[darcs-users] Darcs Build Error

[Simon Marlow]

On 5/9/05, Anthony Metcalf <anthony.metcalf at anferny.ath.cx> wrote:
> Rebuild dependencies ...
> ghc  -cpp  -package parsec -package unix -O -funbox-strict-fields  -Wall
> -Werror -package util -I. -DHAVE_CURSES -DHAVE_CURL -c AntiMemo.lhs ghc
> -cpp  -package parsec -package unix -O -funbox-strict-fields  -Wall
> -Werror -package util -I. -DHAVE_CURSES -DHAVE_CURL -c Autoconf.lhs ghc
> -cpp  -package parsec -package unix -O -funbox-strict-fields  -Wall
> -Werror -package util -I. -DHAVE_CURSES -DHAVE_CURL -c AtExit.lhs ghc
> -cpp  -package parsec -package unix -O -funbox-strict-fields  -Wall
> -Werror -package util -I. -DHAVE_CURSES -DHAVE_CURL -c
> FastPackedString.hs ghc  -cpp  -package parsec -package unix -O
> -funbox-strict-fields  -Wall -Werror -package util -I. -DHAVE_CURSES
> -DHAVE_CURL -c Printer.lhs ghc  -cpp  -package parsec -package unix -O
> -funbox-strict-fields  -Wall -Werror -package util -I. -DHAVE_CURSES
> -DHAVE_CURL -c Workaround.hs ghc  -cpp  -package parsec -package unix -O
> -funbox-strict-fields  -Wall -Werror -package util -I. -DHAVE_CURSES
> -DHAVE_CURL -c SignalHandler.lhs ghc  -cpp  -package parsec -package
> unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c DarcsUtils.lhs ghc  -cpp  -package parsec
> -package unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c DarcsURL.hs ghc  -cpp  -package parsec
> -package unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c Lock.lhs ghc  -cpp  -package parsec
> -package unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c CheckFileSystem.lhs ghc  -cpp  -package
> parsec -package unix -O -funbox-strict-fields  -Wall -Werror -package
> util -I. -DHAVE_CURSES -DHAVE_CURL -c Exec.lhs ghc  -cpp  -package
> parsec -package unix -O -funbox-strict-fields  -Wall -Werror -package
> util -I. -DHAVE_CURSES -DHAVE_CURL -c Curl.hs ghc  -cpp  -package parsec
> -package unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c CommandLine.lhs ghc  -cpp  -package parsec
> -package unix -O -funbox-strict-fields  -Wall -Werror -package util -I.
> -DHAVE_CURSES -DHAVE_CURL -c PatchMatchData.lhs ghc  -cpp  -package
> parsec -package unix -O -funbox-strict-fields  -Wall -Werror -package
> util -I. -DHAVE_CURSES -DHAVE_CURL -c DarcsFlags.lhs ghc  -cpp  -package
> parsec -package unix -O -funbox-strict-fields  -Wall -Werror -package
> util -I. -DHAVE_CURSES -DHAVE_CURL -c External.hs ghc  -cpp  -package
> parsec -package unix -O -funbox-strict-fields  -Wall -Werror -package
> util -I. -DHAVE_CURSES -DHAVE_CURL -c ColourPrinter.lhs ghc  -cpp
> -package parsec -package unix -O -funbox-strict-fields  -Wall -Werror
> -package util -I. -DHAVE_CURSES -DHAVE_CURL -no-auto-all
> -funfolding-use-threshold=20 -c SHA1.lhs ghc-6.2: panic! (the
> `impossible' happened, GHC version 6.2):        Prelude.read: no parse
>
> Please report it as a compiler bug to glasgow-haskell-bugs at haskell.org,
> or http://sourceforge.net/projects/ghc/.

It's the -funfolding-use-threashold=20 flag that's causing the
problem.  Prior to 6.2.2, you had to write it as
-funfolding-use-threshold20 (ie. without the '=').  From 6.2.2, the
'=' was allowed.  The best fix is to remove the '='.

Cheers,
  Simon