Generalized newtype deriving with associated types

When I have a

    class Foo a where
	type Bar a
	foobar :: a -> Bar a

an

instance Foo Fooey ...

and

newtype Fooey2 = F2 (Fooey) deriving (Foo) 

I expect the automatically generated deriving to include

type Bar Fooey2 = Bar Fooey

but this is not the case: I cannot get an associated type from a newtype to resolve to anything. My guess is that the combination of -XTypeFamilies and -XGeneralizedNewtypeDeriving is rare enough that this may simply not have been thought of yet, but it's something I'd like to see fixed.

Trac metadata

Trac field	Value
Version	6.10.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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