24 lines · cpp
1// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.33 -std=c++20 -verify=supported %s2// RUN: %clang_cc1 -fms-compatibility -fms-compatibility-version=19.32 -std=c++20 -verify=unsupported %s3// supported-no-diagnostics4 5[[nodiscard]]6[[msvc::constexpr]] // unsupported-warning {{unknown attribute 'msvc::constexpr' ignored}}7inline void* operator new(decltype(sizeof(void*)), void* p) noexcept { return p; }8 9namespace std {10 constexpr int* construct_at(int* p, int v) {11 [[msvc::constexpr]] return ::new (p) int(v); // unsupported-warning {{unknown attribute 'msvc::constexpr' ignored}}12 }13}14 15constexpr bool check_std_construct_at() { int x; return *std::construct_at(&x, 42) == 42; }16static_assert(check_std_construct_at());17 18constexpr int* construct_at(int* p, int v) { [[msvc::constexpr]] return ::new (p) int(v); } // unsupported-error {{constexpr function never produces a constant expression}} \19 // unsupported-warning {{unknown attribute 'msvc::constexpr' ignored}} \20 // unsupported-note 2{{this placement new expression is not supported in constant expressions before C++2c}}21constexpr bool check_construct_at() { int x; return *construct_at(&x, 42) == 42; } // unsupported-note {{in call to 'construct_at(&x, 42)'}}22static_assert(check_construct_at()); // unsupported-error {{static assertion expression is not an integral constant expression}}\23 // unsupported-note {{in call to 'check_construct_at()'}}24