## Summary GHC 9.4.1 alpha2 build failure while compiling with GHC 8.10.5. The build failure looks as: ``` karel@silence:/tmp/ghc-9.4.0.20220523$ ./hadrian/build Up to date | Configure package 'rts' | Run GhcPkg Dependencies Stage0: directory | Run GhcPkg Dependencies Stage0: unix | Run Ghc CompileHs Stage0: libraries/bytestring/Data/ByteString/Internal.hs => _build/stage0/libraries/bytestring/build/Data/ByteString/Internal.o Command line: /export/home/karel/sfw/ghc-8.10.5/bin/ghc -Wall -Wcompat -hisuf hi -osuf o -hcsuf hc -static -hide-all-packages -no-user-package-db '-package-env -' '-package-db _build/stage0/lib/package.conf.d' '-this-unit-id bytestring-0.11.3.0' '-package-id base-4.14.2.0' '-package-id deepseq-1.4.4.0' '-package-id ghc-prim-0.6.1' '-package-id template-haskell-2.19.0.0' -i -i/tmp/ghc-9.4.0.20220523/_build/stage0/libraries/bytestring/build -i/tmp/ghc-9.4.0.20220523/_build/stage0/libraries/bytestring/build/autogen -i/tmp/ghc-9.4.0.20220523/libraries/bytestring -I_build/stage0/libraries/bytestring/build -I_build/stage0/libraries/bytestring/build/include -Ilibraries/bytestring/include -I/export/home/karel/sfw/ghc-8.10.5/lib/ghc-8.10.5/base-4.14.2.0/include -I/export/home/karel/sfw/ghc-8.10.5/lib/ghc-8.10.5/integer-gmp-1.0.3.0/include -I/export/home/karel/sfw/ghc-8.10.5/lib/ghc-8.10.5/include -optP-include -optP_build/stage0/libraries/bytestring/build/autogen/cabal_macros.h -outputdir _build/stage0/libraries/bytestring/build -fdiagnostics-color=always -optc-Wno-error=inline -optP-Wno-nonportable-include-path -c libraries/bytestring/Data/ByteString/Internal.hs -o _build/stage0/libraries/bytestring/build/Data/ByteString/Internal.o -O -H32m -Wall -fwarn-tabs -O2 -fmax-simplifier-iterations=10 -fdicts-cheap -fspec-constr-count=6 -XHaskell2010 -fno-warn-deprecated-flags ===> Command failed with error code: 1 libraries/bytestring/Data/ByteString/Internal.hs:292:23: error: • Couldn't match type ‘m’ with ‘TH.Q’ ‘m’ is a rigid type variable bound by the type signature for: TH.lift :: forall (m :: * -> *). TH.Quote m => ByteString -> m TH.Exp at libraries/bytestring/Data/ByteString/Internal.hs:292:3-6 Expected type: m TH.Exp Actual type: TH.Q TH.Exp • In the expression: [| unsafePackLenLiteral |] `TH.appE` TH.litE (TH.integerL (fromIntegral len)) `TH.appE` TH.litE (TH.BytesPrimL $ TH.Bytes ptr 0 (fromIntegral len)) In an equation for ‘TH.lift’: TH.lift (BS ptr len) = [| unsafePackLenLiteral |] `TH.appE` TH.litE (TH.integerL (fromIntegral len)) `TH.appE` TH.litE (TH.BytesPrimL $ TH.Bytes ptr 0 (fromIntegral len)) In the instance declaration for ‘TH.Lift ByteString’ • Relevant bindings include lift :: ByteString -> m TH.Exp (bound at libraries/bytestring/Data/ByteString/Internal.hs:292:3) | 292 | lift (BS ptr len) = [| unsafePackLenLiteral |] | ^^^^^^^^^^^^^^^^^^^^^^^^^^... Command failed ``` ## Steps to reproduce On Linux/x64, install GHC 8.10.5 and try to compile GHC 9.4.1 alpha2 with it. ## Expected behavior I expect GHC to be compiled well. ## Environment * GHC version used: 8.10.5 Optional: * Operating System: Ubuntu 20.04 LTS * System Architecture: amd64