1error[E0282]: type annotations needed for `Option<T>` 2 --> $DIR/unboxed-closures-failed-recursive-fn-2.rs:16:32 3 | 4LL | let mut closure0 = None; 5 | ------------ consider giving `closure0` the explicit type `Option<T>`, with the type parameters specified 6... 7LL | return c(); 8 | ^^^ cannot infer type 9 | 10 = note: type must be known at this point 11 12error: aborting due to previous error 13 14For more information about this error, try `rustc --explain E0282`. 15