61 lines
1.5 KiB
C++
61 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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// <string>
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// const charT& front() const; // constexpr since C++20
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// charT& front(); // constexpr since C++20
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#include <string>
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#include <cassert>
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#include "test_macros.h"
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#include "min_allocator.h"
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template <class S>
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TEST_CONSTEXPR_CXX20 void
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test(S s)
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{
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const S& cs = s;
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ASSERT_SAME_TYPE(decltype( s.front()), typename S::reference);
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ASSERT_SAME_TYPE(decltype(cs.front()), typename S::const_reference);
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LIBCPP_ASSERT_NOEXCEPT( s.front());
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LIBCPP_ASSERT_NOEXCEPT( cs.front());
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assert(&cs.front() == &cs[0]);
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assert(&s.front() == &s[0]);
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s.front() = typename S::value_type('z');
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assert(s.front() == typename S::value_type('z'));
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}
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TEST_CONSTEXPR_CXX20 bool test() {
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{
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typedef std::string S;
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test(S("1"));
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test(S("1234567890123456789012345678901234567890"));
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}
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#if TEST_STD_VER >= 11
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{
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typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
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test(S("1"));
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test(S("1234567890123456789012345678901234567890"));
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}
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#endif
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return true;
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}
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int main(int, char**)
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{
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test();
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#if TEST_STD_VER > 17
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static_assert(test());
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#endif
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return 0;
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}
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