But the problem is NOT with that import. It's with the OPTIONS_GHC in
GHC.Internal.Classes, which is not in the external-modules section.
I did as you suggested but I'm still getting the stuff below
Warning: Specifying an absolute path to the project file is deprecated. Use
--project-dir to set the project's directory.
Configuration is affected by cabal.project at
'/home/simonpj/code/HEAD-19/hadrian'.
Up to date
Warning: Specifying an absolute path to the project file is deprecated. Use
--project-dir to set the project's directory.
Configuration is affected by cabal.project at
'/home/simonpj/code/HEAD-19/hadrian'.
]0;Starting...(/home/simonpj/code/HEAD-19) | Copy file:
utils/haddock/haddock-api/resources/html/Classic.theme/plus.gif =>
_build/stage1/lib/html/Classic.theme/plus.gif
| Run Ghc FindHsDependencies (Stage0 InTreeLibs):
libraries/ghc-boot-th/GHC/Boot/TH/Lib.hs (and 14 more) =>
_build/stage0/libraries/ghc-boot-th-next/.dependencies.mk
/home/simonpj/code/HEAD-19/libraries/ghc-boot-th-next/../ghc-internal/src/GHC/Internal/Classes.hs:10:17:
error: [GHC-04924]
Unknown flag in {-# OPTIONS_GHC #-} pragma: -fdefines-known-key-names
|
10 | {-# OPTIONS_GHC -fdefines-known-key-names #-}
| ^^^^^^^^^^^^^^^^^^^^^^^^^
]0;Finished in 2.54s(/home/simonpj/code/HEAD-19) Development.Shake.cmd,
system command failed
Command line: /home/simonpj/.ghcup/bin/ghc -M -include-cpp-deps -hisuf hi
-osuf o -hcsuf hc -static -hide-all-packages -no-user-package-db
'-package-env -' '-package-db _build/stage0/inplace/package.conf.d'
'-this-unit-id ghc-boot-th-next-9.15-inplace' '-this-package-name
ghc-boot-th-next' '-package-id base-4.21.0.0-ae91' '-package-id
ghc-prim-0.13.0-e168' '-package-id pretty-1.1.3.6-fe44' -i
-i/home/simonpj/code/HEAD-19/_build/stage0/libraries/ghc-boot-th-next/build
-i/home/simonpj/code/HEAD-19/_build/stage0/libraries/ghc-boot-th-next/build/autogen
-i/home/simonpj/code/HEAD-19/libraries/ghc-boot-th-next/../ghc-boot-th
-i/home/simonpj/code/HEAD-19/libraries/ghc-boot-th-next/../ghc-internal/src
-I_build/stage0/libraries/ghc-boot-th-next/build
-I/home/simonpj/.ghcup/ghc/9.12.2/lib/ghc-9.12.2/lib/x86_64-linux-ghc-9.12.2-a828/ghc-internal-9.1202.0-1465/include
-I/home/simonpj/.ghcup/ghc/9.12.2/lib/ghc-9.12.2/lib/x86_64-linux-ghc-9.12.2-a828/ghc-bignum-1.3-6db4/include
-I/home/simonpj/.ghcup/ghc/9.12.2/lib/ghc-9.12.2/lib/x86_64-linux-ghc-9.12.2-a828/rts-1.0.2/include
-optP-include
-optP_build/stage0/libraries/ghc-boot-th-next/build/autogen/cabal_macros.h
-optP-DBOOTSTRAP_TH -outputdir
_build/stage0/libraries/ghc-boot-th-next/build -fdiagnostics-color=always
-XHaskell2010 -XNoImplicitPrelude -optc-Wno-error=inline -include-pkg-deps
-dep-makefile _build/stage0/libraries/ghc-boot-th-next/.dependencies.mk
-dep-suffix '' -fno-warn-deprecated-flags -O +RTS -O64M -RTS
@/tmp/extra-file-89749345684126-2082901-0
Exit code: 1
Stderr:
/home/simonpj/code/HEAD-19/libraries/ghc-boot-th-next/../ghc-internal/src/GHC/Internal/Classes.hs:10:17:
error: [GHC-04924]
Unknown flag in {-# OPTIONS_GHC #-} pragma: -fdefines-known-key-names
|
10 | {-# OPTIONS_GHC -fdefines-known-key-names #-}
| ^^^^^^^^^^^^^^^^^^^^^^^^^
On Wed, 25 Mar 2026 at 13:17, Teo Camarasu <[email protected]> wrote:
> > *But what business does the bootstrap compiler have with compiling
> GHC.Internal.Classes? *
>
> Aha! I see the issue.
>
> If you look here:
> https://gitlab.haskell.org/ghc/ghc/-/blob/master/libraries/ghc-boot-th/ghc-boot-th.cabal.in#L55
>
> if flag(bootstrap)
> cpp-options: -DBOOTSTRAP_TH
> build-depends:
> ghc-prim
> hs-source-dirs: @SourceRoot@ ../ghc-internal/src
> exposed-modules:
> GHC.Boot.TH.Lib
> GHC.Boot.TH.Syntax
> GHC.Boot.TH.Monad
> other-modules:
> GHC.Internal.TH.Lib
> GHC.Internal.TH.Syntax
> GHC.Internal.TH.Monad
> GHC.Internal.ForeignSrcLang
> GHC.Internal.LanguageExtensions
> GHC.Internal.Lexeme
>
> You can see the modules that we vendor from `ghc-internal` under
> `other-modules.
>
> One of those is `GHC.Internal.ForeignSrcLang` and in your PR you add:
> ```
> import GHC.Internal.Classes( (==) ) -- For known-key names
> ```
> This needs to go inside the `else` branch of the `ifdef BOOTSTRAP_TH`
> pragma.
>
> I think if you do the same thing for any `ghc-internal` imports in the
> other modules mentioned above then you should be fine.
>
> I really should add a note explaining this BOOTSTRAP_TH business,
> especially because it is quite hacky(!).
> Note [Bootstrapping Template Haskell] does a good job of explaining the
> design decisions we made to get here, but we need another note to explain
> this CPP soup.
>
> Cheers,
> Teo
>
>
>
_______________________________________________
ghc-devs mailing list -- [email protected]
To unsubscribe send an email to [email protected]
