error[E0594]: cannot assign to `x`, as it is a captured variable in a `Fn` closure --> $DIR/fn-closure-mutable-capture.rs:5:17 | LL | pub fn bar(_f: F) {} | - change this to accept `FnMut` instead of `Fn` ... LL | bar(move || x = 1); | --- ------- ^^^^^ cannot assign | | | | | in this closure | expects `Fn` instead of `FnMut` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0594`.