| 1 | //===-- declval utility -----------------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | #ifndef LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H |
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| 9 | #define LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H |
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| 10 | |
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| 11 | #include "src/__support/CPP/type_traits/add_rvalue_reference.h" |
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| 12 | #include "src/__support/CPP/type_traits/always_false.h" |
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| 13 | |
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| 14 | namespace LIBC_NAMESPACE::cpp { |
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| 15 | |
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| 16 | // declval |
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| 17 | template <typename T> cpp::add_rvalue_reference_t<T> declval() { |
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| 18 | static_assert(cpp::always_false<T>, |
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| 19 | "declval not allowed in an evaluated context" ); |
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| 20 | } |
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| 21 | |
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| 22 | } // namespace LIBC_NAMESPACE::cpp |
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| 23 | |
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| 24 | #endif // LLVM_LIBC_SRC___SUPPORT_CPP_UTILITY_DECLVAL_H |
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| 25 | |
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