tests/ui/unsafe/unsafe-fn-used-as-value.rs - toolchain/rustc - Git at Google

 unsafe fn f() {
     return;
 }

 fn main() {
     let x = f;
     x();
     //~^ ERROR call to unsafe function `f` is unsafe
 }
	unsafe fn f() {
	return;
	}

	fn main() {
	let x = f;
	x();
	//~^ ERROR call to unsafe function `f` is unsafe
	}