(->) used prefix doesn't work with unboxed kinds

This fails, but should succeed
    f :: (->) Int# Int#
    f x = x


-- Here's the comment from TypeRep:
--
-- funTyCon = mkFunTyCon funTyConName 
--		(mkArrowKinds [liftedTypeKind, 
liftedTypeKind]
--				liftedTypeKind)
-- You might think that (->) should have type (? -> ? -> 
*), and you'd be right
-- But if we do that we get kind errors when saying
--	instance Control.Arrow (->)
-- becuase the expected kind is (*->*->*).  The trouble 
is that the
-- expected/actual stuff in the unifier does not go 
contra-variant, whereas
-- the kind sub-typing does.  Sigh.  It really only 
matters if you use (->) in
-- a prefix way, thus:  (->) Int# Int#.  And this is 
unusual.

Trac metadata

Trac field	Value
Version	None
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture