ghc panic kindFunResult with template haskell 'isInstance'

--TH.hs

{-# OPTIONS_GHC -Wall #-}
{-# LANGUAGE TemplateHaskell #-}

module TH
       ( SomeClass
       , doThStuff
       ) where

import Control.Monad ( void )
import Language.Haskell.TH

class SomeClass a where

doThStuff :: Name -> Q [Dec]
doThStuff name = reify name >>= go

go :: Info -> Q [Dec]
go (TyConI (DataD [] _ _ [(NormalC _ [(_,typ)])] _)) = do
  void (isInstance ''SomeClass [typ])  -- THIS LINE CRASHES GHC
  return []
go _ = fail "wrong info"

-- Bug.hs

{-# OPTIONS_GHC -Wall #-}
{-# LANGUAGE TemplateHaskell #-}

module Bug
       ( Bar(..)
       ) where

import TH

data Foo a = Foo a
instance SomeClass (Foo a)

data Bar f = Bar (Foo (f Int))
doThStuff ''Bar

I get this error:

$ runghc -ddump-splices Bug.hs 

Bug.hs:1:1:
    Exception when trying to run compile-time code:
      ghc: panic! (the 'impossible' happened)
  (GHC version 7.10.3 for x86_64-unknown-linux):
	kindFunResult

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

    Code: doThStuff ''Bar

If I comment out either instance SomeClass (Foo a) or void (isInstance ''SomeClass [typ]), the crash does not occur.

Trac metadata

Trac field	Value
Version	7.10.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Template Haskell
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