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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, c++20
// <functional>
// template<class F, class... Args>
// constexpr unspecified bind_back(F&& f, Args&&... args);
#include <functional>
#include "types.h"
constexpr int pass(int n) { return n; }
void test() {
{ // Test calling constexpr function from non-constexpr `bind_back` result
auto f1 = std::bind_back(pass, 1);
static_assert(f1() == 1); // expected-error {{static assertion expression is not an integral constant expression}}
}
{ // Test calling `bind_back` with template function
auto f1 = std::bind_back(do_nothing, 2);
// expected-error@-1 {{no matching function for call to 'bind_back'}}
}
{ // Mandates: is_constructible_v<decay_t<F>, F>
struct F {
F() = default;
F(const F&) = default;
F(F&) = delete;
void operator()() {}
};
F f;
auto f1 = std::bind_back(f);
// expected-error-re@*:* {{static assertion failed{{.*}}bind_back requires decay_t<F> to be constructible from F}}
}
{ // Mandates: is_move_constructible_v<decay_t<F>>
struct F {
F() = default;
F(const F&) = default;
F(F&&) = delete;
void operator()() {}
};
F f;
auto f1 = std::bind_back(f);
// expected-error-re@*:* {{static assertion failed{{.*}}bind_back requires decay_t<F> to be move constructible}}
}
{ // Mandates: (is_constructible_v<decay_t<Args>, Args> && ...)
struct Arg {
Arg() = default;
Arg(const Arg&) = default;
Arg(Arg&) = delete;
};
Arg x;
auto f = std::bind_back([](const Arg&) {}, x);
// expected-error-re@*:* {{static assertion failed{{.*}}bind_back requires all decay_t<Args> to be constructible from respective Args}}
// expected-error@*:* {{no matching constructor for initialization}}
}
{ // Mandates: (is_move_constructible_v<decay_t<Args>> && ...)
struct Arg {
Arg() = default;
Arg(const Arg&) = default;
Arg(Arg&&) = delete;
};
Arg x;
auto f = std::bind_back([](Arg&) {}, x);
// expected-error-re@*:* {{static assertion failed{{.*}}bind_back requires all decay_t<Args> to be move constructible}}
}
}
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