[mpilgrem]

Template Α: This PR modifies behaviour or interface

Include the following checklist in your PR:

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
  • Is the change significant? If so, remember to add significance: significant in the changelog file.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

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See:

• Why is SetupHooks.lhs unsupported? #12473

The change to the code follows the pattern of the lines immediately above.

The change to the documentation now distinguishes between a module and its source file.

[ulysses4ever]

Thanks for picking this up! The docs changes are a clear improvement — separating the SetupHooks module from its source file reads much better.

The code change needs one more step, though: as written it finds SetupHooks.lhs but then copies it verbatim to dist-newstyle/.../setup/SetupHooks.hs, so GHC will try to parse the literate source as plain Haskell when it builds the Setup and hooks executables. The Custom branch just above avoids this by running ppUnlit on the .lhs source — we need the same here. Details and a suggestion inline.

The new test also can't see this, since cabal check doesn't go through updateSetupScript (and already accepted SetupHooks.lhs before this PR). A build-based test would catch both the original bug and the unlit issue; see inline.