error[E0004]: non-exhaustive patterns: `None` and `Some(_)` not covered --> $DIR/E0004-2.rs:4:11 | LL | match x { } | ^ patterns `None` and `Some(_)` not covered | note: `Option` defined here --> $SRC_DIR/core/src/option.rs:LL:COL | LL | pub enum Option { | ------------------ ... LL | None, | ^^^^ not covered ... LL | Some(#[stable(feature = "rust1", since = "1.0.0")] T), | ^^^^ not covered = note: the matched value is of type `Option` help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms | LL ~ match x { LL + None | Some(_) => todo!(), LL ~ } | error: aborting due to previous error For more information about this error, try `rustc --explain E0004`.