01afa5c6e4
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@189772 91177308-0d34-0410-b5e6-96231b3b80d8
81 lines
1.8 KiB
C++
81 lines
1.8 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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// <optional>
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// template <class U> constexpr T optional<T>::value_or(U&& v) const&;
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#include <optional>
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#include <type_traits>
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#include <cassert>
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#if _LIBCPP_STD_VER > 11
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struct Y
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{
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int i_;
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constexpr Y(int i) : i_(i) {}
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};
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struct X
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{
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int i_;
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constexpr X(int i) : i_(i) {}
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constexpr X(const Y& y) : i_(y.i_) {}
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constexpr X(Y&& y) : i_(y.i_+1) {}
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friend constexpr bool operator==(const X& x, const X& y)
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{return x.i_ == y.i_;}
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};
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#endif // _LIBCPP_STD_VER > 11
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int main()
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{
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#if _LIBCPP_STD_VER > 11
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{
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constexpr std::optional<X> opt(2);
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constexpr Y y(3);
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static_assert(opt.value_or(y) == 2, "");
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}
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{
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constexpr std::optional<X> opt(2);
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static_assert(opt.value_or(Y(3)) == 2, "");
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}
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{
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constexpr std::optional<X> opt;
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constexpr Y y(3);
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static_assert(opt.value_or(y) == 3, "");
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}
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{
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constexpr std::optional<X> opt;
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static_assert(opt.value_or(Y(3)) == 4, "");
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}
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{
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const std::optional<X> opt(2);
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const Y y(3);
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assert(opt.value_or(y) == 2);
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}
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{
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const std::optional<X> opt(2);
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assert(opt.value_or(Y(3)) == 2);
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}
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{
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const std::optional<X> opt;
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const Y y(3);
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assert(opt.value_or(y) == 3);
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}
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{
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const std::optional<X> opt;
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assert(opt.value_or(Y(3)) == 4);
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}
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#endif // _LIBCPP_STD_VER > 11
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}
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