Making a core app with a function having context in core2core plugin?

Hi GHC Devs, Is it possible to make a core app with a function having contexts? For example, let us take showable :: P.Show a => a -> String showable = P.show Say, I would like to app showable with (Just 'a') in the core, which requires the following code showable @ (Maybe Char) *($fShowMaybe @ Char $fShowChar)* (Just @ Char (C# 'a')) But I couldn't find a way to construct the dictionary required by showable function myself in the core. Is there any ghc api using which I can get the required dictionary for a particular type (in the above case, Dictionary for Show instance of Maybe Char). Regards, Magesh B