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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14
// XFAIL: with_system_cxx_lib=macosx10.12
// XFAIL: with_system_cxx_lib=macosx10.11
// XFAIL: with_system_cxx_lib=macosx10.10
// XFAIL: with_system_cxx_lib=macosx10.9
// XFAIL: with_system_cxx_lib=macosx10.7
// XFAIL: with_system_cxx_lib=macosx10.8
// <variant>
// template <class Visitor, class... Variants>
// constexpr see below visit(Visitor&& vis, Variants&&... vars);
#include <cassert>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
#include <variant>
#include "test_macros.h"
#include "type_id.h"
#include "variant_test_helpers.hpp"
enum CallType : unsigned {
CT_None,
CT_NonConst = 1,
CT_Const = 2,
CT_LValue = 4,
CT_RValue = 8
};
inline constexpr CallType operator|(CallType LHS, CallType RHS) {
return static_cast<CallType>(static_cast<unsigned>(LHS) |
static_cast<unsigned>(RHS));
}
struct ForwardingCallObject {
template <class... Args> bool operator()(Args &&...) & {
set_call<Args &&...>(CT_NonConst | CT_LValue);
return true;
}
template <class... Args> bool operator()(Args &&...) const & {
set_call<Args &&...>(CT_Const | CT_LValue);
return true;
}
// Don't allow the call operator to be invoked as an rvalue.
template <class... Args> bool operator()(Args &&...) && {
set_call<Args &&...>(CT_NonConst | CT_RValue);
return true;
}
template <class... Args> bool operator()(Args &&...) const && {
set_call<Args &&...>(CT_Const | CT_RValue);
return true;
}
template <class... Args> static void set_call(CallType type) {
assert(last_call_type == CT_None);
assert(last_call_args == nullptr);
last_call_type = type;
last_call_args = std::addressof(makeArgumentID<Args...>());
}
template <class... Args> static bool check_call(CallType type) {
bool result = last_call_type == type && last_call_args &&
*last_call_args == makeArgumentID<Args...>();
last_call_type = CT_None;
last_call_args = nullptr;
return result;
}
static CallType last_call_type;
static const TypeID *last_call_args;
};
CallType ForwardingCallObject::last_call_type = CT_None;
const TypeID *ForwardingCallObject::last_call_args = nullptr;
void test_call_operator_forwarding() {
using Fn = ForwardingCallObject;
Fn obj{};
const Fn &cobj = obj;
{ // test call operator forwarding - no variant
std::visit(obj);
assert(Fn::check_call<>(CT_NonConst | CT_LValue));
std::visit(cobj);
assert(Fn::check_call<>(CT_Const | CT_LValue));
std::visit(std::move(obj));
assert(Fn::check_call<>(CT_NonConst | CT_RValue));
std::visit(std::move(cobj));
assert(Fn::check_call<>(CT_Const | CT_RValue));
}
{ // test call operator forwarding - single variant, single arg
using V = std::variant<int>;
V v(42);
std::visit(obj, v);
assert(Fn::check_call<int &>(CT_NonConst | CT_LValue));
std::visit(cobj, v);
assert(Fn::check_call<int &>(CT_Const | CT_LValue));
std::visit(std::move(obj), v);
assert(Fn::check_call<int &>(CT_NonConst | CT_RValue));
std::visit(std::move(cobj), v);
assert(Fn::check_call<int &>(CT_Const | CT_RValue));
}
{ // test call operator forwarding - single variant, multi arg
using V = std::variant<int, long, double>;
V v(42l);
std::visit(obj, v);
assert(Fn::check_call<long &>(CT_NonConst | CT_LValue));
std::visit(cobj, v);
assert(Fn::check_call<long &>(CT_Const | CT_LValue));
std::visit(std::move(obj), v);
assert(Fn::check_call<long &>(CT_NonConst | CT_RValue));
std::visit(std::move(cobj), v);
assert(Fn::check_call<long &>(CT_Const | CT_RValue));
}
{ // test call operator forwarding - multi variant, multi arg
using V = std::variant<int, long, double>;
using V2 = std::variant<int *, std::string>;
V v(42l);
V2 v2("hello");
std::visit(obj, v, v2);
assert((Fn::check_call<long &, std::string &>(CT_NonConst | CT_LValue)));
std::visit(cobj, v, v2);
assert((Fn::check_call<long &, std::string &>(CT_Const | CT_LValue)));
std::visit(std::move(obj), v, v2);
assert((Fn::check_call<long &, std::string &>(CT_NonConst | CT_RValue)));
std::visit(std::move(cobj), v, v2);
assert((Fn::check_call<long &, std::string &>(CT_Const | CT_RValue)));
}
}
void test_argument_forwarding() {
using Fn = ForwardingCallObject;
Fn obj{};
const auto Val = CT_LValue | CT_NonConst;
{ // single argument - value type
using V = std::variant<int>;
V v(42);
const V &cv = v;
std::visit(obj, v);
assert(Fn::check_call<int &>(Val));
std::visit(obj, cv);
assert(Fn::check_call<const int &>(Val));
std::visit(obj, std::move(v));
assert(Fn::check_call<int &&>(Val));
std::visit(obj, std::move(cv));
assert(Fn::check_call<const int &&>(Val));
}
#if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
{ // single argument - lvalue reference
using V = std::variant<int &>;
int x = 42;
V v(x);
const V &cv = v;
std::visit(obj, v);
assert(Fn::check_call<int &>(Val));
std::visit(obj, cv);
assert(Fn::check_call<int &>(Val));
std::visit(obj, std::move(v));
assert(Fn::check_call<int &>(Val));
std::visit(obj, std::move(cv));
assert(Fn::check_call<int &>(Val));
}
{ // single argument - rvalue reference
using V = std::variant<int &&>;
int x = 42;
V v(std::move(x));
const V &cv = v;
std::visit(obj, v);
assert(Fn::check_call<int &>(Val));
std::visit(obj, cv);
assert(Fn::check_call<int &>(Val));
std::visit(obj, std::move(v));
assert(Fn::check_call<int &&>(Val));
std::visit(obj, std::move(cv));
assert(Fn::check_call<int &&>(Val));
}
{ // multi argument - multi variant
using S = const std::string &;
using V = std::variant<int, S, long &&>;
const std::string str = "hello";
long l = 43;
V v1(42);
const V &cv1 = v1;
V v2(str);
const V &cv2 = v2;
V v3(std::move(l));
const V &cv3 = v3;
std::visit(obj, v1, v2, v3);
assert((Fn::check_call<int &, S, long &>(Val)));
std::visit(obj, cv1, cv2, std::move(v3));
assert((Fn::check_call<const int &, S, long &&>(Val)));
}
#endif
}
struct ReturnFirst {
template <class... Args> constexpr int operator()(int f, Args &&...) const {
return f;
}
};
struct ReturnArity {
template <class... Args> constexpr int operator()(Args &&...) const {
return sizeof...(Args);
}
};
void test_constexpr() {
constexpr ReturnFirst obj{};
constexpr ReturnArity aobj{};
{
using V = std::variant<int>;
constexpr V v(42);
static_assert(std::visit(obj, v) == 42, "");
}
{
using V = std::variant<short, long, char>;
constexpr V v(42l);
static_assert(std::visit(obj, v) == 42, "");
}
{
using V1 = std::variant<int>;
using V2 = std::variant<int, char *, long long>;
using V3 = std::variant<bool, int, int>;
constexpr V1 v1;
constexpr V2 v2(nullptr);
constexpr V3 v3;
static_assert(std::visit(aobj, v1, v2, v3) == 3, "");
}
{
using V1 = std::variant<int>;
using V2 = std::variant<int, char *, long long>;
using V3 = std::variant<void *, int, int>;
constexpr V1 v1;
constexpr V2 v2(nullptr);
constexpr V3 v3;
static_assert(std::visit(aobj, v1, v2, v3) == 3, "");
}
}
void test_exceptions() {
#ifndef TEST_HAS_NO_EXCEPTIONS
ReturnArity obj{};
auto test = [&](auto &&... args) {
try {
std::visit(obj, args...);
} catch (const std::bad_variant_access &) {
return true;
} catch (...) {
}
return false;
};
{
using V = std::variant<int, MakeEmptyT>;
V v;
makeEmpty(v);
assert(test(v));
}
{
using V = std::variant<int, MakeEmptyT>;
using V2 = std::variant<long, std::string, void *>;
V v;
makeEmpty(v);
V2 v2("hello");
assert(test(v, v2));
}
{
using V = std::variant<int, MakeEmptyT>;
using V2 = std::variant<long, std::string, void *>;
V v;
makeEmpty(v);
V2 v2("hello");
assert(test(v2, v));
}
{
using V = std::variant<int, MakeEmptyT>;
using V2 = std::variant<long, std::string, void *, MakeEmptyT>;
V v;
makeEmpty(v);
V2 v2;
makeEmpty(v2);
assert(test(v, v2));
}
#endif
}
// See http://llvm.org/PR31916
void test_caller_accepts_nonconst() {
struct A {};
struct Visitor {
void operator()(A&) {}
};
std::variant<A> v;
std::visit(Visitor{}, v);
}
int main() {
test_call_operator_forwarding();
test_argument_forwarding();
test_constexpr();
test_exceptions();
test_caller_accepts_nonconst();
}
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