remove compiler errors for deferred function mismatched types

Before this fix, it was not possible to compile a catalog that used a `Deferred` value for a typed parameter class; the compiler would error with a message stating that the type expected did not match `Deferred`. With this fix, the compiler will inspect the Deferred class's return type and ensure it matches the class parameter type. If the Deferred function has no return type, the compiler will warn that it cannot guarantee the type will adhere to the type the class specifies.