I got the following error: "Type Checker: Cannot apply expression of type Procedure, since it is not a function type" What is the rationale behind this? I'm constructing a function wrapper that uses apply, but I don't know how to type a function in the most general way. The code is like: (define (wrapper fun . args) ... ... (apply fun args)) I expect functions to have any numbers/types of arguments but always return a type B. I tried something like (All (A) (A ... A -> B)) but it does not catch all cases... so I tried to use the type Procedure, which according to the documentation "is the supertype of all function types." Thanks -- Ismael