Invalid redundant pattern matches with -XTypeFamilyDependencies

The following code triggers a warning about a redundant pattern match for foo:

{-# LANGUAGE TypeFamilies, TypeFamilyDependencies #-}

type family F r s = f | f -> r s

type instance F (Bar h (Foo r)) (Bar h (Foo s)) = Bar h (Bar r s)

data Bar s b
data Foo a

foo :: (F cr cu ~ Bar h (Bar r u), 
        F cu cs ~ Bar (Foo h) (Bar u s))
    => Bar h (Bar r u) -> Bar (Foo h) (Bar u s) -> Foo (cr -> cs)
foo = undefined

warning: [-Woverlapping-patterns]
    Pattern match is redundant
    In an equation for ‘foo’: foo = ..

This warning seems invalid to me: I'm not sure how a single definition could constitute a redundant pattern match. Moreover, if I try to address the warning by removing the "redundant" pattern, the code (of course) fails to compile because there is no accompanying binding for the signature of foo.

Trac metadata

Trac field	Value
Version	8.0.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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