tests/ui/parser/extern-no-fn.rs - rust - Git at Google

 extern "C" {
     f();
     //~^ ERROR missing `fn` or `struct` for function or struct definition
     //~| HELP if you meant to call a macro, try
 }

 fn main() {
 }
	extern "C" {
	f();
	//~^ ERROR missing `fn` or `struct` for function or struct definition
	//~\| HELP if you meant to call a macro, try
	}

	fn main() {
	}