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08242cbd9b
* Update specification text from N4387 * Delete not_brace_initializable.fail.cpp: it's redundant with nullopt_t.fail.cpp * is_empty<T> implies is_class<T> * is_literal is deprecated; directly verify that we can create a nullopt_t in a constexpr context Differential Revision: D37024 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@312256 91177308-0d34-0410-b5e6-96231b3b80d8
41 lines
1.0 KiB
C++
41 lines
1.0 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++98, c++03, c++11, c++14
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// <optional>
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// struct nullopt_t{see below};
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// inline constexpr nullopt_t nullopt(unspecified);
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// [optional.nullopt]/2:
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// Type nullopt_t shall not have a default constructor or an initializer-list
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// constructor, and shall not be an aggregate.
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#include <optional>
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#include <type_traits>
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using std::nullopt_t;
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using std::nullopt;
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constexpr bool test()
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{
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nullopt_t foo{nullopt};
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(void)foo;
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return true;
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}
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int main()
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{
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static_assert(std::is_empty_v<nullopt_t>);
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static_assert(!std::is_default_constructible_v<nullopt_t>);
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static_assert(std::is_same_v<const nullopt_t, decltype(nullopt)>);
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static_assert(test());
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}
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