`coerce` has an impossible type

GHCi, version 7.8.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> :set -fprint-explicit-foralls
Prelude> :set -fprint-explicit-kinds
Prelude> import Data.Coerce
Prelude Data.Coerce> :t coerce
coerce
  :: forall (k :: BOX) (a :: k) (b :: k). Coercible k a b => a -> b

Are those types a and b really of kind k? They certainly shouldn't be.

This is worse in HEAD: GHC panics. (Actually, I think panicking is an improvement.)

Easy to fix, happily. Will do so in the course of other work.

Trac metadata

Trac field	Value
Version	7.8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture