f72b3e1c07
Adds explanation why `is_constructible` evaluates to false. This reapplies as-is e476f968bc8e438a0435d10934f148de570db8eb. This was reverted in 16d5db71b3c38f21aa17783a8758f947dca5883f because of a test failure in libc++. The test failure in libc++ is interesting in that, in the absence of nested diagnostics a bunch of diagnostics are emitted as error instead of notes, which we cannot silence with `-verify-ignore-unexpected`. The fix here is to prevent the diagnostics to be emitted in the first place. However this is clearly not ideal and we should make sure to deploy a better solution in the clang 22 time frame, in the lines of https://discourse.llvm.org/t/rfc-add-a-new-text-diagnostics-format-that-supports-nested-diagnostics/87641/12 Fixes #150601 --------- Co-authored-by: Shamshura Egor <164661612+egorshamshura@users.noreply.github.com>
88 lines
2.7 KiB
C++
88 lines
2.7 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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}}
|
|
// expected-error@*:* 0-1{{call to deleted constructor of 'F'}}
|
|
// expected-error@*:* 0-1{{call to deleted constructor of 'Arg'}}
|
|
}
|
|
|
|
{ // 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}}
|
|
}
|
|
}
|