Interesting. Is this case also an example, or is it a non-feature?

 

class C t where

    type K t :: Type

    type T t :: K t -> Type

 

    m :: t -> T t a

 

 

Ah, that’s quite different!  We should do strongly-connected-component analysis of the associated-type declarations within a single class declaration…. but we don’t currently do that.   No difficulty in principle, I think.

 

You could open a ticket.   (Do include a link to this email thread and to #12088)