diff options
| -rw-r--r-- | libcxx/include/optional | 10 | ||||
| -rw-r--r-- | libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/empty_in_place_t_does_not_clobber.pass.cpp | 41 |
2 files changed, 48 insertions, 3 deletions
diff --git a/libcxx/include/optional b/libcxx/include/optional index be584b3cee1..7c136aec3a2 100644 --- a/libcxx/include/optional +++ b/libcxx/include/optional @@ -687,11 +687,15 @@ public: _LIBCPP_INLINE_VISIBILITY constexpr optional(optional&&) = default; _LIBCPP_INLINE_VISIBILITY constexpr optional(nullopt_t) noexcept {} - template <class... _Args, class = enable_if_t< - is_constructible_v<value_type, _Args...>> + template <class _InPlaceT, class... _Args, class = enable_if_t< + __lazy_and< + is_same<_InPlaceT, in_place_t>, + is_constructible<value_type, _Args...> + >::value + > > _LIBCPP_INLINE_VISIBILITY - constexpr explicit optional(in_place_t, _Args&&... __args) + constexpr explicit optional(_InPlaceT, _Args&&... __args) : __base(in_place, _VSTD::forward<_Args>(__args)...) {} template <class _Up, class... _Args, class = enable_if_t< diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/empty_in_place_t_does_not_clobber.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/empty_in_place_t_does_not_clobber.pass.cpp new file mode 100644 index 00000000000..84db7ea024f --- /dev/null +++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/empty_in_place_t_does_not_clobber.pass.cpp @@ -0,0 +1,41 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// UNSUPPORTED: c++98, c++03, c++11, c++14 +// <optional> + +// constexpr optional(in_place_t); + +// Test that the SFINAE "is_constructible<value_type>" isn't evaluated by the +// in_place_t constructor with no arguments when the Clang is trying to check +// copy constructor. + +#include <optional> +#include <type_traits> +#include <cassert> + +#include "test_macros.h" +#include "archetypes.hpp" + +using std::optional; + +struct Wrapped { + struct Inner { + bool Dummy = true; + }; + std::optional<Inner> inner; +}; + +int main(int, char**) { + static_assert(std::is_default_constructible<Wrapped::Inner>::value, ""); + Wrapped w; + w.inner.emplace(); + assert(w.inner.has_value()); + + return 0; +} |
