Lets say I'm running the plugin on a function with signature `Floating a => a -> a`, then the plugin has access to the `Floating` dictionary for the type. But if I want to add two numbers together, I need the `Num` dictionary. I know I should have access to `Num` since it's a superclass of `Floating`. How can I get access to these superclass dictionaries?
I don't have a working code for this but this should get you started: let ord_dictionary :: Id = ... ord_class :: Class = ... in mkApps (Var (head (classSCSels ord_class))) [Var ord_dictionary] I don't know how to get Class for Ord. I do `head` here because in the case of Ord we only have one superclass so `classSCSels` should have one Id. Then I apply ord_dictionary to this selector and it should return dictionary for Eq. I assumed you already have ord_dictionary, it should be passed to your function already if you had `(Ord a) => ` in your function. Now I realized you asked for getting Num from Floating. I think you should follow a similar path except you need two applications, first to get Fractional from Floating and second to get Num from Fractional: mkApps (Var (head (classSCSels fractional_class))) [mkApps (Var (head (classSCSels floating_class))) [Var floating_dictionary]] Return value should be a Num dictionary.