error[E0282]: type annotations needed --> $DIR/hidden-type-is-opaque-2.rs:8:17 | LL | Thunk::new(|mut cont| { | ^^^^^^^^ consider giving this closure parameter a type | = note: type must be known at this point error[E0282]: type annotations needed --> $DIR/hidden-type-is-opaque-2.rs:17:17 | LL | Thunk::new(|mut cont| { | ^^^^^^^^ consider giving this closure parameter a type | = note: type must be known at this point error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0282`.