ghc crashes on th splices in instance context

Given Class.hs:

module Class where

class Foo a where
    bar :: a -> Int

TH.hs

{-# LANGUAGE TemplateHaskell #-}
module TH where

import Class
import Language.Haskell.TH

mkFun :: Q [Dec]
mkFun = return [FunD 'bar [Clause [WildP] (NormalB (LitE (IntegerL 0)))
                                     []]]

and Instance.hs

{-# LANGUAGE TemplateHaskell #-}
module Instance where

import TH
import Class

instance Foo Bool where
    $(mkFun)

compiling the project crashes ghc with

#ghc --make Instance.hs
[2 of 3] Compiling TH               ( TH.hs, TH.o )
[3 of 3] Compiling Instance         ( Instance.hs, Instance.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 7.8.3 for x86_64-unknown-linux):
        cvBindsAndSigs $[splice{v}]mkFun{v}

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

Trac metadata

Trac field	Value
Version	7.8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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