TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);

    return BuildCXXTypeId(TypeInfoType, OpLoc, TInfo, RParenLoc);
  }

  // The operand is an expression.
  ExprResult Result =
      BuildCXXTypeId(TypeInfoType, OpLoc, (Expr *)TyOrExpr, RParenLoc);

  if (!getLangOpts().RTTIData && !Result.isInvalid())
    if (auto *CTE = dyn_cast<CXXTypeidExpr>(Result.get()))
      if (CTE->isPotentiallyEvaluated() && !CTE->isMostDerived(Context))
        Diag(OpLoc, diag::warn_no_typeid_with_rtti_disabled)
            << (getDiagnostics().getDiagnosticOptions().getFormat() ==
                DiagnosticOptions::MSVC);
  return Result;
}

/// Grabs __declspec(uuid()) off a type, or returns 0 if we cannot resolve to
/// a single GUID.
static void
getUuidAttrOfType(Sema &SemaRef, QualType QT,
                  llvm::SmallSetVector<const UuidAttr *, 1> &UuidAttrs) {
  // Optionally remove one level of pointer, reference or array indirection.
  const Type *Ty = QT.getTypePtr();
  if (QT->isPointerType() || QT->isReferenceType())
    Ty = QT->getPointeeType().getTypePtr();
  else if (QT->isArrayType())
    Ty = Ty->getBaseElementTypeUnsafe();

  const auto *TD = Ty->getAsTagDecl();
  if (!TD)
    return;

  if (const auto *Uuid = TD->getMostRecentDecl()->getAttr<UuidAttr>()) {
    UuidAttrs.insert(Uuid);
    return;
  }

  // __uuidof can grab UUIDs from template arguments.
  if (const auto *CTSD = dyn_cast<ClassTemplateSpecializationDecl>(TD)) {
    const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
    for (const TemplateArgument &TA : TAL.asArray()) {
      const UuidAttr *UuidForTA = nullptr;
      if (TA.getKind() == TemplateArgument::Type)
        getUuidAttrOfType(SemaRef, TA.getAsType(), UuidAttrs);
      else if (TA.getKind() == TemplateArgument::Declaration)
        getUuidAttrOfType(SemaRef, TA.getAsDecl()->getType(), UuidAttrs);

      if (UuidForTA)
        UuidAttrs.insert(UuidForTA);
    }
  }
}

/// Build a Microsoft __uuidof expression with a type operand.
ExprResult Sema::BuildCXXUuidof(QualType Type,
                                SourceLocation TypeidLoc,
                                TypeSourceInfo *Operand,
                                SourceLocation RParenLoc) {
  MSGuidDecl *Guid = nullptr;
  if (!Operand->getType()->isDependentType()) {
    llvm::SmallSetVector<const UuidAttr *, 1> UuidAttrs;
    getUuidAttrOfType(*this, Operand->getType(), UuidAttrs);
    if (UuidAttrs.empty())
      return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
    if (UuidAttrs.size() > 1)
      return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
    Guid = UuidAttrs.back()->getGuidDecl();
  }

  return new (Context)
      CXXUuidofExpr(Type, Operand, Guid, SourceRange(TypeidLoc, RParenLoc));
}

/// Build a Microsoft __uuidof expression with an expression operand.
ExprResult Sema::BuildCXXUuidof(QualType Type, SourceLocation TypeidLoc,
                                Expr *E, SourceLocation RParenLoc) {
  MSGuidDecl *Guid = nullptr;
  if (!E->getType()->isDependentType()) {
    if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) {
      // A null pointer results in {00000000-0000-0000-0000-000000000000}.
      Guid = Context.getMSGuidDecl(MSGuidDecl::Parts{});
    } else {
      llvm::SmallSetVector<const UuidAttr *, 1> UuidAttrs;
      getUuidAttrOfType(*this, E->getType(), UuidAttrs);
      if (UuidAttrs.empty())
        return ExprError(Diag(TypeidLoc, diag::err_uuidof_without_guid));
      if (UuidAttrs.size() > 1)
        return ExprError(Diag(TypeidLoc, diag::err_uuidof_with_multiple_guids));
      Guid = UuidAttrs.back()->getGuidDecl();
    }
  }

  return new (Context)
      CXXUuidofExpr(Type, E, Guid, SourceRange(TypeidLoc, RParenLoc));
}

/// ActOnCXXUuidof - Parse __uuidof( type-id ) or __uuidof (expression);
ExprResult
Sema::ActOnCXXUuidof(SourceLocation OpLoc, SourceLocation LParenLoc,
                     bool isType, void *TyOrExpr, SourceLocation RParenLoc) {
  QualType GuidType = Context.getMSGuidType();
  GuidType.addConst();

  if (isType) {
    // The operand is a type; handle it as such.
    TypeSourceInfo *TInfo = nullptr;
    QualType T = GetTypeFromParser(ParsedType::getFromOpaquePtr(TyOrExpr),
                                   &TInfo);
    if (T.isNull())
      return ExprError();

    if (!TInfo)
      TInfo = Context.getTrivialTypeSourceInfo(T, OpLoc);

    return BuildCXXUuidof(GuidType, OpLoc, TInfo, RParenLoc);
  }

  // The operand is an expression.
  return BuildCXXUuidof(GuidType, OpLoc, (Expr*)TyOrExpr, RParenLoc);
}

/// ActOnCXXBoolLiteral - Parse {true,false} literals.
ExprResult
Sema::ActOnCXXBoolLiteral(SourceLocation OpLoc, tok::TokenKind Kind) {
  assert((Kind == tok::kw_true || Kind == tok::kw_false) &&
         "Unknown C++ Boolean value!");
  return new (Context)
      CXXBoolLiteralExpr(Kind == tok::kw_true, Context.BoolTy, OpLoc);
}

/// ActOnCXXNullPtrLiteral - Parse 'nullptr'.
ExprResult
Sema::ActOnCXXNullPtrLiteral(SourceLocation Loc) {
  return new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
}

/// ActOnCXXThrow - Parse throw expressions.
ExprResult
Sema::ActOnCXXThrow(Scope *S, SourceLocation OpLoc, Expr *Ex) {
  bool IsThrownVarInScope = false;
  if (Ex) {
    // C++0x [class.copymove]p31:
    //   When certain criteria are met, an implementation is allowed to omit the
    //   copy/move construction of a class object [...]
    //
    //     - in a throw-expression, when the operand is the name of a
    //       non-volatile automatic object (other than a function or catch-
    //       clause parameter) whose scope does not extend beyond the end of the
    //       innermost enclosing try-block (if there is one), the copy/move
    //       operation from the operand to the exception object (15.1) can be
    //       omitted by constructing the automatic object directly into the
    //       exception object
    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Ex->IgnoreParens()))
      if (VarDecl *Var = dyn_cast<VarDecl>(DRE->getDecl())) {
        if (Var->hasLocalStorage() && !Var->getType().isVolatileQualified()) {
          for( ; S; S = S->getParent()) {
            if (S->isDeclScope(Var)) {
              IsThrownVarInScope = true;
              break;
            }

            if (S->getFlags() &
                (Scope::FnScope | Scope::ClassScope | Scope::BlockScope |
                 Scope::FunctionPrototypeScope | Scope::ObjCMethodScope |
                 Scope::TryScope))
              break;
          }
        }
      }
  }

  return BuildCXXThrow(OpLoc, Ex, IsThrownVarInScope);
}

ExprResult Sema::BuildCXXThrow(SourceLocation OpLoc, Expr *Ex,
                               bool IsThrownVarInScope) {
  // Don't report an error if 'throw' is used in system headers.
  if (!getLangOpts().CXXExceptions &&
      !getSourceManager().isInSystemHeader(OpLoc) && !getLangOpts().CUDA) {
    // Delay error emission for the OpenMP device code.
    targetDiag(OpLoc, diag::err_exceptions_disabled) << "throw";
  }

  // Exceptions aren't allowed in CUDA device code.
  if (getLangOpts().CUDA)
    CUDADiagIfDeviceCode(OpLoc, diag::err_cuda_device_exceptions)
        << "throw" << CurrentCUDATarget();

  if (getCurScope() && getCurScope()->isOpenMPSimdDirectiveScope())
    Diag(OpLoc, diag::err_omp_simd_region_cannot_use_stmt) << "throw";

  if (Ex && !Ex->isTypeDependent()) {
    // Initialize the exception result.  This implicitly weeds out
    // abstract types or types with inaccessible copy constructors.

    // C++0x [class.copymove]p31:
    //   When certain criteria are met, an implementation is allowed to omit the
    //   copy/move construction of a class object [...]
    //
    //     - in a throw-expression, when the operand is the name of a
    //       non-volatile automatic object (other than a function or
    //       catch-clause
    //       parameter) whose scope does not extend beyond the end of the
    //       innermost enclosing try-block (if there is one), the copy/move
    //       operation from the operand to the exception object (15.1) can be
    //       omitted by constructing the automatic object directly into the
    //       exception object
    NamedReturnInfo NRInfo =
        IsThrownVarInScope ? getNamedReturnInfo(Ex) : NamedReturnInfo();

    QualType ExceptionObjectTy = Context.getExceptionObjectType(Ex->getType());
    if (CheckCXXThrowOperand(OpLoc, ExceptionObjectTy, Ex))
      return ExprError();

    InitializedEntity Entity =
        InitializedEntity::InitializeException(OpLoc, ExceptionObjectTy);
    ExprResult Res = PerformMoveOrCopyInitialization(Entity, NRInfo, Ex);
    if (Res.isInvalid())
      return ExprError();
    Ex = Res.get();
  }

  // PPC MMA non-pointer types are not allowed as throw expr types.
  if (Ex && Context.getTargetInfo().getTriple().isPPC64())
    CheckPPCMMAType(Ex->getType(), Ex->getBeginLoc());

  return new (Context)
      CXXThrowExpr(Ex, Context.VoidTy, OpLoc, IsThrownVarInScope);
}

static void
collectPublicBases(CXXRecordDecl *RD,
                   llvm::DenseMap<CXXRecordDecl *, unsigned> &SubobjectsSeen,
                   llvm::SmallPtrSetImpl<CXXRecordDecl *> &VBases,
                   llvm::SetVector<CXXRecordDecl *> &PublicSubobjectsSeen,
                   bool ParentIsPublic) {
  for (const CXXBaseSpecifier &BS : RD->bases()) {
    CXXRecordDecl *BaseDecl = BS.getType()->getAsCXXRecordDecl();
    bool NewSubobject;
    // Virtual bases constitute the same subobject.  Non-virtual bases are
    // always distinct subobjects.
    if (BS.isVirtual())
      NewSubobject = VBases.insert(BaseDecl).second;
    else
      NewSubobject = true;

    if (NewSubobject)
      ++SubobjectsSeen[BaseDecl];

    // Only add subobjects which have public access throughout the entire chain.
    bool PublicPath = ParentIsPublic && BS.getAccessSpecifier() == AS_public;
    if (PublicPath)
      PublicSubobjectsSeen.insert(BaseDecl);

    // Recurse on to each base subobject.
    collectPublicBases(BaseDecl, SubobjectsSeen, VBases, PublicSubobjectsSeen,
                       PublicPath);
  }
}

static void getUnambiguousPublicSubobjects(
    CXXRecordDecl *RD, llvm::SmallVectorImpl<CXXRecordDecl *> &Objects) {
  llvm::DenseMap<CXXRecordDecl *, unsigned> SubobjectsSeen;
  llvm::SmallSet<CXXRecordDecl *, 2> VBases;
  llvm::SetVector<CXXRecordDecl *> PublicSubobjectsSeen;
  SubobjectsSeen[RD] = 1;
  PublicSubobjectsSeen.insert(RD);
  collectPublicBases(RD, SubobjectsSeen, VBases, PublicSubobjectsSeen,
                     /*ParentIsPublic=*/true);

  for (CXXRecordDecl *PublicSubobject : PublicSubobjectsSeen) {
    // Skip ambiguous objects.
    if (SubobjectsSeen[PublicSubobject] > 1)
      continue;

    Objects.push_back(PublicSubobject);
  }
}

/// CheckCXXThrowOperand - Validate the operand of a throw.
bool Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc,
                                QualType ExceptionObjectTy, Expr *E) {
  //   If the type of the exception would be an incomplete type or a pointer
  //   to an incomplete type other than (cv) void the program is ill-formed.
  QualType Ty = ExceptionObjectTy;
  bool isPointer = false;
  if (const PointerType* Ptr = Ty->getAs<PointerType>()) {
    Ty = Ptr->getPointeeType();
    isPointer = true;
  }
  if (!isPointer || !Ty->isVoidType()) {
    if (RequireCompleteType(ThrowLoc, Ty,
                            isPointer ? diag::err_throw_incomplete_ptr
                                      : diag::err_throw_incomplete,
                            E->getSourceRange()))
      return true;

    if (!isPointer && Ty->isSizelessType()) {
      Diag(ThrowLoc, diag::err_throw_sizeless) << Ty << E->getSourceRange();
      return true;
    }

    if (RequireNonAbstractType(ThrowLoc, ExceptionObjectTy,
                               diag::err_throw_abstract_type, E))
      return true;
  }

  // If the exception has class type, we need additional handling.
  CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
  if (!RD)
    return false;

  // If we are throwing a polymorphic class type or pointer thereof,
  // exception handling will make use of the vtable.
  MarkVTableUsed(ThrowLoc, RD);

  // If a pointer is thrown, the referenced object will not be destroyed.
  if (isPointer)
    return false;

  // If the class has a destructor, we must be able to call it.
  if (!RD->hasIrrelevantDestructor()) {
    if (CXXDestructorDecl *Destructor = LookupDestructor(RD)) {
      MarkFunctionReferenced(E->getExprLoc(), Destructor);
      CheckDestructorAccess(E->getExprLoc(), Destructor,
                            PDiag(diag::err_access_dtor_exception) << Ty);
      if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
        return true;
    }
  }

  // The MSVC ABI creates a list of all types which can catch the exception
  // object.  This list also references the appropriate copy constructor to call
  // if the object is caught by value and has a non-trivial copy constructor.
  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
    // We are only interested in the public, unambiguous bases contained within
    // the exception object.  Bases which are ambiguous or otherwise
    // inaccessible are not catchable types.
    llvm::SmallVector<CXXRecordDecl *, 2> UnambiguousPublicSubobjects;
    getUnambiguousPublicSubobjects(RD, UnambiguousPublicSubobjects);

    for (CXXRecordDecl *Subobject : UnambiguousPublicSubobjects) {
      // Attempt to lookup the copy constructor.  Various pieces of machinery
      // will spring into action, like template instantiation, which means this
      // cannot be a simple walk of the class's decls.  Instead, we must perform
      // lookup and overload resolution.
      CXXConstructorDecl *CD = LookupCopyingConstructor(Subobject, 0);
      if (!CD || CD->isDeleted())
        continue;

      // Mark the constructor referenced as it is used by this throw expression.
      MarkFunctionReferenced(E->getExprLoc(), CD);

      // Skip this copy constructor if it is trivial, we don't need to record it
      // in the catchable type data.
      if (CD->isTrivial())
        continue;

      // The copy constructor is non-trivial, create a mapping from this class
      // type to this constructor.
      // N.B.  The selection of copy constructor is not sensitive to this
      // particular throw-site.  Lookup will be performed at the catch-site to
      // ensure that the copy constructor is, in fact, accessible (via
      // friendship or any other means).
      Context.addCopyConstructorForExceptionObject(Subobject, CD);

      // We don't keep the instantiated default argument expressions around so
      // we must rebuild them here.
      for (unsigned I = 1, E = CD->getNumParams(); I != E; ++I) {
        if (CheckCXXDefaultArgExpr(ThrowLoc, CD, CD->getParamDecl(I)))
          return true;
      }
    }
  }

  // Under the Itanium C++ ABI, memory for the exception object is allocated by
  // the runtime with no ability for the compiler to request additional
  // alignment. Warn if the exception type requires alignment beyond the minimum
  // guaranteed by the target C++ runtime.
  if (Context.getTargetInfo().getCXXABI().isItaniumFamily()) {
    CharUnits TypeAlign = Context.getTypeAlignInChars(Ty);
    CharUnits ExnObjAlign = Context.getExnObjectAlignment();
    if (ExnObjAlign < TypeAlign) {
      Diag(ThrowLoc, diag::warn_throw_underaligned_obj);
      Diag(ThrowLoc, diag::note_throw_underaligned_obj)
          << Ty << (unsigned)TypeAlign.getQuantity()
          << (unsigned)ExnObjAlign.getQuantity();
    }
  }

  return false;
}

static QualType adjustCVQualifiersForCXXThisWithinLambda(
    ArrayRef<FunctionScopeInfo *> FunctionScopes, QualType ThisTy,
    DeclContext *CurSemaContext, ASTContext &ASTCtx) {

  QualType ClassType = ThisTy->getPointeeType();
  LambdaScopeInfo *CurLSI = nullptr;
  DeclContext *CurDC = CurSemaContext;

  // Iterate through the stack of lambdas starting from the innermost lambda to
  // the outermost lambda, checking if '*this' is ever captured by copy - since
  // that could change the cv-qualifiers of the '*this' object.
  // The object referred to by '*this' starts out with the cv-qualifiers of its
  // member function.  We then start with the innermost lambda and iterate
  // outward checking to see if any lambda performs a by-copy capture of '*this'
  // - and if so, any nested lambda must respect the 'constness' of that
  // capturing lamdbda's call operator.
  //

  // Since the FunctionScopeInfo stack is representative of the lexical
  // nesting of the lambda expressions during initial parsing (and is the best
  // place for querying information about captures about lambdas that are
  // partially processed) and perhaps during instantiation of function templates
  // that contain lambda expressions that need to be transformed BUT not
  // necessarily during instantiation of a nested generic lambda's function call
  // operator (which might even be instantiated at the end of the TU) - at which
  // time the DeclContext tree is mature enough to query capture information
  // reliably - we use a two pronged approach to walk through all the lexically
  // enclosing lambda expressions:
  //
  //  1) Climb down the FunctionScopeInfo stack as long as each item represents
  //  a Lambda (i.e. LambdaScopeInfo) AND each LSI's 'closure-type' is lexically
  //  enclosed by the call-operator of the LSI below it on the stack (while
  //  tracking the enclosing DC for step 2 if needed).  Note the topmost LSI on
  //  the stack represents the innermost lambda.
  //
  //  2) If we run out of enclosing LSI's, check if the enclosing DeclContext
  //  represents a lambda's call operator.  If it does, we must be instantiating
  //  a generic lambda's call operator (represented by the Current LSI, and
  //  should be the only scenario where an inconsistency between the LSI and the
  //  DeclContext should occur), so climb out the DeclContexts if they
  //  represent lambdas, while querying the corresponding closure types
  //  regarding capture information.

  // 1) Climb down the function scope info stack.
  for (int I = FunctionScopes.size();
       I-- && isa<LambdaScopeInfo>(FunctionScopes[I]) &&
       (!CurLSI || !CurLSI->Lambda || CurLSI->Lambda->getDeclContext() ==
                       cast<LambdaScopeInfo>(FunctionScopes[I])->CallOperator);
       CurDC = getLambdaAwareParentOfDeclContext(CurDC)) {
    CurLSI = cast<LambdaScopeInfo>(FunctionScopes[I]);

    if (!CurLSI->isCXXThisCaptured())
        continue;

    auto C = CurLSI->getCXXThisCapture();

    if (C.isCopyCapture()) {
      ClassType.removeLocalCVRQualifiers(Qualifiers::CVRMask);
      if (CurLSI->CallOperator->isConst())
        ClassType.addConst();
      return ASTCtx.getPointerType(ClassType);
    }
  }

  // 2) We've run out of ScopeInfos but check if CurDC is a lambda (which can
  // happen during instantiation of its nested generic lambda call operator)
  if (isLambdaCallOperator(CurDC)) {
    assert(CurLSI && "While computing 'this' capture-type for a generic "
                     "lambda, we must have a corresponding LambdaScopeInfo");
    assert(isGenericLambdaCallOperatorSpecialization(CurLSI->CallOperator) &&
           "While computing 'this' capture-type for a generic lambda, when we "
           "run out of enclosing LSI's, yet the enclosing DC is a "
           "lambda-call-operator we must be (i.e. Current LSI) in a generic "
           "lambda call oeprator");
    assert(CurDC == getLambdaAwareParentOfDeclContext(CurLSI->CallOperator));

    auto IsThisCaptured =
        [](CXXRecordDecl *Closure, bool &IsByCopy, bool &IsConst) {
      IsConst = false;
      IsByCopy = false;
      for (auto &&C : Closure->captures()) {
        if (C.capturesThis()) {
          if (C.getCaptureKind() == LCK_StarThis)
            IsByCopy = true;
          if (Closure->getLambdaCallOperator()->isConst())
            IsConst = true;
          return true;
        }
      }
      return false;
    };

    bool IsByCopyCapture = false;
    bool IsConstCapture = false;
    CXXRecordDecl *Closure = cast<CXXRecordDecl>(CurDC->getParent());
    while (Closure &&
           IsThisCaptured(Closure, IsByCopyCapture, IsConstCapture)) {
      if (IsByCopyCapture) {
        ClassType.removeLocalCVRQualifiers(Qualifiers::CVRMask);
        if (IsConstCapture)
          ClassType.addConst();
        return ASTCtx.getPointerType(ClassType);
      }
      Closure = isLambdaCallOperator(Closure->getParent())
                    ? cast<CXXRecordDecl>(Closure->getParent()->getParent())
                    : nullptr;
    }
  }
  return ASTCtx.getPointerType(ClassType);
}

QualType Sema::getCurrentThisType() {
  DeclContext *DC = getFunctionLevelDeclContext();
  QualType ThisTy = CXXThisTypeOverride;

  if (CXXMethodDecl *method = dyn_cast<CXXMethodDecl>(DC)) {
    if (method && method->isInstance())
      ThisTy = method->getThisType();
  }

  if (ThisTy.isNull() && isLambdaCallOperator(CurContext) &&
      inTemplateInstantiation() && isa<CXXRecordDecl>(DC)) {

    // This is a lambda call operator that is being instantiated as a default
    // initializer. DC must point to the enclosing class type, so we can recover
    // the 'this' type from it.
    QualType ClassTy = Context.getTypeDeclType(cast<CXXRecordDecl>(DC));
    // There are no cv-qualifiers for 'this' within default initializers,
    // per [expr.prim.general]p4.
    ThisTy = Context.getPointerType(ClassTy);
  }

  // If we are within a lambda's call operator, the cv-qualifiers of 'this'
  // might need to be adjusted if the lambda or any of its enclosing lambda's
  // captures '*this' by copy.
  if (!ThisTy.isNull() && isLambdaCallOperator(CurContext))
    return adjustCVQualifiersForCXXThisWithinLambda(FunctionScopes, ThisTy,
                                                    CurContext, Context);
  return ThisTy;
}

Sema::CXXThisScopeRAII::CXXThisScopeRAII(Sema &S,
                                         Decl *ContextDecl,
                                         Qualifiers CXXThisTypeQuals,
                                         bool Enabled)
  : S(S), OldCXXThisTypeOverride(S.CXXThisTypeOverride), Enabled(false)
{
  if (!Enabled || !ContextDecl)
    return;

  CXXRecordDecl *Record = nullptr;
  if (ClassTemplateDecl *Template = dyn_cast<ClassTemplateDecl>(ContextDecl))
    Record = Template->getTemplatedDecl();
  else
    Record = cast<CXXRecordDecl>(ContextDecl);

  QualType T = S.Context.getRecordType(Record);
  T = S.getASTContext().getQualifiedType(T, CXXThisTypeQuals);

  S.CXXThisTypeOverride = S.Context.getPointerType(T);

  this->Enabled = true;
}


Sema::CXXThisScopeRAII::~CXXThisScopeRAII() {
  if (Enabled) {
    S.CXXThisTypeOverride = OldCXXThisTypeOverride;
  }
}

static void buildLambdaThisCaptureFixit(Sema &Sema, LambdaScopeInfo *LSI) {
  SourceLocation DiagLoc = LSI->IntroducerRange.getEnd();
  assert(!LSI->isCXXThisCaptured());
  //  [=, this] {};   // until C++20: Error: this when = is the default
  if (LSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_LambdaByval &&
      !Sema.getLangOpts().CPlusPlus20)
    return;
  Sema.Diag(DiagLoc, diag::note_lambda_this_capture_fixit)
      << FixItHint::CreateInsertion(
             DiagLoc, LSI->NumExplicitCaptures > 0 ? ", this" : "this");
}

bool Sema::CheckCXXThisCapture(SourceLocation Loc, const bool Explicit,
    bool BuildAndDiagnose, const unsigned *const FunctionScopeIndexToStopAt,
    const bool ByCopy) {
  // We don't need to capture this in an unevaluated context.
  if (isUnevaluatedContext() && !Explicit)
    return true;

  assert((!ByCopy || Explicit) && "cannot implicitly capture *this by value");

  const int MaxFunctionScopesIndex = FunctionScopeIndexToStopAt
                                         ? *FunctionScopeIndexToStopAt
                                         : FunctionScopes.size() - 1;

  // Check that we can capture the *enclosing object* (referred to by '*this')
  // by the capturing-entity/closure (lambda/block/etc) at
  // MaxFunctionScopesIndex-deep on the FunctionScopes stack.

  // Note: The *enclosing object* can only be captured by-value by a
  // closure that is a lambda, using the explicit notation:
  //    [*this] { ... }.
  // Every other capture of the *enclosing object* results in its by-reference
  // capture.

  // For a closure 'L' (at MaxFunctionScopesIndex in the FunctionScopes
  // stack), we can capture the *enclosing object* only if:
  // - 'L' has an explicit byref or byval capture of the *enclosing object*
  // -  or, 'L' has an implicit capture.
  // AND
  //   -- there is no enclosing closure
  //   -- or, there is some enclosing closure 'E' that has already captured the
  //      *enclosing object*, and every intervening closure (if any) between 'E'
  //      and 'L' can implicitly capture the *enclosing object*.
  //   -- or, every enclosing closure can implicitly capture the
  //      *enclosing object*


  unsigned NumCapturingClosures = 0;
  for (int idx = MaxFunctionScopesIndex; idx >= 0; idx--) {
    if (CapturingScopeInfo *CSI =
            dyn_cast<CapturingScopeInfo>(FunctionScopes[idx])) {
      if (CSI->CXXThisCaptureIndex != 0) {
        // 'this' is already being captured; there isn't anything more to do.
        CSI->Captures[CSI->CXXThisCaptureIndex - 1].markUsed(BuildAndDiagnose);
        break;
      }
      LambdaScopeInfo *LSI = dyn_cast<LambdaScopeInfo>(CSI);
      if (LSI && isGenericLambdaCallOperatorSpecialization(LSI->CallOperator)) {
        // This context can't implicitly capture 'this'; fail out.
        if (BuildAndDiagnose) {
          Diag(Loc, diag::err_this_capture)
              << (Explicit && idx == MaxFunctionScopesIndex);
          if (!Explicit)
            buildLambdaThisCaptureFixit(*this, LSI);
        }
        return true;
      }
      if (CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_LambdaByref ||
          CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_LambdaByval ||
          CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_Block ||
          CSI->ImpCaptureStyle == CapturingScopeInfo::ImpCap_CapturedRegion ||
          (Explicit && idx == MaxFunctionScopesIndex)) {
        // Regarding (Explicit && idx == MaxFunctionScopesIndex): only the first
        // iteration through can be an explicit capture, all enclosing closures,
        // if any, must perform implicit captures.

        // This closure can capture 'this'; continue looking upwards.
        NumCapturingClosures++;
        continue;
      }
      // This context can't implicitly capture 'this'; fail out.
      if (BuildAndDiagnose)
        Diag(Loc, diag::err_this_capture)
            << (Explicit && idx == MaxFunctionScopesIndex);

      if (!Explicit)
        buildLambdaThisCaptureFixit(*this, LSI);
      return true;
    }
    break;
  }
  if (!BuildAndDiagnose) return false;

  // If we got here, then the closure at MaxFunctionScopesIndex on the
  // FunctionScopes stack, can capture the *enclosing object*, so capture it
  // (including implicit by-reference captures in any enclosing closures).

  // In the loop below, respect the ByCopy flag only for the closure requesting
  // the capture (i.e. first iteration through the loop below).  Ignore it for
  // all enclosing closure's up to NumCapturingClosures (since they must be
  // implicitly capturing the *enclosing  object* by reference (see loop
  // above)).
  assert((!ByCopy ||
          dyn_cast<LambdaScopeInfo>(FunctionScopes[MaxFunctionScopesIndex])) &&
         "Only a lambda can capture the enclosing object (referred to by "
         "*this) by copy");
  QualType ThisTy = getCurrentThisType();
  for (int idx = MaxFunctionScopesIndex; NumCapturingClosures;
       --idx, --NumCapturingClosures) {
    CapturingScopeInfo *CSI = cast<CapturingScopeInfo>(FunctionScopes[idx]);

    // The type of the corresponding data member (not a 'this' pointer if 'by
    // copy').
    QualType CaptureType = ThisTy;
    if (ByCopy) {
      // If we are capturing the object referred to by '*this' by copy, ignore
      // any cv qualifiers inherited from the type of the member function for
      // the type of the closure-type's corresponding data member and any use
      // of 'this'.
      CaptureType = ThisTy->getPointeeType();
      CaptureType.removeLocalCVRQualifiers(Qualifiers::CVRMask);
    }

    bool isNested = NumCapturingClosures > 1;
    CSI->addThisCapture(isNested, Loc, CaptureType, ByCopy);
  }
  return false;
}

ExprResult Sema::ActOnCXXThis(SourceLocation Loc) {
  /// C++ 9.3.2: In the body of a non-static member function, the keyword this
  /// is a non-lvalue expression whose value is the address of the object for
  /// which the function is called.

  QualType ThisTy = getCurrentThisType();
  if (ThisTy.isNull())
    return Diag(Loc, diag::err_invalid_this_use);
  return BuildCXXThisExpr(Loc, ThisTy, /*IsImplicit=*/false);
}

Expr *Sema::BuildCXXThisExpr(SourceLocation Loc, QualType Type,
                             bool IsImplicit) {
  auto *This = new (Context) CXXThisExpr(Loc, Type, IsImplicit);
  MarkThisReferenced(This);
  return This;
}

void Sema::MarkThisReferenced(CXXThisExpr *This) {
  CheckCXXThisCapture(This->getExprLoc());
}

bool Sema::isThisOutsideMemberFunctionBody(QualType BaseType) {
  // If we're outside the body of a member function, then we'll have a specified
  // type for 'this'.
  if (CXXThisTypeOverride.isNull())
    return false;

  // Determine whether we're looking into a class that's currently being
  // defined.
  CXXRecordDecl *Class = BaseType->getAsCXXRecordDecl();
  return Class && Class->isBeingDefined();
}

/// Parse construction of a specified type.
/// Can be interpreted either as function-style casting ("int(x)")
/// or class type construction ("ClassType(x,y,z)")
/// or creation of a value-initialized type ("int()").
ExprResult
Sema::ActOnCXXTypeConstructExpr(ParsedType TypeRep,
                                SourceLocation LParenOrBraceLoc,
                                MultiExprArg exprs,
                                SourceLocation RParenOrBraceLoc,
                                bool ListInitialization) {
  if (!TypeRep)
    return ExprError();

  TypeSourceInfo *TInfo;
  QualType Ty = GetTypeFromParser(TypeRep, &TInfo);
  if (!TInfo)
    TInfo = Context.getTrivialTypeSourceInfo(Ty, SourceLocation());

  auto Result = BuildCXXTypeConstructExpr(TInfo, LParenOrBraceLoc, exprs,
                                          RParenOrBraceLoc, ListInitialization);
  // Avoid creating a non-type-dependent expression that contains typos.
  // Non-type-dependent expressions are liable to be discarded without
  // checking for embedded typos.
  if (!Result.isInvalid() && Result.get()->isInstantiationDependent() &&
      !Result.get()->isTypeDependent())
    Result = CorrectDelayedTyposInExpr(Result.get());
  else if (Result.isInvalid())
    Result = CreateRecoveryExpr(TInfo->getTypeLoc().getBeginLoc(),
                                RParenOrBraceLoc, exprs, Ty);
  return Result;
}

ExprResult
Sema::BuildCXXTypeConstructExpr(TypeSourceInfo *TInfo,
                                SourceLocation LParenOrBraceLoc,
                                MultiExprArg Exprs,
                                SourceLocation RParenOrBraceLoc,
                                bool ListInitialization) {
  QualType Ty = TInfo->getType();
  SourceLocation TyBeginLoc = TInfo->getTypeLoc().getBeginLoc();

  assert((!ListInitialization ||
          (Exprs.size() == 1 && isa<InitListExpr>(Exprs[0]))) &&
         "List initialization must have initializer list as expression.");
  SourceRange FullRange = SourceRange(TyBeginLoc, RParenOrBraceLoc);

  InitializedEntity Entity = InitializedEntity::InitializeTemporary(TInfo);
  InitializationKind Kind =
      Exprs.size()
          ? ListInitialization
                ? InitializationKind::CreateDirectList(
                      TyBeginLoc, LParenOrBraceLoc, RParenOrBraceLoc)
                : InitializationKind::CreateDirect(TyBeginLoc, LParenOrBraceLoc,
                                                   RParenOrBraceLoc)
          : InitializationKind::CreateValue(TyBeginLoc, LParenOrBraceLoc,
                                            RParenOrBraceLoc);

  // C++1z [expr.type.conv]p1:
  //   If the type is a placeholder for a deduced class type, [...perform class
  //   template argument deduction...]
  DeducedType *Deduced = Ty->getContainedDeducedType();
  if (Deduced && isa<DeducedTemplateSpecializationType>(Deduced)) {
    Ty = DeduceTemplateSpecializationFromInitializer(TInfo, Entity,
                                                     Kind, Exprs);
    if (Ty.isNull())
      return ExprError();
    Entity = InitializedEntity::InitializeTemporary(TInfo, Ty);
  }

  if (Ty->isDependentType() || CallExpr::hasAnyTypeDependentArguments(Exprs)) {
    // FIXME: CXXUnresolvedConstructExpr does not model list-initialization
    // directly. We work around this by dropping the locations of the braces.
    SourceRange Locs = ListInitialization
                           ? SourceRange()
                           : SourceRange(LParenOrBraceLoc, RParenOrBraceLoc);
    return CXXUnresolvedConstructExpr::Create(Context, Ty.getNonReferenceType(),
                                              TInfo, Locs.getBegin(), Exprs,
                                              Locs.getEnd());
  }

  // C++ [expr.type.conv]p1:
  // If the expression list is a parenthesized single expression, the type
  // conversion expression is equivalent (in definedness, and if defined in
  // meaning) to the corresponding cast expression.
  if (Exprs.size() == 1 && !ListInitialization &&
      !isa<InitListExpr>(Exprs[0])) {
    Expr *Arg = Exprs[0];
    return BuildCXXFunctionalCastExpr(TInfo, Ty, LParenOrBraceLoc, Arg,
                                      RParenOrBraceLoc);
  }

  //   For an expression of the form T(), T shall not be an array type.
  QualType ElemTy = Ty;
  if (Ty->isArrayType()) {
    if (!ListInitialization)
      return ExprError(Diag(TyBeginLoc, diag::err_value_init_for_array_type)
                         << FullRange);
    ElemTy = Context.getBaseElementType(Ty);
  }

  // There doesn't seem to be an explicit rule against this but sanity demands
  // we only construct objects with object types.
  if (Ty->isFunctionType())
    return ExprError(Diag(TyBeginLoc, diag::err_init_for_function_type)
                       << Ty << FullRange);

  // C++17 [expr.type.conv]p2:
  //   If the type is cv void and the initializer is (), the expression is a
  //   prvalue of the specified type that performs no initialization.
  if (!Ty->isVoidType() &&
      RequireCompleteType(TyBeginLoc, ElemTy,
                          diag::err_invalid_incomplete_type_use, FullRange))
    return ExprError();

  //   Otherwise, the expression is a prvalue of the specified type whose
  //   result object is direct-initialized (11.6) with the initializer.
  InitializationSequence InitSeq(*this, Entity, Kind, Exprs);
  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Exprs);

  if (Result.isInvalid())
    return Result;

  Expr *Inner = Result.get();
  if (CXXBindTemporaryExpr *BTE = dyn_cast_or_null<CXXBindTemporaryExpr>(Inner))
    Inner = BTE->getSubExpr();
  if (!isa<CXXTemporaryObjectExpr>(Inner) &&
      !isa<CXXScalarValueInitExpr>(Inner)) {
    // If we created a CXXTemporaryObjectExpr, that node also represents the
    // functional cast. Otherwise, create an explicit cast to represent
    // the syntactic form of a functional-style cast that was used here.
    //
    // FIXME: Creating a CXXFunctionalCastExpr around a CXXConstructExpr
    // would give a more consistent AST representation than using a
    // CXXTemporaryObjectExpr. It's also weird that the functional cast
    // is sometimes handled by initialization and sometimes not.
    QualType ResultType = Result.get()->getType();
    SourceRange Locs = ListInitialization
                           ? SourceRange()
                           : SourceRange(LParenOrBraceLoc, RParenOrBraceLoc);
    Result = CXXFunctionalCastExpr::Create(
        Context, ResultType, Expr::getValueKindForType(Ty), TInfo, CK_NoOp,
        Result.get(), /*Path=*/nullptr, CurFPFeatureOverrides(),
        Locs.getBegin(), Locs.getEnd());
  }

  return Result;
}

bool Sema::isUsualDeallocationFunction(const CXXMethodDecl *Method) {
  // [CUDA] Ignore this function, if we can't call it.
  const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext);
  if (getLangOpts().CUDA) {
    auto CallPreference = IdentifyCUDAPreference(Caller, Method);
    // If it's not callable at all, it's not the right function.
    if (CallPreference < CFP_WrongSide)
      return false;
    if (CallPreference == CFP_WrongSide) {
      // Maybe. We have to check if there are better alternatives.
      DeclContext::lookup_result R =
          Method->getDeclContext()->lookup(Method->getDeclName());
      for (const auto *D : R) {
        if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
          if (IdentifyCUDAPreference(Caller, FD) > CFP_WrongSide)
            return false;
        }
      }
      // We've found no better variants.
    }
  }

  SmallVector<const FunctionDecl*, 4> PreventedBy;
  bool Result = Method->isUsualDeallocationFunction(PreventedBy);

  if (Result || !getLangOpts().CUDA || PreventedBy.empty())
    return Result;

  // In case of CUDA, return true if none of the 1-argument deallocator
  // functions are actually callable.
  return llvm::none_of(PreventedBy, [&](const FunctionDecl *FD) {
    assert(FD->getNumParams() == 1 &&
           "Only single-operand functions should be in PreventedBy");
    return IdentifyCUDAPreference(Caller, FD) >= CFP_HostDevice;
  });
}

/// Determine whether the given function is a non-placement
/// deallocation function.
static bool isNonPlacementDeallocationFunction(Sema &S, FunctionDecl *FD) {
  if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FD))
    return S.isUsualDeallocationFunction(Method);

  if (FD->getOverloadedOperator() != OO_Delete &&
      FD->getOverloadedOperator() != OO_Array_Delete)
    return false;

  unsigned UsualParams = 1;

  if (S.getLangOpts().SizedDeallocation && UsualParams < FD->getNumParams() &&
      S.Context.hasSameUnqualifiedType(
          FD->getParamDecl(UsualParams)->getType(),
          S.Context.getSizeType()))
    ++UsualParams;

  if (S.getLangOpts().AlignedAllocation && UsualParams < FD->getNumParams() &&
      S.Context.hasSameUnqualifiedType(
          FD->getParamDecl(UsualParams)->getType(),
          S.Context.getTypeDeclType(S.getStdAlignValT())))
    ++UsualParams;

  return UsualParams == FD->getNumParams();
}

namespace {
  struct UsualDeallocFnInfo {
    UsualDeallocFnInfo() : Found(), FD(nullptr) {}
    UsualDeallocFnInfo(Sema &S, DeclAccessPair Found)
        : Found(Found), FD(dyn_cast<FunctionDecl>(Found->getUnderlyingDecl())),
          Destroying(false), HasSizeT(false), HasAlignValT(false),
          CUDAPref(Sema::CFP_Native) {
      // A function template declaration is never a usual deallocation function.
      if (!FD)
        return;
      unsigned NumBaseParams = 1;
      if (FD->isDestroyingOperatorDelete()) {
        Destroying = true;
        ++NumBaseParams;
      }

      if (NumBaseParams < FD->getNumParams() &&
          S.Context.hasSameUnqualifiedType(
              FD->getParamDecl(NumBaseParams)->getType(),
              S.Context.getSizeType())) {
        ++NumBaseParams;
        HasSizeT = true;
      }

      if (NumBaseParams < FD->getNumParams() &&
          FD->getParamDecl(NumBaseParams)->getType()->isAlignValT()) {
        ++NumBaseParams;
        HasAlignValT = true;
      }

      // In CUDA, determine how much we'd like / dislike to call this.
      if (S.getLangOpts().CUDA)
        if (auto *Caller = dyn_cast<FunctionDecl>(S.CurContext))
          CUDAPref = S.IdentifyCUDAPreference(Caller, FD);
    }

    explicit operator bool() const { return FD; }

    bool isBetterThan(const UsualDeallocFnInfo &Other, bool WantSize,
                      bool WantAlign) const {
      // C++ P0722:
      //   A destroying operator delete is preferred over a non-destroying
      //   operator delete.
      if (Destroying != Other.Destroying)
        return Destroying;

      // C++17 [expr.delete]p10:
      //   If the type has new-extended alignment, a function with a parameter
      //   of type std::align_val_t is preferred; otherwise a function without
      //   such a parameter is preferred
      if (HasAlignValT != Other.HasAlignValT)
        return HasAlignValT == WantAlign;

      if (HasSizeT != Other.HasSizeT)
        return HasSizeT == WantSize;

      // Use CUDA call preference as a tiebreaker.
      return CUDAPref > Other.CUDAPref;
    }

    DeclAccessPair Found;
    FunctionDecl *FD;
    bool Destroying, HasSizeT, HasAlignValT;
    Sema::CUDAFunctionPreference CUDAPref;
  };
}

/// Determine whether a type has new-extended alignment. This may be called when
/// the type is incomplete (for a delete-expression with an incomplete pointee
/// type), in which case it will conservatively return false if the alignment is
/// not known.
static bool hasNewExtendedAlignment(Sema &S, QualType AllocType) {
  return S.getLangOpts().AlignedAllocation &&
         S.getASTContext().getTypeAlignIfKnown(AllocType) >
             S.getASTContext().getTargetInfo().getNewAlign();
}

/// Select the correct "usual" deallocation function to use from a selection of
/// deallocation functions (either global or class-scope).
static UsualDeallocFnInfo resolveDeallocationOverload(
    Sema &S, LookupResult &R, bool WantSize, bool WantAlign,
    llvm::SmallVectorImpl<UsualDeallocFnInfo> *BestFns = nullptr) {
  UsualDeallocFnInfo Best;

  for (auto I = R.begin(), E = R.end(); I != E; ++I) {
    UsualDeallocFnInfo Info(S, I.getPair());
    if (!Info || !isNonPlacementDeallocationFunction(S, Info.FD) ||
        Info.CUDAPref == Sema::CFP_Never)
      continue;

    if (!Best) {
      Best = Info;
      if (BestFns)
        BestFns->push_back(Info);
      continue;
    }

    if (Best.isBetterThan(Info, WantSize, WantAlign))
      continue;

    //   If more than one preferred function is found, all non-preferred
    //   functions are eliminated from further consideration.
    if (BestFns && Info.isBetterThan(Best, WantSize, WantAlign))
      BestFns->clear();

    Best = Info;
    if (BestFns)
      BestFns->push_back(Info);
  }

  return Best;
}

/// Determine whether a given type is a class for which 'delete[]' would call
/// a member 'operator delete[]' with a 'size_t' parameter. This implies that
/// we need to store the array size (even if the type is
/// trivially-destructible).
static bool doesUsualArrayDeleteWantSize(Sema &S, SourceLocation loc,
                                         QualType allocType) {
  const RecordType *record =
    allocType->getBaseElementTypeUnsafe()->getAs<RecordType>();
  if (!record) return false;

  // Try to find an operator delete[] in class scope.

  DeclarationName deleteName =
    S.Context.DeclarationNames.getCXXOperatorName(OO_Array_Delete);
  LookupResult ops(S, deleteName, loc, Sema::LookupOrdinaryName);
  S.LookupQualifiedName(ops, record->getDecl());

  // We're just doing this for information.
  ops.suppressDiagnostics();

  // Very likely: there's no operator delete[].
  if (ops.empty()) return false;

  // If it's ambiguous, it should be illegal to call operator delete[]
  // on this thing, so it doesn't matter if we allocate extra space or not.
  if (ops.isAmbiguous()) return false;

  // C++17 [expr.delete]p10:
  //   If the deallocation functions have class scope, the one without a
  //   parameter of type std::size_t is selected.
  auto Best = resolveDeallocationOverload(
      S, ops, /*WantSize*/false,
      /*WantAlign*/hasNewExtendedAlignment(S, allocType));
  return Best && Best.HasSizeT;
}

/// Parsed a C++ 'new' expression (C++ 5.3.4).
///
/// E.g.:
/// @code new (memory) int[size][4] @endcode
/// or
/// @code ::new Foo(23, "hello") @endcode
///
/// \param StartLoc The first location of the expression.
/// \param UseGlobal True if 'new' was prefixed with '::'.
/// \param PlacementLParen Opening paren of the placement arguments.
/// \param PlacementArgs Placement new arguments.
/// \param PlacementRParen Closing paren of the placement arguments.
/// \param TypeIdParens If the type is in parens, the source range.
/// \param D The type to be allocated, as well as array dimensions.
/// \param Initializer The initializing expression or initializer-list, or null
///   if there is none.
ExprResult
Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                  SourceLocation PlacementLParen, MultiExprArg PlacementArgs,
                  SourceLocation PlacementRParen, SourceRange TypeIdParens,
                  Declarator &D, Expr *Initializer) {
  Optional<Expr *> ArraySize;
  // If the specified type is an array, unwrap it and save the expression.
  if (D.getNumTypeObjects() > 0 &&
      D.getTypeObject(0).Kind == DeclaratorChunk::Array) {
    DeclaratorChunk &Chunk = D.getTypeObject(0);
    if (D.getDeclSpec().hasAutoTypeSpec())
      return ExprError(Diag(Chunk.Loc, diag::err_new_array_of_auto)
        << D.getSourceRange());
    if (Chunk.Arr.hasStatic)
      return ExprError(Diag(Chunk.Loc, diag::err_static_illegal_in_new)
        << D.getSourceRange());
    if (!Chunk.Arr.NumElts && !Initializer)
      return ExprError(Diag(Chunk.Loc, diag::err_array_new_needs_size)
        << D.getSourceRange());

    ArraySize = static_cast<Expr*>(Chunk.Arr.NumElts);
    D.DropFirstTypeObject();
  }

  // Every dimension shall be of constant size.
  if (ArraySize) {
    for (unsigned I = 0, N = D.getNumTypeObjects(); I < N; ++I) {
      if (D.getTypeObject(I).Kind != DeclaratorChunk::Array)
        break;

      DeclaratorChunk::ArrayTypeInfo &Array = D.getTypeObject(I).Arr;
      if (Expr *NumElts = (Expr *)Array.NumElts) {
        if (!NumElts->isTypeDependent() && !NumElts->isValueDependent()) {
          // FIXME: GCC permits constant folding here. We should either do so consistently
          // or not do so at all, rather than changing behavior in C++14 onwards.
          if (getLangOpts().CPlusPlus14) {
            // C++1y [expr.new]p6: Every constant-expression in a noptr-new-declarator
            //   shall be a converted constant expression (5.19) of type std::size_t
            //   and shall evaluate to a strictly positive value.
            llvm::APSInt Value(Context.getIntWidth(Context.getSizeType()));
            Array.NumElts
             = CheckConvertedConstantExpression(NumElts, Context.getSizeType(), Value,
                                                CCEK_ArrayBound)
                 .get();
          } else {
            Array.NumElts =
                VerifyIntegerConstantExpression(
                    NumElts, nullptr, diag::err_new_array_nonconst, AllowFold)
                    .get();
          }
          if (!Array.NumElts)
            return ExprError();
        }
      }
    }
  }

  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, /*Scope=*/nullptr);
  QualType AllocType = TInfo->getType();
  if (D.isInvalidType())
    return ExprError();

  SourceRange DirectInitRange;
  if (ParenListExpr *List = dyn_cast_or_null<ParenListExpr>(Initializer))
    DirectInitRange = List->getSourceRange();

  return BuildCXXNew(SourceRange(StartLoc, D.getEndLoc()), UseGlobal,
                     PlacementLParen, PlacementArgs, PlacementRParen,
                     TypeIdParens, AllocType, TInfo, ArraySize, DirectInitRange,
                     Initializer);
}

static bool isLegalArrayNewInitializer(CXXNewExpr::InitializationStyle Style,
                                       Expr *Init) {
  if (!Init)
    return true;
  if (ParenListExpr *PLE = dyn_cast<ParenListExpr>(Init))
    return PLE->getNumExprs() == 0;
  if (isa<ImplicitValueInitExpr>(Init))
    return true;
  else if (CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init))
    return !CCE->isListInitialization() &&
           CCE->getConstructor()->isDefaultConstructor();
  else if (Style == CXXNewExpr::ListInit) {
    assert(isa<InitListExpr>(Init) &&
           "Shouldn't create list CXXConstructExprs for arrays.");
    return true;
  }
  return false;
}

bool
Sema::isUnavailableAlignedAllocationFunction(const FunctionDecl &FD) const {
  if (!getLangOpts().AlignedAllocationUnavailable)
    return false;
  if (FD.isDefined())
    return false;
  Optional<unsigned> AlignmentParam;
  if (FD.isReplaceableGlobalAllocationFunction(&AlignmentParam) &&
      AlignmentParam.hasValue())
    return true;
  return false;
}

// Emit a diagnostic if an aligned allocation/deallocation function that is not
// implemented in the standard library is selected.
void Sema::diagnoseUnavailableAlignedAllocation(const FunctionDecl &FD,
                                                SourceLocation Loc) {
  if (isUnavailableAlignedAllocationFunction(FD)) {
    const llvm::Triple &T = getASTContext().getTargetInfo().getTriple();
    StringRef OSName = AvailabilityAttr::getPlatformNameSourceSpelling(
        getASTContext().getTargetInfo().getPlatformName());
    VersionTuple OSVersion = alignedAllocMinVersion(T.getOS());

    OverloadedOperatorKind Kind = FD.getDeclName().getCXXOverloadedOperator();
    bool IsDelete = Kind == OO_Delete || Kind == OO_Array_Delete;
    Diag(Loc, diag::err_aligned_allocation_unavailable)
        << IsDelete << FD.getType().getAsString() << OSName
        << OSVersion.getAsString() << OSVersion.empty();
    Diag(Loc, diag::note_silence_aligned_allocation_unavailable);
  }
}

ExprResult
Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
                  SourceLocation PlacementLParen,
                  MultiExprArg PlacementArgs,
                  SourceLocation PlacementRParen,
                  SourceRange TypeIdParens,
                  QualType AllocType,
                  TypeSourceInfo *AllocTypeInfo,
                  Optional<Expr *> ArraySize,
                  SourceRange DirectInitRange,
                  Expr *Initializer) {
  SourceRange TypeRange = AllocTypeInfo->getTypeLoc().getSourceRange();
  SourceLocation StartLoc = Range.getBegin();

  CXXNewExpr::InitializationStyle initStyle;
  if (DirectInitRange.isValid()) {
    assert(Initializer && "Have parens but no initializer.");
    initStyle = CXXNewExpr::CallInit;
  } else if (Initializer && isa<InitListExpr>(Initializer))
    initStyle = CXXNewExpr::ListInit;
  else {
    assert((!Initializer || isa<ImplicitValueInitExpr>(Initializer) ||
            isa<CXXConstructExpr>(Initializer)) &&
           "Initializer expression that cannot have been implicitly created.");
    initStyle = CXXNewExpr::NoInit;
  }

  Expr **Inits = &Initializer;
  unsigned NumInits = Initializer ? 1 : 0;
  if (ParenListExpr *List = dyn_cast_or_null<ParenListExpr>(Initializer)) {
    assert(initStyle == CXXNewExpr::CallInit && "paren init for non-call init");
    Inits = List->getExprs();
    NumInits = List->getNumExprs();
  }

  // C++11 [expr.new]p15:
  //   A new-expression that creates an object of type T initializes that
  //   object as follows:
  InitializationKind Kind
      //     - If the new-initializer is omitted, the object is default-
      //       initialized (8.5); if no initialization is performed,
      //       the object has indeterminate value
      = initStyle == CXXNewExpr::NoInit
            ? InitializationKind::CreateDefault(TypeRange.getBegin())
            //     - Otherwise, the new-initializer is interpreted according to
            //     the
            //       initialization rules of 8.5 for direct-initialization.
            : initStyle == CXXNewExpr::ListInit
                  ? InitializationKind::CreateDirectList(
                        TypeRange.getBegin(), Initializer->getBeginLoc(),
                        Initializer->getEndLoc())
                  : InitializationKind::CreateDirect(TypeRange.getBegin(),
                                                     DirectInitRange.getBegin(),
                                                     DirectInitRange.getEnd());

  // C++11 [dcl.spec.auto]p6. Deduce the type which 'auto' stands in for.
  auto *Deduced = AllocType->getContainedDeducedType();
  if (Deduced && isa<DeducedTemplateSpecializationType>(Deduced)) {
    if (ArraySize)
      return ExprError(
          Diag(ArraySize ? (*ArraySize)->getExprLoc() : TypeRange.getBegin(),
               diag::err_deduced_class_template_compound_type)
          << /*array*/ 2
          << (ArraySize ? (*ArraySize)->getSourceRange() : TypeRange));

    InitializedEntity Entity
      = InitializedEntity::InitializeNew(StartLoc, AllocType);
    AllocType = DeduceTemplateSpecializationFromInitializer(
        AllocTypeInfo, Entity, Kind, MultiExprArg(Inits, NumInits));
    if (AllocType.isNull())
      return ExprError();
  } else if (Deduced) {
    bool Braced = (initStyle == CXXNewExpr::ListInit);
    if (NumInits == 1) {
      if (auto p = dyn_cast_or_null<InitListExpr>(Inits[0])) {
        Inits = p->getInits();
        NumInits = p->getNumInits();
        Braced = true;
      }
    }

    if (initStyle == CXXNewExpr::NoInit || NumInits == 0)
      return ExprError(Diag(StartLoc, diag::err_auto_new_requires_ctor_arg)
                       << AllocType << TypeRange);
    if (NumInits > 1) {
      Expr *FirstBad = Inits[1];
      return ExprError(Diag(FirstBad->getBeginLoc(),
                            diag::err_auto_new_ctor_multiple_expressions)
                       << AllocType << TypeRange);
    }
    if (Braced && !getLangOpts().CPlusPlus17)
      Diag(Initializer->getBeginLoc(), diag::ext_auto_new_list_init)
          << AllocType << TypeRange;
    Expr *Deduce = Inits[0];
    QualType DeducedType;
    if (DeduceAutoType(AllocTypeInfo, Deduce, DeducedType) == DAR_Failed)
      return ExprError(Diag(StartLoc, diag::err_auto_new_deduction_failure)
                       << AllocType << Deduce->getType()
                       << TypeRange << Deduce->getSourceRange());
    if (DeducedType.isNull())
      return ExprError();
    AllocType = DeducedType;
  }

  // Per C++0x [expr.new]p5, the type being constructed may be a
  // typedef of an array type.
  if (!ArraySize) {
    if (const ConstantArrayType *Array
                              = Context.getAsConstantArrayType(AllocType)) {
      ArraySize = IntegerLiteral::Create(Context, Array->getSize(),
                                         Context.getSizeType(),
                                         TypeRange.getEnd());
      AllocType = Array->getElementType();
    }
  }

  if (CheckAllocatedType(AllocType, TypeRange.getBegin(), TypeRange))
    return ExprError();

  // In ARC, infer 'retaining' for the allocated
  if (getLangOpts().ObjCAutoRefCount &&
      AllocType.getObjCLifetime() == Qualifiers::OCL_None &&
      AllocType->isObjCLifetimeType()) {
    AllocType = Context.getLifetimeQualifiedType(AllocType,
                                    AllocType->getObjCARCImplicitLifetime());
  }

  QualType ResultType = Context.getPointerType(AllocType);

  if (ArraySize && *ArraySize &&
      (*ArraySize)->getType()->isNonOverloadPlaceholderType()) {
    ExprResult result = CheckPlaceholderExpr(*ArraySize);
    if (result.isInvalid()) return ExprError();
    ArraySize = result.get();
  }
  // C++98 5.3.4p6: "The expression in a direct-new-declarator shall have
  //   integral or enumeration type with a non-negative value."
  // C++11 [expr.new]p6: The expression [...] shall be of integral or unscoped
  //   enumeration type, or a class type for which a single non-explicit
  //   conversion function to integral or unscoped enumeration type exists.
  // C++1y [expr.new]p6: The expression [...] is implicitly converted to
  //   std::size_t.
  llvm::Optional<uint64_t> KnownArraySize;
  if (ArraySize && *ArraySize && !(*ArraySize)->isTypeDependent()) {
    ExprResult ConvertedSize;
    if (getLangOpts().CPlusPlus14) {
      assert(Context.getTargetInfo().getIntWidth() && "Builtin type of size 0?");

      ConvertedSize = PerformImplicitConversion(*ArraySize, Context.getSizeType(),
                                                AA_Converting);

      if (!ConvertedSize.isInvalid() &&
          (*ArraySize)->getType()->getAs<RecordType>())
        // Diagnose the compatibility of this conversion.
        Diag(StartLoc, diag::warn_cxx98_compat_array_size_conversion)
          << (*ArraySize)->getType() << 0 << "'size_t'";
    } else {
      class SizeConvertDiagnoser : public ICEConvertDiagnoser {
      protected:
        Expr *ArraySize;

      public:
        SizeConvertDiagnoser(Expr *ArraySize)
            : ICEConvertDiagnoser(/*AllowScopedEnumerations*/false, false, false),
              ArraySize(ArraySize) {}

        SemaDiagnosticBuilder diagnoseNotInt(Sema &S, SourceLocation Loc,
                                             QualType T) override {
          return S.Diag(Loc, diag::err_array_size_not_integral)
                   << S.getLangOpts().CPlusPlus11 << T;
        }

        SemaDiagnosticBuilder diagnoseIncomplete(
            Sema &S, SourceLocation Loc, QualType T) override {
          return S.Diag(Loc, diag::err_array_size_incomplete_type)
                   << T << ArraySize->getSourceRange();
        }

        SemaDiagnosticBuilder diagnoseExplicitConv(
            Sema &S, SourceLocation Loc, QualType T, QualType ConvTy) override {
          return S.Diag(Loc, diag::err_array_size_explicit_conversion) << T << ConvTy;
        }

        SemaDiagnosticBuilder noteExplicitConv(
            Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
          return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
                   << ConvTy->isEnumeralType() << ConvTy;
        }

        SemaDiagnosticBuilder diagnoseAmbiguous(
            Sema &S, SourceLocation Loc, QualType T) override {
          return S.Diag(Loc, diag::err_array_size_ambiguous_conversion) << T;
        }

        SemaDiagnosticBuilder noteAmbiguous(
            Sema &S, CXXConversionDecl *Conv, QualType ConvTy) override {
          return S.Diag(Conv->getLocation(), diag::note_array_size_conversion)
                   << ConvTy->isEnumeralType() << ConvTy;
        }

        SemaDiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
                                                 QualType T,
                                                 QualType ConvTy) override {
          return S.Diag(Loc,
                        S.getLangOpts().CPlusPlus11
                          ? diag::warn_cxx98_compat_array_size_conversion
                          : diag::ext_array_size_conversion)
                   << T << ConvTy->isEnumeralType() << ConvTy;
        }
      } SizeDiagnoser(*ArraySize);

      ConvertedSize = PerformContextualImplicitConversion(StartLoc, *ArraySize,
                                                          SizeDiagnoser);
    }
    if (ConvertedSize.isInvalid())
      return ExprError();

    ArraySize = ConvertedSize.get();
    QualType SizeType = (*ArraySize)->getType();

    if (!SizeType->isIntegralOrUnscopedEnumerationType())
      return ExprError();

    // C++98 [expr.new]p7:
    //   The expression in a direct-new-declarator shall have integral type
    //   with a non-negative value.
    //
    // Let's see if this is a constant < 0. If so, we reject it out of hand,
    // per CWG1464. Otherwise, if it's not a constant, we must have an
    // unparenthesized array type.
    if (!(*ArraySize)->isValueDependent()) {
      // We've already performed any required implicit conversion to integer or
      // unscoped enumeration type.
      // FIXME: Per CWG1464, we are required to check the value prior to
      // converting to size_t. This will never find a negative array size in
      // C++14 onwards, because Value is always unsigned here!
      if (Optional<llvm::APSInt> Value =
              (*ArraySize)->getIntegerConstantExpr(Context)) {
        if (Value->isSigned() && Value->isNegative()) {
          return ExprError(Diag((*ArraySize)->getBeginLoc(),
                                diag::err_typecheck_negative_array_size)
                           << (*ArraySize)->getSourceRange());
        }

        if (!AllocType->isDependentType()) {
          unsigned ActiveSizeBits = ConstantArrayType::getNumAddressingBits(
              Context, AllocType, *Value);
          if (ActiveSizeBits > ConstantArrayType::getMaxSizeBits(Context))
            return ExprError(
                Diag((*ArraySize)->getBeginLoc(), diag::err_array_too_large)
                << toString(*Value, 10) << (*ArraySize)->getSourceRange());
        }

        KnownArraySize = Value->getZExtValue();
      } else if (TypeIdParens.isValid()) {
        // Can't have dynamic array size when the type-id is in parentheses.
        Diag((*ArraySize)->getBeginLoc(), diag::ext_new_paren_array_nonconst)
            << (*ArraySize)->getSourceRange()
            << FixItHint::CreateRemoval(TypeIdParens.getBegin())
            << FixItHint::CreateRemoval(TypeIdParens.getEnd());

        TypeIdParens = SourceRange();
      }
    }

    // Note that we do *not* convert the argument in any way.  It can
    // be signed, larger than size_t, whatever.
  }

  FunctionDecl *OperatorNew = nullptr;
  FunctionDecl *OperatorDelete = nullptr;
  unsigned Alignment =
      AllocType->isDependentType() ? 0 : Context.getTypeAlign(AllocType);
  unsigned NewAlignment = Context.getTargetInfo().getNewAlign();
  bool PassAlignment = getLangOpts().AlignedAllocation &&
                       Alignment > NewAlignment;

  AllocationFunctionScope Scope = UseGlobal ? AFS_Global : AFS_Both;
  if (!AllocType->isDependentType() &&
      !Expr::hasAnyTypeDependentArguments(PlacementArgs) &&
      FindAllocationFunctions(
          StartLoc, SourceRange(PlacementLParen, PlacementRParen), Scope, Scope,
          AllocType, ArraySize.hasValue(), PassAlignment, PlacementArgs,
          OperatorNew, OperatorDelete))
    return ExprError();

  // If this is an array allocation, compute whether the usual array
  // deallocation function for the type has a size_t parameter.
  bool UsualArrayDeleteWantsSize = false;
  if (ArraySize && !AllocType->isDependentType())
    UsualArrayDeleteWantsSize =
        doesUsualArrayDeleteWantSize(*this, StartLoc, AllocType);

  SmallVector<Expr *, 8> AllPlaceArgs;
  if (OperatorNew) {
    auto *Proto = OperatorNew->getType()->castAs<FunctionProtoType>();
    VariadicCallType CallType = Proto->isVariadic() ? VariadicFunction
                                                    : VariadicDoesNotApply;

    // We've already converted the placement args, just fill in any default
    // arguments. Skip the first parameter because we don't have a corresponding
    // argument. Skip the second parameter too if we're passing in the
    // alignment; we've already filled it in.
    unsigned NumImplicitArgs = PassAlignment ? 2 : 1;
    if (GatherArgumentsForCall(PlacementLParen, OperatorNew, Proto,
                               NumImplicitArgs, PlacementArgs, AllPlaceArgs,
                               CallType))
      return ExprError();

    if (!AllPlaceArgs.empty())
      PlacementArgs = AllPlaceArgs;

    // We would like to perform some checking on the given `operator new` call,
    // but the PlacementArgs does not contain the implicit arguments,
    // namely allocation size and maybe allocation alignment,
    // so we need to conjure them.

    QualType SizeTy = Context.getSizeType();
    unsigned SizeTyWidth = Context.getTypeSize(SizeTy);

    llvm::APInt SingleEltSize(
        SizeTyWidth, Context.getTypeSizeInChars(AllocType).getQuantity());

    // How many bytes do we want to allocate here?
    llvm::Optional<llvm::APInt> AllocationSize;
    if (!ArraySize.hasValue() && !AllocType->isDependentType()) {
      // For non-array operator new, we only want to allocate one element.
      AllocationSize = SingleEltSize;
    } else if (KnownArraySize.hasValue() && !AllocType->isDependentType()) {
      // For array operator new, only deal with static array size case.
      bool Overflow;
      AllocationSize = llvm::APInt(SizeTyWidth, *KnownArraySize)
                           .umul_ov(SingleEltSize, Overflow);
      (void)Overflow;
      assert(
          !Overflow &&
          "Expected that all the overflows would have been handled already.");
    }

    IntegerLiteral AllocationSizeLiteral(
        Context,
        AllocationSize.getValueOr(llvm::APInt::getNullValue(SizeTyWidth)),
        SizeTy, SourceLocation());
    // Otherwise, if we failed to constant-fold the allocation size, we'll
    // just give up and pass-in something opaque, that isn't a null pointer.
    OpaqueValueExpr OpaqueAllocationSize(SourceLocation(), SizeTy, VK_PRValue,
                                         OK_Ordinary, /*SourceExpr=*/nullptr);

    // Let's synthesize the alignment argument in case we will need it.
    // Since we *really* want to allocate these on stack, this is slightly ugly
    // because there might not be a `std::align_val_t` type.
    EnumDecl *StdAlignValT = getStdAlignValT();
    QualType AlignValT =
        StdAlignValT ? Context.getTypeDeclType(StdAlignValT) : SizeTy;
    IntegerLiteral AlignmentLiteral(
        Context,
        llvm::APInt(Context.getTypeSize(SizeTy),
                    Alignment / Context.getCharWidth()),
        SizeTy, SourceLocation());
    ImplicitCastExpr DesiredAlignment(ImplicitCastExpr::OnStack, AlignValT,
                                      CK_IntegralCast, &AlignmentLiteral,
                                      VK_PRValue, FPOptionsOverride());

    // Adjust placement args by prepending conjured size and alignment exprs.
    llvm::SmallVector<Expr *, 8> CallArgs;
    CallArgs.reserve(NumImplicitArgs + PlacementArgs.size());
    CallArgs.emplace_back(AllocationSize.hasValue()
                              ? static_cast<Expr *>(&AllocationSizeLiteral)
                              : &OpaqueAllocationSize);
    if (PassAlignment)
      CallArgs.emplace_back(&DesiredAlignment);
    CallArgs.insert(CallArgs.end(), PlacementArgs.begin(), PlacementArgs.end());

    DiagnoseSentinelCalls(OperatorNew, PlacementLParen, CallArgs);

    checkCall(OperatorNew, Proto, /*ThisArg=*/nullptr, CallArgs,
              /*IsMemberFunction=*/false, StartLoc, Range, CallType);

    // Warn if the type is over-aligned and is being allocated by (unaligned)
    // global operator new.
    if (PlacementArgs.empty() && !PassAlignment &&
        (OperatorNew->isImplicit() ||
         (OperatorNew->getBeginLoc().isValid() &&
          getSourceManager().isInSystemHeader(OperatorNew->getBeginLoc())))) {
      if (Alignment > NewAlignment)
        Diag(StartLoc, diag::warn_overaligned_type)
            << AllocType
            << unsigned(Alignment / Context.getCharWidth())
            << unsigned(NewAlignment / Context.getCharWidth());
    }
  }

  // Array 'new' can't have any initializers except empty parentheses.
  // Initializer lists are also allowed, in C++11. Rely on the parser for the
  // dialect distinction.
  if (ArraySize && !isLegalArrayNewInitializer(initStyle, Initializer)) {
    SourceRange InitRange(Inits[0]->getBeginLoc(),
                          Inits[NumInits - 1]->getEndLoc());
    Diag(StartLoc, diag::err_new_array_init_args) << InitRange;
    return ExprError();
  }

  // If we can perform the initialization, and we've not already done so,
  // do it now.
  if (!AllocType->isDependentType() &&
      !Expr::hasAnyTypeDependentArguments(
          llvm::makeArrayRef(Inits, NumInits))) {
    // The type we initialize is the complete type, including the array bound.
    QualType InitType;
    if (KnownArraySize)
      InitType = Context.getConstantArrayType(
          AllocType,
          llvm::APInt(Context.getTypeSize(Context.getSizeType()),
                      *KnownArraySize),
          *ArraySize, ArrayType::Normal, 0);
    else if (ArraySize)
      InitType =
          Context.getIncompleteArrayType(AllocType, ArrayType::Normal, 0);
    else
      InitType = AllocType;

    InitializedEntity Entity
      = InitializedEntity::InitializeNew(StartLoc, InitType);
    InitializationSequence InitSeq(*this, Entity, Kind,
                                   MultiExprArg(Inits, NumInits));
    ExprResult FullInit = InitSeq.Perform(*this, Entity, Kind,
                                          MultiExprArg(Inits, NumInits));
    if (FullInit.isInvalid())
      return ExprError();

    // FullInit is our initializer; strip off CXXBindTemporaryExprs, because
    // we don't want the initialized object to be destructed.
    // FIXME: We should not create these in the first place.
    if (CXXBindTemporaryExpr *Binder =
            dyn_cast_or_null<CXXBindTemporaryExpr>(FullInit.get()))
      FullInit = Binder->getSubExpr();

    Initializer = FullInit.get();

    // FIXME: If we have a KnownArraySize, check that the array bound of the
    // initializer is no greater than that constant value.

    if (ArraySize && !*ArraySize) {
      auto *CAT = Context.getAsConstantArrayType(Initializer->getType());
      if (CAT) {
        // FIXME: Track that the array size was inferred rather than explicitly
        // specified.
        ArraySize = IntegerLiteral::Create(
            Context, CAT->getSize(), Context.getSizeType(), TypeRange.getEnd());
      } else {
        Diag(TypeRange.getEnd(), diag::err_new_array_size_unknown_from_init)
            << Initializer->getSourceRange();
      }
    }
  }

  // Mark the new and delete operators as referenced.
  if (OperatorNew) {
    if (DiagnoseUseOfDecl(OperatorNew, StartLoc))
      return ExprError();
    MarkFunctionReferenced(StartLoc, OperatorNew);
  }
  if (OperatorDelete) {
    if (DiagnoseUseOfDecl(OperatorDelete, StartLoc))
      return ExprError();
    MarkFunctionReferenced(StartLoc, OperatorDelete);
  }

  return CXXNewExpr::Create(Context, UseGlobal, OperatorNew, OperatorDelete,
                            PassAlignment, UsualArrayDeleteWantsSize,
                            PlacementArgs, TypeIdParens, ArraySize, initStyle,
                            Initializer, ResultType, AllocTypeInfo, Range,
                            DirectInitRange);
}

/// Checks that a type is suitable as the allocated type
/// in a new-expression.
bool Sema::CheckAllocatedType(QualType AllocType, SourceLocation Loc,
                              SourceRange R) {
  // C++ 5.3.4p1: "[The] type shall be a complete object type, but not an
  //   abstract class type or array thereof.
  if (AllocType->isFunctionType())
    return Diag(Loc, diag::err_bad_new_type)
      << AllocType << 0 << R;
  else if (AllocType->isReferenceType())
    return Diag(Loc, diag::err_bad_new_type)
      << AllocType << 1 << R;
  else if (!AllocType->isDependentType() &&
           RequireCompleteSizedType(
               Loc, AllocType, diag::err_new_incomplete_or_sizeless_type, R))
    return true;
  else if (RequireNonAbstractType(Loc, AllocType,
                                  diag::err_allocation_of_abstract_type))
    return true;
  else if (AllocType->isVariablyModifiedType())
    return Diag(Loc, diag::err_variably_modified_new_type)
             << AllocType;
  else if (AllocType.getAddressSpace() != LangAS::Default &&
           !getLangOpts().OpenCLCPlusPlus)
    return Diag(Loc, diag::err_address_space_qualified_new)
      << AllocType.getUnqualifiedType()
      << AllocType.getQualifiers().getAddressSpaceAttributePrintValue();
  else if (getLangOpts().ObjCAutoRefCount) {
    if (const ArrayType *AT = Context.getAsArrayType(AllocType)) {
      QualType BaseAllocType = Context.getBaseElementType(AT);
      if (BaseAllocType.getObjCLifetime() == Qualifiers::OCL_None &&
          BaseAllocType->isObjCLifetimeType())
        return Diag(Loc, diag::err_arc_new_array_without_ownership)
          << BaseAllocType;
    }
  }

  return false;
}

static bool resolveAllocationOverload(
    Sema &S, LookupResult &R, SourceRange Range, SmallVectorImpl<Expr *> &Args,
    bool &PassAlignment, FunctionDecl *&Operator,
    OverloadCandidateSet *AlignedCandidates, Expr *AlignArg, bool Diagnose) {
  OverloadCandidateSet Candidates(R.getNameLoc(),
                                  OverloadCandidateSet::CSK_Normal);
  for (LookupResult::iterator Alloc = R.begin(), AllocEnd = R.end();
       Alloc != AllocEnd; ++Alloc) {
    // Even member operator new/delete are implicitly treated as
    // static, so don't use AddMemberCandidate.
    NamedDecl *D = (*Alloc)->getUnderlyingDecl();

    if (FunctionTemplateDecl *FnTemplate = dyn_cast<FunctionTemplateDecl>(D)) {
      S.AddTemplateOverloadCandidate(FnTemplate, Alloc.getPair(),
                                     /*ExplicitTemplateArgs=*/nullptr, Args,
                                     Candidates,
                                     /*SuppressUserConversions=*/false);
      continue;
    }

    FunctionDecl *Fn = cast<FunctionDecl>(D);
    S.AddOverloadCandidate(Fn, Alloc.getPair(), Args, Candidates,
                           /*SuppressUserConversions=*/false);
  }

  // Do the resolution.
  OverloadCandidateSet::iterator Best;
  switch (Candidates.BestViableFunction(S, R.getNameLoc(), Best)) {
  case OR_Success: {
    // Got one!
    FunctionDecl *FnDecl = Best->Function;
    if (S.CheckAllocationAccess(R.getNameLoc(), Range, R.getNamingClass(),
                                Best->FoundDecl) == Sema::AR_inaccessible)
      return true;

    Operator = FnDecl;
    return false;
  }

  case OR_No_Viable_Function:
    // C++17 [expr.new]p13:
    //   If no matching function is found and the allocated object type has
    //   new-extended alignment, the alignment argument is removed from the
    //   argument list, and overload resolution is performed again.
    if (PassAlignment) {
      PassAlignment = false;
      AlignArg = Args[1];
      Args.erase(Args.begin() + 1);
      return resolveAllocationOverload(S, R, Range, Args, PassAlignment,
                                       Operator, &Candidates, AlignArg,
                                       Diagnose);
    }

    // MSVC will fall back on trying to find a matching global operator new
    // if operator new[] cannot be found.  Also, MSVC will leak by not
    // generating a call to operator delete or operator delete[], but we
    // will not replicate that bug.
    // FIXME: Find out how this interacts with the std::align_val_t fallback
    // once MSVC implements it.
    if (R.getLookupName().getCXXOverloadedOperator() == OO_Array_New &&
        S.Context.getLangOpts().MSVCCompat) {
      R.clear();
      R.setLookupName(S.Context.DeclarationNames.getCXXOperatorName(OO_New));
      S.LookupQualifiedName(R, S.Context.getTranslationUnitDecl());
      // FIXME: This will give bad diagnostics pointing at the wrong functions.
      return resolveAllocationOverload(S, R, Range, Args, PassAlignment,
                                       Operator, /*Candidates=*/nullptr,
                                       /*AlignArg=*/nullptr, Diagnose);
    }

    if (Diagnose) {
      // If this is an allocation of the form 'new (p) X' for some object
      // pointer p (or an expression that will decay to such a pointer),
      // diagnose the missing inclusion of <new>.
      if (!R.isClassLookup() && Args.size() == 2 &&
          (Args[1]->getType()->isObjectPointerType() ||
           Args[1]->getType()->isArrayType())) {
        S.Diag(R.getNameLoc(), diag::err_need_header_before_placement_new)
            << R.getLookupName() << Range;
        // Listing the candidates is unlikely to be useful; skip it.
        return true;
      }

      // Finish checking all candidates before we note any. This checking can
      // produce additional diagnostics so can't be interleaved with our
      // emission of notes.
      //
      // For an aligned allocation, separately check the aligned and unaligned
      // candidates with their respective argument lists.
      SmallVector<OverloadCandidate*, 32> Cands;
      SmallVector<OverloadCandidate*, 32> AlignedCands;
      llvm::SmallVector<Expr*, 4> AlignedArgs;
      if (AlignedCandidates) {
        auto IsAligned = [](OverloadCandidate &C) {
          return C.Function->getNumParams() > 1 &&
                 C.Function->getParamDecl(1)->getType()->isAlignValT();
        };
        auto IsUnaligned = [&](OverloadCandidate &C) { return !IsAligned(C); };

        AlignedArgs.reserve(Args.size() + 1);
        AlignedArgs.push_back(Args[0]);
        AlignedArgs.push_back(AlignArg);
        AlignedArgs.append(Args.begin() + 1, Args.end());
        AlignedCands = AlignedCandidates->CompleteCandidates(
            S, OCD_AllCandidates, AlignedArgs, R.getNameLoc(), IsAligned);

        Cands = Candidates.CompleteCandidates(S, OCD_AllCandidates, Args,
                                              R.getNameLoc(), IsUnaligned);
      } else {
        Cands = Candidates.CompleteCandidates(S, OCD_AllCandidates, Args,
                                              R.getNameLoc());
      }

      S.Diag(R.getNameLoc(), diag::err_ovl_no_viable_function_in_call)
          << R.getLookupName() << Range;
      if (AlignedCandidates)
        AlignedCandidates->NoteCandidates(S, AlignedArgs, AlignedCands, "",
                                          R.getNameLoc());
      Candidates.NoteCandidates(S, Args, Cands, "", R.getNameLoc());
    }
    return true;

  case OR_Ambiguous:
    if (Diagnose) {
      Candidates.NoteCandidates(
          PartialDiagnosticAt(R.getNameLoc(),
                              S.PDiag(diag::err_ovl_ambiguous_call)
                                  << R.getLookupName() << Range),
          S, OCD_AmbiguousCandidates, Args);
    }
    return true;

  case OR_Deleted: {
    if (Diagnose) {
      Candidates.NoteCandidates(
          PartialDiagnosticAt(R.getNameLoc(),
                              S.PDiag(diag::err_ovl_deleted_call)
                                  << R.getLookupName() << Range),
          S, OCD_AllCandidates, Args);
    }
    return true;
  }
  }
  llvm_unreachable("Unreachable, bad result from BestViableFunction");
}

bool Sema::FindAllocationFunctions(SourceLocation StartLoc, SourceRange Range,
                                   AllocationFunctionScope NewScope,
                                   AllocationFunctionScope DeleteScope,
                                   QualType AllocType, bool IsArray,
                                   bool &PassAlignment, MultiExprArg PlaceArgs,
                                   FunctionDecl *&OperatorNew,
                                   FunctionDecl *&OperatorDelete,
                                   bool Diagnose) {
  // --- Choosing an allocation function ---
  // C++ 5.3.4p8 - 14 & 18
  // 1) If looking in AFS_Global scope for allocation functions, only look in
  //    the global scope. Else, if AFS_Class, only look in the scope of the
  //    allocated class. If AFS_Both, look in both.
  // 2) If an array size is given, look for operator new[], else look for
  //   operator new.
  // 3) The first argument is always size_t. Append the arguments from the
  //   placement form.

  SmallVector<Expr*, 8> AllocArgs;
  AllocArgs.reserve((PassAlignment ? 2 : 1) + PlaceArgs.size());

  // We don't care about the actual value of these arguments.
  // FIXME: Should the Sema create the expression and embed it in the syntax
  // tree? Or should the consumer just recalculate the value?
  // FIXME: Using a dummy value will interact poorly with attribute enable_if.
  IntegerLiteral Size(Context, llvm::APInt::getNullValue(
                      Context.getTargetInfo().getPointerWidth(0)),
                      Context.getSizeType(),
                      SourceLocation());
  AllocArgs.push_back(&Size);

  QualType AlignValT = Context.VoidTy;
  if (PassAlignment) {
    DeclareGlobalNewDelete();
    AlignValT = Context.getTypeDeclType(getStdAlignValT());
  }
  CXXScalarValueInitExpr Align(AlignValT, nullptr, SourceLocation());
  if (PassAlignment)
    AllocArgs.push_back(&Align);

  AllocArgs.insert(AllocArgs.end(), PlaceArgs.begin(), PlaceArgs.end());

  // C++ [expr.new]p8:
  //   If the allocated type is a non-array type, the allocation
  //   function's name is operator new and the deallocation function's
  //   name is operator delete. If the allocated type is an array
  //   type, the allocation function's name is operator new[] and the
  //   deallocation function's name is operator delete[].
  DeclarationName NewName = Context.DeclarationNames.getCXXOperatorName(
      IsArray ? OO_Array_New : OO_New);

  QualType AllocElemType = Context.getBaseElementType(AllocType);

  // Find the allocation function.
  {
    LookupResult R(*this, NewName, StartLoc, LookupOrdinaryName);

    // C++1z [expr.new]p9:
    //   If the new-expression begins with a unary :: operator, the allocation
    //   function's name is looked up in the global scope. Otherwise, if the
    //   allocated type is a class type T or array thereof, the allocation
    //   function's name is looked up in the scope of T.
    if (AllocElemType->isRecordType() && NewScope != AFS_Global)
      LookupQualifiedName(R, AllocElemType->getAsCXXRecordDecl());

    // We can see ambiguity here if the allocation function is found in
    // multiple base classes.
    if (R.isAmbiguous())
      return true;

    //   If this lookup fails to find the name, or if the allocated type is not
    //   a class type, the allocation function's name is looked up in the
    //   global scope.
    if (R.empty()) {
      if (NewScope == AFS_Class)
        return true;

      LookupQualifiedName(R, Context.getTranslationUnitDecl());
    }

    if (getLangOpts().OpenCLCPlusPlus && R.empty()) {
      if (PlaceArgs.empty()) {
        Diag(StartLoc, diag::err_openclcxx_not_supported) << "default new";
      } else {
        Diag(StartLoc, diag::err_openclcxx_placement_new);
      }
      return true;
    }

    assert(!R.empty() && "implicitly declared allocation functions not found");
    assert(!R.isAmbiguous() && "global allocation functions are ambiguous");

    // We do our own custom access checks below.
    R.suppressDiagnostics();

    if (resolveAllocationOverload(*this, R, Range, AllocArgs, PassAlignment,
                                  OperatorNew, /*Candidates=*/nullptr,
                                  /*AlignArg=*/nullptr, Diagnose))
      return true;
  }

  // We don't need an operator delete if we're running under -fno-exceptions.
  if (!getLangOpts().Exceptions) {
    OperatorDelete = nullptr;
    return false;
  }

  // Note, the name of OperatorNew might have been changed from array to
  // non-array by resolveAllocationOverload.
  DeclarationName DeleteName = Context.DeclarationNames.getCXXOperatorName(
      OperatorNew->getDeclName().getCXXOverloadedOperator() == OO_Array_New
          ? OO_Array_Delete
          : OO_Delete);

  // C++ [expr.new]p19:
  //
  //   If the new-expression begins with a unary :: operator, the
  //   deallocation function's name is looked up in the global
  //   scope. Otherwise, if the allocated type is a class type T or an
  //   array thereof, the deallocation function's name is looked up in
  //   the scope of T. If this lookup fails to find the name, or if
  //   the allocated type is not a class type or array thereof, the
  //   deallocation function's name is looked up in the global scope.
  LookupResult FoundDelete(*this, DeleteName, StartLoc, LookupOrdinaryName);
  if (AllocElemType->isRecordType() && DeleteScope != AFS_Global) {
    auto *RD =
        cast<CXXRecordDecl>(AllocElemType->castAs<RecordType>()->getDecl());
    LookupQualifiedName(FoundDelete, RD);
  }
  if (FoundDelete.isAmbiguous())
    return true; // FIXME: clean up expressions?

  // Filter out any destroying operator deletes. We can't possibly call such a
  // function in this context, because we're handling the case where the object
  // was not successfully constructed.
  // FIXME: This is not covered by the language rules yet.
  {
    LookupResult::Filter Filter = FoundDelete.makeFilter();
    while (Filter.hasNext()) {
      auto *FD = dyn_cast<FunctionDecl>(Filter.next()->getUnderlyingDecl());
      if (FD && FD->isDestroyingOperatorDelete())
        Filter.erase();
    }
    Filter.done();
  }

  bool FoundGlobalDelete = FoundDelete.empty();
  if (FoundDelete.empty()) {
    FoundDelete.clear(LookupOrdinaryName);

    if (DeleteScope == AFS_Class)
      return true;

    DeclareGlobalNewDelete();
    LookupQualifiedName(FoundDelete, Context.getTranslationUnitDecl());
  }

  FoundDelete.suppressDiagnostics();

  SmallVector<std::pair<DeclAccessPair,FunctionDecl*>, 2> Matches;

  // Whether we're looking for a placement operator delete is dictated
  // by whether we selected a placement operator new, not by whether
  // we had explicit placement arguments.  This matters for things like
  //   struct A { void *operator new(size_t, int = 0); ... };
  //   A *a = new A()
  //
  // We don't have any definition for what a "placement allocation function"
  // is, but we assume it's any allocation function whose
  // parameter-declaration-clause is anything other than (size_t).
  //
  // FIXME: Should (size_t, std::align_val_t) also be considered non-placement?
  // This affects whether an exception from the constructor of an overaligned
  // type uses the sized or non-sized form of aligned operator delete.
  bool isPlacementNew = !PlaceArgs.empty() || OperatorNew->param_size() != 1 ||
                        OperatorNew->isVariadic();

  if (isPlacementNew) {
    // C++ [expr.new]p20:
    //   A declaration of a placement deallocation function matches the
    //   declaration of a placement allocation function if it has the
    //   same number of parameters and, after parameter transformations
    //   (8.3.5), all parameter types except the first are
    //   identical. [...]
    //
    // To perform this comparison, we compute the function type that
    // the deallocation function should have, and use that type both
    // for template argument deduction and for comparison purposes.
    QualType ExpectedFunctionType;
    {
      auto *Proto = OperatorNew->getType()->castAs<FunctionProtoType>();

      SmallVector<QualType, 4> ArgTypes;
      ArgTypes.push_back(Context.VoidPtrTy);
      for (unsigned I = 1, N = Proto->getNumParams(); I < N; ++I)
        ArgTypes.push_back(Proto->getParamType(I));

      FunctionProtoType::ExtProtoInfo EPI;
      // FIXME: This is not part of the standard's rule.
      EPI.Variadic = Proto->isVariadic();

      ExpectedFunctionType
        = Context.getFunctionType(Context.VoidTy, ArgTypes, EPI);
    }

    for (LookupResult::iterator D = FoundDelete.begin(),
                             DEnd = FoundDelete.end();
         D != DEnd; ++D) {
      FunctionDecl *Fn = nullptr;
      if (FunctionTemplateDecl *FnTmpl =
              dyn_cast<FunctionTemplateDecl>((*D)->getUnderlyingDecl())) {
        // Perform template argument deduction to try to match the
        // expected function type.
        TemplateDeductionInfo Info(StartLoc);
        if (DeduceTemplateArguments(FnTmpl, nullptr, ExpectedFunctionType, Fn,
                                    Info))
          continue;
      } else
        Fn = cast<FunctionDecl>((*D)->getUnderlyingDecl());

      if (Context.hasSameType(adjustCCAndNoReturn(Fn->getType(),
                                                  ExpectedFunctionType,
                                                  /*AdjustExcpetionSpec*/true),
                              ExpectedFunctionType))
        Matches.push_back(std::make_pair(D.getPair(), Fn));
    }

    if (getLangOpts().CUDA)
      EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(CurContext), Matches);
  } else {
    // C++1y [expr.new]p22:
    //   For a non-placement allocation function, the normal deallocation
    //   function lookup is used
    //
    // Per [expr.delete]p10, this lookup prefers a member operator delete
    // without a size_t argument, but prefers a non-member operator delete
    // with a size_t where possible (which it always is in this case).
    llvm::SmallVector<UsualDeallocFnInfo, 4> BestDeallocFns;
    UsualDeallocFnInfo Selected = resolveDeallocationOverload(
        *this, FoundDelete, /*WantSize*/ FoundGlobalDelete,
        /*WantAlign*/ hasNewExtendedAlignment(*this, AllocElemType),
        &BestDeallocFns);
    if (Selected)
      Matches.push_back(std::make_pair(Selected.Found, Selected.FD));
    else {
      // If we failed to select an operator, all remaining functions are viable
      // but ambiguous.
      for (auto Fn : BestDeallocFns)
        Matches.push_back(std::make_pair(Fn.Found, Fn.FD));
    }
  }

  // C++ [expr.new]p20:
  //   [...] If the lookup finds a single matching deallocation
  //   function, that function will be called; otherwise, no
  //   deallocation function will be called.
  if (Matches.size() == 1) {
    OperatorDelete = Matches[0].second;

    // C++1z [expr.new]p23:
    //   If the lookup finds a usual deallocation function (3.7.4.2)
    //   with a parameter of type std::size_t and that function, considered
    //   as a placement deallocation function, would have been
    //   selected as a match for the allocation function, the program
    //   is ill-formed.
    if (getLangOpts().CPlusPlus11 && isPlacementNew &&
        isNonPlacementDeallocationFunction(*this, OperatorDelete)) {
      UsualDeallocFnInfo Info(*this,
                              DeclAccessPair::make(OperatorDelete, AS_public));
      // Core issue, per mail to core reflector, 2016-10-09:
      //   If this is a member operator delete, and there is a corresponding
      //   non-sized member operator delete, this isn't /really/ a sized
      //   deallocation function, it just happens to have a size_t parameter.
      bool IsSizedDelete = Info.HasSizeT;
      if (IsSizedDelete && !FoundGlobalDelete) {
        auto NonSizedDelete =
            resolveDeallocationOverload(*this, FoundDelete, /*WantSize*/false,
                                        /*WantAlign*/Info.HasAlignValT);
        if (NonSizedDelete && !NonSizedDelete.HasSizeT &&
            NonSizedDelete.HasAlignValT == Info.HasAlignValT)
          IsSizedDelete = false;
      }

      if (IsSizedDelete) {
        SourceRange R = PlaceArgs.empty()
                            ? SourceRange()
                            : SourceRange(PlaceArgs.front()->getBeginLoc(),
                                          PlaceArgs.back()->getEndLoc());
        Diag(StartLoc, diag::err_placement_new_non_placement_delete) << R;
        if (!OperatorDelete->isImplicit())
          Diag(OperatorDelete->getLocation(), diag::note_previous_decl)
              << DeleteName;
      }
    }

    CheckAllocationAccess(StartLoc, Range, FoundDelete.getNamingClass(),
                          Matches[0].first);
  } else if (!Matches.empty()) {
    // We found multiple suitable operators. Per [expr.new]p20, that means we
    // call no 'operator delete' function, but we should at least warn the user.
    // FIXME: Suppress this warning if the construction cannot throw.
    Diag(StartLoc, diag::warn_ambiguous_suitable_delete_function_found)
      << DeleteName << AllocElemType;

    for (auto &Match : Matches)
      Diag(Match.second->getLocation(),
           diag::note_member_declared_here) << DeleteName;
  }

  return false;
}

/// DeclareGlobalNewDelete - Declare the global forms of operator new and
/// delete. These are:
/// @code
///   // C++03:
///   void* operator new(std::size_t) throw(std::bad_alloc);
///   void* operator new[](std::size_t) throw(std::bad_alloc);
///   void operator delete(void *) throw();
///   void operator delete[](void *) throw();
///   // C++11:
///   void* operator new(std::size_t);
///   void* operator new[](std::size_t);
///   void operator delete(void *) noexcept;
///   void operator delete[](void *) noexcept;
///   // C++1y:
///   void* operator new(std::size_t);
///   void* operator new[](std::size_t);
///   void operator delete(void *) noexcept;
///   void operator delete[](void *) noexcept;
///   void operator delete(void *, std::size_t) noexcept;
///   void operator delete[](void *, std::size_t) noexcept;
/// @endcode
/// Note that the placement and nothrow forms of new are *not* implicitly
/// declared. Their use requires including \<new\>.
void Sema::DeclareGlobalNewDelete() {
  if (GlobalNewDeleteDeclared)
    return;

  // The implicitly declared new and delete operators
  // are not supported in OpenCL.
  if (getLangOpts().OpenCLCPlusPlus)
    return;

  // C++ [basic.std.dynamic]p2:
  //   [...] The following allocation and deallocation functions (18.4) are
  //   implicitly declared in global scope in each translation unit of a
  //   program
  //
  //     C++03:
  //     void* operator new(std::size_t) throw(std::bad_alloc);
  //     void* operator new[](std::size_t) throw(std::bad_alloc);
  //     void  operator delete(void*) throw();
  //     void  operator delete[](void*) throw();
  //     C++11:
  //     void* operator new(std::size_t);
  //     void* operator new[](std::size_t);
  //     void  operator delete(void*) noexcept;
  //     void  operator delete[](void*) noexcept;
  //     C++1y:
  //     void* operator new(std::size_t);
  //     void* operator new[](std::size_t);
  //     void  operator delete(void*) noexcept;
  //     void  operator delete[](void*) noexcept;
  //     void  operator delete(void*, std::size_t) noexcept;
  //     void  operator delete[](void*, std::size_t) noexcept;
  //
  //   These implicit declarations introduce only the function names operator
  //   new, operator new[], operator delete, operator delete[].
  //
  // Here, we need to refer to std::bad_alloc, so we will implicitly declare
  // "std" or "bad_alloc" as necessary to form the exception specification.
  // However, we do not make these implicit declarations visible to name
  // lookup.
  if (!StdBadAlloc && !getLangOpts().CPlusPlus11) {
    // The "std::bad_alloc" class has not yet been declared, so build it
    // implicitly.
    StdBadAlloc = CXXRecordDecl::Create(Context, TTK_Class,
                                        getOrCreateStdNamespace(),
                                        SourceLocation(), SourceLocation(),
                                      &PP.getIdentifierTable().get("bad_alloc"),
                                        nullptr);
    getStdBadAlloc()->setImplicit(true);
  }
  if (!StdAlignValT && getLangOpts().AlignedAllocation) {
    // The "std::align_val_t" enum class has not yet been declared, so build it
    // implicitly.
    auto *AlignValT = EnumDecl::Create(
        Context, getOrCreateStdNamespace(), SourceLocation(), SourceLocation(),
        &PP.getIdentifierTable().get("align_val_t"), nullptr, true, true, true);
    AlignValT->setIntegerType(Context.getSizeType());
    AlignValT->setPromotionType(Context.getSizeType());
    AlignValT->setImplicit(true);
    StdAlignValT = AlignValT;
  }

  GlobalNewDeleteDeclared = true;

  QualType VoidPtr = Context.getPointerType(Context.VoidTy);
  QualType SizeT = Context.getSizeType();

  auto DeclareGlobalAllocationFunctions = [&](OverloadedOperatorKind Kind,
                                              QualType Return, QualType Param) {
    llvm::SmallVector<QualType, 3> Params;
    Params.push_back(Param);

    // Create up to four variants of the function (sized/aligned).
    bool HasSizedVariant = getLangOpts().SizedDeallocation &&
                           (Kind == OO_Delete || Kind == OO_Array_Delete);
    bool HasAlignedVariant = getLangOpts().AlignedAllocation;

    int NumSizeVariants = (HasSizedVariant ? 2 : 1);
    int NumAlignVariants = (HasAlignedVariant ? 2 : 1);
    for (int Sized = 0; Sized < NumSizeVariants; ++Sized) {
      if (Sized)
        Params.push_back(SizeT);

      for (int Aligned = 0; Aligned < NumAlignVariants; ++Aligned) {
        if (Aligned)
          Params.push_back(Context.getTypeDeclType(getStdAlignValT()));

        DeclareGlobalAllocationFunction(
            Context.DeclarationNames.getCXXOperatorName(Kind), Return, Params);

        if (Aligned)
          Params.pop_back();
      }
    }
  };

  DeclareGlobalAllocationFunctions(OO_New, VoidPtr, SizeT);
  DeclareGlobalAllocationFunctions(OO_Array_New, VoidPtr, SizeT);
  DeclareGlobalAllocationFunctions(OO_Delete, Context.VoidTy, VoidPtr);
  DeclareGlobalAllocationFunctions(OO_Array_Delete, Context.VoidTy, VoidPtr);
}

/// DeclareGlobalAllocationFunction - Declares a single implicit global
/// allocation function if it doesn't already exist.
void Sema::DeclareGlobalAllocationFunction(DeclarationName Name,
                                           QualType Return,
                                           ArrayRef<QualType> Params) {
  DeclContext *GlobalCtx = Context.getTranslationUnitDecl();

  // Check if this function is already declared.
  DeclContext::lookup_result R = GlobalCtx->lookup(Name);
  for (DeclContext::lookup_iterator Alloc = R.begin(), AllocEnd = R.end();
       Alloc != AllocEnd; ++Alloc) {
    // Only look at non-template functions, as it is the predefined,
    // non-templated allocation function we are trying to declare here.
    if (FunctionDecl *Func = dyn_cast<FunctionDecl>(*Alloc)) {
      if (Func->getNumParams() == Params.size()) {
        llvm::SmallVector<QualType, 3> FuncParams;
        for (auto *P : Func->parameters())
          FuncParams.push_back(
              Context.getCanonicalType(P->getType().getUnqualifiedType()));
        if (llvm::makeArrayRef(FuncParams) == Params) {
          // Make the function visible to name lookup, even if we found it in
          // an unimported module. It either is an implicitly-declared global
          // allocation function, or is suppressing that function.
          Func->setVisibleDespiteOwningModule();
          return;
        }
      }
    }
  }

  FunctionProtoType::ExtProtoInfo EPI(Context.getDefaultCallingConvention(
      /*IsVariadic=*/false, /*IsCXXMethod=*/false, /*IsBuiltin=*/true));

  QualType BadAllocType;
  bool HasBadAllocExceptionSpec
    = (Name.getCXXOverloadedOperator() == OO_New ||
       Name.getCXXOverloadedOperator() == OO_Array_New);
  if (HasBadAllocExceptionSpec) {
    if (!getLangOpts().CPlusPlus11) {
      BadAllocType = Context.getTypeDeclType(getStdBadAlloc());
      assert(StdBadAlloc && "Must have std::bad_alloc declared");
      EPI.ExceptionSpec.Type = EST_Dynamic;
      EPI.ExceptionSpec.Exceptions = llvm::makeArrayRef(BadAllocType);
    }
  } else {
    EPI.ExceptionSpec =
        getLangOpts().CPlusPlus11 ? EST_BasicNoexcept : EST_DynamicNone;
  }

  auto CreateAllocationFunctionDecl = [&](Attr *ExtraAttr) {
    QualType FnType = Context.getFunctionType(Return, Params, EPI);
    FunctionDecl *Alloc = FunctionDecl::Create(
        Context, GlobalCtx, SourceLocation(), SourceLocation(), Name,
        FnType, /*TInfo=*/nullptr, SC_None, false, true);
    Alloc->setImplicit();
    // Global allocation functions should always be visible.
    Alloc->setVisibleDespiteOwningModule();

    Alloc->addAttr(VisibilityAttr::CreateImplicit(
        Context, LangOpts.GlobalAllocationFunctionVisibilityHidden
                     ? VisibilityAttr::Hidden
                     : VisibilityAttr::Default));

    llvm::SmallVector<ParmVarDecl *, 3> ParamDecls;
    for (QualType T : Params) {
      ParamDecls.push_back(ParmVarDecl::Create(
          Context, Alloc, SourceLocation(), SourceLocation(), nullptr, T,
          /*TInfo=*/nullptr, SC_None, nullptr));
      ParamDecls.back()->setImplicit();
    }
    Alloc->setParams(ParamDecls);
    if (ExtraAttr)
      Alloc->addAttr(ExtraAttr);
    AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction(Alloc);
    Context.getTranslationUnitDecl()->addDecl(Alloc);
    IdResolver.tryAddTopLevelDecl(Alloc, Name);
  };

  if (!LangOpts.CUDA)
    CreateAllocationFunctionDecl(nullptr);
  else {
    // Host and device get their own declaration so each can be
    // defined or re-declared independently.
    CreateAllocationFunctionDecl(CUDAHostAttr::CreateImplicit(Context));
    CreateAllocationFunctionDecl(CUDADeviceAttr::CreateImplicit(Context));
  }
}

FunctionDecl *Sema::FindUsualDeallocationFunction(SourceLocation StartLoc,
                                                  bool CanProvideSize,
                                                  bool Overaligned,
                                                  DeclarationName Name) {
  DeclareGlobalNewDelete();

  LookupResult FoundDelete(*this, Name, StartLoc, LookupOrdinaryName);
  LookupQualifiedName(FoundDelete, Context.getTranslationUnitDecl());

  // FIXME: It's possible for this to result in ambiguity, through a
  // user-declared variadic operator delete or the enable_if attribute. We
  // should probably not consider those cases to be usual deallocation
  // functions. But for now we just make an arbitrary choice in that case.
  auto Result = resolveDeallocationOverload(*this, FoundDelete, CanProvideSize,
                                            Overaligned);
  assert(Result.FD && "operator delete missing from global scope?");
  return Result.FD;
}

FunctionDecl *Sema::FindDeallocationFunctionForDestructor(SourceLocation Loc,
                                                          CXXRecordDecl *RD) {
  DeclarationName Name = Context.DeclarationNames.getCXXOperatorName(OO_Delete);

  FunctionDecl *OperatorDelete = nullptr;
  if (FindDeallocationFunction(Loc, RD, Name, OperatorDelete))
    return nullptr;
  if (OperatorDelete)
    return OperatorDelete;

  // If there's no class-specific operator delete, look up the global
  // non-array delete.
  return FindUsualDeallocationFunction(
      Loc, true, hasNewExtendedAlignment(*this, Context.getRecordType(RD)),
      Name);
}

bool Sema::FindDeallocationFunction(SourceLocation StartLoc, CXXRecordDecl *RD,
                                    DeclarationName Name,
                                    FunctionDecl *&Operator, bool Diagnose) {
  LookupResult Found(*this, Name, StartLoc, LookupOrdinaryName);
  // Try to find operator delete/operator delete[] in class scope.
  LookupQualifiedName(Found, RD);

  if (Found.isAmbiguous())
    return true;

  Found.suppressDiagnostics();

  bool Overaligned = hasNewExtendedAlignment(*this, Context.getRecordType(RD));

  // C++17 [expr.delete]p10:
  //   If the deallocation functions have class scope, the one without a
  //   parameter of type std::size_t is selected.
  llvm::SmallVector<UsualDeallocFnInfo, 4> Matches;
  resolveDeallocationOverload(*this, Found, /*WantSize*/ false,
                              /*WantAlign*/ Overaligned, &Matches);

  // If we could find an overload, use it.
  if (Matches.size() == 1) {
    Operator = cast<CXXMethodDecl>(Matches[0].FD);

    // FIXME: DiagnoseUseOfDecl?
    if (Operator->isDeleted()) {
      if (Diagnose) {
        Diag(StartLoc, diag::err_deleted_function_use);
        NoteDeletedFunction(Operator);
      }
      return true;
    }

    if (CheckAllocationAccess(StartLoc, SourceRange(), Found.getNamingClass(),
                              Matches[0].Found, Diagnose) == AR_inaccessible)
      return true;

    return false;
  }

  // We found multiple suitable operators; complain about the ambiguity.
  // FIXME: The standard doesn't say to do this; it appears that the intent
  // is that this should never happen.
  if (!Matches.empty()) {
    if (Diagnose) {
      Diag(StartLoc, diag::err_ambiguous_suitable_delete_member_function_found)
        << Name << RD;
      for (auto &Match : Matches)
        Diag(Match.FD->getLocation(), diag::note_member_declared_here) << Name;
    }
    return true;
  }

  // We did find operator delete/operator delete[] declarations, but
  // none of them were suitable.
  if (!Found.empty()) {
    if (Diagnose) {
      Diag(StartLoc, diag::err_no_suitable_delete_member_function_found)
        << Name << RD;

      for (NamedDecl *D : Found)
        Diag(D->getUnderlyingDecl()->getLocation(),
             diag::note_member_declared_here) << Name;
    }
    return true;
  }

  Operator = nullptr;
  return false;
}

namespace {
/// Checks whether delete-expression, and new-expression used for
///  initializing deletee have the same array form.
class MismatchingNewDeleteDetector {
public:
  enum MismatchResult {
    /// Indicates that there is no mismatch or a mismatch cannot be proven.
    NoMismatch,
    /// Indicates that variable is initialized with mismatching form of \a new.
    VarInitMismatches,
    /// Indicates that member is initialized with mismatching form of \a new.
    MemberInitMismatches,
    /// Indicates that 1 or more constructors' definitions could not been
    /// analyzed, and they will be checked again at the end of translation unit.
    AnalyzeLater
  };

  /// \param EndOfTU True, if this is the final analysis at the end of
  /// translation unit. False, if this is the initial analysis at the point
  /// delete-expression was encountered.
  explicit MismatchingNewDeleteDetector(bool EndOfTU)
      : Field(nullptr), IsArrayForm(false), EndOfTU(EndOfTU),
        HasUndefinedConstructors(false) {}

  /// Checks whether pointee of a delete-expression is initialized with
  /// matching form of new-expression.
  ///
  /// If return value is \c VarInitMismatches or \c MemberInitMismatches at the
  /// point where delete-expression is encountered, then a warning will be
  /// issued immediately. If return value is \c AnalyzeLater at the point where
  /// delete-expression is seen, then member will be analyzed at the end of
  /// translation unit. \c AnalyzeLater is returned iff at least one constructor
  /// couldn't be analyzed. If at least one constructor initializes the member
  /// with matching type of new, the return value is \c NoMismatch.
  MismatchResult analyzeDeleteExpr(const CXXDeleteExpr *DE);
  /// Analyzes a class member.
  /// \param Field Class member to analyze.
  /// \param DeleteWasArrayForm Array form-ness of the delete-expression used
  /// for deleting the \p Field.
  MismatchResult analyzeField(FieldDecl *Field, bool DeleteWasArrayForm);
  FieldDecl *Field;
  /// List of mismatching new-expressions used for initialization of the pointee
  llvm::SmallVector<const CXXNewExpr *, 4> NewExprs;
  /// Indicates whether delete-expression was in array form.
  bool IsArrayForm;

private:
  const bool EndOfTU;
  /// Indicates that there is at least one constructor without body.
  bool HasUndefinedConstructors;
  /// Returns \c CXXNewExpr from given initialization expression.
  /// \param E Expression used for initializing pointee in delete-expression.
  /// E can be a single-element \c InitListExpr consisting of new-expression.
  const CXXNewExpr *getNewExprFromInitListOrExpr(const Expr *E);
  /// Returns whether member is initialized with mismatching form of
  /// \c new either by the member initializer or in-class initialization.
  ///
  /// If bodies of all constructors are not visible at the end of translation
  /// unit or at least one constructor initializes member with the matching
  /// form of \c new, mismatch cannot be proven, and this function will return
  /// \c NoMismatch.
  MismatchResult analyzeMemberExpr(const MemberExpr *ME);
  /// Returns whether variable is initialized with mismatching form of
  /// \c new.
  ///
  /// If variable is initialized with matching form of \c new or variable is not
  /// initialized with a \c new expression, this function will return true.
  /// If variable is initialized with mismatching form of \c new, returns false.
  /// \param D Variable to analyze.
  bool hasMatchingVarInit(const DeclRefExpr *D);
  /// Checks whether the constructor initializes pointee with mismatching
  /// form of \c new.
  ///
  /// Returns true, if member is initialized with matching form of \c new in
  /// member initializer list. Returns false, if member is initialized with the
  /// matching form of \c new in this constructor's initializer or given
  /// constructor isn't defined at the point where delete-expression is seen, or
  /// member isn't initialized by the constructor.
  bool hasMatchingNewInCtor(const CXXConstructorDecl *CD);
  /// Checks whether member is initialized with matching form of
  /// \c new in member initializer list.
  bool hasMatchingNewInCtorInit(const CXXCtorInitializer *CI);
  /// Checks whether member is initialized with mismatching form of \c new by
  /// in-class initializer.
  MismatchResult analyzeInClassInitializer();
};
}

MismatchingNewDeleteDetector::MismatchResult
MismatchingNewDeleteDetector::analyzeDeleteExpr(const CXXDeleteExpr *DE) {
  NewExprs.clear();
  assert(DE && "Expected delete-expression");
  IsArrayForm = DE->isArrayForm();
  const Expr *E = DE->getArgument()->IgnoreParenImpCasts();
  if (const MemberExpr *ME = dyn_cast<const MemberExpr>(E)) {
    return analyzeMemberExpr(ME);
  } else if (const DeclRefExpr *D = dyn_cast<const DeclRefExpr>(E)) {
    if (!hasMatchingVarInit(D))
      return VarInitMismatches;
  }
  return NoMismatch;
}

const CXXNewExpr *
MismatchingNewDeleteDetector::getNewExprFromInitListOrExpr(const Expr *E) {
  assert(E != nullptr && "Expected a valid initializer expression");
  E = E->IgnoreParenImpCasts();
  if (const InitListExpr *ILE = dyn_cast<const InitListExpr>(E)) {
    if (ILE->getNumInits() == 1)
      E = dyn_cast<const CXXNewExpr>(ILE->getInit(0)->IgnoreParenImpCasts());
  }

  return dyn_cast_or_null<const CXXNewExpr>(E);
}

bool MismatchingNewDeleteDetector::hasMatchingNewInCtorInit(
    const CXXCtorInitializer *CI) {
  const CXXNewExpr *NE = nullptr;
  if (Field == CI->getMember() &&
      (NE = getNewExprFromInitListOrExpr(CI->getInit()))) {
    if (NE->isArray() == IsArrayForm)
      return true;
    else
      NewExprs.push_back(NE);
  }
  return false;
}

bool MismatchingNewDeleteDetector::hasMatchingNewInCtor(
    const CXXConstructorDecl *CD) {
  if (CD->isImplicit())
    return false;
  const FunctionDecl *Definition = CD;
  if (!CD->isThisDeclarationADefinition() && !CD->isDefined(Definition)) {
    HasUndefinedConstructors = true;
    return EndOfTU;
  }
  for (const auto *CI : cast<const CXXConstructorDecl>(Definition)->inits()) {
    if (hasMatchingNewInCtorInit(CI))
      return true;
  }
  return false;
}

MismatchingNewDeleteDetector::MismatchResult
MismatchingNewDeleteDetector::analyzeInClassInitializer() {
  assert(Field != nullptr && "This should be called only for members");
  const Expr *InitExpr = Field->getInClassInitializer();
  if (!InitExpr)
    return EndOfTU ? NoMismatch : AnalyzeLater;
  if (const CXXNewExpr *NE = getNewExprFromInitListOrExpr(InitExpr)) {
    if (NE->isArray() != IsArrayForm) {
      NewExprs.push_back(NE);
      return MemberInitMismatches;
    }
  }
  return NoMismatch;
}

MismatchingNewDeleteDetector::MismatchResult
MismatchingNewDeleteDetector::analyzeField(FieldDecl *Field,
                                           bool DeleteWasArrayForm) {
  assert(Field != nullptr && "Analysis requires a valid class member.");
  this->Field = Field;
  IsArrayForm = DeleteWasArrayForm;
  const CXXRecordDecl *RD = cast<const CXXRecordDecl>(Field->getParent());
  for (const auto *CD : RD->ctors()) {
    if (hasMatchingNewInCtor(CD))
      return NoMismatch;
  }
  if (HasUndefinedConstructors)
    return EndOfTU ? NoMismatch : AnalyzeLater;
  if (!NewExprs.empty())
    return MemberInitMismatches;
  return Field->hasInClassInitializer() ? analyzeInClassInitializer()
                                        : NoMismatch;
}

MismatchingNewDeleteDetector::MismatchResult
MismatchingNewDeleteDetector::analyzeMemberExpr(const MemberExpr *ME) {
  assert(ME != nullptr && "Expected a member expression");
  if (FieldDecl *F = dyn_cast<FieldDecl>(ME->getMemberDecl()))
    return analyzeField(F, IsArrayForm);
  return NoMismatch;
}

bool MismatchingNewDeleteDetector::hasMatchingVarInit(const DeclRefExpr *D) {
  const CXXNewExpr *NE = nullptr;
  if (const VarDecl *VD = dyn_cast<const VarDecl>(D->getDecl())) {
    if (VD->hasInit() && (NE = getNewExprFromInitListOrExpr(VD->getInit())) &&
        NE->isArray() != IsArrayForm) {
      NewExprs.push_back(NE);
    }
  }
  return NewExprs.empty();
}

static void
DiagnoseMismatchedNewDelete(Sema &SemaRef, SourceLocation DeleteLoc,
                            const MismatchingNewDeleteDetector &Detector) {
  SourceLocation EndOfDelete = SemaRef.getLocForEndOfToken(DeleteLoc);
  FixItHint H;
  if (!Detector.IsArrayForm)
    H = FixItHint::CreateInsertion(EndOfDelete, "[]");
  else {
    SourceLocation RSquare = Lexer::findLocationAfterToken(
        DeleteLoc, tok::l_square, SemaRef.getSourceManager(),
        SemaRef.getLangOpts(), true);
    if (RSquare.isValid())
      H = FixItHint::CreateRemoval(SourceRange(EndOfDelete, RSquare));
  }
  SemaRef.Diag(DeleteLoc, diag::warn_mismatched_delete_new)
      << Detector.IsArrayForm << H;

  for (const auto *NE : Detector.NewExprs)
    SemaRef.Diag(NE->getExprLoc(), diag::note_allocated_here)
        << Detector.IsArrayForm;
}

void Sema::AnalyzeDeleteExprMismatch(const CXXDeleteExpr *DE) {
  if (Diags.isIgnored(diag::warn_mismatched_delete_new, SourceLocation()))
    return;
  MismatchingNewDeleteDetector Detector(/*EndOfTU=*/false);
  switch (Detector.analyzeDeleteExpr(DE)) {
  case MismatchingNewDeleteDetector::VarInitMismatches:
  case MismatchingNewDeleteDetector::MemberInitMismatches: {
    DiagnoseMismatchedNewDelete(*this, DE->getBeginLoc(), Detector);
    break;
  }
  case MismatchingNewDeleteDetector::AnalyzeLater: {
    DeleteExprs[Detector.Field].push_back(
        std::make_pair(DE->getBeginLoc(), DE->isArrayForm()));
    break;
  }
  case MismatchingNewDeleteDetector::NoMismatch:
    break;
  }
}

void Sema::AnalyzeDeleteExprMismatch(FieldDecl *Field, SourceLocation DeleteLoc,
                                     bool DeleteWasArrayForm) {
  MismatchingNewDeleteDetector Detector(/*EndOfTU=*/true);
  switch (Detector.analyzeField(Field, DeleteWasArrayForm)) {
  case MismatchingNewDeleteDetector::VarInitMismatches:
    llvm_unreachable("This analysis should have been done for class members.");
  case MismatchingNewDeleteDetector::AnalyzeLater:
    llvm_unreachable("Analysis cannot be postponed any point beyond end of "
                     "translation unit.");
  case MismatchingNewDeleteDetector::MemberInitMismatches:
    DiagnoseMismatchedNewDelete(*this, DeleteLoc, Detector);
    break;
  case MismatchingNewDeleteDetector::NoMismatch:
    break;
  }
}

/// ActOnCXXDelete - Parsed a C++ 'delete' expression (C++ 5.3.5), as in:
/// @code ::delete ptr; @endcode
/// or
/// @code delete [] ptr; @endcode
ExprResult
Sema::ActOnCXXDelete(SourceLocation StartLoc, bool UseGlobal,
                     bool ArrayForm, Expr *ExE) {
  // C++ [expr.delete]p1:
  //   The operand shall have a pointer type, or a class type having a single
  //   non-explicit conversion function to a pointer type. The result has type
  //   void.
  //
  // DR599 amends "pointer type" to "pointer to object type" in both cases.

  ExprResult Ex = ExE;
  FunctionDecl *OperatorDelete = nullptr;
  bool ArrayFormAsWritten = ArrayForm;
  bool UsualArrayDeleteWantsSize = false;

  if (!Ex.get()->isTypeDependent()) {
    // Perform lvalue-to-rvalue cast, if needed.
    Ex = DefaultLvalueConversion(Ex.get());
    if (Ex.isInvalid())
      return ExprError();

    QualType Type = Ex.get()->getType();

    class DeleteConverter : public ContextualImplicitConverter {
    public:
      DeleteConverter() : ContextualImplicitConverter(false, true) {}

      bool match(QualType ConvType) override {
        // FIXME: If we have an operator T* and an operator void*, we must pick
        // the operator T*.
        if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
          if (ConvPtrType->getPointeeType()->isIncompleteOrObjectType())
            return true;
        return false;
      }

      SemaDiagnosticBuilder diagnoseNoMatch(Sema &S, SourceLocation Loc,
                                            QualType T) override {
        return S.Diag(Loc, diag::err_delete_operand) << T;
      }

      SemaDiagnosticBuilder diagnoseIncomplete(Sema &S, SourceLocation Loc,
                                               QualType T) override {
        return S.Diag(Loc, diag::err_delete_incomplete_class_type) << T;
      }

      SemaDiagnosticBuilder diagnoseExplicitConv(Sema &S, SourceLocation Loc,
                                                 QualType T,
                                                 QualType ConvTy) override {
        return S.Diag(Loc, diag::err_delete_explicit_conversion) << T << ConvTy;
      }

      SemaDiagnosticBuilder noteExplicitConv(Sema &S, CXXConversionDecl *Conv,
                                             QualType ConvTy) override {
        return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
          << ConvTy;
      }

      SemaDiagnosticBuilder diagnoseAmbiguous(Sema &S, SourceLocation Loc,
                                              QualType T) override {
        return S.Diag(Loc, diag::err_ambiguous_delete_operand) << T;
      }

      SemaDiagnosticBuilder noteAmbiguous(Sema &S, CXXConversionDecl *Conv,
                                          QualType ConvTy) override {
        return S.Diag(Conv->getLocation(), diag::note_delete_conversion)
          << ConvTy;
      }

      SemaDiagnosticBuilder diagnoseConversion(Sema &S, SourceLocation Loc,
                                               QualType T,
                                               QualType ConvTy) override {
        llvm_unreachable("conversion functions are permitted");
      }
    } Converter;

    Ex = PerformContextualImplicitConversion(StartLoc, Ex.get(), Converter);
    if (Ex.isInvalid())
      return ExprError();
    Type = Ex.get()->getType();
    if (!Converter.match(Type))
      // FIXME: PerformContextualImplicitConversion should return ExprError
      //        itself in this case.
      return ExprError();

    QualType Pointee = Type->castAs<PointerType>()->getPointeeType();
    QualType PointeeElem = Context.getBaseElementType(Pointee);

    if (Pointee.getAddressSpace() != LangAS::Default &&
        !getLangOpts().OpenCLCPlusPlus)
      return Diag(Ex.get()->getBeginLoc(),
                  diag::err_address_space_qualified_delete)
             << Pointee.getUnqualifiedType()
             << Pointee.getQualifiers().getAddressSpaceAttributePrintValue();

    CXXRecordDecl *PointeeRD = nullptr;
    if (Pointee->isVoidType() && !isSFINAEContext()) {
      // The C++ standard bans deleting a pointer to a non-object type, which
      // effectively bans deletion of "void*". However, most compilers support
      // this, so we treat it as a warning unless we're in a SFINAE context.
      Diag(StartLoc, diag::ext_delete_void_ptr_operand)
        << Type << Ex.get()->getSourceRange();
    } else if (Pointee->isFunctionType() || Pointee->isVoidType() ||
               Pointee->isSizelessType()) {
      return ExprError(Diag(StartLoc, diag::err_delete_operand)
        << Type << Ex.get()->getSourceRange());
    } else if (!Pointee->isDependentType()) {
      // FIXME: This can result in errors if the definition was imported from a
      // module but is hidden.
      if (!RequireCompleteType(StartLoc, Pointee,
                               diag::warn_delete_incomplete, Ex.get())) {
        if (const RecordType *RT = PointeeElem->getAs<RecordType>())
          PointeeRD = cast<CXXRecordDecl>(RT->getDecl());
      }
    }

    if (Pointee->isArrayType() && !ArrayForm) {
      Diag(StartLoc, diag::warn_delete_array_type)
          << Type << Ex.get()->getSourceRange()
          << FixItHint::CreateInsertion(getLocForEndOfToken(StartLoc), "[]");
      ArrayForm = true;
    }

    DeclarationName DeleteName = Context.DeclarationNames.getCXXOperatorName(
                                      ArrayForm ? OO_Array_Delete : OO_Delete);

    if (PointeeRD) {
      if (!UseGlobal &&
          FindDeallocationFunction(StartLoc, PointeeRD, DeleteName,
                                   OperatorDelete))
        return ExprError();

      // If we're allocating an array of records, check whether the
      // usual operator delete[] has a size_t parameter.
      if (ArrayForm) {
        // If the user specifically asked to use the global allocator,
        // we'll need to do the lookup into the class.
        if (UseGlobal)
          UsualArrayDeleteWantsSize =
            doesUsualArrayDeleteWantSize(*this, StartLoc, PointeeElem);

        // Otherwise, the usual operator delete[] should be the
        // function we just found.
        else if (OperatorDelete && isa<CXXMethodDecl>(OperatorDelete))
          UsualArrayDeleteWantsSize =
            UsualDeallocFnInfo(*this,
                               DeclAccessPair::make(OperatorDelete, AS_public))
              .HasSizeT;
      }

      if (!PointeeRD->hasIrrelevantDestructor())
        if (CXXDestructorDecl *Dtor = LookupDestructor(PointeeRD)) {
          MarkFunctionReferenced(StartLoc,
                                    const_cast<CXXDestructorDecl*>(Dtor));
          if (DiagnoseUseOfDecl(Dtor, StartLoc))
            return ExprError();
        }

      CheckVirtualDtorCall(PointeeRD->getDestructor(), StartLoc,
                           /*IsDelete=*/true, /*CallCanBeVirtual=*/true,
                           /*WarnOnNonAbstractTypes=*/!ArrayForm,
                           SourceLocation());
    }

    if (!OperatorDelete) {
      if (getLangOpts().OpenCLCPlusPlus) {
        Diag(StartLoc, diag::err_openclcxx_not_supported) << "default delete";
        return ExprError();
      }

      bool IsComplete = isCompleteType(StartLoc, Pointee);
      bool CanProvideSize =
          IsComplete && (!ArrayForm || UsualArrayDeleteWantsSize ||
                         Pointee.isDestructedType());
      bool Overaligned = hasNewExtendedAlignment(*this, Pointee);

      // Look for a global declaration.
      OperatorDelete = FindUsualDeallocationFunction(StartLoc, CanProvideSize,
                                                     Overaligned, DeleteName);
    }

    MarkFunctionReferenced(StartLoc, OperatorDelete);

    // Check access and ambiguity of destructor if we're going to call it.
    // Note that this is required even for a virtual delete.
    bool IsVirtualDelete = false;
    if (PointeeRD) {
      if (CXXDestructorDecl *Dtor = LookupDestructor(PointeeRD)) {
        CheckDestructorAccess(Ex.get()->getExprLoc(), Dtor,
                              PDiag(diag::err_access_dtor) << PointeeElem);
        IsVirtualDelete = Dtor->isVirtual();
      }
    }

    DiagnoseUseOfDecl(OperatorDelete, StartLoc);

    // Convert the operand to the type of the first parameter of operator
    // delete. This is only necessary if we selected a destroying operator
    // delete that we are going to call (non-virtually); converting to void*
    // is trivial and left to AST consumers to handle.
    QualType ParamType = OperatorDelete->getParamDecl(0)->getType();
    if (!IsVirtualDelete && !ParamType->getPointeeType()->isVoidType()) {
      Qualifiers Qs = Pointee.getQualifiers();
      if (Qs.hasCVRQualifiers()) {
        // Qualifiers are irrelevant to this conversion; we're only looking
        // for access and ambiguity.
        Qs.removeCVRQualifiers();
        QualType Unqual = Context.getPointerType(
            Context.getQualifiedType(Pointee.getUnqualifiedType(), Qs));
        Ex = ImpCastExprToType(Ex.get(), Unqual, CK_NoOp);
      }
      Ex = PerformImplicitConversion(Ex.get(), ParamType, AA_Passing);
      if (Ex.isInvalid())
        return ExprError();
    }
  }

  CXXDeleteExpr *Result = new (Context) CXXDeleteExpr(
      Context.VoidTy, UseGlobal, ArrayForm, ArrayFormAsWritten,
      UsualArrayDeleteWantsSize, OperatorDelete, Ex.get(), StartLoc);
  AnalyzeDeleteExprMismatch(Result);
  return Result;
}

static bool resolveBuiltinNewDeleteOverload(Sema &S, CallExpr *TheCall,
                                            bool IsDelete,
                                            FunctionDecl *&Operator) {

  DeclarationName NewName = S.Context.DeclarationNames.getCXXOperatorName(
      IsDelete ? OO_Delete : OO_New);

  LookupResult R(S, NewName, TheCall->getBeginLoc(), Sema::LookupOrdinaryName);
  S.LookupQualifiedName(R, S.Context.getTranslationUnitDecl());
  assert(!R.empty() && "implicitly declared allocation functions not found");
  assert(!R.isAmbiguous() && "global allocation functions are ambiguous");

  // We do our own custom access checks below.
  R.suppressDiagnostics();

  SmallVector<Expr *, 8> Args(TheCall->arg_begin(), TheCall->arg_end());
  OverloadCandidateSet Candidates(R.getNameLoc(),
                                  OverloadCandidateSet::CSK_Normal);
  for (LookupResult::iterator FnOvl = R.begin(), FnOvlEnd = R.end();
       FnOvl != FnOvlEnd; ++FnOvl) {
    // Even member operator new/delete are implicitly treated as
    // static, so don't use AddMemberCandidate.
    NamedDecl *D = (*FnOvl)->getUnderlyingDecl();

    if (FunctionTemplateDecl *FnTemplate = dyn_cast<FunctionTemplateDecl>(D)) {
      S.AddTemplateOverloadCandidate(FnTemplate, FnOvl.getPair(),
                                     /*ExplicitTemplateArgs=*/nullptr, Args,
                                     Candidates,
                                     /*SuppressUserConversions=*/false);
      continue;
    }

    FunctionDecl *Fn = cast<FunctionDecl>(D);
    S.AddOverloadCandidate(Fn, FnOvl.getPair(), Args, Candidates,
                           /*SuppressUserConversions=*/false);
  }

  SourceRange Range = TheCall->getSourceRange();

  // Do the resolution.
  OverloadCandidateSet::iterator Best;
  switch (Candidates.BestViableFunction(S, R.getNameLoc(), Best)) {
  case OR_Success: {
    // Got one!
    FunctionDecl *FnDecl = Best->Function;
    assert(R.getNamingClass() == nullptr &&
           "class members should not be considered");

    if (!FnDecl->isReplaceableGlobalAllocationFunction()) {
      S.Diag(R.getNameLoc(), diag::err_builtin_operator_new_delete_not_usual)
          << (IsDelete ? 1 : 0) << Range;
      S.Diag(FnDecl->getLocation(), diag::note_non_usual_function_declared_here)
          << R.getLookupName() << FnDecl->getSourceRange();
      return true;
    }

    Operator = FnDecl;
    return false;
  }

  case OR_No_Viable_Function:
    Candidates.NoteCandidates(
        PartialDiagnosticAt(R.getNameLoc(),
                            S.PDiag(diag::err_ovl_no_viable_function_in_call)
                                << R.getLookupName() << Range),
        S, OCD_AllCandidates, Args);
    return true;

  case OR_Ambiguous:
    Candidates.NoteCandidates(
        PartialDiagnosticAt(R.getNameLoc(),
                            S.PDiag(diag::err_ovl_ambiguous_call)
                                << R.getLookupName() << Range),
        S, OCD_AmbiguousCandidates, Args);
    return true;

  case OR_Deleted: {
    Candidates.NoteCandidates(
        PartialDiagnosticAt(R.getNameLoc(), S.PDiag(diag::err_ovl_deleted_call)
                                                << R.getLookupName() << Range),
        S, OCD_AllCandidates, Args);
    return true;
  }
  }
  llvm_unreachable("Unreachable, bad result from BestViableFunction");
}

ExprResult
Sema::SemaBuiltinOperatorNewDeleteOverloaded(ExprResult TheCallResult,
                                             bool IsDelete) {
  CallExpr *TheCall = cast<CallExpr>(TheCallResult.get());
  if (!getLangOpts().CPlusPlus) {
    Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language)
        << (IsDelete ? "__builtin_operator_delete" : "__builtin_operator_new")
        << "C++";
    return ExprError();
  }
  // CodeGen assumes it can find the global new and delete to call,
  // so ensure that they are declared.
  DeclareGlobalNewDelete();

  FunctionDecl *OperatorNewOrDelete = nullptr;
  if (resolveBuiltinNewDeleteOverload(*this, TheCall, IsDelete,
                                      OperatorNewOrDelete))
    return ExprError();
  assert(OperatorNewOrDelete && "should be found");

  DiagnoseUseOfDecl(OperatorNewOrDelete, TheCall->getExprLoc());
  MarkFunctionReferenced(TheCall->getExprLoc(), OperatorNewOrDelete);

  TheCall->setType(OperatorNewOrDelete->getReturnType());
  for (unsigned i = 0; i != TheCall->getNumArgs(); ++i) {
    QualType ParamTy = OperatorNewOrDelete->getParamDecl(i)->getType();
    InitializedEntity Entity =
        InitializedEntity::InitializeParameter(Context, ParamTy, false);
    ExprResult Arg = PerformCopyInitialization(
        Entity, TheCall->getArg(i)->getBeginLoc(), TheCall->getArg(i));
    if (Arg.isInvalid())
      return ExprError();
    TheCall->setArg(i, Arg.get());
  }
  auto Callee = dyn_cast<ImplicitCastExpr>(TheCall->getCallee());
  assert(Callee && Callee->getCastKind() == CK_BuiltinFnToFnPtr &&
         "Callee expected to be implicit cast to a builtin function pointer");
  Callee->setType(OperatorNewOrDelete->getType());

  return TheCallResult;
}

void Sema::CheckVirtualDtorCall(CXXDestructorDecl *dtor, SourceLocation Loc,
                                bool IsDelete, bool CallCanBeVirtual,
                                bool WarnOnNonAbstractTypes,
                                SourceLocation DtorLoc) {
  if (!dtor || dtor->isVirtual() || !CallCanBeVirtual || isUnevaluatedContext())
    return;

  // C++ [expr.delete]p3:
  //   In the first alternative (delete object), if the static type of the
  //   object to be deleted is different from its dynamic type, the static
  //   type shall be a base class of the dynamic type of the object to be
  //   deleted and the static type shall have a virtual destructor or the
  //   behavior is undefined.
  //
  const CXXRecordDecl *PointeeRD = dtor->getParent();
  // Note: a final class cannot be derived from, no issue there
  if (!PointeeRD->isPolymorphic() || PointeeRD->hasAttr<FinalAttr>())
    return;

  // If the superclass is in a system header, there's nothing that can be done.
  // The `delete` (where we emit the warning) can be in a system header,
  // what matters for this warning is where the deleted type is defined.
  if (getSourceManager().isInSystemHeader(PointeeRD->getLocation()))
    return;

  QualType ClassType = dtor->getThisType()->getPointeeType();
  if (PointeeRD->isAbstract()) {
    // If the class is abstract, we warn by default, because we're
    // sure the code has undefined behavior.
    Diag(Loc, diag::warn_delete_abstract_non_virtual_dtor) << (IsDelete ? 0 : 1)
                                                           << ClassType;
  } else if (WarnOnNonAbstractTypes) {
    // Otherwise, if this is not an array delete, it's a bit suspect,
    // but not necessarily wrong.
    Diag(Loc, diag::warn_delete_non_virtual_dtor) << (IsDelete ? 0 : 1)
                                                  << ClassType;
  }
  if (!IsDelete) {
    std::string TypeStr;
    ClassType.getAsStringInternal(TypeStr, getPrintingPolicy());
    Diag(DtorLoc, diag::note_delete_non_virtual)
        << FixItHint::CreateInsertion(DtorLoc, TypeStr + "::");
  }
}

Sema::ConditionResult Sema::ActOnConditionVariable(Decl *ConditionVar,
                                                   SourceLocation StmtLoc,
                                                   ConditionKind CK) {
  ExprResult E =
      CheckConditionVariable(cast<VarDecl>(ConditionVar), StmtLoc, CK);
  if (E.isInvalid())
    return ConditionError();
  return ConditionResult(*this, ConditionVar, MakeFullExpr(E.get(), StmtLoc),
                         CK == ConditionKind::ConstexprIf);
}

/// Check the use of the given variable as a C++ condition in an if,
/// while, do-while, or switch statement.
ExprResult Sema::CheckConditionVariable(VarDecl *ConditionVar,
                                        SourceLocation StmtLoc,
                                        ConditionKind CK) {
  if (ConditionVar->isInvalidDecl())
    return ExprError();

  QualType T = ConditionVar->getType();

  // C++ [stmt.select]p2:
  //   The declarator shall not specify a function or an array.
  if (T->isFunctionType())
    return ExprError(Diag(ConditionVar->getLocation(),
                          diag::err_invalid_use_of_function_type)
                       << ConditionVar->getSourceRange());
  else if (T->isArrayType())
    return ExprError(Diag(ConditionVar->getLocation(),
                          diag::err_invalid_use_of_array_type)
                     << ConditionVar->getSourceRange());

  ExprResult Condition = BuildDeclRefExpr(
      ConditionVar, ConditionVar->getType().getNonReferenceType(), VK_LValue,
      ConditionVar->getLocation());

  switch (CK) {
  case ConditionKind::Boolean:
    return CheckBooleanCondition(StmtLoc, Condition.get());

  case ConditionKind::ConstexprIf:
    return CheckBooleanCondition(StmtLoc, Condition.get(), true);

  case ConditionKind::Switch:
    return CheckSwitchCondition(StmtLoc, Condition.get());
  }

  llvm_unreachable("unexpected condition kind");
}

/// CheckCXXBooleanCondition - Returns true if a conversion to bool is invalid.
ExprResult Sema::CheckCXXBooleanCondition(Expr *CondExpr, bool IsConstexpr) {
  // C++11 6.4p4:
  // The value of a condition that is an initialized declaration in a statement
  // other than a switch statement is the value of the declared variable
  // implicitly converted to type bool. If that conversion is ill-formed, the
  // program is ill-formed.
  // The value of a condition that is an expression is the value of the
  // expression, implicitly converted to bool.
  //
  // C++2b 8.5.2p2
  // If the if statement is of the form if constexpr, the value of the condition
  // is contextually converted to bool and the converted expression shall be
  // a constant expression.
  //

  ExprResult E = PerformContextuallyConvertToBool(CondExpr);
  if (!IsConstexpr || E.isInvalid() || E.get()->isValueDependent())
    return E;

  // FIXME: Return this value to the caller so they don't need to recompute it.
  llvm::APSInt Cond;
  E = VerifyIntegerConstantExpression(
      E.get(), &Cond,
      diag::err_constexpr_if_condition_expression_is_not_constant);
  return E;
}

/// Helper function to determine whether this is the (deprecated) C++
/// conversion from a string literal to a pointer to non-const char or
/// non-const wchar_t (for narrow and wide string literals,
/// respectively).
bool
Sema::IsStringLiteralToNonConstPointerConversion(Expr *From, QualType ToType) {
  // Look inside the implicit cast, if it exists.
  if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(From))
    From = Cast->getSubExpr();

  // A string literal (2.13.4) that is not a wide string literal can
  // be converted to an rvalue of type "pointer to char"; a wide
  // string literal can be converted to an rvalue of type "pointer
  // to wchar_t" (C++ 4.2p2).
  if (StringLiteral *StrLit = dyn_cast<StringLiteral>(From->IgnoreParens()))
    if (const PointerType *ToPtrType = ToType->getAs<PointerType>())
      if (const BuiltinType *ToPointeeType
          = ToPtrType->getPointeeType()->getAs<BuiltinType>()) {
        // This conversion is considered only when there is an
        // explicit appropriate pointer target type (C++ 4.2p2).
        if (!ToPtrType->getPointeeType().hasQualifiers()) {
          switch (StrLit->getKind()) {
            case StringLiteral::UTF8:
            case StringLiteral::UTF16:
            case StringLiteral::UTF32:
              // We don't allow UTF literals to be implicitly converted
              break;
            case StringLiteral::Ascii:
              return (ToPointeeType->getKind() == BuiltinType::Char_U ||
                      ToPointeeType->getKind() == BuiltinType::Char_S);
            case StringLiteral::Wide:
              return Context.typesAreCompatible(Context.getWideCharType(),
                                                QualType(ToPointeeType, 0));
          }
        }
      }

  return false;
}

static ExprResult BuildCXXCastArgument(Sema &S,
                                       SourceLocation CastLoc,
                                       QualType Ty,
                                       CastKind Kind,
                                       CXXMethodDecl *Method,
                                       DeclAccessPair FoundDecl,
                                       bool HadMultipleCandidates,
                                       Expr *From) {
  switch (Kind) {
  default: llvm_unreachable("Unhandled cast kind!");
  case CK_ConstructorConversion: {
    CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Method);
    SmallVector<Expr*, 8> ConstructorArgs;

    if (S.RequireNonAbstractType(CastLoc, Ty,
                                 diag::err_allocation_of_abstract_type))
      return ExprError();

    if (S.CompleteConstructorCall(Constructor, Ty, From, CastLoc,
                                  ConstructorArgs))
      return ExprError();

    S.CheckConstructorAccess(CastLoc, Constructor, FoundDecl,
                             InitializedEntity::InitializeTemporary(Ty));
    if (S.DiagnoseUseOfDecl(Method, CastLoc))
      return ExprError();

    ExprResult Result = S.BuildCXXConstructExpr(
        CastLoc, Ty, FoundDecl, cast<CXXConstructorDecl>(Method),
        ConstructorArgs, HadMultipleCandidates,
        /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
        CXXConstructExpr::CK_Complete, SourceRange());
    if (Result.isInvalid())
      return ExprError();

    return S.MaybeBindToTemporary(Result.getAs<Expr>());
  }

  case CK_UserDefinedConversion: {
    assert(!From->getType()->isPointerType() && "Arg can't have pointer type!");

    S.CheckMemberOperatorAccess(CastLoc, From, /*arg*/ nullptr, FoundDecl);
    if (S.DiagnoseUseOfDecl(Method, CastLoc))
      return ExprError();

    // Create an implicit call expr that calls it.
    CXXConversionDecl *Conv = cast<CXXConversionDecl>(Method);
    ExprResult Result = S.BuildCXXMemberCallExpr(From, FoundDecl, Conv,
                                                 HadMultipleCandidates);
    if (Result.isInvalid())
      return ExprError();
    // Record usage of conversion in an implicit cast.
    Result = ImplicitCastExpr::Create(S.Context, Result.get()->getType(),
                                      CK_UserDefinedConversion, Result.get(),
                                      nullptr, Result.get()->getValueKind(),
                                      S.CurFPFeatureOverrides());

    return S.MaybeBindToTemporary(Result.get());
  }
  }
}

/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType using the pre-computed implicit
/// conversion sequence ICS. Returns the converted
/// expression. Action is the kind of conversion we're performing,
/// used in the error message.
ExprResult
Sema::PerformImplicitConversion(Expr *From, QualType ToType,
                                const ImplicitConversionSequence &ICS,
                                AssignmentAction Action,
                                CheckedConversionKind CCK) {
  // C++ [over.match.oper]p7: [...] operands of class type are converted [...]
  if (CCK == CCK_ForBuiltinOverloadedOp && !From->getType()->isRecordType())
    return From;

  switch (ICS.getKind()) {
  case ImplicitConversionSequence::StandardConversion: {
    ExprResult Res = PerformImplicitConversion(From, ToType, ICS.Standard,
                                               Action, CCK);
    if (Res.isInvalid())
      return ExprError();
    From = Res.get();
    break;
  }

  case ImplicitConversionSequence::UserDefinedConversion: {

      FunctionDecl *FD = ICS.UserDefined.ConversionFunction;
      CastKind CastKind;
      QualType BeforeToType;
      assert(FD && "no conversion function for user-defined conversion seq");
      if (const CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(FD)) {
        CastKind = CK_UserDefinedConversion;

        // If the user-defined conversion is specified by a conversion function,
        // the initial standard conversion sequence converts the source type to
        // the implicit object parameter of the conversion function.
        BeforeToType = Context.getTagDeclType(Conv->getParent());
      } else {
        const CXXConstructorDecl *Ctor = cast<CXXConstructorDecl>(FD);
        CastKind = CK_ConstructorConversion;
        // Do no conversion if dealing with ... for the first conversion.
        if (!ICS.UserDefined.EllipsisConversion) {
          // If the user-defined conversion is specified by a constructor, the
          // initial standard conversion sequence converts the source type to
          // the type required by the argument of the constructor
          BeforeToType = Ctor->getParamDecl(0)->getType().getNonReferenceType();
        }
      }
      // Watch out for ellipsis conversion.
      if (!ICS.UserDefined.EllipsisConversion) {
        ExprResult Res =
          PerformImplicitConversion(From, BeforeToType,
                                    ICS.UserDefined.Before, AA_Converting,
                                    CCK);
        if (Res.isInvalid())
          return ExprError();
        From = Res.get();
      }

      ExprResult CastArg = BuildCXXCastArgument(
          *this, From->getBeginLoc(), ToType.getNonReferenceType(), CastKind,
          cast<CXXMethodDecl>(FD), ICS.UserDefined.FoundConversionFunction,
          ICS.UserDefined.HadMultipleCandidates, From);

      if (CastArg.isInvalid())
        return ExprError();

      From = CastArg.get();

      // C++ [over.match.oper]p7:
      //   [...] the second standard conversion sequence of a user-defined
      //   conversion sequence is not applied.
      if (CCK == CCK_ForBuiltinOverloadedOp)
        return From;

      return PerformImplicitConversion(From, ToType, ICS.UserDefined.After,
                                       AA_Converting, CCK);
  }

  case ImplicitConversionSequence::AmbiguousConversion:
    ICS.DiagnoseAmbiguousConversion(*this, From->getExprLoc(),
                          PDiag(diag::err_typecheck_ambiguous_condition)
                            << From->getSourceRange());
    return ExprError();

  case ImplicitConversionSequence::EllipsisConversion:
    llvm_unreachable("Cannot perform an ellipsis conversion");

  case ImplicitConversionSequence::BadConversion:
    Sema::AssignConvertType ConvTy =
        CheckAssignmentConstraints(From->getExprLoc(), ToType, From->getType());
    bool Diagnosed = DiagnoseAssignmentResult(
        ConvTy == Compatible ? Incompatible : ConvTy, From->getExprLoc(),
        ToType, From->getType(), From, Action);
    assert(Diagnosed && "failed to diagnose bad conversion"); (void)Diagnosed;
    return ExprError();
  }

  // Everything went well.
  return From;
}

/// PerformImplicitConversion - Perform an implicit conversion of the
/// expression From to the type ToType by following the standard
/// conversion sequence SCS. Returns the converted
/// expression. Flavor is the context in which we're performing this
/// conversion, for use in error messages.
ExprResult
Sema::PerformImplicitConversion(Expr *From, QualType ToType,
                                const StandardConversionSequence& SCS,
                                AssignmentAction Action,
                                CheckedConversionKind CCK) {
  bool CStyle = (CCK == CCK_CStyleCast || CCK == CCK_FunctionalCast);

  // Overall FIXME: we are recomputing too many types here and doing far too
  // much extra work. What this means is that we need to keep track of more
  // information that is computed when we try the implicit conversion initially,
  // so that we don't need to recompute anything here.
  QualType FromType = From->getType();

  if (SCS.CopyConstructor) {
    // FIXME: When can ToType be a reference type?
    assert(!ToType->isReferenceType());
    if (SCS.Second == ICK_Derived_To_Base) {
      SmallVector<Expr*, 8> ConstructorArgs;
      if (CompleteConstructorCall(
              cast<CXXConstructorDecl>(SCS.CopyConstructor), ToType, From,
              /*FIXME:ConstructLoc*/ SourceLocation(), ConstructorArgs))
        return ExprError();
      return BuildCXXConstructExpr(
          /*FIXME:ConstructLoc*/ SourceLocation(), ToType,
          SCS.FoundCopyConstructor, SCS.CopyConstructor,
          ConstructorArgs, /*HadMultipleCandidates*/ false,
          /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
          CXXConstructExpr::CK_Complete, SourceRange());
    }
    return BuildCXXConstructExpr(
        /*FIXME:ConstructLoc*/ SourceLocation(), ToType,
        SCS.FoundCopyConstructor, SCS.CopyConstructor,
        From, /*HadMultipleCandidates*/ false,
        /*ListInit*/ false, /*StdInitListInit*/ false, /*ZeroInit*/ false,
        CXXConstructExpr::CK_Complete, SourceRange());
  }

  // Resolve overloaded function references.
  if (Context.hasSameType(FromType, Context.OverloadTy)) {
    DeclAccessPair Found;
    FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(From, ToType,
                                                          true, Found);
    if (!Fn)
      return ExprError();

    if (DiagnoseUseOfDecl(Fn, From->getBeginLoc()))
      return ExprError();

    From = FixOverloadedFunctionReference(From, Found, Fn);
    FromType = From->getType();
  }

  // If we're converting to an atomic type, first convert to the corresponding
  // non-atomic type.
  QualType ToAtomicType;
  if (const AtomicType *ToAtomic = ToType->getAs<AtomicType>()) {
    ToAtomicType = ToType;
    ToType = ToAtomic->getValueType();
  }

  QualType InitialFromType = FromType;
  // Perform the first implicit conversion.
  switch (SCS.First) {
  case ICK_Identity:
    if (const AtomicType *FromAtomic = FromType->getAs<AtomicType>()) {
      FromType = FromAtomic->getValueType().getUnqualifiedType();
      From = ImplicitCastExpr::Create(Context, FromType, CK_AtomicToNonAtomic,
                                      From, /*BasePath=*/nullptr, VK_PRValue,
                                      FPOptionsOverride());
    }
    break;

  case ICK_Lvalue_To_Rvalue: {
    assert(From->getObjectKind() != OK_ObjCProperty);
    ExprResult FromRes = DefaultLvalueConversion(From);
    if (FromRes.isInvalid())
      return ExprError();

    From = FromRes.get();
    FromType = From->getType();
    break;
  }

  case ICK_Array_To_Pointer:
    FromType = Context.getArrayDecayedType(FromType);
    From = ImpCastExprToType(From, FromType, CK_ArrayToPointerDecay, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_Function_To_Pointer:
    FromType = Context.getPointerType(FromType);
    From = ImpCastExprToType(From, FromType, CK_FunctionToPointerDecay,
                             VK_PRValue, /*BasePath=*/nullptr, CCK)
               .get();
    break;

  default:
    llvm_unreachable("Improper first standard conversion");
  }

  // Perform the second implicit conversion
  switch (SCS.Second) {
  case ICK_Identity:
    // C++ [except.spec]p5:
    //   [For] assignment to and initialization of pointers to functions,
    //   pointers to member functions, and references to functions: the
    //   target entity shall allow at least the exceptions allowed by the
    //   source value in the assignment or initialization.
    switch (Action) {
    case AA_Assigning:
    case AA_Initializing:
      // Note, function argument passing and returning are initialization.
    case AA_Passing:
    case AA_Returning:
    case AA_Sending:
    case AA_Passing_CFAudited:
      if (CheckExceptionSpecCompatibility(From, ToType))
        return ExprError();
      break;

    case AA_Casting:
    case AA_Converting:
      // Casts and implicit conversions are not initialization, so are not
      // checked for exception specification mismatches.
      break;
    }
    // Nothing else to do.
    break;

  case ICK_Integral_Promotion:
  case ICK_Integral_Conversion:
    if (ToType->isBooleanType()) {
      assert(FromType->castAs<EnumType>()->getDecl()->isFixed() &&
             SCS.Second == ICK_Integral_Promotion &&
             "only enums with fixed underlying type can promote to bool");
      From = ImpCastExprToType(From, ToType, CK_IntegralToBoolean, VK_PRValue,
                               /*BasePath=*/nullptr, CCK)
                 .get();
    } else {
      From = ImpCastExprToType(From, ToType, CK_IntegralCast, VK_PRValue,
                               /*BasePath=*/nullptr, CCK)
                 .get();
    }
    break;

  case ICK_Floating_Promotion:
  case ICK_Floating_Conversion:
    From = ImpCastExprToType(From, ToType, CK_FloatingCast, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_Complex_Promotion:
  case ICK_Complex_Conversion: {
    QualType FromEl = From->getType()->castAs<ComplexType>()->getElementType();
    QualType ToEl = ToType->castAs<ComplexType>()->getElementType();
    CastKind CK;
    if (FromEl->isRealFloatingType()) {
      if (ToEl->isRealFloatingType())
        CK = CK_FloatingComplexCast;
      else
        CK = CK_FloatingComplexToIntegralComplex;
    } else if (ToEl->isRealFloatingType()) {
      CK = CK_IntegralComplexToFloatingComplex;
    } else {
      CK = CK_IntegralComplexCast;
    }
    From = ImpCastExprToType(From, ToType, CK, VK_PRValue, /*BasePath=*/nullptr,
                             CCK)
               .get();
    break;
  }

  case ICK_Floating_Integral:
    if (ToType->isRealFloatingType())
      From = ImpCastExprToType(From, ToType, CK_IntegralToFloating, VK_PRValue,
                               /*BasePath=*/nullptr, CCK)
                 .get();
    else
      From = ImpCastExprToType(From, ToType, CK_FloatingToIntegral, VK_PRValue,
                               /*BasePath=*/nullptr, CCK)
                 .get();
    break;

  case ICK_Compatible_Conversion:
    From = ImpCastExprToType(From, ToType, CK_NoOp, From->getValueKind(),
                             /*BasePath=*/nullptr, CCK).get();
    break;

  case ICK_Writeback_Conversion:
  case ICK_Pointer_Conversion: {
    if (SCS.IncompatibleObjC && Action != AA_Casting) {
      // Diagnose incompatible Objective-C conversions
      if (Action == AA_Initializing || Action == AA_Assigning)
        Diag(From->getBeginLoc(),
             diag::ext_typecheck_convert_incompatible_pointer)
            << ToType << From->getType() << Action << From->getSourceRange()
            << 0;
      else
        Diag(From->getBeginLoc(),
             diag::ext_typecheck_convert_incompatible_pointer)
            << From->getType() << ToType << Action << From->getSourceRange()
            << 0;

      if (From->getType()->isObjCObjectPointerType() &&
          ToType->isObjCObjectPointerType())
        EmitRelatedResultTypeNote(From);
    } else if (getLangOpts().allowsNonTrivialObjCLifetimeQualifiers() &&
               !CheckObjCARCUnavailableWeakConversion(ToType,
                                                      From->getType())) {
      if (Action == AA_Initializing)
        Diag(From->getBeginLoc(), diag::err_arc_weak_unavailable_assign);
      else
        Diag(From->getBeginLoc(), diag::err_arc_convesion_of_weak_unavailable)
            << (Action == AA_Casting) << From->getType() << ToType
            << From->getSourceRange();
    }

    // Defer address space conversion to the third conversion.
    QualType FromPteeType = From->getType()->getPointeeType();
    QualType ToPteeType = ToType->getPointeeType();
    QualType NewToType = ToType;
    if (!FromPteeType.isNull() && !ToPteeType.isNull() &&
        FromPteeType.getAddressSpace() != ToPteeType.getAddressSpace()) {
      NewToType = Context.removeAddrSpaceQualType(ToPteeType);
      NewToType = Context.getAddrSpaceQualType(NewToType,
                                               FromPteeType.getAddressSpace());
      if (ToType->isObjCObjectPointerType())
        NewToType = Context.getObjCObjectPointerType(NewToType);
      else if (ToType->isBlockPointerType())
        NewToType = Context.getBlockPointerType(NewToType);
      else
        NewToType = Context.getPointerType(NewToType);
    }

    CastKind Kind;
    CXXCastPath BasePath;
    if (CheckPointerConversion(From, NewToType, Kind, BasePath, CStyle))
      return ExprError();

    // Make sure we extend blocks if necessary.
    // FIXME: doing this here is really ugly.
    if (Kind == CK_BlockPointerToObjCPointerCast) {
      ExprResult E = From;
      (void) PrepareCastToObjCObjectPointer(E);
      From = E.get();
    }
    if (getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
      CheckObjCConversion(SourceRange(), NewToType, From, CCK);
    From = ImpCastExprToType(From, NewToType, Kind, VK_PRValue, &BasePath, CCK)
               .get();
    break;
  }

  case ICK_Pointer_Member: {
    CastKind Kind;
    CXXCastPath BasePath;
    if (CheckMemberPointerConversion(From, ToType, Kind, BasePath, CStyle))
      return ExprError();
    if (CheckExceptionSpecCompatibility(From, ToType))
      return ExprError();

    // We may not have been able to figure out what this member pointer resolved
    // to up until this exact point.  Attempt to lock-in it's inheritance model.
    if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
      (void)isCompleteType(From->getExprLoc(), From->getType());
      (void)isCompleteType(From->getExprLoc(), ToType);
    }

    From =
        ImpCastExprToType(From, ToType, Kind, VK_PRValue, &BasePath, CCK).get();
    break;
  }

  case ICK_Boolean_Conversion:
    // Perform half-to-boolean conversion via float.
    if (From->getType()->isHalfType()) {
      From = ImpCastExprToType(From, Context.FloatTy, CK_FloatingCast).get();
      FromType = Context.FloatTy;
    }

    From = ImpCastExprToType(From, Context.BoolTy,
                             ScalarTypeToBooleanCastKind(FromType), VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_Derived_To_Base: {
    CXXCastPath BasePath;
    if (CheckDerivedToBaseConversion(
            From->getType(), ToType.getNonReferenceType(), From->getBeginLoc(),
            From->getSourceRange(), &BasePath, CStyle))
      return ExprError();

    From = ImpCastExprToType(From, ToType.getNonReferenceType(),
                      CK_DerivedToBase, From->getValueKind(),
                      &BasePath, CCK).get();
    break;
  }

  case ICK_Vector_Conversion:
    From = ImpCastExprToType(From, ToType, CK_BitCast, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_SVE_Vector_Conversion:
    From = ImpCastExprToType(From, ToType, CK_BitCast, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_Vector_Splat: {
    // Vector splat from any arithmetic type to a vector.
    Expr *Elem = prepareVectorSplat(ToType, From).get();
    From = ImpCastExprToType(Elem, ToType, CK_VectorSplat, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;
  }

  case ICK_Complex_Real:
    // Case 1.  x -> _Complex y
    if (const ComplexType *ToComplex = ToType->getAs<ComplexType>()) {
      QualType ElType = ToComplex->getElementType();
      bool isFloatingComplex = ElType->isRealFloatingType();

      // x -> y
      if (Context.hasSameUnqualifiedType(ElType, From->getType())) {
        // do nothing
      } else if (From->getType()->isRealFloatingType()) {
        From = ImpCastExprToType(From, ElType,
                isFloatingComplex ? CK_FloatingCast : CK_FloatingToIntegral).get();
      } else {
        assert(From->getType()->isIntegerType());
        From = ImpCastExprToType(From, ElType,
                isFloatingComplex ? CK_IntegralToFloating : CK_IntegralCast).get();
      }
      // y -> _Complex y
      From = ImpCastExprToType(From, ToType,
                   isFloatingComplex ? CK_FloatingRealToComplex
                                     : CK_IntegralRealToComplex).get();

    // Case 2.  _Complex x -> y
    } else {
      auto *FromComplex = From->getType()->castAs<ComplexType>();
      QualType ElType = FromComplex->getElementType();
      bool isFloatingComplex = ElType->isRealFloatingType();

      // _Complex x -> x
      From = ImpCastExprToType(From, ElType,
                               isFloatingComplex ? CK_FloatingComplexToReal
                                                 : CK_IntegralComplexToReal,
                               VK_PRValue, /*BasePath=*/nullptr, CCK)
                 .get();

      // x -> y
      if (Context.hasSameUnqualifiedType(ElType, ToType)) {
        // do nothing
      } else if (ToType->isRealFloatingType()) {
        From = ImpCastExprToType(From, ToType,
                                 isFloatingComplex ? CK_FloatingCast
                                                   : CK_IntegralToFloating,
                                 VK_PRValue, /*BasePath=*/nullptr, CCK)
                   .get();
      } else {
        assert(ToType->isIntegerType());
        From = ImpCastExprToType(From, ToType,
                                 isFloatingComplex ? CK_FloatingToIntegral
                                                   : CK_IntegralCast,
                                 VK_PRValue, /*BasePath=*/nullptr, CCK)
                   .get();
      }
    }
    break;

  case ICK_Block_Pointer_Conversion: {
    LangAS AddrSpaceL =
        ToType->castAs<BlockPointerType>()->getPointeeType().getAddressSpace();
    LangAS AddrSpaceR =
        FromType->castAs<BlockPointerType>()->getPointeeType().getAddressSpace();
    assert(Qualifiers::isAddressSpaceSupersetOf(AddrSpaceL, AddrSpaceR) &&
           "Invalid cast");
    CastKind Kind =
        AddrSpaceL != AddrSpaceR ? CK_AddressSpaceConversion : CK_BitCast;
    From = ImpCastExprToType(From, ToType.getUnqualifiedType(), Kind,
                             VK_PRValue, /*BasePath=*/nullptr, CCK)
               .get();
    break;
  }

  case ICK_TransparentUnionConversion: {
    ExprResult FromRes = From;
    Sema::AssignConvertType ConvTy =
      CheckTransparentUnionArgumentConstraints(ToType, FromRes);
    if (FromRes.isInvalid())
      return ExprError();
    From = FromRes.get();
    assert ((ConvTy == Sema::Compatible) &&
            "Improper transparent union conversion");
    (void)ConvTy;
    break;
  }

  case ICK_Zero_Event_Conversion:
  case ICK_Zero_Queue_Conversion:
    From = ImpCastExprToType(From, ToType,
                             CK_ZeroToOCLOpaqueType,
                             From->getValueKind()).get();
    break;

  case ICK_Lvalue_To_Rvalue:
  case ICK_Array_To_Pointer:
  case ICK_Function_To_Pointer:
  case ICK_Function_Conversion:
  case ICK_Qualification:
  case ICK_Num_Conversion_Kinds:
  case ICK_C_Only_Conversion:
  case ICK_Incompatible_Pointer_Conversion:
    llvm_unreachable("Improper second standard conversion");
  }

  switch (SCS.Third) {
  case ICK_Identity:
    // Nothing to do.
    break;

  case ICK_Function_Conversion:
    // If both sides are functions (or pointers/references to them), there could
    // be incompatible exception declarations.
    if (CheckExceptionSpecCompatibility(From, ToType))
      return ExprError();

    From = ImpCastExprToType(From, ToType, CK_NoOp, VK_PRValue,
                             /*BasePath=*/nullptr, CCK)
               .get();
    break;

  case ICK_Qualification: {
    ExprValueKind VK = From->getValueKind();
    CastKind CK = CK_NoOp;

    if (ToType->isReferenceType() &&
        ToType->getPointeeType().getAddressSpace() !=
            From->getType().getAddressSpace())
      CK = CK_AddressSpaceConversion;

    if (ToType->isPointerType() &&
        ToType->getPointeeType().getAddressSpace() !=
            From->getType()->getPointeeType().getAddressSpace())
      CK = CK_AddressSpaceConversion;

    From = ImpCastExprToType(From, ToType.getNonLValueExprType(Context), CK, VK,
                             /*BasePath=*/nullptr, CCK)
               .get();

    if (SCS.DeprecatedStringLiteralToCharPtr &&
        !getLangOpts().WritableStrings) {
      Diag(From->getBeginLoc(),
           getLangOpts().CPlusPlus11
               ? diag::ext_deprecated_string_literal_conversion
               : diag::warn_deprecated_string_literal_conversion)
          << ToType.getNonReferenceType();
    }

    break;
  }

  default:
    llvm_unreachable("Improper third standard conversion");
  }

  // If this conversion sequence involved a scalar -> atomic conversion, perform
  // that conversion now.
  if (!ToAtomicType.isNull()) {
    assert(Context.hasSameType(
        ToAtomicType->castAs<AtomicType>()->getValueType(), From->getType()));
    From = ImpCastExprToType(From, ToAtomicType, CK_NonAtomicToAtomic,
                             VK_PRValue, nullptr, CCK)
               .get();
  }

  // Materialize a temporary if we're implicitly converting to a reference
  // type. This is not required by the C++ rules but is necessary to maintain
  // AST invariants.
  if (ToType->isReferenceType() && From->isPRValue()) {
    ExprResult Res = TemporaryMaterializationConversion(From);
    if (Res.isInvalid())
      return ExprError();
    From = Res.get();
  }

  // If this conversion sequence succeeded and involved implicitly converting a
  // _Nullable type to a _Nonnull one, complain.
  if (!isCast(CCK))
    diagnoseNullableToNonnullConversion(ToType, InitialFromType,
                                        From->getBeginLoc());

  return From;
}

/// Check the completeness of a type in a unary type trait.
///
/// If the particular type trait requires a complete type, tries to complete
/// it. If completing the type fails, a diagnostic is emitted and false
/// returned. If completing the type succeeds or no completion was required,
/// returns true.
static bool CheckUnaryTypeTraitTypeCompleteness(Sema &S, TypeTrait UTT,
                                                SourceLocation Loc,
                                                QualType ArgTy) {
  // C++0x [meta.unary.prop]p3:
  //   For all of the class templates X declared in this Clause, instantiating
  //   that template with a template argument that is a class template
  //   specialization may result in the implicit instantiation of the template
  //   argument if and only if the semantics of X require that the argument
  //   must be a complete type.
  // We apply this rule to all the type trait expressions used to implement
  // these class templates. We also try to follow any GCC documented behavior
  // in these expressions to ensure portability of standard libraries.
  switch (UTT) {
  default: llvm_unreachable("not a UTT");
    // is_complete_type somewhat obviously cannot require a complete type.
  case UTT_IsCompleteType:
    // Fall-through

    // These traits are modeled on the type predicates in C++0x
    // [meta.unary.cat] and [meta.unary.comp]. They are not specified as
    // requiring a complete type, as whether or not they return true cannot be
    // impacted by the completeness of the type.
  case UTT_IsVoid:
  case UTT_IsIntegral:
  case UTT_IsFloatingPoint:
  case UTT_IsArray:
  case UTT_IsPointer:
  case UTT_IsLvalueReference:
  case UTT_IsRvalueReference:
  case UTT_IsMemberFunctionPointer:
  case UTT_IsMemberObjectPointer:
  case UTT_IsEnum:
  case UTT_IsUnion:
  case UTT_IsClass:
  case UTT_IsFunction:
  case UTT_IsReference:
  case UTT_IsArithmetic:
  case UTT_IsFundamental:
  case UTT_IsObject:
  case UTT_IsScalar:
  case UTT_IsCompound:
  case UTT_IsMemberPointer:
    // Fall-through

    // These traits are modeled on type predicates in C++0x [meta.unary.prop]
    // which requires some of its traits to have the complete type. However,
    // the completeness of the type cannot impact these traits' semantics, and
    // so they don't require it. This matches the comments on these traits in
    // Table 49.
  case UTT_IsConst:
  case UTT_IsVolatile:
  case UTT_IsSigned:
  case UTT_IsUnsigned:

  // This type trait always returns false, checking the type is moot.
  case UTT_IsInterfaceClass:
    return true;

  // C++14 [meta.unary.prop]:
  //   If T is a non-union class type, T shall be a complete type.
  case UTT_IsEmpty:
  case UTT_IsPolymorphic:
  case UTT_IsAbstract:
    if (const auto *RD = ArgTy->getAsCXXRecordDecl())
      if (!RD->isUnion())
        return !S.RequireCompleteType(
            Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
    return true;

  // C++14 [meta.unary.prop]:
  //   If T is a class type, T shall be a complete type.
  case UTT_IsFinal:
  case UTT_IsSealed:
    if (ArgTy->getAsCXXRecordDecl())
      return !S.RequireCompleteType(
          Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
    return true;

  // C++1z [meta.unary.prop]:
  //   remove_all_extents_t<T> shall be a complete type or cv void.
  case UTT_IsAggregate:
  case UTT_IsTrivial:
  case UTT_IsTriviallyCopyable:
  case UTT_IsStandardLayout:
  case UTT_IsPOD:
  case UTT_IsLiteral:
  // Per the GCC type traits documentation, T shall be a complete type, cv void,
  // or an array of unknown bound. But GCC actually imposes the same constraints
  // as above.
  case UTT_HasNothrowAssign:
  case UTT_HasNothrowMoveAssign:
  case UTT_HasNothrowConstructor:
  case UTT_HasNothrowCopy:
  case UTT_HasTrivialAssign:
  case UTT_HasTrivialMoveAssign:
  case UTT_HasTrivialDefaultConstructor:
  case UTT_HasTrivialMoveConstructor:
  case UTT_HasTrivialCopy:
  case UTT_HasTrivialDestructor:
  case UTT_HasVirtualDestructor:
    ArgTy = QualType(ArgTy->getBaseElementTypeUnsafe(), 0);
    LLVM_FALLTHROUGH;

  // C++1z [meta.unary.prop]:
  //   T shall be a complete type, cv void, or an array of unknown bound.
  case UTT_IsDestructible:
  case UTT_IsNothrowDestructible:
  case UTT_IsTriviallyDestructible:
  case UTT_HasUniqueObjectRepresentations:
    if (ArgTy->isIncompleteArrayType() || ArgTy->isVoidType())
      return true;

    return !S.RequireCompleteType(
        Loc, ArgTy, diag::err_incomplete_type_used_in_type_trait_expr);
  }
}

static bool HasNoThrowOperator(const RecordType *RT, OverloadedOperatorKind Op,
                               Sema &Self, SourceLocation KeyLoc, ASTContext &C,
                               bool (CXXRecordDecl::*HasTrivial)() const,
                               bool (CXXRecordDecl::*HasNonTrivial)() const,
                               bool (CXXMethodDecl::*IsDesiredOp)() const)
{
  CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
  if ((RD->*HasTrivial)() && !(RD->*HasNonTrivial)())
    return true;

  DeclarationName Name = C.DeclarationNames.getCXXOperatorName(Op);
  DeclarationNameInfo NameInfo(Name, KeyLoc);
  LookupResult Res(Self, NameInfo, Sema::LookupOrdinaryName);
  if (Self.LookupQualifiedName(Res, RD)) {
    bool FoundOperator = false;
    Res.suppressDiagnostics();
    for (LookupResult::iterator Op = Res.begin(), OpEnd = Res.end();
         Op != OpEnd; ++Op) {
      if (isa<FunctionTemplateDecl>(*Op))
        continue;

      CXXMethodDecl *Operator = cast<CXXMethodDecl>(*Op);
      if((Operator->*IsDesiredOp)()) {
        FoundOperator = true;
        auto *CPT = Operator->getType()->castAs<FunctionProtoType>();
        CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
        if (!CPT || !CPT->isNothrow())
          return false;
      }
    }
    return FoundOperator;
  }
  return false;
}

static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
                                   SourceLocation KeyLoc, QualType T) {
  assert(!T->isDependentType() && "Cannot evaluate traits of dependent type");

  ASTContext &C = Self.Context;
  switch(UTT) {
  default: llvm_unreachable("not a UTT");
    // Type trait expressions corresponding to the primary type category
    // predicates in C++0x [meta.unary.cat].
  case UTT_IsVoid:
    return T->isVoidType();
  case UTT_IsIntegral:
    return T->isIntegralType(C);
  case UTT_IsFloatingPoint:
    return T->isFloatingType();
  case UTT_IsArray:
    return T->isArrayType();
  case UTT_IsPointer:
    return T->isAnyPointerType();
  case UTT_IsLvalueReference:
    return T->isLValueReferenceType();
  case UTT_IsRvalueReference:
    return T->isRValueReferenceType();
  case UTT_IsMemberFunctionPointer:
    return T->isMemberFunctionPointerType();
  case UTT_IsMemberObjectPointer:
    return T->isMemberDataPointerType();
  case UTT_IsEnum:
    return T->isEnumeralType();
  case UTT_IsUnion:
    return T->isUnionType();
  case UTT_IsClass:
    return T->isClassType() || T->isStructureType() || T->isInterfaceType();
  case UTT_IsFunction:
    return T->isFunctionType();

    // Type trait expressions which correspond to the convenient composition
    // predicates in C++0x [meta.unary.comp].
  case UTT_IsReference:
    return T->isReferenceType();
  case UTT_IsArithmetic:
    return T->isArithmeticType() && !T->isEnumeralType();
  case UTT_IsFundamental:
    return T->isFundamentalType();
  case UTT_IsObject:
    return T->isObjectType();
  case UTT_IsScalar:
    // Note: semantic analysis depends on Objective-C lifetime types to be
    // considered scalar types. However, such types do not actually behave
    // like scalar types at run time (since they may require retain/release
    // operations), so we report them as non-scalar.
    if (T->isObjCLifetimeType()) {
      switch (T.getObjCLifetime()) {
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
        return true;

      case Qualifiers::OCL_Strong:
      case Qualifiers::OCL_Weak:
      case Qualifiers::OCL_Autoreleasing:
        return false;
      }
    }

    return T->isScalarType();
  case UTT_IsCompound:
    return T->isCompoundType();
  case UTT_IsMemberPointer:
    return T->isMemberPointerType();

    // Type trait expressions which correspond to the type property predicates
    // in C++0x [meta.unary.prop].
  case UTT_IsConst:
    return T.isConstQualified();
  case UTT_IsVolatile:
    return T.isVolatileQualified();
  case UTT_IsTrivial:
    return T.isTrivialType(C);
  case UTT_IsTriviallyCopyable:
    return T.isTriviallyCopyableType(C);
  case UTT_IsStandardLayout:
    return T->isStandardLayoutType();
  case UTT_IsPOD:
    return T.isPODType(C);
  case UTT_IsLiteral:
    return T->isLiteralType(C);
  case UTT_IsEmpty:
    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return !RD->isUnion() && RD->isEmpty();
    return false;
  case UTT_IsPolymorphic:
    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return !RD->isUnion() && RD->isPolymorphic();
    return false;
  case UTT_IsAbstract:
    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return !RD->isUnion() && RD->isAbstract();
    return false;
  case UTT_IsAggregate:
    // Report vector extensions and complex types as aggregates because they
    // support aggregate initialization. GCC mirrors this behavior for vectors
    // but not _Complex.
    return T->isAggregateType() || T->isVectorType() || T->isExtVectorType() ||
           T->isAnyComplexType();
  // __is_interface_class only returns true when CL is invoked in /CLR mode and
  // even then only when it is used with the 'interface struct ...' syntax
  // Clang doesn't support /CLR which makes this type trait moot.
  case UTT_IsInterfaceClass:
    return false;
  case UTT_IsFinal:
  case UTT_IsSealed:
    if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return RD->hasAttr<FinalAttr>();
    return false;
  case UTT_IsSigned:
    // Enum types should always return false.
    // Floating points should always return true.
    return T->isFloatingType() ||
           (T->isSignedIntegerType() && !T->isEnumeralType());
  case UTT_IsUnsigned:
    // Enum types should always return false.
    return T->isUnsignedIntegerType() && !T->isEnumeralType();

    // Type trait expressions which query classes regarding their construction,
    // destruction, and copying. Rather than being based directly on the
    // related type predicates in the standard, they are specified by both
    // GCC[1] and the Embarcadero C++ compiler[2], and Clang implements those
    // specifications.
    //
    //   1: http://gcc.gnu/.org/onlinedocs/gcc/Type-Traits.html
    //   2: http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
    //
    // Note that these builtins do not behave as documented in g++: if a class
    // has both a trivial and a non-trivial special member of a particular kind,
    // they return false! For now, we emulate this behavior.
    // FIXME: This appears to be a g++ bug: more complex cases reveal that it
    // does not correctly compute triviality in the presence of multiple special
    // members of the same kind. Revisit this once the g++ bug is fixed.
  case UTT_HasTrivialDefaultConstructor:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If __is_pod (type) is true then the trait is true, else if type is
    //   a cv class or union type (or array thereof) with a trivial default
    //   constructor ([class.ctor]) then the trait is true, else it is false.
    if (T.isPODType(C))
      return true;
    if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
      return RD->hasTrivialDefaultConstructor() &&
             !RD->hasNonTrivialDefaultConstructor();
    return false;
  case UTT_HasTrivialMoveConstructor:
    //  This trait is implemented by MSVC 2012 and needed to parse the
    //  standard library headers. Specifically this is used as the logic
    //  behind std::is_trivially_move_constructible (20.9.4.3).
    if (T.isPODType(C))
      return true;
    if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
      return RD->hasTrivialMoveConstructor() && !RD->hasNonTrivialMoveConstructor();
    return false;
  case UTT_HasTrivialCopy:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If __is_pod (type) is true or type is a reference type then
    //   the trait is true, else if type is a cv class or union type
    //   with a trivial copy constructor ([class.copy]) then the trait
    //   is true, else it is false.
    if (T.isPODType(C) || T->isReferenceType())
      return true;
    if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return RD->hasTrivialCopyConstructor() &&
             !RD->hasNonTrivialCopyConstructor();
    return false;
  case UTT_HasTrivialMoveAssign:
    //  This trait is implemented by MSVC 2012 and needed to parse the
    //  standard library headers. Specifically it is used as the logic
    //  behind std::is_trivially_move_assignable (20.9.4.3)
    if (T.isPODType(C))
      return true;
    if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
      return RD->hasTrivialMoveAssignment() && !RD->hasNonTrivialMoveAssignment();
    return false;
  case UTT_HasTrivialAssign:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If type is const qualified or is a reference type then the
    //   trait is false. Otherwise if __is_pod (type) is true then the
    //   trait is true, else if type is a cv class or union type with
    //   a trivial copy assignment ([class.copy]) then the trait is
    //   true, else it is false.
    // Note: the const and reference restrictions are interesting,
    // given that const and reference members don't prevent a class
    // from having a trivial copy assignment operator (but do cause
    // errors if the copy assignment operator is actually used, q.v.
    // [class.copy]p12).

    if (T.isConstQualified())
      return false;
    if (T.isPODType(C))
      return true;
    if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      return RD->hasTrivialCopyAssignment() &&
             !RD->hasNonTrivialCopyAssignment();
    return false;
  case UTT_IsDestructible:
  case UTT_IsTriviallyDestructible:
  case UTT_IsNothrowDestructible:
    // C++14 [meta.unary.prop]:
    //   For reference types, is_destructible<T>::value is true.
    if (T->isReferenceType())
      return true;

    // Objective-C++ ARC: autorelease types don't require destruction.
    if (T->isObjCLifetimeType() &&
        T.getObjCLifetime() == Qualifiers::OCL_Autoreleasing)
      return true;

    // C++14 [meta.unary.prop]:
    //   For incomplete types and function types, is_destructible<T>::value is
    //   false.
    if (T->isIncompleteType() || T->isFunctionType())
      return false;

    // A type that requires destruction (via a non-trivial destructor or ARC
    // lifetime semantics) is not trivially-destructible.
    if (UTT == UTT_IsTriviallyDestructible && T.isDestructedType())
      return false;

    // C++14 [meta.unary.prop]:
    //   For object types and given U equal to remove_all_extents_t<T>, if the
    //   expression std::declval<U&>().~U() is well-formed when treated as an
    //   unevaluated operand (Clause 5), then is_destructible<T>::value is true
    if (auto *RD = C.getBaseElementType(T)->getAsCXXRecordDecl()) {
      CXXDestructorDecl *Destructor = Self.LookupDestructor(RD);
      if (!Destructor)
        return false;
      //  C++14 [dcl.fct.def.delete]p2:
      //    A program that refers to a deleted function implicitly or
      //    explicitly, other than to declare it, is ill-formed.
      if (Destructor->isDeleted())
        return false;
      if (C.getLangOpts().AccessControl && Destructor->getAccess() != AS_public)
        return false;
      if (UTT == UTT_IsNothrowDestructible) {
        auto *CPT = Destructor->getType()->castAs<FunctionProtoType>();
        CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
        if (!CPT || !CPT->isNothrow())
          return false;
      }
    }
    return true;

  case UTT_HasTrivialDestructor:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
    //   If __is_pod (type) is true or type is a reference type
    //   then the trait is true, else if type is a cv class or union
    //   type (or array thereof) with a trivial destructor
    //   ([class.dtor]) then the trait is true, else it is
    //   false.
    if (T.isPODType(C) || T->isReferenceType())
      return true;

    // Objective-C++ ARC: autorelease types don't require destruction.
    if (T->isObjCLifetimeType() &&
        T.getObjCLifetime() == Qualifiers::OCL_Autoreleasing)
      return true;

    if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl())
      return RD->hasTrivialDestructor();
    return false;
  // TODO: Propagate nothrowness for implicitly declared special members.
  case UTT_HasNothrowAssign:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If type is const qualified or is a reference type then the
    //   trait is false. Otherwise if __has_trivial_assign (type)
    //   is true then the trait is true, else if type is a cv class
    //   or union type with copy assignment operators that are known
    //   not to throw an exception then the trait is true, else it is
    //   false.
    if (C.getBaseElementType(T).isConstQualified())
      return false;
    if (T->isReferenceType())
      return false;
    if (T.isPODType(C) || T->isObjCLifetimeType())
      return true;

    if (const RecordType *RT = T->getAs<RecordType>())
      return HasNoThrowOperator(RT, OO_Equal, Self, KeyLoc, C,
                                &CXXRecordDecl::hasTrivialCopyAssignment,
                                &CXXRecordDecl::hasNonTrivialCopyAssignment,
                                &CXXMethodDecl::isCopyAssignmentOperator);
    return false;
  case UTT_HasNothrowMoveAssign:
    //  This trait is implemented by MSVC 2012 and needed to parse the
    //  standard library headers. Specifically this is used as the logic
    //  behind std::is_nothrow_move_assignable (20.9.4.3).
    if (T.isPODType(C))
      return true;

    if (const RecordType *RT = C.getBaseElementType(T)->getAs<RecordType>())
      return HasNoThrowOperator(RT, OO_Equal, Self, KeyLoc, C,
                                &CXXRecordDecl::hasTrivialMoveAssignment,
                                &CXXRecordDecl::hasNonTrivialMoveAssignment,
                                &CXXMethodDecl::isMoveAssignmentOperator);
    return false;
  case UTT_HasNothrowCopy:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If __has_trivial_copy (type) is true then the trait is true, else
    //   if type is a cv class or union type with copy constructors that are
    //   known not to throw an exception then the trait is true, else it is
    //   false.
    if (T.isPODType(C) || T->isReferenceType() || T->isObjCLifetimeType())
      return true;
    if (CXXRecordDecl *RD = T->getAsCXXRecordDecl()) {
      if (RD->hasTrivialCopyConstructor() &&
          !RD->hasNonTrivialCopyConstructor())
        return true;

      bool FoundConstructor = false;
      unsigned FoundTQs;
      for (const auto *ND : Self.LookupConstructors(RD)) {
        // A template constructor is never a copy constructor.
        // FIXME: However, it may actually be selected at the actual overload
        // resolution point.
        if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
          continue;
        // UsingDecl itself is not a constructor
        if (isa<UsingDecl>(ND))
          continue;
        auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
        if (Constructor->isCopyConstructor(FoundTQs)) {
          FoundConstructor = true;
          auto *CPT = Constructor->getType()->castAs<FunctionProtoType>();
          CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
          if (!CPT)
            return false;
          // TODO: check whether evaluating default arguments can throw.
          // For now, we'll be conservative and assume that they can throw.
          if (!CPT->isNothrow() || CPT->getNumParams() > 1)
            return false;
        }
      }

      return FoundConstructor;
    }
    return false;
  case UTT_HasNothrowConstructor:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html
    //   If __has_trivial_constructor (type) is true then the trait is
    //   true, else if type is a cv class or union type (or array
    //   thereof) with a default constructor that is known not to
    //   throw an exception then the trait is true, else it is false.
    if (T.isPODType(C) || T->isObjCLifetimeType())
      return true;
    if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl()) {
      if (RD->hasTrivialDefaultConstructor() &&
          !RD->hasNonTrivialDefaultConstructor())
        return true;

      bool FoundConstructor = false;
      for (const auto *ND : Self.LookupConstructors(RD)) {
        // FIXME: In C++0x, a constructor template can be a default constructor.
        if (isa<FunctionTemplateDecl>(ND->getUnderlyingDecl()))
          continue;
        // UsingDecl itself is not a constructor
        if (isa<UsingDecl>(ND))
          continue;
        auto *Constructor = cast<CXXConstructorDecl>(ND->getUnderlyingDecl());
        if (Constructor->isDefaultConstructor()) {
          FoundConstructor = true;
          auto *CPT = Constructor->getType()->castAs<FunctionProtoType>();
          CPT = Self.ResolveExceptionSpec(KeyLoc, CPT);
          if (!CPT)
            return false;
          // FIXME: check whether evaluating default arguments can throw.
          // For now, we'll be conservative and assume that they can throw.
          if (!CPT->isNothrow() || CPT->getNumParams() > 0)
            return false;
        }
      }
      return FoundConstructor;
    }
    return false;
  case UTT_HasVirtualDestructor:
    // http://gcc.gnu.org/onlinedocs/gcc/Type-Traits.html:
    //   If type is a class type with a virtual destructor ([class.dtor])
    //   then the trait is true, else it is false.
    if (CXXRecordDecl *RD = T->getAsCXXRecordDecl())
      if (CXXDestructorDecl *Destructor = Self.LookupDestructor(RD))
        return Destructor->isVirtual();
    return false;

    // These type trait expressions are modeled on the specifications for the
    // Embarcadero C++0x type trait functions:
    //   http://docwiki.embarcadero.com/RADStudio/XE/en/Type_Trait_Functions_(C%2B%2B0x)_Index
  case UTT_IsCompleteType:
    // http://docwiki.embarcadero.com/RADStudio/XE/en/Is_complete_type_(typename_T_):
    //   Returns True if and only if T is a complete type at the point of the
    //   function call.
    return !T->isIncompleteType();
  case UTT_HasUniqueObjectRepresentations:
    return C.hasUniqueObjectRepresentations(T);
  }
}

static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
                                    QualType RhsT, SourceLocation KeyLoc);

static bool evaluateTypeTrait(Sema &S, TypeTrait Kind, SourceLocation KWLoc,
                              ArrayRef<TypeSourceInfo *> Args,
                              SourceLocation RParenLoc) {
  if (Kind <= UTT_Last)
    return EvaluateUnaryTypeTrait(S, Kind, KWLoc, Args[0]->getType());

  // Evaluate BTT_ReferenceBindsToTemporary alongside the IsConstructible
  // traits to avoid duplication.
  if (Kind <= BTT_Last && Kind != BTT_ReferenceBindsToTemporary)
    return EvaluateBinaryTypeTrait(S, Kind, Args[0]->getType(),
                                   Args[1]->getType(), RParenLoc);

  switch (Kind) {
  case clang::BTT_ReferenceBindsToTemporary:
  case clang::TT_IsConstructible:
  case clang::TT_IsNothrowConstructible:
  case clang::TT_IsTriviallyConstructible: {
    // C++11 [meta.unary.prop]:
    //   is_trivially_constructible is defined as:
    //
    //     is_constructible<T, Args...>::value is true and the variable
    //     definition for is_constructible, as defined below, is known to call
    //     no operation that is not trivial.
    //
    //   The predicate condition for a template specialization
    //   is_constructible<T, Args...> shall be satisfied if and only if the
    //   following variable definition would be well-formed for some invented
    //   variable t:
    //
    //     T t(create<Args>()...);
    assert(!Args.empty());

    // Precondition: T and all types in the parameter pack Args shall be
    // complete types, (possibly cv-qualified) void, or arrays of
    // unknown bound.
    for (const auto *TSI : Args) {
      QualType ArgTy = TSI->getType();
      if (ArgTy->isVoidType() || ArgTy->isIncompleteArrayType())
        continue;

      if (S.RequireCompleteType(KWLoc, ArgTy,
          diag::err_incomplete_type_used_in_type_trait_expr))
        return false;
    }

    // Make sure the first argument is not incomplete nor a function type.
    QualType T = Args[0]->getType();
    if (T->isIncompleteType() || T->isFunctionType())
      return false;

    // Make sure the first argument is not an abstract type.
    CXXRecordDecl *RD = T->getAsCXXRecordDecl();
    if (RD && RD->isAbstract())
      return false;

    llvm::BumpPtrAllocator OpaqueExprAllocator;
    SmallVector<Expr *, 2> ArgExprs;
    ArgExprs.reserve(Args.size() - 1);
    for (unsigned I = 1, N = Args.size(); I != N; ++I) {
      QualType ArgTy = Args[I]->getType();
      if (ArgTy->isObjectType() || ArgTy->isFunctionType())
        ArgTy = S.Context.getRValueReferenceType(ArgTy);
      ArgExprs.push_back(
          new (OpaqueExprAllocator.Allocate<OpaqueValueExpr>())
              OpaqueValueExpr(Args[I]->getTypeLoc().getBeginLoc(),
                              ArgTy.getNonLValueExprType(S.Context),
                              Expr::getValueKindForType(ArgTy)));
    }

    // Perform the initialization in an unevaluated context within a SFINAE
    // trap at translation unit scope.
    EnterExpressionEvaluationContext Unevaluated(
        S, Sema::ExpressionEvaluationContext::Unevaluated);
    Sema::SFINAETrap SFINAE(S, /*AccessCheckingSFINAE=*/true);
    Sema::ContextRAII TUContext(S, S.Context.getTranslationUnitDecl());
    InitializedEntity To(InitializedEntity::InitializeTemporary(Args[0]));
    InitializationKind InitKind(InitializationKind::CreateDirect(KWLoc, KWLoc,
                                                                 RParenLoc));
    InitializationSequence Init(S, To, InitKind, ArgExprs);
    if (Init.Failed())
      return false;

    ExprResult Result = Init.Perform(S, To, InitKind, ArgExprs);
    if (Result.isInvalid() || SFINAE.hasErrorOccurred())
      return false;

    if (Kind == clang::TT_IsConstructible)
      return true;

    if (Kind == clang::BTT_ReferenceBindsToTemporary) {
      if (!T->isReferenceType())
        return false;

      return !Init.isDirectReferenceBinding();
    }

    if (Kind == clang::TT_IsNothrowConstructible)
      return S.canThrow(Result.get()) == CT_Cannot;

    if (Kind == clang::TT_IsTriviallyConstructible) {
      // Under Objective-C ARC and Weak, if the destination has non-trivial
      // Objective-C lifetime, this is a non-trivial construction.
      if (T.getNonReferenceType().hasNonTrivialObjCLifetime())
        return false;

      // The initialization succeeded; now make sure there are no non-trivial
      // calls.
      return !Result.get()->hasNonTrivialCall(S.Context);
    }

    llvm_unreachable("unhandled type trait");
    return false;
  }
    default: llvm_unreachable("not a TT");
  }

  return false;
}

ExprResult Sema::BuildTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                                ArrayRef<TypeSourceInfo *> Args,
                                SourceLocation RParenLoc) {
  QualType ResultType = Context.getLogicalOperationType();

  if (Kind <= UTT_Last && !CheckUnaryTypeTraitTypeCompleteness(
                               *this, Kind, KWLoc, Args[0]->getType()))
    return ExprError();

  bool Dependent = false;
  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
    if (Args[I]->getType()->isDependentType()) {
      Dependent = true;
      break;
    }
  }

  bool Result = false;
  if (!Dependent)
    Result = evaluateTypeTrait(*this, Kind, KWLoc, Args, RParenLoc);

  return TypeTraitExpr::Create(Context, ResultType, KWLoc, Kind, Args,
                               RParenLoc, Result);
}

ExprResult Sema::ActOnTypeTrait(TypeTrait Kind, SourceLocation KWLoc,
                                ArrayRef<ParsedType> Args,
                                SourceLocation RParenLoc) {
  SmallVector<TypeSourceInfo *, 4> ConvertedArgs;
  ConvertedArgs.reserve(Args.size());

  for (unsigned I = 0, N = Args.size(); I != N; ++I) {
    TypeSourceInfo *TInfo;
    QualType T = GetTypeFromParser(Args[I], &TInfo);
    if (!TInfo)
      TInfo = Context.getTrivialTypeSourceInfo(T, KWLoc);

    ConvertedArgs.push_back(TInfo);
  }

  return BuildTypeTrait(Kind, KWLoc, ConvertedArgs, RParenLoc);
}

static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, QualType LhsT,
                                    QualType RhsT, SourceLocation KeyLoc) {
  assert(!LhsT->isDependentType() && !RhsT->isDependentType() &&
         "Cannot evaluate traits of dependent types");

  switch(BTT) {
  case BTT_IsBaseOf: {
    // C++0x [meta.rel]p2
    // Base is a base class of Derived without regard to cv-qualifiers or
    // Base and Derived are not unions and name the same class type without
    // regard to cv-qualifiers.

    const RecordType *lhsRecord = LhsT->getAs<RecordType>();
    const RecordType *rhsRecord = RhsT->getAs<RecordType>();
    if (!rhsRecord || !lhsRecord) {
      const ObjCObjectType *LHSObjTy = LhsT->getAs<ObjCObjectType>();
      const ObjCObjectType *RHSObjTy = RhsT->getAs<ObjCObjectType>();
      if (!LHSObjTy || !RHSObjTy)
        return false;

      ObjCInterfaceDecl *BaseInterface = LHSObjTy->getInterface();
      ObjCInterfaceDecl *DerivedInterface = RHSObjTy->getInterface();
      if (!BaseInterface || !DerivedInterface)
        return false;

      if (Self.RequireCompleteType(
              KeyLoc, RhsT, diag::err_incomplete_type_used_in_type_trait_expr))
        return false;

      return BaseInterface->isSuperClassOf(DerivedInterface);
    }

    assert(Self.Context.hasSameUnqualifiedType(LhsT, RhsT)
             == (lhsRecord == rhsRecord));

    // Unions are never base classes, and never have base classes.
    // It doesn't matter if they are complete or not. See PR#41843
    if (lhsRecord && lhsRecord->getDecl()->isUnion())
      return false;
    if (rhsRecord && rhsRecord->getDecl()->isUnion())
      return false;

    if (lhsRecord == rhsRecord)
      return true;

    // C++0x [meta.rel]p2:
    //   If Base and Derived are class types and are different types
    //   (ignoring possible cv-qualifiers) then Derived shall be a
    //   complete type.
    if (Self.RequireCompleteType(KeyLoc, RhsT,
                          diag::err_incomplete_type_used_in_type_trait_expr))
      return false;

    return cast<CXXRecordDecl>(rhsRecord->getDecl())
      ->isDerivedFrom(cast<CXXRecordDecl>(lhsRecord->getDecl()));
  }
  case BTT_IsSame:
    return Self.Context.hasSameType(LhsT, RhsT);
  case BTT_TypeCompatible: {
    // GCC ignores cv-qualifiers on arrays for this builtin.
    Qualifiers LhsQuals, RhsQuals;
    QualType Lhs = Self.getASTContext().getUnqualifiedArrayType(LhsT, LhsQuals);
    QualType Rhs = Self.getASTContext().getUnqualifiedArrayType(RhsT, RhsQuals);
    return Self.Context.typesAreCompatible(Lhs, Rhs);
  }
  case BTT_IsConvertible:
  case BTT_IsConvertibleTo: {
    // C++0x [meta.rel]p4:
    //   Given the following function prototype:
    //
    //     template <class T>
    //       typename add_rvalue_reference<T>::type create();
    //
    //   the predicate condition for a template specialization
    //   is_convertible<From, To> shall be satisfied if and only if
    //   the return expression in the following code would be
    //   well-formed, including any implicit conversions to the return
    //   type of the function:
    //
    //     To test() {
    //       return create<From>();
    //     }
    //
    //   Access checking is performed as if in a context unrelated to To and
    //   From. Only the validity of the immediate context of the expression
    //   of the return-statement (including conversions to the return type)
    //   is considered.
    //
    // We model the initialization as a copy-initialization of a temporary
    // of the appropriate type, which for this expression is identical to the
    // return statement (since NRVO doesn't apply).

    // Functions aren't allowed to return function or array types.
    if (RhsT->isFunctionType() || RhsT->isArrayType())
      return false;

    // A return statement in a void function must have void type.
    if (RhsT->isVoidType())
      return LhsT->isVoidType();

    // A function definition requires a complete, non-abstract return type.
    if (!Self.isCompleteType(KeyLoc, RhsT) || Self.isAbstractType(KeyLoc, RhsT))
      return false;

    // Compute the result of add_rvalue_reference.
    if (LhsT->isObjectType() || LhsT->isFunctionType())
      LhsT = Self.Context.getRValueReferenceType(LhsT);

    // Build a fake source and destination for initialization.
    InitializedEntity To(InitializedEntity::InitializeTemporary(RhsT));
    OpaqueValueExpr From(KeyLoc, LhsT.getNonLValueExprType(Self.Context),
                         Expr::getValueKindForType(LhsT));
    Expr *FromPtr = &From;
    InitializationKind Kind(InitializationKind::CreateCopy(KeyLoc,
                                                           SourceLocation()));

    // Perform the initialization in an unevaluated context within a SFINAE
    // trap at translation unit scope.
    EnterExpressionEvaluationContext Unevaluated(
        Self, Sema::ExpressionEvaluationContext::Unevaluated);
    Sema::SFINAETrap SFINAE(Self, /*AccessCheckingSFINAE=*/true);
    Sema::ContextRAII TUContext(Self, Self.Context.getTranslationUnitDecl());
    InitializationSequence Init(Self, To, Kind, FromPtr);
    if (Init.Failed())
      return false;

    ExprResult Result = Init.Perform(Self, To, Kind, FromPtr);
    return !Result.isInvalid() && !SFINAE.hasErrorOccurred();
  }

  case BTT_IsAssignable:
  case BTT_IsNothrowAssignable:
  case BTT_IsTriviallyAssignable: {
    // C++11 [meta.unary.prop]p3:
    //   is_trivially_assignable is defined as:
    //     is_assignable<T, U>::value is true and the assignment, as defined by
    //     is_assignable, is known to call no operation that is not trivial
    //
    //   is_assignable is defined as:
    //     The expression declval<T>() = declval<U>() is well-formed when
    //     treated as an unevaluated operand (Clause 5).
    //
    //   For both, T and U shall be complete types, (possibly cv-qualified)
    //   void, or arrays of unknown bound.
    if (!LhsT->isVoidType() && !LhsT->isIncompleteArrayType() &&
        Self.RequireCompleteType(KeyLoc, LhsT,
          diag::err_incomplete_type_used_in_type_trait_expr))
      return false;
    if (!RhsT->isVoidType() && !RhsT->isIncompleteArrayType() &&
        Self.RequireCompleteType(KeyLoc, RhsT,
          diag::err_incomplete_type_used_in_type_trait_expr))
      return false;

    // cv void is never assignable.
    if (LhsT->isVoidType() || RhsT->isVoidType())
      return false;

    // Build expressions that emulate the effect of declval<T>() and
    // declval<U>().
    if (LhsT->isObjectType() || LhsT->isFunctionType())
      LhsT = Self.Context.getRValueReferenceType(LhsT);
    if (RhsT->isObjectType() || RhsT->isFunctionType())
      RhsT = Self.Context.getRValueReferenceType(RhsT);
    OpaqueValueExpr Lhs(KeyLoc, LhsT.getNonLValueExprType(Self.Context),
                        Expr::getValueKindForType(LhsT));
    OpaqueValueExpr Rhs(KeyLoc, RhsT.getNonLValueExprType(Self.Context),
                        Expr::getValueKindForType(RhsT));

    // Attempt the assignment in an unevaluated context within a SFINAE
    // trap at translation unit scope.
    EnterExpressionEvaluationContext Unevaluated(
        Self, Sema::ExpressionEvaluationContext::Unevaluated);
    Sema::SFINAETrap SFINAE(Self, /*AccessCheckingSFINAE=*/true);
    Sema::ContextRAII TUContext(Self, Self.Context.getTranslationUnitDecl());
    ExprResult Result = Self.BuildBinOp(/*S=*/nullptr, KeyLoc, BO_Assign, &Lhs,
                                        &Rhs);
    if (Result.isInvalid())
      return false;

    // Treat the assignment as unused for the purpose of -Wdeprecated-volatile.
    Self.CheckUnusedVolatileAssignment(Result.get());

    if (SFINAE.hasErrorOccurred())
      return false;

    if (BTT == BTT_IsAssignable)
      return true;

    if (BTT == BTT_IsNothrowAssignable)
      return Self.canThrow(Result.get()) == CT_Cannot;

    if (BTT == BTT_IsTriviallyAssignable) {
      // Under Objective-C ARC and Weak, if the destination has non-trivial
      // Objective-C lifetime, this is a non-trivial assignment.
      if (LhsT.getNonReferenceType().hasNonTrivialObjCLifetime())
        return false;

      return !Result.get()->hasNonTrivialCall(Self.Context);
    }

    llvm_unreachable("unhandled type trait");
    return false;
  }
    default: llvm_unreachable("not a BTT");
  }
  llvm_unreachable("Unknown type trait or not implemented");
}

ExprResult Sema::ActOnArrayTypeTrait(ArrayTypeTrait ATT,
                                     SourceLocation KWLoc,
                                     ParsedType Ty,
                                     Expr* DimExpr,
                                     SourceLocation RParen) {
  TypeSourceInfo *TSInfo;
  QualType T = GetTypeFromParser(Ty, &TSInfo);
  if (!TSInfo)
    TSInfo = Context.getTrivialTypeSourceInfo(T);

  return BuildArrayTypeTrait(ATT, KWLoc, TSInfo, DimExpr, RParen);
}

static uint64_t EvaluateArrayTypeTrait(Sema &Self, ArrayTypeTrait ATT,
                                           QualType T, Expr *DimExpr,
                                           SourceLocation KeyLoc) {
  assert(!T->isDependentType() && "Cannot evaluate traits of dependent type");

  switch(ATT) {
  case ATT_ArrayRank:
    if (T->isArrayType()) {
      unsigned Dim = 0;
      while (const ArrayType *AT = Self.Context.getAsArrayType(T)) {
        ++Dim;
        T = AT->getElementType();
      }
      return Dim;
    }
    return 0;

  case ATT_ArrayExtent: {
    llvm::APSInt Value;
    uint64_t Dim;
    if (Self.VerifyIntegerConstantExpression(
                DimExpr, &Value, diag::err_dimension_expr_not_constant_integer)
            .isInvalid())
      return 0;
    if (Value.isSigned() && Value.isNegative()) {
      Self.Diag(KeyLoc, diag::err_dimension_expr_not_constant_integer)
        << DimExpr->getSourceRange();
      return 0;
    }
    Dim = Value.getLimitedValue();

    if (T->isArrayType()) {
      unsigned D = 0;
      bool Matched = false;
      while (const ArrayType *AT = Self.Context.getAsArrayType(T)) {
        if (Dim == D) {
          Matched = true;
          break;
        }
        ++D;
        T = AT->getElementType();
      }

      if (Matched && T->isArrayType()) {
        if (const ConstantArrayType *CAT = Self.Context.getAsConstantArrayType(T))
          return CAT->getSize().getLimitedValue();
      }
    }
    return 0;
  }
  }
  llvm_unreachable("Unknown type trait or not implemented");
}

ExprResult Sema::BuildArrayTypeTrait(ArrayTypeTrait ATT,
                                     SourceLocation KWLoc,
                                     TypeSourceInfo *TSInfo,
                                     Expr* DimExpr,
                                     SourceLocation RParen) {
  QualType T = TSInfo->getType();

  // FIXME: This should likely be tracked as an APInt to remove any host
  // assumptions about the width of size_t on the target.
  uint64_t Value = 0;
  if (!T->isDependentType())
    Value = EvaluateArrayTypeTrait(*this, ATT, T, DimExpr, KWLoc);

  // While the specification for these traits from the Embarcadero C++
  // compiler's documentation says the return type is 'unsigned int', Clang
  // returns 'size_t'. On Windows, the primary platform for the Embarcadero
  // compiler, there is no difference. On several other platforms this is an
  // important distinction.
  return new (Context) ArrayTypeTraitExpr(KWLoc, ATT, TSInfo, Value, DimExpr,
                                          RParen, Context.getSizeType());
}

ExprResult Sema::ActOnExpressionTrait(ExpressionTrait ET,
                                      SourceLocation KWLoc,
                                      Expr *Queried,
                                      SourceLocation RParen) {
  // If error parsing the expression, ignore.
  if (!Queried)
    return ExprError();

  ExprResult Result = BuildExpressionTrait(ET, KWLoc, Queried, RParen);

  return Result;
}

static bool EvaluateExpressionTrait(ExpressionTrait ET, Expr *E) {
  switch (ET) {
  case ET_IsLValueExpr: return E->isLValue();
  case ET_IsRValueExpr:
    return E->isPRValue();
  }
  llvm_unreachable("Expression trait not covered by switch");
}

ExprResult Sema::BuildExpressionTrait(ExpressionTrait ET,
                                      SourceLocation KWLoc,
                                      Expr *Queried,
                                      SourceLocation RParen) {
  if (Queried->isTypeDependent()) {
    // Delay type-checking for type-dependent expressions.
  } else if (Queried->getType()->isPlaceholderType()) {
    ExprResult PE = CheckPlaceholderExpr(Queried);
    if (PE.isInvalid()) return ExprError();
    return BuildExpressionTrait(ET, KWLoc, PE.get(), RParen);
  }

  bool Value = EvaluateExpressionTrait(ET, Queried);

  return new (Context)
      ExpressionTraitExpr(KWLoc, ET, Queried, Value, RParen, Context.BoolTy);
}

QualType Sema::CheckPointerToMemberOperands(ExprResult &LHS, ExprResult &RHS,
                                            ExprValueKind &VK,
                                            SourceLocation Loc,
                                            bool isIndirect) {
  assert(!LHS.get()->getType()->isPlaceholderType() &&
         !RHS.get()->getType()->isPlaceholderType() &&
         "placeholders should have been weeded out by now");

  // The LHS undergoes lvalue conversions if this is ->*, and undergoes the
  // temporary materialization conversion otherwise.
  if (isIndirect)
    LHS = DefaultLvalueConversion(LHS.get());
  else if (LHS.get()->isPRValue())
    LHS = TemporaryMaterializationConversion(LHS.get());
  if (LHS.isInvalid())
    return QualType();

  // The RHS always undergoes lvalue conversions.
  RHS = DefaultLvalueConversion(RHS.get());
  if (RHS.isInvalid()) return QualType();

  const char *OpSpelling = isIndirect ? "->*" : ".*";
  // C++ 5.5p2
  //   The binary operator .* [p3: ->*] binds its second operand, which shall
  //   be of type "pointer to member of T" (where T is a completely-defined
  //   class type) [...]
  QualType RHSType = RHS.get()->getType();
  const MemberPointerType *MemPtr = RHSType->getAs<MemberPointerType>();
  if (!MemPtr) {
    Diag(Loc, diag::err_bad_memptr_rhs)
      << OpSpelling << RHSType << RHS.get()->getSourceRange();
    return QualType();
  }

  QualType Class(MemPtr->getClass(), 0);

  // Note: C++ [expr.mptr.oper]p2-3 says that the class type into which the
  // member pointer points must be completely-defined. However, there is no
  // reason for this semantic distinction, and the rule is not enforced by
  // other compilers. Therefore, we do not check this property, as it is
  // likely to be considered a defect.

  // C++ 5.5p2
  //   [...] to its first operand, which shall be of class T or of a class of
  //   which T is an unambiguous and accessible base class. [p3: a pointer to
  //   such a class]
  QualType LHSType = LHS.get()->getType();
  if (isIndirect) {
    if (const PointerType *Ptr = LHSType->getAs<PointerType>())
      LHSType = Ptr->getPointeeType();
    else {
      Diag(Loc, diag::err_bad_memptr_lhs)
        << OpSpelling << 1 << LHSType
        << FixItHint::CreateReplacement(SourceRange(Loc), ".*");
      return QualType();
    }
  }

  if (!Context.hasSameUnqualifiedType(Class, LHSType)) {
    // If we want to check the hierarchy, we need a complete type.
    if (RequireCompleteType(Loc, LHSType, diag::err_bad_memptr_lhs,
                            OpSpelling, (int)isIndirect)) {
      return QualType();
    }

    if (!IsDerivedFrom(Loc, LHSType, Class)) {
      Diag(Loc, diag::err_bad_memptr_lhs) << OpSpelling
        << (int)isIndirect << LHS.get()->getType();
      return QualType();
    }

    CXXCastPath BasePath;
    if (CheckDerivedToBaseConversion(
            LHSType, Class, Loc,
            SourceRange(LHS.get()->getBeginLoc(), RHS.get()->getEndLoc()),
            &BasePath))
      return QualType();

    // Cast LHS to type of use.
    QualType UseType = Context.getQualifiedType(Class, LHSType.getQualifiers());
    if (isIndirect)
      UseType = Context.getPointerType(UseType);
    ExprValueKind VK = isIndirect ? VK_PRValue : LHS.get()->getValueKind();
    LHS = ImpCastExprToType(LHS.get(), UseType, CK_DerivedToBase, VK,
                            &BasePath);
  }

  if (isa<CXXScalarValueInitExpr>(RHS.get()->IgnoreParens())) {
    // Diagnose use of pointer-to-member type which when used as
    // the functional cast in a pointer-to-member expression.
    Diag(Loc, diag::err_pointer_to_member_type) << isIndirect;
     return QualType();
  }

  // C++ 5.5p2
  //   The result is an object or a function of the type specified by the
  //   second operand.
  // The cv qualifiers are the union of those in the pointer and the left side,
  // in accordance with 5.5p5 and 5.2.5.
  QualType Result = MemPtr->getPointeeType();
  Result = Context.getCVRQualifiedType(Result, LHSType.getCVRQualifiers());

  // C++0x [expr.mptr.oper]p6:
  //   In a .* expression whose object expression is an rvalue, the program is
  //   ill-formed if the second operand is a pointer to member function with
  //   ref-qualifier &. In a ->* expression or in a .* expression whose object
  //   expression is an lvalue, the program is ill-formed if the second operand
  //   is a pointer to member function with ref-qualifier &&.
  if (const FunctionProtoType *Proto = Result->getAs<FunctionProtoType>()) {
    switch (Proto->getRefQualifier()) {
    case RQ_None:
      // Do nothing
      break;

    case RQ_LValue:
      if (!isIndirect && !LHS.get()->Classify(Context).isLValue()) {
        // C++2a allows functions with ref-qualifier & if their cv-qualifier-seq
        // is (exactly) 'const'.
        if (Proto->isConst() && !Proto->isVolatile())
          Diag(Loc, getLangOpts().CPlusPlus20
                        ? diag::warn_cxx17_compat_pointer_to_const_ref_member_on_rvalue
                        : diag::ext_pointer_to_const_ref_member_on_rvalue);
        else
          Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
              << RHSType << 1 << LHS.get()->getSourceRange();
      }
      break;

    case RQ_RValue:
      if (isIndirect || !LHS.get()->Classify(Context).isRValue())
        Diag(Loc, diag::err_pointer_to_member_oper_value_classify)
          << RHSType << 0 << LHS.get()->getSourceRange();
      break;
    }
  }

  // C++ [expr.mptr.oper]p6:
  //   The result of a .* expression whose second operand is a pointer
  //   to a data member is of the same value category as its
  //   first operand. The result of a .* expression whose second
  //   operand is a pointer to a member function is a prvalue. The
  //   result of an ->* expression is an lvalue if its second operand
  //   is a pointer to data member and a prvalue otherwise.
  if (Result->isFunctionType()) {
    VK = VK_PRValue;
    return Context.BoundMemberTy;
  } else if (isIndirect) {
    VK = VK_LValue;
  } else {
    VK = LHS.get()->getValueKind();
  }

  return Result;
}

/// Try to convert a type to another according to C++11 5.16p3.
///
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, the two operands are attempted to be
/// converted to each other. This function does the conversion in one direction.
/// It returns true if the program is ill-formed and has already been diagnosed
/// as such.
static bool TryClassUnification(Sema &Self, Expr *From, Expr *To,
                                SourceLocation QuestionLoc,
                                bool &HaveConversion,
                                QualType &ToType) {
  HaveConversion = false;
  ToType = To->getType();

  InitializationKind Kind =
      InitializationKind::CreateCopy(To->getBeginLoc(), SourceLocation());
  // C++11 5.16p3
  //   The process for determining whether an operand expression E1 of type T1
  //   can be converted to match an operand expression E2 of type T2 is defined
  //   as follows:
  //   -- If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
  //      implicitly converted to type "lvalue reference to T2", subject to the
  //      constraint that in the conversion the reference must bind directly to
  //      an lvalue.
  //   -- If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
  //      implicitly converted to the type "rvalue reference to R2", subject to
  //      the constraint that the reference must bind directly.
  if (To->isLValue() || To->isXValue()) {
    QualType T = To->isLValue() ? Self.Context.getLValueReferenceType(ToType)
                                : Self.Context.getRValueReferenceType(ToType);

    InitializedEntity Entity = InitializedEntity::InitializeTemporary(T);

    InitializationSequence InitSeq(Self, Entity, Kind, From);
    if (InitSeq.isDirectReferenceBinding()) {
      ToType = T;
      HaveConversion = true;
      return false;
    }

    if (InitSeq.isAmbiguous())
      return InitSeq.Diagnose(Self, Entity, Kind, From);
  }

  //   -- If E2 is an rvalue, or if the conversion above cannot be done:
  //      -- if E1 and E2 have class type, and the underlying class types are
  //         the same or one is a base class of the other:
  QualType FTy = From->getType();
  QualType TTy = To->getType();
  const RecordType *FRec = FTy->getAs<RecordType>();
  const RecordType *TRec = TTy->getAs<RecordType>();
  bool FDerivedFromT = FRec && TRec && FRec != TRec &&
                       Self.IsDerivedFrom(QuestionLoc, FTy, TTy);
  if (FRec && TRec && (FRec == TRec || FDerivedFromT ||
                       Self.IsDerivedFrom(QuestionLoc, TTy, FTy))) {
    //         E1 can be converted to match E2 if the class of T2 is the
    //         same type as, or a base class of, the class of T1, and
    //         [cv2 > cv1].
    if (FRec == TRec || FDerivedFromT) {
      if (TTy.isAtLeastAsQualifiedAs(FTy)) {
        InitializedEntity Entity = InitializedEntity::InitializeTemporary(TTy);
        InitializationSequence InitSeq(Self, Entity, Kind, From);
        if (InitSeq) {
          HaveConversion = true;
          return false;
        }

        if (InitSeq.isAmbiguous())
          return InitSeq.Diagnose(Self, Entity, Kind, From);
      }
    }

    return false;
  }

  //     -- Otherwise: E1 can be converted to match E2 if E1 can be
  //        implicitly converted to the type that expression E2 would have
  //        if E2 were converted to an rvalue (or the type it has, if E2 is
  //        an rvalue).
  //
  // This actually refers very narrowly to the lvalue-to-rvalue conversion, not
  // to the array-to-pointer or function-to-pointer conversions.
  TTy = TTy.getNonLValueExprType(Self.Context);

  InitializedEntity Entity = InitializedEntity::InitializeTemporary(TTy);
  InitializationSequence InitSeq(Self, Entity, Kind, From);
  HaveConversion = !InitSeq.Failed();
  ToType = TTy;
  if (InitSeq.isAmbiguous())
    return InitSeq.Diagnose(Self, Entity, Kind, From);

  return false;
}

/// Try to find a common type for two according to C++0x 5.16p5.
///
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, overload resolution is used to find a
/// conversion to a common type.
static bool FindConditionalOverload(Sema &Self, ExprResult &LHS, ExprResult &RHS,
                                    SourceLocation QuestionLoc) {
  Expr *Args[2] = { LHS.get(), RHS.get() };
  OverloadCandidateSet CandidateSet(QuestionLoc,
                                    OverloadCandidateSet::CSK_Operator);
  Self.AddBuiltinOperatorCandidates(OO_Conditional, QuestionLoc, Args,
                                    CandidateSet);

  OverloadCandidateSet::iterator Best;
  switch (CandidateSet.BestViableFunction(Self, QuestionLoc, Best)) {
    case OR_Success: {
      // We found a match. Perform the conversions on the arguments and move on.
      ExprResult LHSRes = Self.PerformImplicitConversion(
          LHS.get(), Best->BuiltinParamTypes[0], Best->Conversions[0],
          Sema::AA_Converting);
      if (LHSRes.isInvalid())
        break;
      LHS = LHSRes;

      ExprResult RHSRes = Self.PerformImplicitConversion(
          RHS.get(), Best->BuiltinParamTypes[1], Best->Conversions[1],
          Sema::AA_Converting);
      if (RHSRes.isInvalid())
        break;
      RHS = RHSRes;
      if (Best->Function)
        Self.MarkFunctionReferenced(QuestionLoc, Best->Function);
      return false;
    }

    case OR_No_Viable_Function:

      // Emit a better diagnostic if one of the expressions is a null pointer
      // constant and the other is a pointer type. In this case, the user most
      // likely forgot to take the address of the other expression.
      if (Self.DiagnoseConditionalForNull(LHS.get(), RHS.get(), QuestionLoc))
        return true;

      Self.Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
        << LHS.get()->getType() << RHS.get()->getType()
        << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
      return true;

    case OR_Ambiguous:
      Self.Diag(QuestionLoc, diag::err_conditional_ambiguous_ovl)
        << LHS.get()->getType() << RHS.get()->getType()
        << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
      // FIXME: Print the possible common types by printing the return types of
      // the viable candidates.
      break;

    case OR_Deleted:
      llvm_unreachable("Conditional operator has only built-in overloads");
  }
  return true;
}

/// Perform an "extended" implicit conversion as returned by
/// TryClassUnification.
static bool ConvertForConditional(Sema &Self, ExprResult &E, QualType T) {
  InitializedEntity Entity = InitializedEntity::InitializeTemporary(T);
  InitializationKind Kind =
      InitializationKind::CreateCopy(E.get()->getBeginLoc(), SourceLocation());
  Expr *Arg = E.get();
  InitializationSequence InitSeq(Self, Entity, Kind, Arg);
  ExprResult Result = InitSeq.Perform(Self, Entity, Kind, Arg);
  if (Result.isInvalid())
    return true;

  E = Result;
  return false;
}

// Check the condition operand of ?: to see if it is valid for the GCC
// extension.
static bool isValidVectorForConditionalCondition(ASTContext &Ctx,
                                                 QualType CondTy) {
  if (!CondTy->isVectorType() && !CondTy->isExtVectorType())
    return false;
  const QualType EltTy =
      cast<VectorType>(CondTy.getCanonicalType())->getElementType();
  assert(!EltTy->isBooleanType() && !EltTy->isEnumeralType() &&
         "Vectors cant be boolean or enum types");
  return EltTy->isIntegralType(Ctx);
}

QualType Sema::CheckVectorConditionalTypes(ExprResult &Cond, ExprResult &LHS,
                                           ExprResult &RHS,
                                           SourceLocation QuestionLoc) {
  LHS = DefaultFunctionArrayLvalueConversion(LHS.get());
  RHS = DefaultFunctionArrayLvalueConversion(RHS.get());

  QualType CondType = Cond.get()->getType();
  const auto *CondVT = CondType->castAs<VectorType>();
  QualType CondElementTy = CondVT->getElementType();
  unsigned CondElementCount = CondVT->getNumElements();
  QualType LHSType = LHS.get()->getType();
  const auto *LHSVT = LHSType->getAs<VectorType>();
  QualType RHSType = RHS.get()->getType();
  const auto *RHSVT = RHSType->getAs<VectorType>();

  QualType ResultType;


  if (LHSVT && RHSVT) {
    if (isa<ExtVectorType>(CondVT) != isa<ExtVectorType>(LHSVT)) {
      Diag(QuestionLoc, diag::err_conditional_vector_cond_result_mismatch)
          << /*isExtVector*/ isa<ExtVectorType>(CondVT);
      return {};
    }

    // If both are vector types, they must be the same type.
    if (!Context.hasSameType(LHSType, RHSType)) {
      Diag(QuestionLoc, diag::err_conditional_vector_mismatched)
          << LHSType << RHSType;
      return {};
    }
    ResultType = LHSType;
  } else if (LHSVT || RHSVT) {
    ResultType = CheckVectorOperands(
        LHS, RHS, QuestionLoc, /*isCompAssign*/ false, /*AllowBothBool*/ true,
        /*AllowBoolConversions*/ false);
    if (ResultType.isNull())
      return {};
  } else {
    // Both are scalar.
    QualType ResultElementTy;
    LHSType = LHSType.getCanonicalType().getUnqualifiedType();
    RHSType = RHSType.getCanonicalType().getUnqualifiedType();

    if (Context.hasSameType(LHSType, RHSType))
      ResultElementTy = LHSType;
    else
      ResultElementTy =
          UsualArithmeticConversions(LHS, RHS, QuestionLoc, ACK_Conditional);

    if (ResultElementTy->isEnumeralType()) {
      Diag(QuestionLoc, diag::err_conditional_vector_operand_type)
          << ResultElementTy;
      return {};
    }
    if (CondType->isExtVectorType())
      ResultType =
          Context.getExtVectorType(ResultElementTy, CondVT->getNumElements());
    else
      ResultType = Context.getVectorType(
          ResultElementTy, CondVT->getNumElements(), VectorType::GenericVector);

    LHS = ImpCastExprToType(LHS.get(), ResultType, CK_VectorSplat);
    RHS = ImpCastExprToType(RHS.get(), ResultType, CK_VectorSplat);
  }

  assert(!ResultType.isNull() && ResultType->isVectorType() &&
         (!CondType->isExtVectorType() || ResultType->isExtVectorType()) &&
         "Result should have been a vector type");
  auto *ResultVectorTy = ResultType->castAs<VectorType>();
  QualType ResultElementTy = ResultVectorTy->getElementType();
  unsigned ResultElementCount = ResultVectorTy->getNumElements();

  if (ResultElementCount != CondElementCount) {
    Diag(QuestionLoc, diag::err_conditional_vector_size) << CondType
                                                         << ResultType;
    return {};
  }

  if (Context.getTypeSize(ResultElementTy) !=
      Context.getTypeSize(CondElementTy)) {
    Diag(QuestionLoc, diag::err_conditional_vector_element_size) << CondType
                                                                 << ResultType;
    return {};
  }

  return ResultType;
}

/// Check the operands of ?: under C++ semantics.
///
/// See C++ [expr.cond]. Note that LHS is never null, even for the GNU x ?: y
/// extension. In this case, LHS == Cond. (But they're not aliases.)
///
/// This function also implements GCC's vector extension and the
/// OpenCL/ext_vector_type extension for conditionals. The vector extensions
/// permit the use of a?b:c where the type of a is that of a integer vector with
/// the same number of elements and size as the vectors of b and c. If one of
/// either b or c is a scalar it is implicitly converted to match the type of
/// the vector. Otherwise the expression is ill-formed. If both b and c are
/// scalars, then b and c are checked and converted to the type of a if
/// possible.
///
/// The expressions are evaluated differently for GCC's and OpenCL's extensions.
/// For the GCC extension, the ?: operator is evaluated as
///   (a[0] != 0 ? b[0] : c[0], .. , a[n] != 0 ? b[n] : c[n]).
/// For the OpenCL extensions, the ?: operator is evaluated as
///   (most-significant-bit-set(a[0])  ? b[0] : c[0], .. ,
///    most-significant-bit-set(a[n]) ? b[n] : c[n]).
QualType Sema::CXXCheckConditionalOperands(ExprResult &Cond, ExprResult &LHS,
                                           ExprResult &RHS, ExprValueKind &VK,
                                           ExprObjectKind &OK,
                                           SourceLocation QuestionLoc) {
  // FIXME: Handle C99's complex types, block pointers and Obj-C++ interface
  // pointers.

  // Assume r-value.
  VK = VK_PRValue;
  OK = OK_Ordinary;
  bool IsVectorConditional =
      isValidVectorForConditionalCondition(Context, Cond.get()->getType());

  // C++11 [expr.cond]p1
  //   The first expression is contextually converted to bool.
  if (!Cond.get()->isTypeDependent()) {
    ExprResult CondRes = IsVectorConditional
                             ? DefaultFunctionArrayLvalueConversion(Cond.get())
                             : CheckCXXBooleanCondition(Cond.get());
    if (CondRes.isInvalid())
      return QualType();
    Cond = CondRes;
  } else {
    // To implement C++, the first expression typically doesn't alter the result
    // type of the conditional, however the GCC compatible vector extension
    // changes the result type to be that of the conditional. Since we cannot
    // know if this is a vector extension here, delay the conversion of the
    // LHS/RHS below until later.
    return Context.DependentTy;
  }


  // Either of the arguments dependent?
  if (LHS.get()->isTypeDependent() || RHS.get()->isTypeDependent())
    return Context.DependentTy;

  // C++11 [expr.cond]p2
  //   If either the second or the third operand has type (cv) void, ...
  QualType LTy = LHS.get()->getType();
  QualType RTy = RHS.get()->getType();
  bool LVoid = LTy->isVoidType();
  bool RVoid = RTy->isVoidType();
  if (LVoid || RVoid) {
    //   ... one of the following shall hold:
    //   -- The second or the third operand (but not both) is a (possibly
    //      parenthesized) throw-expression; the result is of the type
    //      and value category of the other.
    bool LThrow = isa<CXXThrowExpr>(LHS.get()->IgnoreParenImpCasts());
    bool RThrow = isa<CXXThrowExpr>(RHS.get()->IgnoreParenImpCasts());

    // Void expressions aren't legal in the vector-conditional expressions.
    if (IsVectorConditional) {
      SourceRange DiagLoc =
          LVoid ? LHS.get()->getSourceRange() : RHS.get()->getSourceRange();
      bool IsThrow = LVoid ? LThrow : RThrow;
      Diag(DiagLoc.getBegin(), diag::err_conditional_vector_has_void)
          << DiagLoc << IsThrow;
      return QualType();
    }

    if (LThrow != RThrow) {
      Expr *NonThrow = LThrow ? RHS.get() : LHS.get();
      VK = NonThrow->getValueKind();
      // DR (no number yet): the result is a bit-field if the
      // non-throw-expression operand is a bit-field.
      OK = NonThrow->getObjectKind();
      return NonThrow->getType();
    }

    //   -- Both the second and third operands have type void; the result is of
    //      type void and is a prvalue.
    if (LVoid && RVoid)
      return Context.VoidTy;

    // Neither holds, error.
    Diag(QuestionLoc, diag::err_conditional_void_nonvoid)
      << (LVoid ? RTy : LTy) << (LVoid ? 0 : 1)
      << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
    return QualType();
  }

  // Neither is void.
  if (IsVectorConditional)
    return CheckVectorConditionalTypes(Cond, LHS, RHS, QuestionLoc);

  // C++11 [expr.cond]p3
  //   Otherwise, if the second and third operand have different types, and
  //   either has (cv) class type [...] an attempt is made to convert each of
  //   those operands to the type of the other.
  if (!Context.hasSameType(LTy, RTy) &&
      (LTy->isRecordType() || RTy->isRecordType())) {
    // These return true if a single direction is already ambiguous.
    QualType L2RType, R2LType;
    bool HaveL2R, HaveR2L;
    if (TryClassUnification(*this, LHS.get(), RHS.get(), QuestionLoc, HaveL2R, L2RType))
      return QualType();
    if (TryClassUnification(*this, RHS.get(), LHS.get(), QuestionLoc, HaveR2L, R2LType))
      return QualType();

    //   If both can be converted, [...] the program is ill-formed.
    if (HaveL2R && HaveR2L) {
      Diag(QuestionLoc, diag::err_conditional_ambiguous)
        << LTy << RTy << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
      return QualType();
    }

    //   If exactly one conversion is possible, that conversion is applied to
    //   the chosen operand and the converted operands are used in place of the
    //   original operands for the remainder of this section.
    if (HaveL2R) {
      if (ConvertForConditional(*this, LHS, L2RType) || LHS.isInvalid())
        return QualType();
      LTy = LHS.get()->getType();
    } else if (HaveR2L) {
      if (ConvertForConditional(*this, RHS, R2LType) || RHS.isInvalid())
        return QualType();
      RTy = RHS.get()->getType();
    }
  }

  // C++11 [expr.cond]p3
  //   if both are glvalues of the same value category and the same type except
  //   for cv-qualification, an attempt is made to convert each of those
  //   operands to the type of the other.
  // FIXME:
  //   Resolving a defect in P0012R1: we extend this to cover all cases where
  //   one of the operands is reference-compatible with the other, in order
  //   to support conditionals between functions differing in noexcept. This
  //   will similarly cover difference in array bounds after P0388R4.
  // FIXME: If LTy and RTy have a composite pointer type, should we convert to
  //   that instead?
  ExprValueKind LVK = LHS.get()->getValueKind();
  ExprValueKind RVK = RHS.get()->getValueKind();
  if (!Context.hasSameType(LTy, RTy) && LVK == RVK && LVK != VK_PRValue) {
    // DerivedToBase was already handled by the class-specific case above.
    // FIXME: Should we allow ObjC conversions here?
    const ReferenceConversions AllowedConversions =
        ReferenceConversions::Qualification |
        ReferenceConversions::NestedQualification |
        ReferenceConversions::Function;

    ReferenceConversions RefConv;
    if (CompareReferenceRelationship(QuestionLoc, LTy, RTy, &RefConv) ==
            Ref_Compatible &&
        !(RefConv & ~AllowedConversions) &&
        // [...] subject to the constraint that the reference must bind
        // directly [...]
        !RHS.get()->refersToBitField() && !RHS.get()->refersToVectorElement()) {
      RHS = ImpCastExprToType(RHS.get(), LTy, CK_NoOp, RVK);
      RTy = RHS.get()->getType();
    } else if (CompareReferenceRelationship(QuestionLoc, RTy, LTy, &RefConv) ==
                   Ref_Compatible &&
               !(RefConv & ~AllowedConversions) &&
               !LHS.get()->refersToBitField() &&
               !LHS.get()->refersToVectorElement()) {
      LHS = ImpCastExprToType(LHS.get(), RTy, CK_NoOp, LVK);
      LTy = LHS.get()->getType();
    }
  }

  // C++11 [expr.cond]p4
  //   If the second and third operands are glvalues of the same value
  //   category and have the same type, the result is of that type and
  //   value category and it is a bit-field if the second or the third
  //   operand is a bit-field, or if both are bit-fields.
  // We only extend this to bitfields, not to the crazy other kinds of
  // l-values.
  bool Same = Context.hasSameType(LTy, RTy);
  if (Same && LVK == RVK && LVK != VK_PRValue &&
      LHS.get()->isOrdinaryOrBitFieldObject() &&
      RHS.get()->isOrdinaryOrBitFieldObject()) {
    VK = LHS.get()->getValueKind();
    if (LHS.get()->getObjectKind() == OK_BitField ||
        RHS.get()->getObjectKind() == OK_BitField)
      OK = OK_BitField;

    // If we have function pointer types, unify them anyway to unify their
    // exception specifications, if any.
    if (LTy->isFunctionPointerType() || LTy->isMemberFunctionPointerType()) {
      Qualifiers Qs = LTy.getQualifiers();
      LTy = FindCompositePointerType(QuestionLoc, LHS, RHS,
                                     /*ConvertArgs*/false);
      LTy = Context.getQualifiedType(LTy, Qs);

      assert(!LTy.isNull() && "failed to find composite pointer type for "
                              "canonically equivalent function ptr types");
      assert(Context.hasSameType(LTy, RTy) && "bad composite pointer type");
    }

    return LTy;
  }

  // C++11 [expr.cond]p5
  //   Otherwise, the result is a prvalue. If the second and third operands
  //   do not have the same type, and either has (cv) class type, ...
  if (!Same && (LTy->isRecordType() || RTy->isRecordType())) {
    //   ... overload resolution is used to determine the conversions (if any)
    //   to be applied to the operands. If the overload resolution fails, the
    //   program is ill-formed.
    if (FindConditionalOverload(*this, LHS, RHS, QuestionLoc))
      return QualType();
  }

  // C++11 [expr.cond]p6
  //   Lvalue-to-rvalue, array-to-pointer, and function-to-pointer standard
  //   conversions are performed on the second and third operands.
  LHS = DefaultFunctionArrayLvalueConversion(LHS.get());
  RHS = DefaultFunctionArrayLvalueConversion(RHS.get());
  if (LHS.isInvalid() || RHS.isInvalid())
    return QualType();
  LTy = LHS.get()->getType();
  RTy = RHS.get()->getType();

  //   After those conversions, one of the following shall hold:
  //   -- The second and third operands have the same type; the result
  //      is of that type. If the operands have class type, the result
  //      is a prvalue temporary of the result type, which is
  //      copy-initialized from either the second operand or the third
  //      operand depending on the value of the first operand.
  if (Context.getCanonicalType(LTy) == Context.getCanonicalType(RTy)) {
    if (LTy->isRecordType()) {
      // The operands have class type. Make a temporary copy.
      InitializedEntity Entity = InitializedEntity::InitializeTemporary(LTy);

      ExprResult LHSCopy = PerformCopyInitialization(Entity,
                                                     SourceLocation(),
                                                     LHS);
      if (LHSCopy.isInvalid())
        return QualType();

      ExprResult RHSCopy = PerformCopyInitialization(Entity,
                                                     SourceLocation(),
                                                     RHS);
      if (RHSCopy.isInvalid())
        return QualType();

      LHS = LHSCopy;
      RHS = RHSCopy;
    }

    // If we have function pointer types, unify them anyway to unify their
    // exception specifications, if any.
    if (LTy->isFunctionPointerType() || LTy->isMemberFunctionPointerType()) {
      LTy = FindCompositePointerType(QuestionLoc, LHS, RHS);
      assert(!LTy.isNull() && "failed to find composite pointer type for "
                              "canonically equivalent function ptr types");
    }

    return LTy;
  }

  // Extension: conditional operator involving vector types.
  if (LTy->isVectorType() || RTy->isVectorType())
    return CheckVectorOperands(LHS, RHS, QuestionLoc, /*isCompAssign*/false,
                               /*AllowBothBool*/true,
                               /*AllowBoolConversions*/false);

  //   -- The second and third operands have arithmetic or enumeration type;
  //      the usual arithmetic conversions are performed to bring them to a
  //      common type, and the result is of that type.
  if (LTy->isArithmeticType() && RTy->isArithmeticType()) {
    QualType ResTy =
        UsualArithmeticConversions(LHS, RHS, QuestionLoc, ACK_Conditional);
    if (LHS.isInvalid() || RHS.isInvalid())
      return QualType();
    if (ResTy.isNull()) {
      Diag(QuestionLoc,
           diag::err_typecheck_cond_incompatible_operands) << LTy << RTy
        << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
      return QualType();
    }

    LHS = ImpCastExprToType(LHS.get(), ResTy, PrepareScalarCast(LHS, ResTy));
    RHS = ImpCastExprToType(RHS.get(), ResTy, PrepareScalarCast(RHS, ResTy));

    return ResTy;
  }

  //   -- The second and third operands have pointer type, or one has pointer
  //      type and the other is a null pointer constant, or both are null
  //      pointer constants, at least one of which is non-integral; pointer
  //      conversions and qualification conversions are performed to bring them
  //      to their composite pointer type. The result is of the composite
  //      pointer type.
  //   -- The second and third operands have pointer to member type, or one has
  //      pointer to member type and the other is a null pointer constant;
  //      pointer to member conversions and qualification conversions are
  //      performed to bring them to a common type, whose cv-qualification
  //      shall match the cv-qualification of either the second or the third
  //      operand. The result is of the common type.
  QualType Composite = FindCompositePointerType(QuestionLoc, LHS, RHS);
  if (!Composite.isNull())
    return Composite;

  // Similarly, attempt to find composite type of two objective-c pointers.
  Composite = FindCompositeObjCPointerType(LHS, RHS, QuestionLoc);
  if (LHS.isInvalid() || RHS.isInvalid())
    return QualType();
  if (!Composite.isNull())
    return Composite;

  // Check if we are using a null with a non-pointer type.
  if (DiagnoseConditionalForNull(LHS.get(), RHS.get(), QuestionLoc))
    return QualType();

  Diag(QuestionLoc, diag::err_typecheck_cond_incompatible_operands)
    << LHS.get()->getType() << RHS.get()->getType()
    << LHS.get()->getSourceRange() << RHS.get()->getSourceRange();
  return QualType();
}

static FunctionProtoType::ExceptionSpecInfo
mergeExceptionSpecs(Sema &S, FunctionProtoType::ExceptionSpecInfo ESI1,
                    FunctionProtoType::ExceptionSpecInfo ESI2,
                    SmallVectorImpl<QualType> &ExceptionTypeStorage) {
  ExceptionSpecificationType EST1 = ESI1.Type;
  ExceptionSpecificationType EST2 = ESI2.Type;

  // If either of them can throw anything, that is the result.
  if (EST1 == EST_None) return ESI1;
  if (EST2 == EST_None) return ESI2;
  if (EST1 == EST_MSAny) return ESI1;
  if (EST2 == EST_MSAny) return ESI2;
  if (EST1 == EST_NoexceptFalse) return ESI1;
  if (EST2 == EST_NoexceptFalse) return ESI2;

  // If either of them is non-throwing, the result is the other.
  if (EST1 == EST_NoThrow) return ESI2;
  if (EST2 == EST_NoThrow) return ESI1;
  if (EST1 == EST_DynamicNone) return ESI2;
  if (EST2 == EST_DynamicNone) return ESI1;
  if (EST1 == EST_BasicNoexcept) return ESI2;
  if (EST2 == EST_BasicNoexcept) return ESI1;
  if (EST1 == EST_NoexceptTrue) return ESI2;
  if (EST2 == EST_NoexceptTrue) return ESI1;

  // If we're left with value-dependent computed noexcept expressions, we're
  // stuck. Before C++17, we can just drop the exception specification entirely,
  // since it's not actually part of the canonical type. And this should never
  // happen in C++17, because it would mean we were computing the composite
  // pointer type of dependent types, which should never happen.
  if (EST1 == EST_DependentNoexcept || EST2 == EST_DependentNoexcept) {
    assert(!S.getLangOpts().CPlusPlus17 &&
           "computing composite pointer type of dependent types");
    return FunctionProtoType::ExceptionSpecInfo();
  }

  // Switch over the possibilities so that people adding new values know to
  // update this function.
  switch (EST1) {
  case EST_None:
  case EST_DynamicNone:
  case EST_MSAny:
  case EST_BasicNoexcept:
  case EST_DependentNoexcept:
  case EST_NoexceptFalse:
  case EST_NoexceptTrue:
  case EST_NoThrow:
    llvm_unreachable("handled above");

  case EST_Dynamic: {
    // This is the fun case: both exception specifications are dynamic. Form
    // the union of the two lists.
    assert(EST2 == EST_Dynamic && "other cases should already be handled");
    llvm::SmallPtrSet<QualType, 8> Found;
    for (auto &Exceptions : {ESI1.Exceptions, ESI2.Exceptions})
      for (QualType E : Exceptions)
        if (Found.insert(S.Context.getCanonicalType(E)).second)
          ExceptionTypeStorage.push_back(E);

    FunctionProtoType::ExceptionSpecInfo Result(EST_Dynamic);
    Result.Exceptions = ExceptionTypeStorage;
    return Result;
  }

  case EST_Unevaluated:
  case EST_Uninstantiated:
  case EST_Unparsed:
    llvm_unreachable("shouldn't see unresolved exception specifications here");
  }

  llvm_unreachable("invalid ExceptionSpecificationType");
}

/// Find a merged pointer type and convert the two expressions to it.
///
/// This finds the composite pointer type for \p E1 and \p E2 according to
/// C++2a [expr.type]p3. It converts both expressions to this type and returns
/// it.  It does not emit diagnostics (FIXME: that's not true if \p ConvertArgs
/// is \c true).
///
/// \param Loc The location of the operator requiring these two expressions to
/// be converted to the composite pointer type.
///
/// \param ConvertArgs If \c false, do not convert E1 and E2 to the target type.
QualType Sema::FindCompositePointerType(SourceLocation Loc,
                                        Expr *&E1, Expr *&E2,
                                        bool ConvertArgs) {
  assert(getLangOpts().CPlusPlus && "This function assumes C++");

  // C++1z [expr]p14:
  //   The composite pointer type of two operands p1 and p2 having types T1
  //   and T2
  QualType T1 = E1->getType(), T2 = E2->getType();

  //   where at least one is a pointer or pointer to member type or
  //   std::nullptr_t is:
  bool T1IsPointerLike = T1->isAnyPointerType() || T1->isMemberPointerType() ||
                         T1->isNullPtrType();
  bool T2IsPointerLike = T2->isAnyPointerType() || T2->isMemberPointerType() ||
                         T2->isNullPtrType();
  if (!T1IsPointerLike && !T2IsPointerLike)
    return QualType();

  //   - if both p1 and p2 are null pointer constants, std::nullptr_t;
  // This can't actually happen, following the standard, but we also use this
  // to implement the end of [expr.conv], which hits this case.
  //
  //   - if either p1 or p2 is a null pointer constant, T2 or T1, respectively;
  if (T1IsPointerLike &&
      E2->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) {
    if (ConvertArgs)
      E2 = ImpCastExprToType(E2, T1, T1->isMemberPointerType()
                                         ? CK_NullToMemberPointer
                                         : CK_NullToPointer).get();
    return T1;
  }
  if (T2IsPointerLike &&
      E1->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull)) {
    if (ConvertArgs)
      E1 = ImpCastExprToType(E1, T2, T2->isMemberPointerType()
                                         ? CK_NullToMemberPointer
                                         : CK_NullToPointer).get();
    return T2;
  }

  // Now both have to be pointers or member pointers.
  if (!T1IsPointerLike || !T2IsPointerLike)
    return QualType();
  assert(!T1->isNullPtrType() && !T2->isNullPtrType() &&
         "nullptr_t should be a null pointer constant");

  struct Step {
    enum Kind { Pointer, ObjCPointer, MemberPointer, Array } K;
    // Qualifiers to apply under the step kind.
    Qualifiers Quals;
    /// The class for a pointer-to-member; a constant array type with a bound
    /// (if any) for an array.
    const Type *ClassOrBound;

    Step(Kind K, const Type *ClassOrBound = nullptr)
        : K(K), Quals(), ClassOrBound(ClassOrBound) {}
    QualType rebuild(ASTContext &Ctx, QualType T) const {
      T = Ctx.getQualifiedType(T, Quals);
      switch (K) {
      case Pointer:
        return Ctx.getPointerType(T);
      case MemberPointer:
        return Ctx.getMemberPointerType(T, ClassOrBound);
      case ObjCPointer:
        return Ctx.getObjCObjectPointerType(T);
      case Array:
        if (auto *CAT = cast_or_null<ConstantArrayType>(ClassOrBound))
          return Ctx.getConstantArrayType(T, CAT->getSize(), nullptr,
                                          ArrayType::Normal, 0);
        else
          return Ctx.getIncompleteArrayType(T, ArrayType::Normal, 0);
      }
      llvm_unreachable("unknown step kind");
    }
  };

  SmallVector<Step, 8> Steps;

  //  - if T1 is "pointer to cv1 C1" and T2 is "pointer to cv2 C2", where C1
  //    is reference-related to C2 or C2 is reference-related to C1 (8.6.3),
  //    the cv-combined type of T1 and T2 or the cv-combined type of T2 and T1,
  //    respectively;
  //  - if T1 is "pointer to member of C1 of type cv1 U1" and T2 is "pointer
  //    to member of C2 of type cv2 U2" for some non-function type U, where
  //    C1 is reference-related to C2 or C2 is reference-related to C1, the
  //    cv-combined type of T2 and T1 or the cv-combined type of T1 and T2,
  //    respectively;
  //  - if T1 and T2 are similar types (4.5), the cv-combined type of T1 and
  //    T2;
  //
  // Dismantle T1 and T2 to simultaneously determine whether they are similar
  // and to prepare to form the cv-combined type if so.
  QualType Composite1 = T1;
  QualType Composite2 = T2;
  unsigned NeedConstBefore = 0;
  while (true) {
    assert(!Composite1.isNull() && !Composite2.isNull());

    Qualifiers Q1, Q2;
    Composite1 = Context.getUnqualifiedArrayType(Composite1, Q1);
    Composite2 = Context.getUnqualifiedArrayType(Composite2, Q2);

    // Top-level qualifiers are ignored. Merge at all lower levels.
    if (!Steps.empty()) {
      // Find the qualifier union: (approximately) the unique minimal set of
      // qualifiers that is compatible with both types.
      Qualifiers Quals = Qualifiers::fromCVRUMask(Q1.getCVRUQualifiers() |
                                                  Q2.getCVRUQualifiers());

      // Under one level of pointer or pointer-to-member, we can change to an
      // unambiguous compatible address space.
      if (Q1.getAddressSpace() == Q2.getAddressSpace()) {
        Quals.setAddressSpace(Q1.getAddressSpace());
      } else if (Steps.size() == 1) {
        bool MaybeQ1 = Q1.isAddressSpaceSupersetOf(Q2);
        bool MaybeQ2 = Q2.isAddressSpaceSupersetOf(Q1);
        if (MaybeQ1 == MaybeQ2)
          return QualType(); // No unique best address space.
        Quals.setAddressSpace(MaybeQ1 ? Q1.getAddressSpace()
                                      : Q2.getAddressSpace());
      } else {
        return QualType();
      }

      // FIXME: In C, we merge __strong and none to __strong at the top level.
      if (Q1.getObjCGCAttr() == Q2.getObjCGCAttr())
        Quals.setObjCGCAttr(Q1.getObjCGCAttr());
      else if (T1->isVoidPointerType() || T2->isVoidPointerType())
        assert(Steps.size() == 1);
      else
        return QualType();

      // Mismatched lifetime qualifiers never compatibly include each other.
      if (Q1.getObjCLifetime() == Q2.getObjCLifetime())
        Quals.setObjCLifetime(Q1.getObjCLifetime());
      else if (T1->isVoidPointerType() || T2->isVoidPointerType())
        assert(Steps.size() == 1);
      else
        return QualType();

      Steps.back().Quals = Quals;
      if (Q1 != Quals || Q2 != Quals)
        NeedConstBefore = Steps.size() - 1;
    }

    // FIXME: Can we unify the following with UnwrapSimilarTypes?
    const PointerType *Ptr1, *Ptr2;
    if ((Ptr1 = Composite1->getAs<PointerType>()) &&
        (Ptr2 = Composite2->getAs<PointerType>())) {
      Composite1 = Ptr1->getPointeeType();
      Composite2 = Ptr2->getPointeeType();
      Steps.emplace_back(Step::Pointer);
      continue;
    }

    const ObjCObjectPointerType *ObjPtr1, *ObjPtr2;
    if ((ObjPtr1 = Composite1->getAs<ObjCObjectPointerType>()) &&
        (ObjPtr2 = Composite2->getAs<ObjCObjectPointerType>())) {
      Composite1 = ObjPtr1->getPointeeType();
      Composite2 = ObjPtr2->getPointeeType();
      Steps.emplace_back(Step::ObjCPointer);
      continue;
    }

    const MemberPointerType *MemPtr1, *MemPtr2;
    if ((MemPtr1 = Composite1->getAs<MemberPointerType>()) &&
        (MemPtr2 = Composite2->getAs<MemberPointerType>())) {
      Composite1 = MemPtr1->getPointeeType();
      Composite2 = MemPtr2->getPointeeType();

      // At the top level, we can perform a base-to-derived pointer-to-member
      // conversion:
      //
      //  - [...] where C1 is reference-related to C2 or C2 is
      //    reference-related to C1
      //
      // (Note that the only kinds of reference-relatedness in scope here are
      // "same type or derived from".) At any other level, the class must
      // exactly match.
      const Type *Class = nullptr;
      QualType Cls1(MemPtr1->getClass(), 0);
      QualType Cls2(MemPtr2->getClass(), 0);
      if (Context.hasSameType(Cls1, Cls2))
        Class = MemPtr1->getClass();
      else if (Steps.empty())
        Class = IsDerivedFrom(Loc, Cls1, Cls2) ? MemPtr1->getClass() :
                IsDerivedFrom(Loc, Cls2, Cls1) ? MemPtr2->getClass() : nullptr;
      if (!Class)
        return QualType();

      Steps.emplace_back(Step::MemberPointer, Class);
      continue;
    }

    // Special case: at the top level, we can decompose an Objective-C pointer
    // and a 'cv void *'. Unify the qualifiers.
    if (Steps.empty() && ((Composite1->isVoidPointerType() &&
                           Composite2->isObjCObjectPointerType()) ||
                          (Composite1->isObjCObjectPointerType() &&
                           Composite2->isVoidPointerType()))) {
      Composite1 = Composite1->getPointeeType();
      Composite2 = Composite2->getPointeeType();
      Steps.emplace_back(Step::Pointer);
      continue;
    }

    // FIXME: arrays

    // FIXME: block pointer types?

    // Cannot unwrap any more types.
    break;
  }

  //  - if T1 or T2 is "pointer to noexcept function" and the other type is
  //    "pointer to function", where the function types are otherwise the same,
  //    "pointer to function";
  //  - if T1 or T2 is "pointer to member of C1 of type function", the other
  //    type is "pointer to member of C2 of type noexcept function", and C1
  //    is reference-related to C2 or C2 is reference-related to C1, where
  //    the function types are otherwise the same, "pointer to member of C2 of
  //    type function" or "pointer to member of C1 of type function",
  //    respectively;
  //
  // We also support 'noreturn' here, so as a Clang extension we generalize the
  // above to:
  //
  //  - [Clang] If T1 and T2 are both of type "pointer to function" or
  //    "pointer to member function" and the pointee types can be unified
  //    by a function pointer conversion, that conversion is applied
  //    before checking the following rules.
  //
  // We've already unwrapped down to the function types, and we want to merge
  // rather than just convert, so do this ourselves rather than calling
  // IsFunctionConversion.
  //
  // FIXME: In order to match the standard wording as closely as possible, we
  // currently only do this under a single level of pointers. Ideally, we would
  // allow this in general, and set NeedConstBefore to the relevant depth on
  // the side(s) where we changed anything. If we permit that, we should also
  // consider this conversion when determining type similarity and model it as
  // a qualification conversion.
  if (Steps.size() == 1) {
    if (auto *FPT1 = Composite1->getAs<FunctionProtoType>()) {
      if (auto *FPT2 = Composite2->getAs<FunctionProtoType>()) {
        FunctionProtoType::ExtProtoInfo EPI1 = FPT1->getExtProtoInfo();
        FunctionProtoType::ExtProtoInfo EPI2 = FPT2->getExtProtoInfo();

        // The result is noreturn if both operands are.
        bool Noreturn =
            EPI1.ExtInfo.getNoReturn() && EPI2.ExtInfo.getNoReturn();
        EPI1.ExtInfo = EPI1.ExtInfo.withNoReturn(Noreturn);
        EPI2.ExtInfo = EPI2.ExtInfo.withNoReturn(Noreturn);

        // The result is nothrow if both operands are.
        SmallVector<QualType, 8> ExceptionTypeStorage;
        EPI1.ExceptionSpec = EPI2.ExceptionSpec =
            mergeExceptionSpecs(*this, EPI1.ExceptionSpec, EPI2.ExceptionSpec,
                                ExceptionTypeStorage);

        Composite1 = Context.getFunctionType(FPT1->getReturnType(),
                                             FPT1->getParamTypes(), EPI1);
        Composite2 = Context.getFunctionType(FPT2->getReturnType(),
                                             FPT2->getParamTypes(), EPI2);
      }
    }
  }

  // There are some more conversions we can perform under exactly one pointer.
  if (Steps.size() == 1 && Steps.front().K == Step::Pointer &&
      !Context.hasSameType(Composite1, Composite2)) {
    //  - if T1 or T2 is "pointer to cv1 void" and the other type is
    //    "pointer to cv2 T", where T is an object type or void,
    //    "pointer to cv12 void", where cv12 is the union of cv1 and cv2;
    if (Composite1->isVoidType() && Composite2->isObjectType())
      Composite2 = Composite1;
    else if (Composite2->isVoidType() && Composite1->isObjectType())
      Composite1 = Composite2;
    //  - if T1 is "pointer to cv1 C1" and T2 is "pointer to cv2 C2", where C1
    //    is reference-related to C2 or C2 is reference-related to C1 (8.6.3),
    //    the cv-combined type of T1 and T2 or the cv-combined type of T2 and
    //    T1, respectively;
    //
    // The "similar type" handling covers all of this except for the "T1 is a
    // base class of T2" case in the definition of reference-related.
    else if (IsDerivedFrom(Loc, Composite1, Composite2))
      Composite1 = Composite2;
    else if (IsDerivedFrom(Loc, Composite2, Composite1))
      Composite2 = Composite1;
  }

  // At this point, either the inner types are the same or we have failed to
  // find a composite pointer type.
  if (!Context.hasSameType(Composite1, Composite2))
    return QualType();

  // Per C++ [conv.qual]p3, add 'const' to every level before the last
  // differing qualifier.
  for (unsigned I = 0; I != NeedConstBefore; ++I)
    Steps[I].Quals.addConst();

  // Rebuild the composite type.
  QualType Composite = Composite1;
  for (auto &S : llvm::reverse(Steps))
    Composite = S.rebuild(Context, Composite);

  if (ConvertArgs) {
    // Convert the expressions to the composite pointer type.
    InitializedEntity Entity =
        InitializedEntity::InitializeTemporary(Composite);
    InitializationKind Kind =
        InitializationKind::CreateCopy(Loc, SourceLocation());

    InitializationSequence E1ToC(*this, Entity, Kind, E1);
    if (!E1ToC)
      return QualType();

    InitializationSequence E2ToC(*this, Entity, Kind, E2);
    if (!E2ToC)
      return QualType();

    // FIXME: Let the caller know if these fail to avoid duplicate diagnostics.
    ExprResult E1Result = E1ToC.Perform(*this, Entity, Kind, E1);
    if (E1Result.isInvalid())
      return QualType();
    E1 = E1Result.get();

    ExprResult E2Result = E2ToC.Perform(*this, Entity, Kind, E2);
    if (E2Result.isInvalid())
      return QualType();
    E2 = E2Result.get();
  }

  return Composite;
}

ExprResult Sema::MaybeBindToTemporary(Expr *E) {
  if (!E)
    return ExprError();

  assert(!isa<CXXBindTemporaryExpr>(E) && "Double-bound temporary?");

  // If the result is a glvalue, we shouldn't bind it.
  if (E->isGLValue())
    return E;

  // In ARC, calls that return a retainable type can return retained,
  // in which case we have to insert a consuming cast.
  if (getLangOpts().ObjCAutoRefCount &&
      E->getType()->isObjCRetainableType()) {

    bool ReturnsRetained;

    // For actual calls, we compute this by examining the type of the
    // called value.
    if (CallExpr *Call = dyn_cast<CallExpr>(E)) {
      Expr *Callee = Call->getCallee()->IgnoreParens();
      QualType T = Callee->getType();

      if (T == Context.BoundMemberTy) {
        // Handle pointer-to-members.
        if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Callee))
          T = BinOp->getRHS()->getType();
        else if (MemberExpr *Mem = dyn_cast<MemberExpr>(Callee))
          T = Mem->getMemberDecl()->getType();
      }

      if (const PointerType *Ptr = T->getAs<PointerType>())
        T = Ptr->getPointeeType();
      else if (const BlockPointerType *Ptr = T->getAs<BlockPointerType>())
        T = Ptr->getPointeeType();
      else if (const MemberPointerType *MemPtr = T->getAs<MemberPointerType>())
        T = MemPtr->getPointeeType();

      auto *FTy = T->castAs<FunctionType>();
      ReturnsRetained = FTy->getExtInfo().getProducesResult();

    // ActOnStmtExpr arranges things so that StmtExprs of retainable
    // type always produce a +1 object.
    } else if (isa<StmtExpr>(E)) {
      ReturnsRetained = true;

    // We hit this case with the lambda conversion-to-block optimization;
    // we don't want any extra casts here.
    } else if (isa<CastExpr>(E) &&
               isa<BlockExpr>(cast<CastExpr>(E)->getSubExpr())) {
      return E;

    // For message sends and property references, we try to find an
    // actual method.  FIXME: we should infer retention by selector in
    // cases where we don't have an actual method.
    } else {
      ObjCMethodDecl *D = nullptr;
      if (ObjCMessageExpr *Send = dyn_cast<ObjCMessageExpr>(E)) {
        D = Send->getMethodDecl();
      } else if (ObjCBoxedExpr *BoxedExpr = dyn_cast<ObjCBoxedExpr>(E)) {
        D = BoxedExpr->getBoxingMethod();
      } else if (ObjCArrayLiteral *ArrayLit = dyn_cast<ObjCArrayLiteral>(E)) {
        // Don't do reclaims if we're using the zero-element array
        // constant.
        if (ArrayLit->getNumElements() == 0 &&
            Context.getLangOpts().ObjCRuntime.hasEmptyCollections())
          return E;

        D = ArrayLit->getArrayWithObjectsMethod();
      } else if (ObjCDictionaryLiteral *DictLit
                                        = dyn_cast<ObjCDictionaryLiteral>(E)) {
        // Don't do reclaims if we're using the zero-element dictionary
        // constant.
        if (DictLit->getNumElements() == 0 &&
            Context.getLangOpts().ObjCRuntime.hasEmptyCollections())
          return E;

        D = DictLit->getDictWithObjectsMethod();
      }

      ReturnsRetained = (D && D->hasAttr<NSReturnsRetainedAttr>());

      // Don't do reclaims on performSelector calls; despite their
      // return type, the invoked method doesn't necessarily actually
      // return an object.
      if (!ReturnsRetained &&
          D && D->getMethodFamily() == OMF_performSelector)
        return E;
    }

    // Don't reclaim an object of Class type.
    if (!ReturnsRetained && E->getType()->isObjCARCImplicitlyUnretainedType())
      return E;

    Cleanup.setExprNeedsCleanups(true);

    CastKind ck = (ReturnsRetained ? CK_ARCConsumeObject
                                   : CK_ARCReclaimReturnedObject);
    return ImplicitCastExpr::Create(Context, E->getType(), ck, E, nullptr,
                                    VK_PRValue, FPOptionsOverride());
  }

  if (E->getType().isDestructedType() == QualType::DK_nontrivial_c_struct)
    Cleanup.setExprNeedsCleanups(true);

  if (!getLangOpts().CPlusPlus)
    return E;

  // Search for the base element type (cf. ASTContext::getBaseElementType) with
  // a fast path for the common case that the type is directly a RecordType.
  const Type *T = Context.getCanonicalType(E->getType().getTypePtr());
  const RecordType *RT = nullptr;
  while (!RT) {
    switch (T->getTypeClass()) {
    case Type::Record:
      RT = cast<RecordType>(T);
      break;
    case Type::ConstantArray:
    case Type::IncompleteArray:
    case Type::VariableArray:
    case Type::DependentSizedArray:
      T = cast<ArrayType>(T)->getElementType().getTypePtr();
      break;
    default:
      return E;
    }
  }

  // That should be enough to guarantee that this type is complete, if we're
  // not processing a decltype expression.
  CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
  if (RD->isInvalidDecl() || RD->isDependentContext())
    return E;

  bool IsDecltype = ExprEvalContexts.back().ExprContext ==
                    ExpressionEvaluationContextRecord::EK_Decltype;
  CXXDestructorDecl *Destructor = IsDecltype ? nullptr : LookupDestructor(RD);

  if (Destructor) {
    MarkFunctionReferenced(E->getExprLoc(), Destructor);
    CheckDestructorAccess(E->getExprLoc(), Destructor,
                          PDiag(diag::err_access_dtor_temp)
                            << E->getType());
    if (DiagnoseUseOfDecl(Destructor, E->getExprLoc()))
      return ExprError();

    // If destructor is trivial, we can avoid the extra copy.
    if (Destructor->isTrivial())
      return E;

    // We need a cleanup, but we don't need to remember the temporary.
    Cleanup.setExprNeedsCleanups(true);
  }

  CXXTemporary *Temp = CXXTemporary::Create(Context, Destructor);
  CXXBindTemporaryExpr *Bind = CXXBindTemporaryExpr::Create(Context, Temp, E);

  if (IsDecltype)
    ExprEvalContexts.back().DelayedDecltypeBinds.push_back(Bind);

  return Bind;
}

ExprResult
Sema::MaybeCreateExprWithCleanups(ExprResult SubExpr) {
  if (SubExpr.isInvalid())
    return ExprError();

  return MaybeCreateExprWithCleanups(SubExpr.get());
}

Expr *Sema::MaybeCreateExprWithCleanups(Expr *SubExpr) {
  assert(SubExpr && "subexpression can't be null!");

  CleanupVarDeclMarking();

  unsigned FirstCleanup = ExprEvalContexts.back().NumCleanupObjects;
  assert(ExprCleanupObjects.size() >= FirstCleanup);
  assert(Cleanup.exprNeedsCleanups() ||
         ExprCleanupObjects.size() == FirstCleanup);
  if (!Cleanup.exprNeedsCleanups())
    return SubExpr;

  auto Cleanups = llvm::makeArrayRef(ExprCleanupObjects.begin() + FirstCleanup,
                                     ExprCleanupObjects.size() - FirstCleanup);

  auto *E = ExprWithCleanups::Create(
      Context, SubExpr, Cleanup.cleanupsHaveSideEffects(), Cleanups);
  DiscardCleanupsInEvaluationContext();

  return E;
}

Stmt *Sema::MaybeCreateStmtWithCleanups(Stmt *SubStmt) {
  assert(SubStmt && "sub-statement can't be null!");

  CleanupVarDeclMarking();

  if (!Cleanup.exprNeedsCleanups())
    return SubStmt;

  // FIXME: In order to attach the temporaries, wrap the statement into
  // a StmtExpr; currently this is only used for asm statements.
  // This is hacky, either create a new CXXStmtWithTemporaries statement or
  // a new AsmStmtWithTemporaries.
  CompoundStmt *CompStmt = CompoundStmt::Create(
      Context, SubStmt, SourceLocation(), SourceLocation());
  Expr *E = new (Context)
      StmtExpr(CompStmt, Context.VoidTy, SourceLocation(), SourceLocation(),
               /*FIXME TemplateDepth=*/0);
  return MaybeCreateExprWithCleanups(E);
}

/// Process the expression contained within a decltype. For such expressions,
/// certain semantic checks on temporaries are delayed until this point, and
/// are omitted for the 'topmost' call in the decltype expression. If the
/// topmost call bound a temporary, strip that temporary off the expression.
ExprResult Sema::ActOnDecltypeExpression(Expr *E) {
  assert(ExprEvalContexts.back().ExprContext ==
             ExpressionEvaluationContextRecord::EK_Decltype &&
         "not in a decltype expression");

  ExprResult Result = CheckPlaceholderExpr(E);
  if (Result.isInvalid())
    return ExprError();
  E = Result.get();

  // C++11 [expr.call]p11:
  //   If a function call is a prvalue of object type,
  // -- if the function call is either
  //   -- the operand of a decltype-specifier, or
  //   -- the right operand of a comma operator that is the operand of a
  //      decltype-specifier,
  //   a temporary object is not introduced for the prvalue.

  // Recursively rebuild ParenExprs and comma expressions to strip out the
  // outermost CXXBindTemporaryExpr, if any.
  if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
    ExprResult SubExpr = ActOnDecltypeExpression(PE->getSubExpr());
    if (SubExpr.isInvalid())
      return ExprError();
    if (SubExpr.get() == PE->getSubExpr())
      return E;
    return ActOnParenExpr(PE->getLParen(), PE->getRParen(), SubExpr.get());
  }
  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
    if (BO->getOpcode() == BO_Comma) {
      ExprResult RHS = ActOnDecltypeExpression(BO->getRHS());
      if (RHS.isInvalid())
        return ExprError();
      if (RHS.get() == BO->getRHS())
        return E;
      return BinaryOperator::Create(Context, BO->getLHS(), RHS.get(), BO_Comma,
                                    BO->getType(), BO->getValueKind(),
                                    BO->getObjectKind(), BO->getOperatorLoc(),
                                    BO->getFPFeatures(getLangOpts()));
    }
  }

  CXXBindTemporaryExpr *TopBind = dyn_cast<CXXBindTemporaryExpr>(E);
  CallExpr *TopCall = TopBind ? dyn_cast<CallExpr>(TopBind->getSubExpr())
                              : nullptr;
  if (TopCall)
    E = TopCall;
  else
    TopBind = nullptr;

  // Disable the special decltype handling now.
  ExprEvalContexts.back().ExprContext =
      ExpressionEvaluationContextRecord::EK_Other;

  Result = CheckUnevaluatedOperand(E);
  if (Result.isInvalid())
    return ExprError();
  E = Result.get();

  // In MS mode, don't perform any extra checking of call return types within a
  // decltype expression.
  if (getLangOpts().MSVCCompat)
    return E;

  // Perform the semantic checks we delayed until this point.
  for (unsigned I = 0, N = ExprEvalContexts.back().DelayedDecltypeCalls.size();
       I != N; ++I) {
    CallExpr *Call = ExprEvalContexts.back().DelayedDecltypeCalls[I];
    if (Call == TopCall)
      continue;

    if (CheckCallReturnType(Call->getCallReturnType(Context),
                            Call->getBeginLoc(), Call, Call->getDirectCallee()))
      return ExprError();
  }

  // Now all relevant types are complete, check the destructors are accessible
  // and non-deleted, and annotate them on the temporaries.
  for (unsigned I = 0, N = ExprEvalContexts.back().DelayedDecltypeBinds.size();
       I != N; ++I) {
    CXXBindTemporaryExpr *Bind =
      ExprEvalContexts.back().DelayedDecltypeBinds[I];
    if (Bind == TopBind)
      continue;

    CXXTemporary *Temp = Bind->getTemporary();

    CXXRecordDecl *RD =
      Bind->getType()->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
    CXXDestructorDecl *Destructor = LookupDestructor(RD);
    Temp->setDestructor(Destructor);

    MarkFunctionReferenced(Bind->getExprLoc(), Destructor);
    CheckDestructorAccess(Bind->getExprLoc(), Destructor,
                          PDiag(diag::err_access_dtor_temp)
                            << Bind->getType());
    if (DiagnoseUseOfDecl(Destructor, Bind->getExprLoc()))
      return ExprError();

    // We need a cleanup, but we don't need to remember the temporary.
    Cleanup.setExprNeedsCleanups(true);
  }

  // Possibly strip off the top CXXBindTemporaryExpr.
  return E;
}

/// Note a set of 'operator->' functions that were used for a member access.
static void noteOperatorArrows(Sema &S,
                               ArrayRef<FunctionDecl *> OperatorArrows) {
  unsigned SkipStart = OperatorArrows.size(), SkipCount = 0;
  // FIXME: Make this configurable?
  unsigned Limit = 9;
  if (OperatorArrows.size() > Limit) {
    // Produce Limit-1 normal notes and one 'skipping' note.
    SkipStart = (Limit - 1) / 2 + (Limit - 1) % 2;
    SkipCount = OperatorArrows.size() - (Limit - 1);
  }

  for (unsigned I = 0; I < OperatorArrows.size(); /**/) {
    if (I == SkipStart) {
      S.Diag(OperatorArrows[I]->getLocation(),
             diag::note_operator_arrows_suppressed)
          << SkipCount;
      I += SkipCount;
    } else {
      S.Diag(OperatorArrows[I]->getLocation(), diag::note_operator_arrow_here)
          << OperatorArrows[I]->getCallResultType();
      ++I;
    }
  }
}

ExprResult Sema::ActOnStartCXXMemberReference(Scope *S, Expr *Base,
                                              SourceLocation OpLoc,
                                              tok::TokenKind OpKind,
                                              ParsedType &ObjectType,
                                              bool &MayBePseudoDestructor) {
  // Since this might be a postfix expression, get rid of ParenListExprs.
  ExprResult Result = MaybeConvertParenListExprToParenExpr(S, Base);
  if (Result.isInvalid()) return ExprError();
  Base = Result.get();

  Result = CheckPlaceholderExpr(Base);
  if (Result.isInvalid()) return ExprError();
  Base = Result.get();

  QualType BaseType = Base->getType();
  MayBePseudoDestructor = false;
  if (BaseType->isDependentType()) {
    // If we have a pointer to a dependent type and are using the -> operator,
    // the object type is the type that the pointer points to. We might still
    // have enough information about that type to do something useful.
    if (OpKind == tok::arrow)
      if (const PointerType *Ptr = BaseType->getAs<PointerType>())
        BaseType = Ptr->getPointeeType();

    ObjectType = ParsedType::make(BaseType);
    MayBePseudoDestructor = true;
    return Base;
  }

  // C++ [over.match.oper]p8:
  //   [...] When operator->returns, the operator-> is applied  to the value
  //   returned, with the original second operand.
  if (OpKind == tok::arrow) {
    QualType StartingType = BaseType;
    bool NoArrowOperatorFound = false;
    bool FirstIteration = true;
    FunctionDecl *CurFD = dyn_cast<FunctionDecl>(CurContext);
    // The set of types we've considered so far.
    llvm::SmallPtrSet<CanQualType,8> CTypes;
    SmallVector<FunctionDecl*, 8> OperatorArrows;
    CTypes.insert(Context.getCanonicalType(BaseType));

    while (BaseType->isRecordType()) {
      if (OperatorArrows.size() >= getLangOpts().ArrowDepth) {
        Diag(OpLoc, diag::err_operator_arrow_depth_exceeded)
          << StartingType << getLangOpts().ArrowDepth << Base->getSourceRange();
        noteOperatorArrows(*this, OperatorArrows);
        Diag(OpLoc, diag::note_operator_arrow_depth)
          << getLangOpts().ArrowDepth;
        return ExprError();
      }

      Result = BuildOverloadedArrowExpr(
          S, Base, OpLoc,
          // When in a template specialization and on the first loop iteration,
          // potentially give the default diagnostic (with the fixit in a
          // separate note) instead of having the error reported back to here
          // and giving a diagnostic with a fixit attached to the error itself.
          (FirstIteration && CurFD && CurFD->isFunctionTemplateSpecialization())
              ? nullptr
              : &NoArrowOperatorFound);
      if (Result.isInvalid()) {
        if (NoArrowOperatorFound) {
          if (FirstIteration) {
            Diag(OpLoc, diag::err_typecheck_member_reference_suggestion)
              << BaseType << 1 << Base->getSourceRange()
              << FixItHint::CreateReplacement(OpLoc, ".");
            OpKind = tok::period;
            break;
          }
          Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
            << BaseType << Base->getSourceRange();
          CallExpr *CE = dyn_cast<CallExpr>(Base);
          if (Decl *CD = (CE ? CE->getCalleeDecl() : nullptr)) {
            Diag(CD->getBeginLoc(),
                 diag::note_member_reference_arrow_from_operator_arrow);
          }
        }
        return ExprError();
      }
      Base = Result.get();
      if (CXXOperatorCallExpr *OpCall = dyn_cast<CXXOperatorCallExpr>(Base))
        OperatorArrows.push_back(OpCall->getDirectCallee());
      BaseType = Base->getType();
      CanQualType CBaseType = Context.getCanonicalType(BaseType);
      if (!CTypes.insert(CBaseType).second) {
        Diag(OpLoc, diag::err_operator_arrow_circular) << StartingType;
        noteOperatorArrows(*this, OperatorArrows);
        return ExprError();
      }
      FirstIteration = false;
    }

    if (OpKind == tok::arrow) {
      if (BaseType->isPointerType())
        BaseType = BaseType->getPointeeType();
      else if (auto *AT = Context.getAsArrayType(BaseType))
        BaseType = AT->getElementType();
    }
  }

  // Objective-C properties allow "." access on Objective-C pointer types,
  // so adjust the base type to the object type itself.
  if (BaseType->isObjCObjectPointerType())
    BaseType = BaseType->getPointeeType();

  // C++ [basic.lookup.classref]p2:
  //   [...] If the type of the object expression is of pointer to scalar
  //   type, the unqualified-id is looked up in the context of the complete
  //   postfix-expression.
  //
  // This also indicates that we could be parsing a pseudo-destructor-name.
  // Note that Objective-C class and object types can be pseudo-destructor
  // expressions or normal member (ivar or property) access expressions, and
  // it's legal for the type to be incomplete if this is a pseudo-destructor
  // call.  We'll do more incomplete-type checks later in the lookup process,
  // so just skip this check for ObjC types.
  if (!BaseType->isRecordType()) {
    ObjectType = ParsedType::make(BaseType);
    MayBePseudoDestructor = true;
    return Base;
  }

  // The object type must be complete (or dependent), or
  // C++11 [expr.prim.general]p3:
  //   Unlike the object expression in other contexts, *this is not required to
  //   be of complete type for purposes of class member access (5.2.5) outside
  //   the member function body.
  if (!BaseType->isDependentType() &&
      !isThisOutsideMemberFunctionBody(BaseType) &&
      RequireCompleteType(OpLoc, BaseType, diag::err_incomplete_member_access))
    return ExprError();

  // C++ [basic.lookup.classref]p2:
  //   If the id-expression in a class member access (5.2.5) is an
  //   unqualified-id, and the type of the object expression is of a class
  //   type C (or of pointer to a class type C), the unqualified-id is looked
  //   up in the scope of class C. [...]
  ObjectType = ParsedType::make(BaseType);
  return Base;
}

static bool CheckArrow(Sema &S, QualType &ObjectType, Expr *&Base,
                       tok::TokenKind &OpKind, SourceLocation OpLoc) {
  if (Base->hasPlaceholderType()) {
    ExprResult result = S.CheckPlaceholderExpr(Base);
    if (result.isInvalid()) return true;
    Base = result.get();
  }
  ObjectType = Base->getType();

  // C++ [expr.pseudo]p2:
  //   The left-hand side of the dot operator shall be of scalar type. The
  //   left-hand side of the arrow operator shall be of pointer to scalar type.
  //   This scalar type is the object type.
  // Note that this is rather different from the normal handling for the
  // arrow operator.
  if (OpKind == tok::arrow) {
    // The operator requires a prvalue, so perform lvalue conversions.
    // Only do this if we might plausibly end with a pointer, as otherwise
    // this was likely to be intended to be a '.'.
    if (ObjectType->isPointerType() || ObjectType->isArrayType() ||
        ObjectType->isFunctionType()) {
      ExprResult BaseResult = S.DefaultFunctionArrayLvalueConversion(Base);
      if (BaseResult.isInvalid())
        return true;
      Base = BaseResult.get();
      ObjectType = Base->getType();
    }

    if (const PointerType *Ptr = ObjectType->getAs<PointerType>()) {
      ObjectType = Ptr->getPointeeType();
    } else if (!Base->isTypeDependent()) {
      // The user wrote "p->" when they probably meant "p."; fix it.
      S.Diag(OpLoc, diag::err_typecheck_member_reference_suggestion)
        << ObjectType << true
        << FixItHint::CreateReplacement(OpLoc, ".");
      if (S.isSFINAEContext())
        return true;

      OpKind = tok::period;
    }
  }

  return false;
}

/// Check if it's ok to try and recover dot pseudo destructor calls on
/// pointer objects.
static bool
canRecoverDotPseudoDestructorCallsOnPointerObjects(Sema &SemaRef,
                                                   QualType DestructedType) {
  // If this is a record type, check if its destructor is callable.
  if (auto *RD = DestructedType->getAsCXXRecordDecl()) {
    if (RD->hasDefinition())
      if (CXXDestructorDecl *D = SemaRef.LookupDestructor(RD))
        return SemaRef.CanUseDecl(D, /*TreatUnavailableAsInvalid=*/false);
    return false;
  }

  // Otherwise, check if it's a type for which it's valid to use a pseudo-dtor.
  return DestructedType->isDependentType() || DestructedType->isScalarType() ||
         DestructedType->isVectorType();
}

ExprResult Sema::BuildPseudoDestructorExpr(Expr *Base,
                                           SourceLocation OpLoc,
                                           tok::TokenKind OpKind,
                                           const CXXScopeSpec &SS,
                                           TypeSourceInfo *ScopeTypeInfo,
                                           SourceLocation CCLoc,
                                           SourceLocation TildeLoc,
                                         PseudoDestructorTypeStorage Destructed) {
  TypeSourceInfo *DestructedTypeInfo = Destructed.getTypeSourceInfo();

  QualType ObjectType;
  if (CheckArrow(*this, ObjectType, Base, OpKind, OpLoc))
    return ExprError();

  if (!ObjectType->isDependentType() && !ObjectType->isScalarType() &&
      !ObjectType->isVectorType()) {
    if (getLangOpts().MSVCCompat && ObjectType->isVoidType())
      Diag(OpLoc, diag::ext_pseudo_dtor_on_void) << Base->getSourceRange();
    else {
      Diag(OpLoc, diag::err_pseudo_dtor_base_not_scalar)
        << ObjectType << Base->getSourceRange();
      return ExprError();
    }
  }

  // C++ [expr.pseudo]p2:
  //   [...] The cv-unqualified versions of the object type and of the type
  //   designated by the pseudo-destructor-name shall be the same type.
  if (DestructedTypeInfo) {
    QualType DestructedType = DestructedTypeInfo->getType();
    SourceLocation DestructedTypeStart
      = DestructedTypeInfo->getTypeLoc().getLocalSourceRange().getBegin();
    if (!DestructedType->isDependentType() && !ObjectType->isDependentType()) {
      if (!Context.hasSameUnqualifiedType(DestructedType, ObjectType)) {
        // Detect dot pseudo destructor calls on pointer objects, e.g.:
        //   Foo *foo;
        //   foo.~Foo();
        if (OpKind == tok::period && ObjectType->isPointerType() &&
            Context.hasSameUnqualifiedType(DestructedType,
                                           ObjectType->getPointeeType())) {
          auto Diagnostic =
              Diag(OpLoc, diag::err_typecheck_member_reference_suggestion)
              << ObjectType << /*IsArrow=*/0 << Base->getSourceRange();

          // Issue a fixit only when the destructor is valid.
          if (canRecoverDotPseudoDestructorCallsOnPointerObjects(
                  *this, DestructedType))
            Diagnostic << FixItHint::CreateReplacement(OpLoc, "->");

          // Recover by setting the object type to the destructed type and the
          // operator to '->'.
          ObjectType = DestructedType;
          OpKind = tok::arrow;
        } else {
          Diag(DestructedTypeStart, diag::err_pseudo_dtor_type_mismatch)
              << ObjectType << DestructedType << Base->getSourceRange()
              << DestructedTypeInfo->getTypeLoc().getLocalSourceRange();

          // Recover by setting the destructed type to the object type.
          DestructedType = ObjectType;
          DestructedTypeInfo =
              Context.getTrivialTypeSourceInfo(ObjectType, DestructedTypeStart);
          Destructed = PseudoDestructorTypeStorage(DestructedTypeInfo);
        }
      } else if (DestructedType.getObjCLifetime() !=
                                                ObjectType.getObjCLifetime()) {

        if (DestructedType.getObjCLifetime() == Qualifiers::OCL_None) {
          // Okay: just pretend that the user provided the correctly-qualified
          // type.
        } else {
          Diag(DestructedTypeStart, diag::err_arc_pseudo_dtor_inconstant_quals)
            << ObjectType << DestructedType << Base->getSourceRange()
            << DestructedTypeInfo->getTypeLoc().getLocalSourceRange();
        }

        // Recover by setting the destructed type to the object type.
        DestructedType = ObjectType;
        DestructedTypeInfo = Context.getTrivialTypeSourceInfo(ObjectType,
                                                           DestructedTypeStart);
        Destructed = PseudoDestructorTypeStorage(DestructedTypeInfo);
      }
    }
  }

  // C++ [expr.pseudo]p2:
  //   [...] Furthermore, the two type-names in a pseudo-destructor-name of the
  //   form
  //
  //     ::[opt] nested-name-specifier[opt] type-name :: ~ type-name
  //
  //   shall designate the same scalar type.
  if (ScopeTypeInfo) {
    QualType ScopeType = ScopeTypeInfo->getType();
    if (!ScopeType->isDependentType() && !ObjectType->isDependentType() &&
        !Context.hasSameUnqualifiedType(ScopeType, ObjectType)) {

      Diag(ScopeTypeInfo->getTypeLoc().getLocalSourceRange().getBegin(),
           diag::err_pseudo_dtor_type_mismatch)
        << ObjectType << ScopeType << Base->getSourceRange()
        << ScopeTypeInfo->getTypeLoc().getLocalSourceRange();

      ScopeType = QualType();
      ScopeTypeInfo = nullptr;
    }
  }

  Expr *Result
    = new (Context) CXXPseudoDestructorExpr(Context, Base,
                                            OpKind == tok::arrow, OpLoc,
                                            SS.getWithLocInContext(Context),
                                            ScopeTypeInfo,
                                            CCLoc,
                                            TildeLoc,
                                            Destructed);

  return Result;
}

ExprResult Sema::ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                           SourceLocation OpLoc,
                                           tok::TokenKind OpKind,
                                           CXXScopeSpec &SS,
                                           UnqualifiedId &FirstTypeName,
                                           SourceLocation CCLoc,
                                           SourceLocation TildeLoc,
                                           UnqualifiedId &SecondTypeName) {
  assert((FirstTypeName.getKind() == UnqualifiedIdKind::IK_TemplateId ||
          FirstTypeName.getKind() == UnqualifiedIdKind::IK_Identifier) &&
         "Invalid first type name in pseudo-destructor");
  assert((SecondTypeName.getKind() == UnqualifiedIdKind::IK_TemplateId ||
          SecondTypeName.getKind() == UnqualifiedIdKind::IK_Identifier) &&
         "Invalid second type name in pseudo-destructor");

  QualType ObjectType;
  if (CheckArrow(*this, ObjectType, Base, OpKind, OpLoc))
    return ExprError();

  // Compute the object type that we should use for name lookup purposes. Only
  // record types and dependent types matter.
  ParsedType ObjectTypePtrForLookup;
  if (!SS.isSet()) {
    if (ObjectType->isRecordType())
      ObjectTypePtrForLookup = ParsedType::make(ObjectType);
    else if (ObjectType->isDependentType())
      ObjectTypePtrForLookup = ParsedType::make(Context.DependentTy);
  }

  // Convert the name of the type being destructed (following the ~) into a
  // type (with source-location information).
  QualType DestructedType;
  TypeSourceInfo *DestructedTypeInfo = nullptr;
  PseudoDestructorTypeStorage Destructed;
  if (SecondTypeName.getKind() == UnqualifiedIdKind::IK_Identifier) {
    ParsedType T = getTypeName(*SecondTypeName.Identifier,
                               SecondTypeName.StartLocation,
                               S, &SS, true, false, ObjectTypePtrForLookup,
                               /*IsCtorOrDtorName*/true);
    if (!T &&
        ((SS.isSet() && !computeDeclContext(SS, false)) ||
         (!SS.isSet() && ObjectType->isDependentType()))) {
      // The name of the type being destroyed is a dependent name, and we
      // couldn't find anything useful in scope. Just store the identifier and
      // it's location, and we'll perform (qualified) name lookup again at
      // template instantiation time.
      Destructed = PseudoDestructorTypeStorage(SecondTypeName.Identifier,
                                               SecondTypeName.StartLocation);
    } else if (!T) {
      Diag(SecondTypeName.StartLocation,
           diag::err_pseudo_dtor_destructor_non_type)
        << SecondTypeName.Identifier << ObjectType;
      if (isSFINAEContext())
        return ExprError();

      // Recover by assuming we had the right type all along.
      DestructedType = ObjectType;
    } else
      DestructedType = GetTypeFromParser(T, &DestructedTypeInfo);
  } else {
    // Resolve the template-id to a type.
    TemplateIdAnnotation *TemplateId = SecondTypeName.TemplateId;
    ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                       TemplateId->NumArgs);
    TypeResult T = ActOnTemplateIdType(S,
                                       SS,
                                       TemplateId->TemplateKWLoc,
                                       TemplateId->Template,
                                       TemplateId->Name,
                                       TemplateId->TemplateNameLoc,
                                       TemplateId->LAngleLoc,
                                       TemplateArgsPtr,
                                       TemplateId->RAngleLoc,
                                       /*IsCtorOrDtorName*/true);
    if (T.isInvalid() || !T.get()) {
      // Recover by assuming we had the right type all along.
      DestructedType = ObjectType;
    } else
      DestructedType = GetTypeFromParser(T.get(), &DestructedTypeInfo);
  }

  // If we've performed some kind of recovery, (re-)build the type source
  // information.
  if (!DestructedType.isNull()) {
    if (!DestructedTypeInfo)
      DestructedTypeInfo = Context.getTrivialTypeSourceInfo(DestructedType,
                                                  SecondTypeName.StartLocation);
    Destructed = PseudoDestructorTypeStorage(DestructedTypeInfo);
  }

  // Convert the name of the scope type (the type prior to '::') into a type.
  TypeSourceInfo *ScopeTypeInfo = nullptr;
  QualType ScopeType;
  if (FirstTypeName.getKind() == UnqualifiedIdKind::IK_TemplateId ||
      FirstTypeName.Identifier) {
    if (FirstTypeName.getKind() == UnqualifiedIdKind::IK_Identifier) {
      ParsedType T = getTypeName(*FirstTypeName.Identifier,
                                 FirstTypeName.StartLocation,
                                 S, &SS, true, false, ObjectTypePtrForLookup,
                                 /*IsCtorOrDtorName*/true);
      if (!T) {
        Diag(FirstTypeName.StartLocation,
             diag::err_pseudo_dtor_destructor_non_type)
          << FirstTypeName.Identifier << ObjectType;

        if (isSFINAEContext())
          return ExprError();

        // Just drop this type. It's unnecessary anyway.
        ScopeType = QualType();
      } else
        ScopeType = GetTypeFromParser(T, &ScopeTypeInfo);
    } else {
      // Resolve the template-id to a type.
      TemplateIdAnnotation *TemplateId = FirstTypeName.TemplateId;
      ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
                                         TemplateId->NumArgs);
      TypeResult T = ActOnTemplateIdType(S,
                                         SS,
                                         TemplateId->TemplateKWLoc,
                                         TemplateId->Template,
                                         TemplateId->Name,
                                         TemplateId->TemplateNameLoc,
                                         TemplateId->LAngleLoc,
                                         TemplateArgsPtr,
                                         TemplateId->RAngleLoc,
                                         /*IsCtorOrDtorName*/true);
      if (T.isInvalid() || !T.get()) {
        // Recover by dropping this type.
        ScopeType = QualType();
      } else
        ScopeType = GetTypeFromParser(T.get(), &ScopeTypeInfo);
    }
  }

  if (!ScopeType.isNull() && !ScopeTypeInfo)
    ScopeTypeInfo = Context.getTrivialTypeSourceInfo(ScopeType,
                                                  FirstTypeName.StartLocation);


  return BuildPseudoDestructorExpr(Base, OpLoc, OpKind, SS,
                                   ScopeTypeInfo, CCLoc, TildeLoc,
                                   Destructed);
}

ExprResult Sema::ActOnPseudoDestructorExpr(Scope *S, Expr *Base,
                                           SourceLocation OpLoc,
                                           tok::TokenKind OpKind,
                                           SourceLocation TildeLoc,
                                           const DeclSpec& DS) {
  QualType ObjectType;
  if (CheckArrow(*this, ObjectType, Base, OpKind, OpLoc))
    return ExprError();

  if (DS.getTypeSpecType() == DeclSpec::TST_decltype_auto) {
    Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
    return true;
  }

  QualType T = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc(),
                                 false);

  TypeLocBuilder TLB;
  DecltypeTypeLoc DecltypeTL = TLB.push<DecltypeTypeLoc>(T);
  DecltypeTL.setNameLoc(DS.getTypeSpecTypeLoc());
  TypeSourceInfo *DestructedTypeInfo = TLB.getTypeSourceInfo(Context, T);
  PseudoDestructorTypeStorage Destructed(DestructedTypeInfo);

  return BuildPseudoDestructorExpr(Base, OpLoc, OpKind, CXXScopeSpec(),
                                   nullptr, SourceLocation(), TildeLoc,
                                   Destructed);
}

ExprResult Sema::BuildCXXMemberCallExpr(Expr *E, NamedDecl *FoundDecl,
                                        CXXConversionDecl *Method,
                                        bool HadMultipleCandidates) {
  // Convert the expression to match the conversion function's implicit object
  // parameter.
  ExprResult Exp = PerformObjectArgumentInitialization(E, /*Qualifier=*/nullptr,
                                          FoundDecl, Method);
  if (Exp.isInvalid())
    return true;

  if (Method->getParent()->isLambda() &&
      Method->getConversionType()->isBlockPointerType()) {
    // This is a lambda conversion to block pointer; check if the argument
    // was a LambdaExpr.
    Expr *SubE = E;
    CastExpr *CE = dyn_cast<CastExpr>(SubE);
    if (CE && CE->getCastKind() == CK_NoOp)
      SubE = CE->getSubExpr();
    SubE = SubE->IgnoreParens();
    if (CXXBindTemporaryExpr *BE = dyn_cast<CXXBindTemporaryExpr>(SubE))
      SubE = BE->getSubExpr();
    if (isa<LambdaExpr>(SubE)) {
      // For the conversion to block pointer on a lambda expression, we
      // construct a special BlockLiteral instead; this doesn't really make
      // a difference in ARC, but outside of ARC the resulting block literal
      // follows the normal lifetime rules for block literals instead of being
      // autoreleased.
      PushExpressionEvaluationContext(
          ExpressionEvaluationContext::PotentiallyEvaluated);
      ExprResult BlockExp = BuildBlockForLambdaConversion(
          Exp.get()->getExprLoc(), Exp.get()->getExprLoc(), Method, Exp.get());
      PopExpressionEvaluationContext();

      // FIXME: This note should be produced by a CodeSynthesisContext.
      if (BlockExp.isInvalid())
        Diag(Exp.get()->getExprLoc(), diag::note_lambda_to_block_conv);
      return BlockExp;
    }
  }

  MemberExpr *ME =
      BuildMemberExpr(Exp.get(), /*IsArrow=*/false, SourceLocation(),
                      NestedNameSpecifierLoc(), SourceLocation(), Method,
                      DeclAccessPair::make(FoundDecl, FoundDecl->getAccess()),
                      HadMultipleCandidates, DeclarationNameInfo(),
                      Context.BoundMemberTy, VK_PRValue, OK_Ordinary);

  QualType ResultType = Method->getReturnType();
  ExprValueKind VK = Expr::getValueKindForType(ResultType);
  ResultType = ResultType.getNonLValueExprType(Context);

  CXXMemberCallExpr *CE = CXXMemberCallExpr::Create(
      Context, ME, /*Args=*/{}, ResultType, VK, Exp.get()->getEndLoc(),
      CurFPFeatureOverrides());

  if (CheckFunctionCall(Method, CE,
                        Method->getType()->castAs<FunctionProtoType>()))
    return ExprError();

  return CheckForImmediateInvocation(CE, CE->getMethodDecl());
}

ExprResult Sema::BuildCXXNoexceptExpr(SourceLocation KeyLoc, Expr *Operand,
                                      SourceLocation RParen) {
  // If the operand is an unresolved lookup expression, the expression is ill-
  // formed per [over.over]p1, because overloaded function names cannot be used
  // without arguments except in explicit contexts.
  ExprResult R = CheckPlaceholderExpr(Operand);
  if (R.isInvalid())
    return R;

  R = CheckUnevaluatedOperand(R.get());
  if (R.isInvalid())
    return ExprError();

  Operand = R.get();

  if (!inTemplateInstantiation() && !Operand->isInstantiationDependent() &&
      Operand->HasSideEffects(Context, false)) {
    // The expression operand for noexcept is in an unevaluated expression
    // context, so side effects could result in unintended consequences.
    Diag(Operand->getExprLoc(), diag::warn_side_effects_unevaluated_context);
  }

  CanThrowResult CanThrow = canThrow(Operand);
  return new (Context)
      CXXNoexceptExpr(Context.BoolTy, Operand, CanThrow, KeyLoc, RParen);
}

ExprResult Sema::ActOnNoexceptExpr(SourceLocation KeyLoc, SourceLocation,
                                   Expr *Operand, SourceLocation RParen) {
  return BuildCXXNoexceptExpr(KeyLoc, Operand, RParen);
}

static void MaybeDecrementCount(
    Expr *E, llvm::DenseMap<const VarDecl *, int> &RefsMinusAssignments) {
  DeclRefExpr *LHS = nullptr;
  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
    if (BO->getLHS()->getType()->isDependentType() ||
        BO->getRHS()->getType()->isDependentType()) {
      if (BO->getOpcode() != BO_Assign)
        return;
    } else if (!BO->isAssignmentOp())
      return;
    LHS = dyn_cast<DeclRefExpr>(BO->getLHS());
  } else if (CXXOperatorCallExpr *COCE = dyn_cast<CXXOperatorCallExpr>(E)) {
    if (COCE->getOperator() != OO_Equal)
      return;
    LHS = dyn_cast<DeclRefExpr>(COCE->getArg(0));
  }
  if (!LHS)
    return;
  VarDecl *VD = dyn_cast<VarDecl>(LHS->getDecl());
  if (!VD)
    return;
  auto iter = RefsMinusAssignments.find(VD);
  if (iter == RefsMinusAssignments.end())
    return;
  iter->getSecond()--;
}

/// Perform the conversions required for an expression used in a
/// context that ignores the result.
ExprResult Sema::IgnoredValueConversions(Expr *E) {
  MaybeDecrementCount(E, RefsMinusAssignments);

  if (E->hasPlaceholderType()) {
    ExprResult result = CheckPlaceholderExpr(E);
    if (result.isInvalid()) return E;
    E = result.get();
  }

  // C99 6.3.2.1:
  //   [Except in specific positions,] an lvalue that does not have
  //   array type is converted to the value stored in the
  //   designated object (and is no longer an lvalue).
  if (E->isPRValue()) {
    // In C, function designators (i.e. expressions of function type)
    // are r-values, but we still want to do function-to-pointer decay
    // on them.  This is both technically correct and convenient for
    // some clients.
    if (!getLangOpts().CPlusPlus && E->getType()->isFunctionType())
      return DefaultFunctionArrayConversion(E);

    return E;
  }

  if (getLangOpts().CPlusPlus) {
    // The C++11 standard defines the notion of a discarded-value expression;
    // normally, we don't need to do anything to handle it, but if it is a
    // volatile lvalue with a special form, we perform an lvalue-to-rvalue
    // conversion.
    if (getLangOpts().CPlusPlus11 && E->isReadIfDiscardedInCPlusPlus11()) {
      ExprResult Res = DefaultLvalueConversion(E);
      if (Res.isInvalid())
        return E;
      E = Res.get();
    } else {
      // Per C++2a [expr.ass]p5, a volatile assignment is not deprecated if
      // it occurs as a discarded-value expression.
      CheckUnusedVolatileAssignment(E);
    }

    // C++1z:
    //   If the expression is a prvalue after this optional conversion, the
    //   temporary materialization conversion is applied.
    //
    // We skip this step: IR generation is able to synthesize the storage for
    // itself in the aggregate case, and adding the extra node to the AST is
    // just clutter.
    // FIXME: We don't emit lifetime markers for the temporaries due to this.
    // FIXME: Do any other AST consumers care about this?
    return E;
  }

  // GCC seems to also exclude expressions of incomplete enum type.
  if (const EnumType *T = E->getType()->getAs<EnumType>()) {
    if (!T->getDecl()->isComplete()) {
      // FIXME: stupid workaround for a codegen bug!
      E = ImpCastExprToType(E, Context.VoidTy, CK_ToVoid).get();
      return E;
    }
  }

  ExprResult Res = DefaultFunctionArrayLvalueConversion(E);
  if (Res.isInvalid())
    return E;
  E = Res.get();

  if (!E->getType()->isVoidType())
    RequireCompleteType(E->getExprLoc(), E->getType(),
                        diag::err_incomplete_type);
  return E;
}

ExprResult Sema::CheckUnevaluatedOperand(Expr *E) {
  // Per C++2a [expr.ass]p5, a volatile assignment is not deprecated if
  // it occurs as an unevaluated operand.
  CheckUnusedVolatileAssignment(E);

  return E;
}

// If we can unambiguously determine whether Var can never be used
// in a constant expression, return true.
//  - if the variable and its initializer are non-dependent, then
//    we can unambiguously check if the variable is a constant expression.
//  - if the initializer is not value dependent - we can determine whether
//    it can be used to initialize a constant expression.  If Init can not
//    be used to initialize a constant expression we conclude that Var can
//    never be a constant expression.
//  - FXIME: if the initializer is dependent, we can still do some analysis and
//    identify certain cases unambiguously as non-const by using a Visitor:
//      - such as those that involve odr-use of a ParmVarDecl, involve a new
//        delete, lambda-expr, dynamic-cast, reinterpret-cast etc...
static inline bool VariableCanNeverBeAConstantExpression(VarDecl *Var,
    ASTContext &Context) {
  if (isa<ParmVarDecl>(Var)) return true;
  const VarDecl *DefVD = nullptr;

  // If there is no initializer - this can not be a constant expression.
  if (!Var->getAnyInitializer(DefVD)) return true;
  assert(DefVD);
  if (DefVD->isWeak()) return false;
  EvaluatedStmt *Eval = DefVD->ensureEvaluatedStmt();

  Expr *Init = cast<Expr>(Eval->Value);

  if (Var->getType()->isDependentType() || Init->isValueDependent()) {
    // FIXME: Teach the constant evaluator to deal with the non-dependent parts
    // of value-dependent expressions, and use it here to determine whether the
    // initializer is a potential constant expression.
    return false;
  }

  return !Var->isUsableInConstantExpressions(Context);
}

/// Check if the current lambda has any potential captures
/// that must be captured by any of its enclosing lambdas that are ready to
/// capture. If there is a lambda that can capture a nested
/// potential-capture, go ahead and do so.  Also, check to see if any
/// variables are uncaptureable or do not involve an odr-use so do not
/// need to be captured.

static void CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(
    Expr *const FE, LambdaScopeInfo *const CurrentLSI, Sema &S) {

  assert(!S.isUnevaluatedContext());
  assert(S.CurContext->isDependentContext());
#ifndef NDEBUG
  DeclContext *DC = S.CurContext;
  while (DC && isa<CapturedDecl>(DC))
    DC = DC->getParent();
  assert(
      CurrentLSI->CallOperator == DC &&
      "The current call operator must be synchronized with Sema's CurContext");
#endif // NDEBUG

  const bool IsFullExprInstantiationDependent = FE->isInstantiationDependent();

  // All the potentially captureable variables in the current nested
  // lambda (within a generic outer lambda), must be captured by an
  // outer lambda that is enclosed within a non-dependent context.
  CurrentLSI->visitPotentialCaptures([&] (VarDecl *Var, Expr *VarExpr) {
    // If the variable is clearly identified as non-odr-used and the full
    // expression is not instantiation dependent, only then do we not
    // need to check enclosing lambda's for speculative captures.
    // For e.g.:
    // Even though 'x' is not odr-used, it should be captured.
    // int test() {
    //   const int x = 10;
    //   auto L = [=](auto a) {
    //     (void) +x + a;
    //   };
    // }
    if (CurrentLSI->isVariableExprMarkedAsNonODRUsed(VarExpr) &&
        !IsFullExprInstantiationDependent)
      return;

    // If we have a capture-capable lambda for the variable, go ahead and
    // capture the variable in that lambda (and all its enclosing lambdas).
    if (const Optional<unsigned> Index =
            getStackIndexOfNearestEnclosingCaptureCapableLambda(
                S.FunctionScopes, Var, S))
      S.MarkCaptureUsedInEnclosingContext(Var, VarExpr->getExprLoc(),
                                          Index.getValue());
    const bool IsVarNeverAConstantExpression =
        VariableCanNeverBeAConstantExpression(Var, S.Context);
    if (!IsFullExprInstantiationDependent || IsVarNeverAConstantExpression) {
      // This full expression is not instantiation dependent or the variable
      // can not be used in a constant expression - which means
      // this variable must be odr-used here, so diagnose a
      // capture violation early, if the variable is un-captureable.
      // This is purely for diagnosing errors early.  Otherwise, this
      // error would get diagnosed when the lambda becomes capture ready.
      QualType CaptureType, DeclRefType;
      SourceLocation ExprLoc = VarExpr->getExprLoc();
      if (S.tryCaptureVariable(Var, ExprLoc, S.TryCapture_Implicit,
                          /*EllipsisLoc*/ SourceLocation(),
                          /*BuildAndDiagnose*/false, CaptureType,
                          DeclRefType, nullptr)) {
        // We will never be able to capture this variable, and we need
        // to be able to in any and all instantiations, so diagnose it.
        S.tryCaptureVariable(Var, ExprLoc, S.TryCapture_Implicit,
                          /*EllipsisLoc*/ SourceLocation(),
                          /*BuildAndDiagnose*/true, CaptureType,
                          DeclRefType, nullptr);
      }
    }
  });

  // Check if 'this' needs to be captured.
  if (CurrentLSI->hasPotentialThisCapture()) {
    // If we have a capture-capable lambda for 'this', go ahead and capture
    // 'this' in that lambda (and all its enclosing lambdas).
    if (const Optional<unsigned> Index =
            getStackIndexOfNearestEnclosingCaptureCapableLambda(
                S.FunctionScopes, /*0 is 'this'*/ nullptr, S)) {
      const unsigned FunctionScopeIndexOfCapturableLambda = Index.getValue();
      S.CheckCXXThisCapture(CurrentLSI->PotentialThisCaptureLocation,
                            /*Explicit*/ false, /*BuildAndDiagnose*/ true,
                            &FunctionScopeIndexOfCapturableLambda);
    }
  }

  // Reset all the potential captures at the end of each full-expression.
  CurrentLSI->clearPotentialCaptures();
}

static ExprResult attemptRecovery(Sema &SemaRef,
                                  const TypoCorrectionConsumer &Consumer,
                                  const TypoCorrection &TC) {
  LookupResult R(SemaRef, Consumer.getLookupResult().getLookupNameInfo(),
                 Consumer.getLookupResult().getLookupKind());
  const CXXScopeSpec *SS = Consumer.getSS();
  CXXScopeSpec NewSS;

  // Use an approprate CXXScopeSpec for building the expr.
  if (auto *NNS = TC.getCorrectionSpecifier())
    NewSS.MakeTrivial(SemaRef.Context, NNS, TC.getCorrectionRange());
  else if (SS && !TC.WillReplaceSpecifier())
    NewSS = *SS;

  if (auto *ND = TC.getFoundDecl()) {
    R.setLookupName(ND->getDeclName());
    R.addDecl(ND);
    if (ND->isCXXClassMember()) {
      // Figure out the correct naming class to add to the LookupResult.
      CXXRecordDecl *Record = nullptr;
      if (auto *NNS = TC.getCorrectionSpecifier())
        Record = NNS->getAsType()->getAsCXXRecordDecl();
      if (!Record)
        Record =
            dyn_cast<CXXRecordDecl>(ND->getDeclContext()->getRedeclContext());
      if (Record)
        R.setNamingClass(Record);

      // Detect and handle the case where the decl might be an implicit
      // member.
      bool MightBeImplicitMember;
      if (!Consumer.isAddressOfOperand())
        MightBeImplicitMember = true;
      else if (!NewSS.isEmpty())
        MightBeImplicitMember = false;
      else if (R.isOverloadedResult())
        MightBeImplicitMember = false;
      else if (R.isUnresolvableResult())
        MightBeImplicitMember = true;
      else
        MightBeImplicitMember = isa<FieldDecl>(ND) ||
                                isa<IndirectFieldDecl>(ND) ||
                                isa<MSPropertyDecl>(ND);

      if (MightBeImplicitMember)
        return SemaRef.BuildPossibleImplicitMemberExpr(
            NewSS, /*TemplateKWLoc*/ SourceLocation(), R,
            /*TemplateArgs*/ nullptr, /*S*/ nullptr);
    } else if (auto *Ivar = dyn_cast<ObjCIvarDecl>(ND)) {
      return SemaRef.LookupInObjCMethod(R, Consumer.getScope(),
                                        Ivar->getIdentifier());
    }
  }

  return SemaRef.BuildDeclarationNameExpr(NewSS, R, /*NeedsADL*/ false,
                                          /*AcceptInvalidDecl*/ true);
}

namespace {
class FindTypoExprs : public RecursiveASTVisitor<FindTypoExprs> {
  llvm::SmallSetVector<TypoExpr *, 2> &TypoExprs;

public:
  explicit FindTypoExprs(llvm::SmallSetVector<TypoExpr *, 2> &TypoExprs)
      : TypoExprs(TypoExprs) {}
  bool VisitTypoExpr(TypoExpr *TE) {
    TypoExprs.insert(TE);
    return true;
  }
};

class TransformTypos : public TreeTransform<TransformTypos> {
  typedef TreeTransform<TransformTypos> BaseTransform;

  VarDecl *InitDecl; // A decl to avoid as a correction because it is in the
                     // process of being initialized.
  llvm::function_ref<ExprResult(Expr *)> ExprFilter;
  llvm::SmallSetVector<TypoExpr *, 2> TypoExprs, AmbiguousTypoExprs;
  llvm::SmallDenseMap<TypoExpr *, ExprResult, 2> TransformCache;
  llvm::SmallDenseMap<OverloadExpr *, Expr *, 4> OverloadResolution;

  /// Emit diagnostics for all of the TypoExprs encountered.
  ///
  /// If the TypoExprs were successfully corrected, then the diagnostics should
  /// suggest the corrections. Otherwise the diagnostics will not suggest
  /// anything (having been passed an empty TypoCorrection).
  ///
  /// If we've failed to correct due to ambiguous corrections, we need to
  /// be sure to pass empty corrections and replacements. Otherwise it's
  /// possible that the Consumer has a TypoCorrection that failed to ambiguity
  /// and we don't want to report those diagnostics.
  void EmitAllDiagnostics(bool IsAmbiguous) {
    for (TypoExpr *TE : TypoExprs) {
      auto &State = SemaRef.getTypoExprState(TE);
      if (State.DiagHandler) {
        TypoCorrection TC = IsAmbiguous
            ? TypoCorrection() : State.Consumer->getCurrentCorrection();
        ExprResult Replacement = IsAmbiguous ? ExprError() : TransformCache[TE];

        // Extract the NamedDecl from the transformed TypoExpr and add it to the
        // TypoCorrection, replacing the existing decls. This ensures the right
        // NamedDecl is used in diagnostics e.g. in the case where overload
        // resolution was used to select one from several possible decls that
        // had been stored in the TypoCorrection.
        if (auto *ND = getDeclFromExpr(
                Replacement.isInvalid() ? nullptr : Replacement.get()))
          TC.setCorrectionDecl(ND);

        State.DiagHandler(TC);
      }
      SemaRef.clearDelayedTypo(TE);
    }
  }

  /// Try to advance the typo correction state of the first unfinished TypoExpr.
  /// We allow advancement of the correction stream by removing it from the
  /// TransformCache which allows `TransformTypoExpr` to advance during the
  /// next transformation attempt.
  ///
  /// Any substitution attempts for the previous TypoExprs (which must have been
  /// finished) will need to be retried since it's possible that they will now
  /// be invalid given the latest advancement.
  ///
  /// We need to be sure that we're making progress - it's possible that the
  /// tree is so malformed that the transform never makes it to the
  /// `TransformTypoExpr`.
  ///
  /// Returns true if there are any untried correction combinations.
  bool CheckAndAdvanceTypoExprCorrectionStreams() {
    for (auto TE : TypoExprs) {
      auto &State = SemaRef.getTypoExprState(TE);
      TransformCache.erase(TE);
      if (!State.Consumer->hasMadeAnyCorrectionProgress())
        return false;
      if (!State.Consumer->finished())
        return true;
      State.Consumer->resetCorrectionStream();
    }
    return false;
  }

  NamedDecl *getDeclFromExpr(Expr *E) {
    if (auto *OE = dyn_cast_or_null<OverloadExpr>(E))
      E = OverloadResolution[OE];

    if (!E)
      return nullptr;
    if (auto *DRE = dyn_cast<DeclRefExpr>(E))
      return DRE->getFoundDecl();
    if (auto *ME = dyn_cast<MemberExpr>(E))
      return ME->getFoundDecl();
    // FIXME: Add any other expr types that could be be seen by the delayed typo
    // correction TreeTransform for which the corresponding TypoCorrection could
    // contain multiple decls.
    return nullptr;
  }

  ExprResult TryTransform(Expr *E) {
    Sema::SFINAETrap Trap(SemaRef);
    ExprResult Res = TransformExpr(E);
    if (Trap.hasErrorOccurred() || Res.isInvalid())
      return ExprError();

    return ExprFilter(Res.get());
  }

  // Since correcting typos may intoduce new TypoExprs, this function
  // checks for new TypoExprs and recurses if it finds any. Note that it will
  // only succeed if it is able to correct all typos in the given expression.
  ExprResult CheckForRecursiveTypos(ExprResult Res, bool &IsAmbiguous) {
    if (Res.isInvalid()) {
      return Res;
    }
    // Check to see if any new TypoExprs were created. If so, we need to recurse
    // to check their validity.
    Expr *FixedExpr = Res.get();

    auto SavedTypoExprs = std::move(TypoExprs);
    auto SavedAmbiguousTypoExprs = std::move(AmbiguousTypoExprs);
    TypoExprs.clear();
    AmbiguousTypoExprs.clear();

    FindTypoExprs(TypoExprs).TraverseStmt(FixedExpr);
    if (!TypoExprs.empty()) {
      // Recurse to handle newly created TypoExprs. If we're not able to
      // handle them, discard these TypoExprs.
      ExprResult RecurResult =
          RecursiveTransformLoop(FixedExpr, IsAmbiguous);
      if (RecurResult.isInvalid()) {
        Res = ExprError();
        // Recursive corrections didn't work, wipe them away and don't add
        // them to the TypoExprs set. Remove them from Sema's TypoExpr list
        // since we don't want to clear them twice. Note: it's possible the
        // TypoExprs were created recursively and thus won't be in our
        // Sema's TypoExprs - they were created in our `RecursiveTransformLoop`.
        auto &SemaTypoExprs = SemaRef.TypoExprs;
        for (auto TE : TypoExprs) {
          TransformCache.erase(TE);
          SemaRef.clearDelayedTypo(TE);

          auto SI = find(SemaTypoExprs, TE);
          if (SI != SemaTypoExprs.end()) {
            SemaTypoExprs.erase(SI);
          }
        }
      } else {
        // TypoExpr is valid: add newly created TypoExprs since we were
        // able to correct them.
        Res = RecurResult;
        SavedTypoExprs.set_union(TypoExprs);
      }
    }

    TypoExprs = std::move(SavedTypoExprs);
    AmbiguousTypoExprs = std::move(SavedAmbiguousTypoExprs);

    return Res;
  }

  // Try to transform the given expression, looping through the correction
  // candidates with `CheckAndAdvanceTypoExprCorrectionStreams`.
  //
  // If valid ambiguous typo corrections are seen, `IsAmbiguous` is set to
  // true and this method immediately will return an `ExprError`.
  ExprResult RecursiveTransformLoop(Expr *E, bool &IsAmbiguous) {
    ExprResult Res;
    auto SavedTypoExprs = std::move(SemaRef.TypoExprs);
    SemaRef.TypoExprs.clear();

    while (true) {
      Res = CheckForRecursiveTypos(TryTransform(E), IsAmbiguous);

      // Recursion encountered an ambiguous correction. This means that our
      // correction itself is ambiguous, so stop now.
      if (IsAmbiguous)
        break;

      // If the transform is still valid after checking for any new typos,
      // it's good to go.
      if (!Res.isInvalid())
        break;

      // The transform was invalid, see if we have any TypoExprs with untried
      // correction candidates.
      if (!CheckAndAdvanceTypoExprCorrectionStreams())
        break;
    }

    // If we found a valid result, double check to make sure it's not ambiguous.
    if (!IsAmbiguous && !Res.isInvalid() && !AmbiguousTypoExprs.empty()) {
      auto SavedTransformCache =
          llvm::SmallDenseMap<TypoExpr *, ExprResult, 2>(TransformCache);

      // Ensure none of the TypoExprs have multiple typo correction candidates
      // with the same edit length that pass all the checks and filters.
      while (!AmbiguousTypoExprs.empty()) {
        auto TE  = AmbiguousTypoExprs.back();

        // TryTransform itself can create new Typos, adding them to the TypoExpr map
        // and invalidating our TypoExprState, so always fetch it instead of storing.
        SemaRef.getTypoExprState(TE).Consumer->saveCurrentPosition();

        TypoCorrection TC = SemaRef.getTypoExprState(TE).Consumer->peekNextCorrection();
        TypoCorrection Next;
        do {
          // Fetch the next correction by erasing the typo from the cache and calling
          // `TryTransform` which will iterate through corrections in
          // `TransformTypoExpr`.
          TransformCache.erase(TE);
          ExprResult AmbigRes = CheckForRecursiveTypos(TryTransform(E), IsAmbiguous);

          if (!AmbigRes.isInvalid() || IsAmbiguous) {
            SemaRef.getTypoExprState(TE).Consumer->resetCorrectionStream();
            SavedTransformCache.erase(TE);
            Res = ExprError();
            IsAmbiguous = true;
            break;
          }
        } while ((Next = SemaRef.getTypoExprState(TE).Consumer->peekNextCorrection()) &&
                 Next.getEditDistance(false) == TC.getEditDistance(false));

        if (IsAmbiguous)
          break;

        AmbiguousTypoExprs.remove(TE);
        SemaRef.getTypoExprState(TE).Consumer->restoreSavedPosition();
        TransformCache[TE] = SavedTransformCache[TE];
      }
      TransformCache = std::move(SavedTransformCache);
    }

    // Wipe away any newly created TypoExprs that we don't know about. Since we
    // clear any invalid TypoExprs in `CheckForRecursiveTypos`, this is only
    // possible if a `TypoExpr` is created during a transformation but then
    // fails before we can discover it.
    auto &SemaTypoExprs = SemaRef.TypoExprs;
    for (auto Iterator = SemaTypoExprs.begin(); Iterator != SemaTypoExprs.end();) {
      auto TE = *Iterator;
      auto FI = find(TypoExprs, TE);
      if (FI != TypoExprs.end()) {
        Iterator++;
        continue;
      }
      SemaRef.clearDelayedTypo(TE);
      Iterator = SemaTypoExprs.erase(Iterator);
    }
    SemaRef.TypoExprs = std::move(SavedTypoExprs);

    return Res;
  }

public:
  TransformTypos(Sema &SemaRef, VarDecl *InitDecl, llvm::function_ref<ExprResult(Expr *)> Filter)
      : BaseTransform(SemaRef), InitDecl(InitDecl), ExprFilter(Filter) {}

  ExprResult RebuildCallExpr(Expr *Callee, SourceLocation LParenLoc,
                                   MultiExprArg Args,
                                   SourceLocation RParenLoc,
                                   Expr *ExecConfig = nullptr) {
    auto Result = BaseTransform::RebuildCallExpr(Callee, LParenLoc, Args,
                                                 RParenLoc, ExecConfig);
    if (auto *OE = dyn_cast<OverloadExpr>(Callee)) {
      if (Result.isUsable()) {
        Expr *ResultCall = Result.get();
        if (auto *BE = dyn_cast<CXXBindTemporaryExpr>(ResultCall))
          ResultCall = BE->getSubExpr();
        if (auto *CE = dyn_cast<CallExpr>(ResultCall))
          OverloadResolution[OE] = CE->getCallee();
      }
    }
    return Result;
  }

  ExprResult TransformLambdaExpr(LambdaExpr *E) { return Owned(E); }

  ExprResult TransformBlockExpr(BlockExpr *E) { return Owned(E); }

  ExprResult Transform(Expr *E) {
    bool IsAmbiguous = false;
    ExprResult Res = RecursiveTransformLoop(E, IsAmbiguous);

    if (!Res.isUsable())
      FindTypoExprs(TypoExprs).TraverseStmt(E);

    EmitAllDiagnostics(IsAmbiguous);

    return Res;
  }

  ExprResult TransformTypoExpr(TypoExpr *E) {
    // If the TypoExpr hasn't been seen before, record it. Otherwise, return the
    // cached transformation result if there is one and the TypoExpr isn't the
    // first one that was encountered.
    auto &CacheEntry = TransformCache[E];
    if (!TypoExprs.insert(E) && !CacheEntry.isUnset()) {
      return CacheEntry;
    }

    auto &State = SemaRef.getTypoExprState(E);
    assert(State.Consumer && "Cannot transform a cleared TypoExpr");

    // For the first TypoExpr and an uncached TypoExpr, find the next likely
    // typo correction and return it.
    while (TypoCorrection TC = State.Consumer->getNextCorrection()) {
      if (InitDecl && TC.getFoundDecl() == InitDecl)
        continue;
      // FIXME: If we would typo-correct to an invalid declaration, it's
      // probably best to just suppress all errors from this typo correction.
      ExprResult NE = State.RecoveryHandler ?
          State.RecoveryHandler(SemaRef, E, TC) :
          attemptRecovery(SemaRef, *State.Consumer, TC);
      if (!NE.isInvalid()) {
        // Check whether there may be a second viable correction with the same
        // edit distance; if so, remember this TypoExpr may have an ambiguous
        // correction so it can be more thoroughly vetted later.
        TypoCorrection Next;
        if ((Next = State.Consumer->peekNextCorrection()) &&
            Next.getEditDistance(false) == TC.getEditDistance(false)) {
          AmbiguousTypoExprs.insert(E);
        } else {
          AmbiguousTypoExprs.remove(E);
        }
        assert(!NE.isUnset() &&
               "Typo was transformed into a valid-but-null ExprResult");
        return CacheEntry = NE;
      }
    }
    return CacheEntry = ExprError();
  }
};
}

ExprResult
Sema::CorrectDelayedTyposInExpr(Expr *E, VarDecl *InitDecl,
                                bool RecoverUncorrectedTypos,
                                llvm::function_ref<ExprResult(Expr *)> Filter) {
  // If the current evaluation context indicates there are uncorrected typos
  // and the current expression isn't guaranteed to not have typos, try to
  // resolve any TypoExpr nodes that might be in the expression.
  if (E && !ExprEvalContexts.empty() && ExprEvalContexts.back().NumTypos &&
      (E->isTypeDependent() || E->isValueDependent() ||
       E->isInstantiationDependent())) {
    auto TyposResolved = DelayedTypos.size();
    auto Result = TransformTypos(*this, InitDecl, Filter).Transform(E);
    TyposResolved -= DelayedTypos.size();
    if (Result.isInvalid() || Result.get() != E) {
      ExprEvalContexts.back().NumTypos -= TyposResolved;
      if (Result.isInvalid() && RecoverUncorrectedTypos) {
        struct TyposReplace : TreeTransform<TyposReplace> {
          TyposReplace(Sema &SemaRef) : TreeTransform(SemaRef) {}
          ExprResult TransformTypoExpr(clang::TypoExpr *E) {
            return this->SemaRef.CreateRecoveryExpr(E->getBeginLoc(),
                                                    E->getEndLoc(), {});
          }
        } TT(*this);
        return TT.TransformExpr(E);
      }
      return Result;
    }
    assert(TyposResolved == 0 && "Corrected typo but got same Expr back?");
  }
  return E;
}

ExprResult Sema::ActOnFinishFullExpr(Expr *FE, SourceLocation CC,
                                     bool DiscardedValue,
                                     bool IsConstexpr) {
  ExprResult FullExpr = FE;

  if (!FullExpr.get())
    return ExprError();

  if (DiagnoseUnexpandedParameterPack(FullExpr.get()))
    return ExprError();

  if (DiscardedValue) {
    // Top-level expressions default to 'id' when we're in a debugger.
    if (getLangOpts().DebuggerCastResultToId &&
        FullExpr.get()->getType() == Context.UnknownAnyTy) {
      FullExpr = forceUnknownAnyToType(FullExpr.get(), Context.getObjCIdType());
      if (FullExpr.isInvalid())
        return ExprError();
    }

    FullExpr = CheckPlaceholderExpr(FullExpr.get());
    if (FullExpr.isInvalid())
      return ExprError();

    FullExpr = IgnoredValueConversions(FullExpr.get());
    if (FullExpr.isInvalid())
      return ExprError();

    DiagnoseUnusedExprResult(FullExpr.get());
  }

  FullExpr = CorrectDelayedTyposInExpr(FullExpr.get(), /*InitDecl=*/nullptr,
                                       /*RecoverUncorrectedTypos=*/true);
  if (FullExpr.isInvalid())
    return ExprError();

  CheckCompletedExpr(FullExpr.get(), CC, IsConstexpr);

  // At the end of this full expression (which could be a deeply nested
  // lambda), if there is a potential capture within the nested lambda,
  // have the outer capture-able lambda try and capture it.
  // Consider the following code:
  // void f(int, int);
  // void f(const int&, double);
  // void foo() {
  //  const int x = 10, y = 20;
  //  auto L = [=](auto a) {
  //      auto M = [=](auto b) {
  //         f(x, b); <-- requires x to be captured by L and M
  //         f(y, a); <-- requires y to be captured by L, but not all Ms
  //      };
  //   };
  // }

  // FIXME: Also consider what happens for something like this that involves
  // the gnu-extension statement-expressions or even lambda-init-captures:
  //   void f() {
  //     const int n = 0;
  //     auto L =  [&](auto a) {
  //       +n + ({ 0; a; });
  //     };
  //   }
  //
  // Here, we see +n, and then the full-expression 0; ends, so we don't
  // capture n (and instead remove it from our list of potential captures),
  // and then the full-expression +n + ({ 0; }); ends, but it's too late
  // for us to see that we need to capture n after all.

  LambdaScopeInfo *const CurrentLSI =
      getCurLambda(/*IgnoreCapturedRegions=*/true);
  // FIXME: PR 17877 showed that getCurLambda() can return a valid pointer
  // even if CurContext is not a lambda call operator. Refer to that Bug Report
  // for an example of the code that might cause this asynchrony.
  // By ensuring we are in the context of a lambda's call operator
  // we can fix the bug (we only need to check whether we need to capture
  // if we are within a lambda's body); but per the comments in that
  // PR, a proper fix would entail :
  //   "Alternative suggestion:
  //   - Add to Sema an integer holding the smallest (outermost) scope
  //     index that we are *lexically* within, and save/restore/set to
  //     FunctionScopes.size() in InstantiatingTemplate's
  //     constructor/destructor.
  //  - Teach the handful of places that iterate over FunctionScopes to
  //    stop at the outermost enclosing lexical scope."
  DeclContext *DC = CurContext;
  while (DC && isa<CapturedDecl>(DC))
    DC = DC->getParent();
  const bool IsInLambdaDeclContext = isLambdaCallOperator(DC);
  if (IsInLambdaDeclContext && CurrentLSI &&
      CurrentLSI->hasPotentialCaptures() && !FullExpr.isInvalid())
    CheckIfAnyEnclosingLambdasMustCaptureAnyPotentialCaptures(FE, CurrentLSI,
                                                              *this);
  return MaybeCreateExprWithCleanups(FullExpr);
}

StmtResult Sema::ActOnFinishFullStmt(Stmt *FullStmt) {
  if (!FullStmt) return StmtError();

  return MaybeCreateStmtWithCleanups(FullStmt);
}

Sema::IfExistsResult
Sema::CheckMicrosoftIfExistsSymbol(Scope *S,
                                   CXXScopeSpec &SS,
                                   const DeclarationNameInfo &TargetNameInfo) {
  DeclarationName TargetName = TargetNameInfo.getName();
  if (!TargetName)
    return IER_DoesNotExist;

  // If the name itself is dependent, then the result is dependent.
  if (TargetName.isDependentName())
    return IER_Dependent;

  // Do the redeclaration lookup in the current scope.
  LookupResult R(*this, TargetNameInfo, Sema::LookupAnyName,
                 Sema::NotForRedeclaration);
  LookupParsedName(R, S, &SS);
  R.suppressDiagnostics();

  switch (R.getResultKind()) {
  case LookupResult::Found:
  case LookupResult::FoundOverloaded:
  case LookupResult::FoundUnresolvedValue:
  case LookupResult::Ambiguous:
    return IER_Exists;

  case LookupResult::NotFound:
    return IER_DoesNotExist;

  case LookupResult::NotFoundInCurrentInstantiation:
    return IER_Dependent;
  }

  llvm_unreachable("Invalid LookupResult Kind!");
}

Sema::IfExistsResult
Sema::CheckMicrosoftIfExistsSymbol(Scope *S, SourceLocation KeywordLoc,
                                   bool IsIfExists, CXXScopeSpec &SS,
                                   UnqualifiedId &Name) {
  DeclarationNameInfo TargetNameInfo = GetNameFromUnqualifiedId(Name);

  // Check for an unexpanded parameter pack.
  auto UPPC = IsIfExists ? UPPC_IfExists : UPPC_IfNotExists;
  if (DiagnoseUnexpandedParameterPack(SS, UPPC) ||
      DiagnoseUnexpandedParameterPack(TargetNameInfo, UPPC))
    return IER_Error;

  return CheckMicrosoftIfExistsSymbol(S, SS, TargetNameInfo);
}

concepts::Requirement *Sema::ActOnSimpleRequirement(Expr *E) {
  return BuildExprRequirement(E, /*IsSimple=*/true,
                              /*NoexceptLoc=*/SourceLocation(),
                              /*ReturnTypeRequirement=*/{});
}

concepts::Requirement *
Sema::ActOnTypeRequirement(SourceLocation TypenameKWLoc, CXXScopeSpec &SS,
                           SourceLocation NameLoc, IdentifierInfo *TypeName,
                           TemplateIdAnnotation *TemplateId) {
  assert(((!TypeName && TemplateId) || (TypeName && !TemplateId)) &&
         "Exactly one of TypeName and TemplateId must be specified.");
  TypeSourceInfo *TSI = nullptr;
  if (TypeName) {
    QualType T = CheckTypenameType(ETK_Typename, TypenameKWLoc,
                                   SS.getWithLocInContext(Context), *TypeName,
                                   NameLoc, &TSI, /*DeducedTypeContext=*/false);
    if (T.isNull())
      return nullptr;
  } else {
    ASTTemplateArgsPtr ArgsPtr(TemplateId->getTemplateArgs(),
                               TemplateId->NumArgs);
    TypeResult T = ActOnTypenameType(CurScope, TypenameKWLoc, SS,
                                     TemplateId->TemplateKWLoc,
                                     TemplateId->Template, TemplateId->Name,
                                     TemplateId->TemplateNameLoc,
                                     TemplateId->LAngleLoc, ArgsPtr,
                                     TemplateId->RAngleLoc);
    if (T.isInvalid())
      return nullptr;
    if (GetTypeFromParser(T.get(), &TSI).isNull())
      return nullptr;
  }
  return BuildTypeRequirement(TSI);
}

concepts::Requirement *
Sema::ActOnCompoundRequirement(Expr *E, SourceLocation NoexceptLoc) {
  return BuildExprRequirement(E, /*IsSimple=*/false, NoexceptLoc,
                              /*ReturnTypeRequirement=*/{});
}

concepts::Requirement *
Sema::ActOnCompoundRequirement(
    Expr *E, SourceLocation NoexceptLoc, CXXScopeSpec &SS,
    TemplateIdAnnotation *TypeConstraint, unsigned Depth) {
  // C++2a [expr.prim.req.compound] p1.3.3
  //   [..] the expression is deduced against an invented function template
  //   F [...] F is a void function template with a single type template
  //   parameter T declared with the constrained-parameter. Form a new
  //   cv-qualifier-seq cv by taking the union of const and volatile specifiers
  //   around the constrained-parameter. F has a single parameter whose
  //   type-specifier is cv T followed by the abstract-declarator. [...]
  //
  // The cv part is done in the calling function - we get the concept with
  // arguments and the abstract declarator with the correct CV qualification and
  // have to synthesize T and the single parameter of F.
  auto &II = Context.Idents.get("expr-type");
  auto *TParam = TemplateTypeParmDecl::Create(Context, CurContext,
                                              SourceLocation(),
                                              SourceLocation(), Depth,
                                              /*Index=*/0, &II,
                                              /*Typename=*/true,
                                              /*ParameterPack=*/false,
                                              /*HasTypeConstraint=*/true);

  if (BuildTypeConstraint(SS, TypeConstraint, TParam,
                          /*EllpsisLoc=*/SourceLocation(),
                          /*AllowUnexpandedPack=*/true))
    // Just produce a requirement with no type requirements.
    return BuildExprRequirement(E, /*IsSimple=*/false, NoexceptLoc, {});

  auto *TPL = TemplateParameterList::Create(Context, SourceLocation(),
                                            SourceLocation(),
                                            ArrayRef<NamedDecl *>(TParam),
                                            SourceLocation(),
                                            /*RequiresClause=*/nullptr);
  return BuildExprRequirement(
      E, /*IsSimple=*/false, NoexceptLoc,
      concepts::ExprRequirement::ReturnTypeRequirement(TPL));
}

concepts::ExprRequirement *
Sema::BuildExprRequirement(
    Expr *E, bool IsSimple, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement) {
  auto Status = concepts::ExprRequirement::SS_Satisfied;
  ConceptSpecializationExpr *SubstitutedConstraintExpr = nullptr;
  if (E->isInstantiationDependent() || ReturnTypeRequirement.isDependent())
    Status = concepts::ExprRequirement::SS_Dependent;
  else if (NoexceptLoc.isValid() && canThrow(E) == CanThrowResult::CT_Can)
    Status = concepts::ExprRequirement::SS_NoexceptNotMet;
  else if (ReturnTypeRequirement.isSubstitutionFailure())
    Status = concepts::ExprRequirement::SS_TypeRequirementSubstitutionFailure;
  else if (ReturnTypeRequirement.isTypeConstraint()) {
    // C++2a [expr.prim.req]p1.3.3
    //     The immediately-declared constraint ([temp]) of decltype((E)) shall
    //     be satisfied.
    TemplateParameterList *TPL =
        ReturnTypeRequirement.getTypeConstraintTemplateParameterList();
    QualType MatchedType =
        getDecltypeForParenthesizedExpr(E).getCanonicalType();
    llvm::SmallVector<TemplateArgument, 1> Args;
    Args.push_back(TemplateArgument(MatchedType));
    TemplateArgumentList TAL(TemplateArgumentList::OnStack, Args);
    MultiLevelTemplateArgumentList MLTAL(TAL);
    for (unsigned I = 0; I < TPL->getDepth(); ++I)
      MLTAL.addOuterRetainedLevel();
    Expr *IDC =
        cast<TemplateTypeParmDecl>(TPL->getParam(0))->getTypeConstraint()
            ->getImmediatelyDeclaredConstraint();
    ExprResult Constraint = SubstExpr(IDC, MLTAL);
    assert(!Constraint.isInvalid() &&
           "Substitution cannot fail as it is simply putting a type template "
           "argument into a concept specialization expression's parameter.");

    SubstitutedConstraintExpr =
        cast<ConceptSpecializationExpr>(Constraint.get());
    if (!SubstitutedConstraintExpr->isSatisfied())
      Status = concepts::ExprRequirement::SS_ConstraintsNotSatisfied;
  }
  return new (Context) concepts::ExprRequirement(E, IsSimple, NoexceptLoc,
                                                 ReturnTypeRequirement, Status,
                                                 SubstitutedConstraintExpr);
}

concepts::ExprRequirement *
Sema::BuildExprRequirement(
    concepts::Requirement::SubstitutionDiagnostic *ExprSubstitutionDiagnostic,
    bool IsSimple, SourceLocation NoexceptLoc,
    concepts::ExprRequirement::ReturnTypeRequirement ReturnTypeRequirement) {
  return new (Context) concepts::ExprRequirement(ExprSubstitutionDiagnostic,
                                                 IsSimple, NoexceptLoc,
                                                 ReturnTypeRequirement);
}

concepts::TypeRequirement *
Sema::BuildTypeRequirement(TypeSourceInfo *Type) {
  return new (Context) concepts::TypeRequirement(Type);
}

concepts::TypeRequirement *
Sema::BuildTypeRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag) {
  return new (Context) concepts::TypeRequirement(SubstDiag);
}

concepts::Requirement *Sema::ActOnNestedRequirement(Expr *Constraint) {
  return BuildNestedRequirement(Constraint);
}

concepts::NestedRequirement *
Sema::BuildNestedRequirement(Expr *Constraint) {
  ConstraintSatisfaction Satisfaction;
  if (!Constraint->isInstantiationDependent() &&
      CheckConstraintSatisfaction(nullptr, {Constraint}, /*TemplateArgs=*/{},
                                  Constraint->getSourceRange(), Satisfaction))
    return nullptr;
  return new (Context) concepts::NestedRequirement(Context, Constraint,
                                                   Satisfaction);
}

concepts::NestedRequirement *
Sema::BuildNestedRequirement(
    concepts::Requirement::SubstitutionDiagnostic *SubstDiag) {
  return new (Context) concepts::NestedRequirement(SubstDiag);
}

RequiresExprBodyDecl *
Sema::ActOnStartRequiresExpr(SourceLocation RequiresKWLoc,
                             ArrayRef<ParmVarDecl *> LocalParameters,
                             Scope *BodyScope) {
  assert(BodyScope);

  RequiresExprBodyDecl *Body = RequiresExprBodyDecl::Create(Context, CurContext,
                                                            RequiresKWLoc);

  PushDeclContext(BodyScope, Body);

  for (ParmVarDecl *Param : LocalParameters) {
    if (Param->hasDefaultArg())
      // C++2a [expr.prim.req] p4
      //     [...] A local parameter of a requires-expression shall not have a
      //     default argument. [...]
      Diag(Param->getDefaultArgRange().getBegin(),
           diag::err_requires_expr_local_parameter_default_argument);
    // Ignore default argument and move on

    Param->setDeclContext(Body);
    // If this has an identifier, add it to the scope stack.
    if (Param->getIdentifier()) {
      CheckShadow(BodyScope, Param);
      PushOnScopeChains(Param, BodyScope);
    }
  }
  return Body;
}

void Sema::ActOnFinishRequiresExpr() {
  assert(CurContext && "DeclContext imbalance!");
  CurContext = CurContext->getLexicalParent();
  assert(CurContext && "Popped translation unit!");
}

ExprResult
Sema::ActOnRequiresExpr(SourceLocation RequiresKWLoc,
                        RequiresExprBodyDecl *Body,
                        ArrayRef<ParmVarDecl *> LocalParameters,
                        ArrayRef<concepts::Requirement *> Requirements,
                        SourceLocation ClosingBraceLoc) {
  auto *RE = RequiresExpr::Create(Context, RequiresKWLoc, Body, LocalParameters,
                                  Requirements, ClosingBraceLoc);
  if (DiagnoseUnexpandedParameterPackInRequiresExpr(RE))
    return ExprError();
  return RE;
}