GHC fails to stop at phase HCc

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

Trac metadata

Trac field	Value
Version	7.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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