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