94461822c7
`subrange` is also a `tuple-like`. To avoid the add entire `subrange` dependencies to `tuple-like`, we need forward declaration of `subrange`. However, the class template constraints of `subrange` currently requires `__iterator/concepts.h`, which requires `<concepts>`. The problem is that currently `tuple-like` is used in several different places, including libc++ extension for pair constructors. we don't want to add `<concepts>` to pair and other stuff. So this change also created several small headers that `subrange`'s declaration needed inside `__iterator/concepts/` Differential Revision: https://reviews.llvm.org/D136268
85 lines
2.1 KiB
C++
85 lines
2.1 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 V base() const & requires copy_constructible<V> { return base_; }
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// constexpr V base() && { return std::move(base_); }
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#include <cassert>
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#include <ranges>
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#include <tuple>
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#include <type_traits>
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#include <utility>
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#include "MoveOnly.h"
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struct View : std::ranges::view_base {
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int i;
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std::tuple<int>* begin() const;
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std::tuple<int>* end() const;
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};
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struct MoveOnlyView : View {
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MoveOnly mo;
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};
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template <class T>
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concept HasBase = requires(T&& t) { std::forward<T>(t).base(); };
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static_assert(HasBase<std::ranges::elements_view<View, 0> const&>);
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static_assert(HasBase<std::ranges::elements_view<View, 0>&&>);
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static_assert(!HasBase<std::ranges::elements_view<MoveOnlyView, 0> const&>);
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static_assert(HasBase<std::ranges::elements_view<MoveOnlyView, 0>&&>);
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constexpr bool test() {
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// const &
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{
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const std::ranges::elements_view<View, 0> ev{View{{}, 5}};
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std::same_as<View> decltype(auto) v = ev.base();
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assert(v.i == 5);
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}
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// &
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{
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std::ranges::elements_view<View, 0> ev{View{{}, 5}};
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std::same_as<View> decltype(auto) v = ev.base();
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assert(v.i == 5);
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}
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// &&
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{
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std::ranges::elements_view<View, 0> ev{View{{}, 5}};
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std::same_as<View> decltype(auto) v = std::move(ev).base();
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assert(v.i == 5);
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}
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// const &&
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{
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const std::ranges::elements_view<View, 0> ev{View{{}, 5}};
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std::same_as<View> decltype(auto) v = std::move(ev).base();
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assert(v.i == 5);
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}
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// move only
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{
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std::ranges::elements_view<MoveOnlyView, 0> ev{MoveOnlyView{{}, 5}};
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std::same_as<MoveOnlyView> decltype(auto) v = std::move(ev).base();
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assert(v.mo.get() == 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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