text: //===----------------------------------------------------------------------===//
  //
  //                     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.
  //
  //===----------------------------------------------------------------------===//
  
  // <functional>
  
  // template<class F>
  // function(F) -> function<see-below>;
  
  // UNSUPPORTED: c++98, c++03, c++11, c++14
  // UNSUPPORTED: libcpp-no-deduction-guides
  
  // The deduction guides for std::function do not handle rvalue-ref qualified
  // call operators and C-style variadics. It also doesn't deduce from nullptr_t.
  // Make sure we stick to the specification.
  
  #include <functional.hxx>
  #include <type_traits.hxx>
  
  
  struct R { };
  struct f0 { R operator()() && { return {}; } };
  struct f1 { R operator()(int, ...) { return {}; } };
  
  int main() {
      std::function f = f0{}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'function'}}
      std::function g = f1{}; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'function'}}
      std::function h = nullptr; // expected-error{{no viable constructor or deduction guide for deduction of template arguments of 'function'}}
  }
  