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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// constexpr const Pred& pred() const;
#include <cassert>
#include <ranges>
#include <type_traits>
#include <utility>
struct View : std::ranges::view_interface<View> {
int* begin() const;
int* end() const;
};
struct Pred {
int i;
bool operator()(int) const;
};
constexpr bool test() {
// &
{
std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
decltype(auto) x = dwv.pred();
static_assert(std::same_as<decltype(x), Pred const&>);
assert(x.i == 5);
}
// const &
{
const std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
decltype(auto) x = dwv.pred();
static_assert(std::same_as<decltype(x), Pred const&>);
assert(x.i == 5);
}
// &&
{
std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
decltype(auto) x = std::move(dwv).pred();
static_assert(std::same_as<decltype(x), Pred const&>);
assert(x.i == 5);
}
// const &&
{
const std::ranges::drop_while_view<View, Pred> dwv{{}, Pred{5}};
decltype(auto) x = std::move(dwv).pred();
static_assert(std::same_as<decltype(x), Pred const&>);
assert(x.i == 5);
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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