1error[E0596]: cannot borrow `bar` as mutable, as it is not declared as mutable
2  --> $DIR/issue-81700-mut-borrow.rs:3:5
3   |
4LL |     let bar = || { foo(x); };
5   |         ---            - calling `bar` requires mutable binding due to mutable borrow of `x`
6   |         |
7   |         help: consider changing this to be mutable: `mut bar`
8LL |     bar();
9   |     ^^^ cannot borrow as mutable
10
11error: aborting due to previous error
12
13For more information about this error, try `rustc --explain E0596`.
14