Currently, when we encounter a INamedTypeSymbol or a function pointer in VisitType, we abandon any attempt to be tail recursive and instead go for a fully recursive solution. This makes the code simple, but it does mean that we are recursive even for the simple case of a named type with one type argument, which is completely possible to handle without any recursion whatsoever. This changes our implementation to always be tail recursive for the last type argument or function pointer type.