1error[E0594]: cannot assign to `counter`, as it is a captured variable in a `Fn` closure 2 --> $DIR/unboxed-closures-mutated-upvar-from-fn-closure.rs:11:9 3 | 4LL | fn call<F>(f: F) where F : Fn() { 5 | - change this to accept `FnMut` instead of `Fn` 6... 7LL | call(|| { 8 | _____----_- 9 | | | 10 | | expects `Fn` instead of `FnMut` 11LL | | counter += 1; 12 | | ^^^^^^^^^^^^ cannot assign 13LL | | 14LL | | }); 15 | |_____- in this closure 16 17error: aborting due to previous error 18 19For more information about this error, try `rustc --explain E0594`. 20