Reloading GHCi with Template Haskell names can panic GHC

First, load the following program into GHCi.

Fun.hs

module Fun where
import Language.Haskell.TH

stuff = do
  -- let x = mkName "X"
  x <- newName "X"
  sequence $ [dataD (return []) x [] [
      normalC x []
    ] []]

thbug.hs

{-# LANGUAGE TemplateHaskell #-}
import Fun

stuff

Then comment out the newName, un comment the mkName and reload GHCi.

ghc: panic! (the 'impossible' happened)
  (GHC version 7.8.3 for x86_64-apple-darwin):
	kcLookupKind APromotionErr RecDataConPE

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

It is important to note this is a valid program, if you then close GHCi and start it again with the modified file, it will load correctly. Reloading after attempting to compile the newName version will cause a panic.

Trac metadata

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