1 files changed, 34 insertions, 15 deletions

diff --git a/clang/lib/Format/SortJavaScriptImports.cpp b/clang/lib/Format/SortJavaScriptImports.cpp
index 77dc0d683e5f..e4107525a7ff 100644
--- a/clang/lib/Format/SortJavaScriptImports.cpp
+++ b/clang/lib/Format/SortJavaScriptImports.cpp
@@ -78,6 +78,7 @@ struct JsModuleReference {
     ABSOLUTE,        // from 'something'
     RELATIVE_PARENT, // from '../*'
     RELATIVE,        // from './*'
+    ALIAS,           // import X = A.B;
   };
   ReferenceCategory Category = ReferenceCategory::SIDE_EFFECT;
   // The URL imported, e.g. `import .. from 'url';`. Empty for `export {a, b};`.
@@ -105,10 +106,12 @@ bool operator<(const JsModuleReference &LHS, const JsModuleReference &RHS) {
     return LHS.IsExport < RHS.IsExport;
   if (LHS.Category != RHS.Category)
     return LHS.Category < RHS.Category;
-  if (LHS.Category == JsModuleReference::ReferenceCategory::SIDE_EFFECT)
-    // Side effect imports might be ordering sensitive. Consider them equal so
-    // that they maintain their relative order in the stable sort below.
-    // This retains transitivity because LHS.Category == RHS.Category here.
+  if (LHS.Category == JsModuleReference::ReferenceCategory::SIDE_EFFECT ||
+      LHS.Category == JsModuleReference::ReferenceCategory::ALIAS)
+    // Side effect imports and aliases might be ordering sensitive. Consider
+    // them equal so that they maintain their relative order in the stable sort
+    // below. This retains transitivity because LHS.Category == RHS.Category
+    // here.
     return false;
   // Empty URLs sort *last* (for export {...};).
   if (LHS.URL.empty() != RHS.URL.empty())
@@ -260,13 +263,13 @@ private:
       while (Start != References.end() && Start->FormattingOff) {
         // Skip over all imports w/ disabled formatting.
         ReferencesSorted.push_back(*Start);
-        Start++;
+        ++Start;
       }
       SmallVector<JsModuleReference, 16> SortChunk;
       while (Start != References.end() && !Start->FormattingOff) {
         // Skip over all imports w/ disabled formatting.
         SortChunk.push_back(*Start);
-        Start++;
+        ++Start;
       }
       llvm::stable_sort(SortChunk);
       mergeModuleReferences(SortChunk);
@@ -338,10 +341,12 @@ private:
     // Stitch together the module reference start...
     Buffer += getSourceText(Reference.Range.getBegin(), Reference.SymbolsStart);
     // ... then the references in order ...
-    for (auto I = Symbols.begin(), E = Symbols.end(); I != E; ++I) {
-      if (I != Symbols.begin())
+    if (!Symbols.empty()) {
+      Buffer += getSourceText(Symbols.front().Range);
+      for (const JsImportedSymbol &Symbol : llvm::drop_begin(Symbols)) {
         Buffer += ",";
-      Buffer += getSourceText(I->Range);
+        Buffer += getSourceText(Symbol.Range);
+      }
     }
     // ... followed by the module reference end.
     Buffer += getSourceText(Reference.SymbolsEnd, Reference.Range.getEnd());
@@ -359,6 +364,7 @@ private:
     bool AnyImportAffected = false;
     bool FormattingOff = false;
     for (auto *Line : AnnotatedLines) {
+      assert(Line->First);
       Current = Line->First;
       LineEnd = Line->Last;
       // clang-format comments toggle formatting on/off.
@@ -395,6 +401,8 @@ private:
       JsModuleReference Reference;
       Reference.FormattingOff = FormattingOff;
       Reference.Range.setBegin(Start);
+      // References w/o a URL, e.g. export {A}, groups with RELATIVE.
+      Reference.Category = JsModuleReference::ReferenceCategory::RELATIVE;
       if (!parseModuleReference(Keywords, Reference)) {
         if (!FirstNonImportLine)
           FirstNonImportLine = Line; // if no comment before.
@@ -410,9 +418,8 @@ private:
                      << ", cat: " << Reference.Category
                      << ", url: " << Reference.URL
                      << ", prefix: " << Reference.Prefix;
-        for (size_t I = 0; I < Reference.Symbols.size(); ++I)
-          llvm::dbgs() << ", " << Reference.Symbols[I].Symbol << " as "
-                       << Reference.Symbols[I].Alias;
+        for (const JsImportedSymbol &Symbol : Reference.Symbols)
+          llvm::dbgs() << ", " << Symbol.Symbol << " as " << Symbol.Alias;
         llvm::dbgs() << ", text: " << getSourceText(Reference.Range);
         llvm::dbgs() << "}\n";
       });
@@ -461,9 +468,6 @@ private:
         Reference.Category = JsModuleReference::ReferenceCategory::RELATIVE;
       else
         Reference.Category = JsModuleReference::ReferenceCategory::ABSOLUTE;
-    } else {
-      // w/o URL groups with "empty".
-      Reference.Category = JsModuleReference::ReferenceCategory::RELATIVE;
     }
     return true;
   }
@@ -499,6 +503,21 @@ private:
       nextToken();
       if (Current->is(Keywords.kw_from))
         return true;
+      // import X = A.B.C;
+      if (Current->is(tok::equal)) {
+        Reference.Category = JsModuleReference::ReferenceCategory::ALIAS;
+        nextToken();
+        while (Current->is(tok::identifier)) {
+          nextToken();
+          if (Current->is(tok::semi)) {
+            nextToken();
+            return true;
+          }
+          if (!Current->is(tok::period))
+            return false;
+          nextToken();
+        }
+      }
       if (Current->isNot(tok::comma))
         return false;
       nextToken(); // eat comma.