error[E0308]: mismatched types --> $DIR/fn-ptr.rs:11:21 | LL | #[target_feature(enable = "sse2")] | ---------------------------------- `#[target_feature]` added here ... LL | let foo: fn() = foo; | ---- ^^^ cannot coerce functions with `#[target_feature]` to safe function pointers | | | expected due to this | = note: expected fn pointer `fn()` found fn item `fn() {foo}` = note: fn items are distinct from fn pointers = note: functions with `#[target_feature]` can only be coerced to `unsafe` function pointers help: consider casting to a fn pointer | LL | let foo: fn() = foo as fn(); | ~~~~~~~~~~~ error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.