error[E0053]: method `owo` has an incompatible type for trait --> $DIR/method-signature-matches.rs:13:15 | LL | fn owo(_: u8) {} | ^^ | | | expected `()`, found `u8` | help: change the parameter type to match the trait: `()` | note: type in trait --> $DIR/method-signature-matches.rs:8:15 | LL | fn owo(x: ()) -> impl Sized; | ^^ = note: expected signature `fn(())` found signature `fn(u8)` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0053`.