C++程序  |  21行  |  501 B

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++98, c++03, c++11
// type_traits

// enable_if

#include <type_traits>

int main()
{
    typedef std::enable_if_t<false> A;
}