id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
6029,GHC fails to stop at phase HCc,liuexp,,"I tried with several different haskell source code and all got the same error:

[liuexp@liuexp pearls]$ ghc -C minfree.hs

addFlag by -C on the commandline:
    Warning: The -fvia-C flag does nothing; it will be removed in a future GHC release
ghc: panic! (the 'impossible' happened)
  (GHC version 7.4.1 for i386-unknown-linux):
	pipeLoop: at phase As but I wanted to stop at phase HCc



here's minfree.hs for reference:

[liuexp@liuexp pearls]$ cat minfree.hs
{-# OPTIONS_GHC -O2 #-}
module Pearls where
import Data.List hiding (union)
import Data.List.Ordered (minus,union)
import Data.Map (Map)
import Data.Set (Set)
import qualified Data.Set as DS
import qualified Data.Map as DM
import Data.Sequence (Seq, (<|), (|>), (><))
import qualified Data.Sequence as S
import qualified Data.Foldable as F

import Control.Monad
import Control.Applicative

--assuming no duplicates
minfree xs = minfrom 0 (length xs,xs)
minfrom a (n,xs)
	|n == 0 = a
	|m == b -a = minfrom b (n-m,vs)
	|otherwise = minfrom a (m,us)
	where 	(us,vs)= partition (<b) xs
		b = a + 1 + n `div` 2
		m = length us
",bug,closed,normal,,Compiler,7.4.1,duplicate,,,Unknown/Multiple,Unknown/Multiple,Other,,,,,