error[E0308]: mismatched types --> $DIR/issue-35030.rs:9:14 | LL | impl Parser for bool { | ---- expected this type parameter LL | fn parse(text: &str) -> Option { LL | Some(true) | ---- ^^^^ expected type parameter `bool`, found `bool` | | | arguments to this enum variant are incorrect | = note: expected type parameter `bool` (type parameter `bool`) found type `bool` (`bool`) help: the type constructed contains `bool` due to the type of the argument passed --> $DIR/issue-35030.rs:9:9 | LL | Some(true) | ^^^^^----^ | | | this argument influences the type of `Some` note: tuple variant defined here --> $SRC_DIR/core/src/option.rs:LL:COL error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.