error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> $DIR/typeck_type_placeholder_item_help.rs:4:15 | LL | fn test1() -> _ { Some(42) } | ^ | | | not allowed in type signatures | help: replace with the correct return type: `Option` error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> $DIR/typeck_type_placeholder_item_help.rs:7:14 | LL | const TEST2: _ = 42u32; | ^ | | | not allowed in type signatures | help: replace `_` with the correct type: `u32` error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> $DIR/typeck_type_placeholder_item_help.rs:10:14 | LL | const TEST3: _ = Some(42); | ^ | | | not allowed in type signatures | help: replace `_` with the correct type: `Option` error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> $DIR/typeck_type_placeholder_item_help.rs:14:18 | LL | const TEST4: _ = 42; | ^ | | | not allowed in type signatures | help: replace `_` with the correct type: `i32` error[E0121]: the type placeholder `_` is not allowed within types on item signatures --> $DIR/typeck_type_placeholder_item_help.rs:21:18 | LL | const TEST5: _ = 13; | ^ | | | not allowed in type signatures | help: replace `_` with the correct type: `i32` error: aborting due to 5 previous errors For more information about this error, try `rustc --explain E0121`.