id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
3886,Standalone deriving of NFData causes panic,blarsen,,"Using the -XStandaloneDeriving option, I tried to generate an NFData instance for the CNF type from the funsat 0.60 package on Hackage.


{{{
{-# LANGUAGE StandaloneDeriving #-}
module Broken where

import Funsat.Types
import Control.Parallel.Strategies

deriving instance NFData AST
}}}


With ghc 6.12.1 on 32-bit Ubuntu, the above causes a panic:

ghc: panic! (the 'impossible' happened)
  (GHC version 6.12.1 for i386-unknown-linux):
	genDerivBinds: bad derived class
    deepseq-1.1.0.0:Control.DeepSeq.NFData{tc rou}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
",bug,closed,normal,,Compiler,6.12.1,duplicate,,,Unknown/Multiple,Unknown/Multiple,Compile-time crash,,,,,