error[E0308]: mismatched types --> $DIR/issue-40000.rs:6:9 | LL | foo(bar); | ^^^ one type is more general than the other | = note: expected trait object `dyn for<'a> Fn(&'a i32)` found trait object `dyn Fn(&i32)` error[E0308]: mismatched types --> $DIR/issue-40000.rs:6:9 | LL | foo(bar); | ^^^ one type is more general than the other | = note: expected trait object `dyn for<'a> Fn(&'a i32)` found trait object `dyn Fn(&i32)` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0308`.