id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
3528,GHC crash: equality and class contexts on datatype accessor,guest,,"The following program:
{{{
{-# LANGUAGE FlexibleContexts, NoMonomorphismRestriction, Rank2Types, TypeFamilies #-}
module Foo where

class A a

data B b = B { 
    c :: (Int ~ Int, A b) => Int
   }

d = c
}}}

produces the following bug when compiled with 'ghc foo.hs':

{{{
ghc: panic! (the 'impossible' happened)
  (GHC version 6.10.4 for i386-unknown-linux):
	applyTypeToArgs
    ipv{v B4} [lid] $dA{v ag5} [lid]
    (ghc-prim:GHC.Types.Int{(w) tc 3J}
       ~
     ghc-prim:GHC.Types.Int{(w) tc 3J},
     main:Foo.A{tc rfx} b{tv ag2} [sk]) =>
    ghc-prim:GHC.Types.Int{(w) tc 3J}

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
}}}",bug,closed,normal,,Compiler (Type checker),6.10.4,worksforme,,reiner.pope@…,Linux,x86,,,,,,