1 error[E0121]: the placeholder `_` is not allowed within types on item signatures for return types
2 --> $DIR/return-cycle.rs:6:17
7 | not allowed in type signatures
8 | help: replace with the correct return type: `Token<()>`
10 error: aborting due to previous error
12 For more information about this error, try `rustc --explain E0121`.