tests/ui/parser/macro/issue-37234.rs - rust-lang/rust - Git at Google

 macro_rules! failed {
     () => {{
         let x = 5 ""; //~ ERROR found `""`
     }}
 }

 fn main() {
     failed!();
 }
	macro_rules! failed {
	() => {{
	let x = 5 ""; //~ ERROR found `""`
	}}
	}

	fn main() {
	failed!();
	}