error[E0308]: mismatched types --> $DIR/issue-3680.rs:13:9 | LL | Err(_) => () | ^^^^^^ expected enum `std::option::Option`, found enum `std::result::Result` | = note: expected type `std::option::Option<_>` found type `std::result::Result<_, _>` error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.