src/test/ui/macros/macro-path-prelude-pass.rs - toolchain/rustc - Git at Google

 // compile-pass

 #![feature(extern_prelude)]

 mod m {
     fn check() {
         std::panic!(); // OK
     }
 }

 fn main() {}
	// compile-pass

	#![feature(extern_prelude)]

	mod m {
	fn check() {
	std::panic!(); // OK
	}
	}

	fn main() {}