GHC crash with TypeInType and pattern synonym

I decided to try playing with the proposed new Typeable interface, faking up types and functions in GHC 8.0.1. Unfortunately, it seems I did something impossible:

{-# LANGUAGE TypeInType, GADTs, ScopedTypeVariables, PatternSynonyms,
      ViewPatterns #-}

module TypeReflection where

data TypeRep (a :: k)

data TRAppG (fun :: k2) where
  TRAppG :: forall k1 (a :: k1 -> k2) (b :: k1) . TypeRep a -> TypeRep b -> TRAppG (a b)

pattern TRApp :: forall k2 (fun :: k2). ()
              => forall k1 (a :: k1 -> k2) (b :: k1). (fun ~ a b)
              => TypeRep a -> TypeRep b -> TypeRep fun
pattern TRApp a b <- ((undefined :: TypeRep fun -> TRAppG fun) -> TRAppG a b)

The error:

[1 of 1] Compiling TypeReflection   ( TypeReflectionTemplate.hs, TypeReflectionTemplate.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 8.0.1 for x86_64-unknown-linux):
        StgCmmEnv: variable not found
  $dIP_a1Aj
  local binds for:
  typeRep
  $tcTypeable
  $tc'C:Typeable
  $tcTypeRep
  $tc'TRAppG
  $WTRAppG
  $tcTRAppG
  $trModule
  $tcTRAppG1_r1KE
  $tc'TRAppG1_r1KS
  $tcTypeRep1_r1KT
  $tcTypeable1_r1KU
  $tc'C:Typeable1_r1KV
  $trModule1_r1KW
  $trModule2_r1KX
  scrut_s1Lg
  cont_s1Lh
  fail_s1Li
  sat_s1Lj
  sat_s1Lk
  sat_s1Ll
  sat_s1Lm
  sat_s1Ln
  sat_s1Lo
  sat_s1Lp
  sat_s1Lq
  sat_s1Lr
  sat_s1Ls
  sat_s1Lt

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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