libcxx/test/std/utilities/function.objects/func.invoke/invoke_r.temporary.verify.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
  10
  11 // <functional>
  12
  13 // template<class R, class F, class... Args>
  14 // constexpr R invoke_r(F&& f, Args&&... args)              // C++23
  15 //     noexcept(is_nothrow_invocable_r_v<R, F, Args...>);
  16 //
  17 // Make sure that we diagnose when std::invoke_r is used with a return type that
  18 // would yield a dangling reference to a temporary.
  19
  20 // TODO: We currently can't diagnose because we don't implement reference_converts_from_temporary.
  21 // XFAIL: *
  22
  23 #include <functional>
  24 #include <cassert>
  25
  26 #include "test_macros.h"
  27
  28 void f() {
  29     auto func = []() -> int { return 0; };
  30     std::invoke_r<int&&>(func); // expected-error {{Returning from invoke_r would bind a temporary object}}
  31 }