[GHC] #9727: -Werror=unused-but-set-variable causes validation error on Windows

[GHC]

#9727: -Werror=unused-but-set-variable causes validation error on Windows
-------------------------------------+-------------------------------------
       Reporter:  gintas             |                   Owner:  gintas
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  Build System       |                 Version:  7.9
       Keywords:                     |        Operating System:  Windows
   Architecture:  Unknown/Multiple   |         Type of failure:  Building
     Difficulty:  Unknown            |  GHC failed
     Blocked By:                     |               Test Case:
Related Tickets:                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 After upgrading the inplace mingw to gcc 4.8.3, validate.sh fails with the
 following error:

 cc1.exe: error: -Werror=unused-but-set-variable: No option -Wunused-but-
 set-variable

 The cause is in mk/validate-settings.mk:

 ifeq "$(GccLT46)" "NO"
 SRC_CC_WARNING_OPTS += -Werror=unused-but-set-variable
 # gcc 4.6 gives 3 warning for giveCapabilityToTask not being inlined
 SRC_CC_WARNING_OPTS += -Wno-error=inline
 endif

 This checks the version of the inplace mingw, but the actual command line
 that fails is not using the inplace mingw (4.8.3), but the host ghc's
 mingw (4.5.3, in /usr/local/mingw).

 Command line:

 C:/Users/Gintas/Downloads/msys32/usr/local/mingw/bin/../libexec/gcc/mingw32/4.5.2/cc1.exe
 -quiet -v -Icompiler/. -Icompiler/parser -Icompiler/utils
 -Icompiler/stage1 -Icompiler/stage1/build/autogen
 -IC:\Users\Gintas\Downloads\msys32\home\Gintas\ghc\inplace/lib/include/
 -iprefix
 c:\users\gintas\downloads\msys32\usr\local\mingw\bin\../lib/gcc/mingw32/4.5.2/
 -isystem
 C:/Users/Gintas/Downloads/msys32/usr/local/mingw/bin/../lib/gcc/mingw32/4.5.2/include
 -isystem
 C:/Users/Gintas/Downloads/msys32/usr/local/mingw/bin/../lib/gcc/mingw32/4.5.2
 /include-fixed -U__i686 -Di386_HOST_ARCH=1 -Dmingw32_HOST_OS=1
 -D__GLASGOW_HASKELL__=708 -U__i686
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\process-1.2.0.0\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\directory-1.2.1.0\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\time-1.4.2\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\Win32-2.3.0.2\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\bytestring-0.10.4.0\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\base-4.7.0.1\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib\integer-
 gmp-0.5.1.0\include
 -isystemC:\Users\Gintas\Downloads\msys32\usr\local\lib/include -include
 compiler/stage1/build/autogen/cabal_macros.h
 compiler/stage1/build/Fingerprint_hsc_make.c -quiet -dumpbase
 Fingerprint_hsc_make.c -march=i686 -march=i686 -auxbase-strip
 compiler/stage1/build/Fingerprint_hsc_make.o -Werror -Wall -Werror=unused-
 but-set-variable -Wno-error=inline -version -fno-stack-protector -o
 C:\Users\Gintas\Downloads\msys32\tmp\ccvafaLk.s

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9727>
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