error[E0004]: non-exhaustive patterns: type std::option::Option is non-empty --> $DIR/E0004-2.rs:14:11 | LL | match x { } //~ ERROR E0004 | ^ | help: Please ensure that all possible cases are being handled; possibly adding wildcards or more match arms. --> $DIR/E0004-2.rs:14:11 | LL | match x { } //~ ERROR E0004 | ^ error: aborting due to previous error For more information about this error, try `rustc --explain E0004`.