error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in type --> $DIR/issue-86642.rs:1:11 | LL | static x: impl Fn(&str) -> Result<&str, ()> = move |source| { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0562`.