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