- //===- llvm/ADT/Identity.h - Provide std::identity from C++20 ---*- 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 
- // 
- //===----------------------------------------------------------------------===// 
- // 
- // This file provides an implementation of std::identity from C++20. 
- // 
- // No library is required when using these functions. 
- // 
- //===----------------------------------------------------------------------===// 
-   
- #ifndef LLVM_ADT_IDENTITY_H 
- #define LLVM_ADT_IDENTITY_H 
-   
-   
- namespace llvm { 
-   
- // Similar to `std::identity` from C++20. 
- template <class Ty> struct identity { 
-   using is_transparent = void; 
-   using argument_type = Ty; 
-   
-   Ty &operator()(Ty &self) const { 
-     return self; 
-   } 
-   const Ty &operator()(const Ty &self) const { 
-     return self; 
-   } 
- }; 
-   
- } // end namespace llvm 
-   
- #endif // LLVM_ADT_IDENTITY_H 
-