{"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"//"}]}
        // 2. The `expected` type parameter does *not* occur in the return expression type. This can
        // 1. `expected` ty is a type parameter;
        //    happen for e.g. `fn foo<T>(t: &T) -> T { t }`, where `expected` is `T` but `found` is