f599e7a789
This patch fixes the constrains on the __perfect_forward constructor and its call operators, which were incorrect. In particular, it makes sure that we closely follow [func.require], which basically says that we must deliver the bound arguments with the appropriate value category or make the call ill-formed, but not silently fall back to using a different value category. As a fly-by, this patch also: - Adds types __bind_front_t and __not_fn_t to make the result of calling bind_front and not_fn more opaque, and improve diagnostics for users. - Adds a bunch of tests for bind_front and remove some that are now redundant. - Adds some missing _LIBCPP_HIDE_FROM_ABI annotations. Immense thanks to @tcanens for raising awareness about this issue, and providing help with the = delete bits. Differential Revision: https://reviews.llvm.org/D107199
51 lines
1.3 KiB
C++
51 lines
1.3 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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// functional
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// template <class F, class... Args>
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// constexpr unspecified bind_front(F&&, Args&&...);
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#include <functional>
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#include "test_macros.h"
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constexpr int pass(const int n) { return n; }
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int simple(int n) { return n; }
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template<class T>
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T do_nothing(T t) { return t; }
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struct NotMoveConst
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{
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NotMoveConst(NotMoveConst &&) = delete;
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NotMoveConst(NotMoveConst const&) = delete;
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NotMoveConst(int) { }
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};
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void testNotMoveConst(NotMoveConst) { }
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int main(int, char**)
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{
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int n = 1;
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const int c = 1;
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auto p = std::bind_front(pass, c);
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static_assert(p() == 1); // expected-error {{static_assert expression is not an integral constant expression}}
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auto d = std::bind_front(do_nothing, n); // expected-error {{no matching function for call to 'bind_front'}}
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auto t = std::bind_front(testNotMoveConst, NotMoveConst(0)); // expected-error {{no matching function for call to 'bind_front'}}
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return 0;
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}
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