[GHC] #8329: dmdTransformDictSelSig panic

18 Sep 2013

      #8329: dmdTransformDictSelSig panic
-----------------------------------+---------------------------------------
       Reporter:  monoidal         |             Owner:
           Type:  bug              |            Status:  new
       Priority:  normal           |         Milestone:
      Component:  Compiler         |           Version:  7.7
       Keywords:                   |  Operating System:  Unknown/Multiple
   Architecture:                   |   Type of failure:  Compile-time crash
  Unknown/Multiple                 |         Test Case:
     Difficulty:  Unknown          |          Blocking:
     Blocked By:                   |
Related Tickets:                   |
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 Installing `xmlhtml` with HEAD panicks, while it works in 7.6.3.

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.7.20130918 for x86_64-unknown-linux):
         dmdTransformDictSelSig: split failed
 }}}

 I reduced this panic to four files:

 Common.hs

 {{{
 module Common where

 import Data.String (fromString)

 encodingName :: String
 encodingName = fromString ""
 }}}

 Meta.hs

 {{{
 {-# OPTIONS_GHC -O0 #-}

 module Meta where

 import Data.String
 }}}

 Parse.hs

 {{{
 module Parse where

 import Meta
 }}}

 XmlHtml.hs

 {{{
 module XmlHtml where

 import Parse
 import Common
 }}}

 Remove *.hi and *.o files and compile `ghc -O XmlHtml` to get the panic.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8329
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