error[E0069]: `return;` in a function whose return type is not `()` --> $DIR/E0069.rs:2:5 | LL | fn foo() -> u8 { | -- expected `u8` because of this return type LL | return; | ^^^^^^ return type is not `()` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0069`.