Instantiation of overloaded definition *in Core*

Erdi, Gergo Gergo.Erdi at sc.com
Mon Oct 4 09:29:42 UTC 2021


PUBLIC

Hi,

I'd like to instantiate Core definitions. For example, suppose I have the following Core definition:

foo :: forall m a b. Monad m => m a -> m b -> m b
foo = \ @m ($d :: Monad m) @a @b (ma :: m a) (mb :: m b) -> ...

Now let's say I'd like to instantiate it for m ~ IO. It is quite straightforward to go from the above to:

foo_IO_0 :: forall a b. Monad IO => IO a -> IO b -> IO b
foo_IO_0 = \ ($d :: Monad IO) @a @b (ma :: IO a) (mb :: IO b) -> ...

However, I would like to go all the way to:

foo_IO :: forall a b. IO a -> IO b -> IO b
foo_IO = \ @a @b (ma :: IO a) (mb :: IO b) -> ...

Because instances are coherent, it should be sound to replace all occurrences of $d with "the" dictionary for Monad IO. However, the places I've found for this kind of query seem to live in the typechecker. How do I access this information while working with Core?

Thanks,
            Gergo

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