My !8750 builds are failing in the Unix library with the "pattern match is redundant" message below.

And indeed the pattern match is redundant.  Here's the .hs version of the file

The red line means that the blue lines will fail.

So the warning looks correct.  But it's stopping my CI from working.  I have no idea why this doesn't happen in HEAD.   Can anyone help?

Thanks

Simon

Command line: _build/stage0/bin/aarch64-linux-gnu-ghc -Wall -Wcompat -fdiagnostics-color=never -dynamic-too -hisuf hi -osuf o -hcsuf hc -static -hide-all-packages -no-user-package-db '-package-env -' '-package-db _build/stage1/lib/package.conf.d' '-this-unit-id unix-2.7.2.2' '-package-id base-4.17.0.0' '-package-id bytestring-0.11.3.1' '-package-id time-1.12.2' -i -i/builds/ghc/ghc/_build/stage1/libraries/unix/build -i/builds/ghc/ghc/_build/stage1/libraries/unix/build/autogen -i/builds/ghc/ghc/libraries/unix -Irts/include -I_build/stage1/libraries/unix/build -I_build/stage1/libraries/unix/build/include -Ilibraries/unix/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/time-1.12.2/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/bytestring-0.11.3.1/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/base-4.17.0.0/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/ghc-bignum-1.3/include -I/builds/ghc/ghc/_build/stage1/lib/aarch64-linux-ghc-9.5.20220906/rts-1.0.2/include -optP-include -optP_build/stage1/libraries/unix/build/autogen/cabal_macros.h -outputdir _build/stage1/libraries/unix/build -Wnoncanonical-monad-instances -optc-Wno-error=inline -optP-Wno-nonportable-include-path -c _build/stage1/libraries/unix/build/System/Posix/Resource.hs -o _build/stage1/libraries/unix/build/System/Posix/Resource.o -fllvm-fill-undef-with-garbage -dno-debug-output -Wall -XHaskell2010 -no-global-package-db -package-db=/builds/ghc/ghc/_build/stage1/lib/package.conf.d -ghcversion-file=rts/include/ghcversion.h -ghcversion-file=rts/include/ghcversion.h -O -Wno-deprecated-flags -Werror -dlint

===> Command failed with error code: 1

libraries/unix/System/Posix/Resource.hsc:107:7: error: [-Woverlapping-patterns, -Werror=overlapping-patterns]

Pattern match is redundant

In an equation for ‘unpackRLimit’:

unpackRLimit other | ((18446744073709551615) :: CRLim)

/= (18446744073709551615)

&& other == (18446744073709551615) = ...

|

107 | | ((#const RLIM_SAVED_CUR) :: CRLim) /= (#const RLIM_INFINITY) &&

| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...