tests/ui/closures/issue-81700-mut-borrow.rs - rust-lang/rust - Git at Google

 fn foo(x: &mut u32) {
     let bar = || { foo(x); };
     bar(); //~ ERROR cannot borrow
 }
 fn main() {}
	fn foo(x: &mut u32) {
	let bar = \|\| { foo(x); };
	bar(); //~ ERROR cannot borrow
	}
	fn main() {}