super
If this is a super cast phrase, then answer the type by which this argument should be looked up. If it is not and does not contain a super cast phrase in its recursive list phrase structure, then answer bottom. Otherwise create a (recursive) tuple type where elements that are supercasts provide their lookup types and the rest provide bottom.
Return
A tuple type with which to compute a type union with the runtime argument types to use for looking up a method definition at a call site. May be bottom.