1 error[E0596]: cannot borrow `bar` as mutable, as it is not declared as mutable
2 --> $DIR/issue-81700-mut-borrow.rs:3:5
4 LL | let bar = || { foo(x); };
5 | --- - calling `bar` requires mutable binding due to mutable borrow of `x`
7 | help: consider changing this to be mutable: `mut bar`
9 | ^^^ cannot borrow as mutable
11 error: aborting due to previous error
13 For more information about this error, try `rustc --explain E0596`.