error[E0004]: non-exhaustive patterns: `(None, None)` and `(Some(_), Some(_))` not covered --> $DIR/issue-2111.rs:2:11 | LL | match (a, b) { | ^^^^^^ patterns `(None, None)` and `(Some(_), Some(_))` not covered | = note: the matched value is of type `(Option, 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 ~ (Some(_), None) | (None, Some(_)) => {}, LL + (None, None) | (Some(_), Some(_)) => todo!() | error: aborting due to previous error For more information about this error, try `rustc --explain E0004`.