Failure to find class instance specified with extra parentheses

The following two-line program fails to compile under GHC 7.6.3 and compiles fine with GHC 7.4.1:

instance Eq (((->) a) b)
instance (Ord b) => Ord (((->) a) b)

Error message:

    Could not deduce (Eq (a -> b))
      arising from the superclasses of an instance declaration
    from the context (Ord b)

Compilation goes through if I tweak the Eq instance to use "((->) a b)" or "(a -> b)" in place of "(((->) a) b)".

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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