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58 lines
1.5 KiB
C++
58 lines
1.5 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// <optional>
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// UNSUPPORTED: c++98, c++03, c++11, c++14
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// UNSUPPORTED: clang-5, apple-clang-9
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// UNSUPPORTED: libcpp-no-deduction-guides
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// Clang 5 will generate bad implicit deduction guides
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// Specifically, for the copy constructor.
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// template<class T>
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// optional(T) -> optional<T>;
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#include <optional>
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#include <cassert>
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#include "test_macros.h"
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struct A {};
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int main(int, char**)
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{
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// Test the explicit deduction guides
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{
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// optional(T)
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std::optional opt(5);
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static_assert(std::is_same_v<decltype(opt), std::optional<int>>, "");
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assert(static_cast<bool>(opt));
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assert(*opt == 5);
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}
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{
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// optional(T)
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std::optional opt(A{});
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static_assert(std::is_same_v<decltype(opt), std::optional<A>>, "");
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assert(static_cast<bool>(opt));
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}
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// Test the implicit deduction guides
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{
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// optional(optional);
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std::optional<char> source('A');
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std::optional opt(source);
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static_assert(std::is_same_v<decltype(opt), std::optional<char>>, "");
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assert(static_cast<bool>(opt) == static_cast<bool>(source));
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assert(*opt == *source);
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}
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return 0;
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}
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