[Pkg-haskell-maintainers] Bug#623067: Generated haskell code fails compiling with -Werror

[Erik de Castro Lopo]

Package: alex
Version: 2.3.5-1
Severity: normal
Tags: patch

Generated code fails when compiled with ghc-7.0.3 as follows:

    Warning: Bindings containing unlifted types should use an outermost bang pattern:
               (base) = alexIndexInt32OffAddr alex_base s
    In the expression:
      let
        (base) = alexIndexInt32OffAddr alex_base s
        ((I# (ord_c))) = ord c
        (offset) = (base +# ord_c)
        ....
      in
        case new_s of {
          -1# -> (new_acc, input)
          _ -> alex_scan_tkn
                 user orig_input (len +# 1#) new_input new_s new_acc }
    In a case alternative:
        Just (c, new_input)
          -> let
               (base) = alexIndexInt32OffAddr alex_base s
               ((I# (ord_c))) = ord c
               ....
             in
               case new_s of {
                 -1# -> (new_acc, input)
                 _ -> alex_scan_tkn
                        user orig_input (len +# 1#) new_input new_s new_acc }

Bug has been reported and the attached patch has already been submitted
upstream as:

    http://trac.haskell.org/haskell-platform/ticket/171


-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=ANSI_X3.4-1968) (ignored: LC_ALL set to C)
Shell: /bin/sh linked to /bin/dash

Versions of packages alex depends on:
ii  libc6                     2.11.2-11      Embedded GNU C Library: Shared lib
ii  libffi5                   3.0.9-3        Foreign Function Interface library
ii  libgmp10                  2:5.0.1+dfsg-7 Multiprecision arithmetic library

alex recommends no packages.

alex suggests no packages.

-- no debconf information
-------------- next part --------------
# Author : Erik de Castro Lopo <erikd at mega-nerd.com>
# Description : Fix generated haskell code so it doesn't fail with -Werror.
# Debian Version : 2.3.5
# Date : Sun, 17 Apr 2011 15:45:41 +1000

Index: alex-2.3.5/templates/GenericTemplate.hs
===================================================================
--- alex-2.3.5.orig/templates/GenericTemplate.hs
+++ alex-2.3.5/templates/GenericTemplate.hs
@@ -9,7 +9,7 @@

 #ifdef ALEX_GHC
 #define ILIT(n) n#
-#define FAST_INT_BINDING(n) (n)
+#define FAST_INT_BINDING(n) (!(n))
 #define IBOX(n) (I# (n))
 #define FAST_INT Int#
 #define LT(n,m) (n <# m)
@@ -57,10 +57,10 @@
 ALEX_IF_BIGENDIAN
   narrow16Int# i
   where
-        i    = word2Int# ((high `uncheckedShiftL#` 8#) `or#` low)
-        high = int2Word# (ord# (indexCharOffAddr# arr (off' +# 1#)))
-        low  = int2Word# (ord# (indexCharOffAddr# arr off'))
-        off' = off *# 2#
+        !i    = word2Int# ((high `uncheckedShiftL#` 8#) `or#` low)
+        !high = int2Word# (ord# (indexCharOffAddr# arr (off' +# 1#)))
+        !low  = int2Word# (ord# (indexCharOffAddr# arr off'))
+        !off' = off *# 2#
 ALEX_ELSE
   indexInt16OffAddr# arr off
 ALEX_ENDIF
@@ -74,14 +74,14 @@
 ALEX_IF_BIGENDIAN
   narrow32Int# i
   where
-   i    = word2Int# ((b3 `uncheckedShiftL#` 24#) `or#`
+   !i    = word2Int# ((b3 `uncheckedShiftL#` 24#) `or#`
 		     (b2 `uncheckedShiftL#` 16#) `or#`
 		     (b1 `uncheckedShiftL#` 8#) `or#` b0)
-   b3   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 3#)))
-   b2   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 2#)))
-   b1   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 1#)))
-   b0   = int2Word# (ord# (indexCharOffAddr# arr off'))
-   off' = off *# 4#
+   !b3   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 3#)))
+   !b2   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 2#)))
+   !b1   = int2Word# (ord# (indexCharOffAddr# arr (off' +# 1#)))
+   !b0   = int2Word# (ord# (indexCharOffAddr# arr off'))
+   !off' = off *# 4#
 ALEX_ELSE
   indexInt32OffAddr# arr off
 ALEX_ENDIF