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