69 lines
1.6 KiB
C++
69 lines
1.6 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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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// constexpr const Pred& pred() const;
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#include <cassert>
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#include <ranges>
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#include <type_traits>
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#include <utility>
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struct View : std::ranges::view_interface<View> {
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int* begin() const;
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int* end() const;
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};
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struct Pred {
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int i;
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bool operator()(int) const;
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};
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constexpr bool test() {
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// &
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{
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std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
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decltype(auto) x = dwv.pred();
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static_assert(std::same_as<decltype(x), Pred const&>);
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assert(x.i == 5);
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}
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// const &
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{
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const std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
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decltype(auto) x = dwv.pred();
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static_assert(std::same_as<decltype(x), Pred const&>);
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assert(x.i == 5);
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}
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// &&
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{
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std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
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decltype(auto) x = std::move(dwv).pred();
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static_assert(std::same_as<decltype(x), Pred const&>);
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assert(x.i == 5);
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}
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// const &&
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{
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const std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
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decltype(auto) x = std::move(dwv).pred();
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static_assert(std::same_as<decltype(x), Pred const&>);
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assert(x.i == 5);
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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