ghc panic in deriving Generic1 on Array#

Compiling the following code

{-# Language DeriveGeneric, MagicHash #-}

module Test where

import GHC.Generics
import GHC.Prim

data Array a = Array (Array# a)
newtype Vec a = MkVec {unVec :: Array a} deriving Generic1

causes panic:

[1 of 1] Compiling Test             ( Test.hs, Test.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 7.6.3 for x86_64-unknown-linux):
	No match in record selector tyConTyVars

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

some comments from IRC:

<monoidal> with deriving Generic1 we get "Can't make a derived instance of `Generic1 Array': Array must not have unlifted or polymorphic arguments" - so it seems the check is not done recursively on used types <monoidal> * deriving Generic1 on Array

Trac metadata

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