src/test/ui/fmt/ifmt-unimpl.rs - third_party/rust - Git at Google

 fn main() {
     format!("{:X}", "3");
     //~^ ERROR: `str: UpperHex` is not satisfied
 }
	fn main() {
	format!("{:X}", "3");
	//~^ ERROR: `str: UpperHex` is not satisfied
	}