How to recompile Haskell with cabal build showing only warnings

Question

When I cabal build my projects, warnings (especially with -Wall) are only shown the first time.

On subsequent builds, everything is cached.

I want to see all warnings of my project again.

I could cabal clean and recompile or use cabal build --ghc-options="-fforce-recomp", but that just takes too long.

How do I do a warning-check only as fast as possible?

Answer 1

I can speed up compilation by factor ~10 skipping code generation:

cabal build --ghc-options="-fforce-recomp -fno-code"

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For only checking individual files, you can use ghc-mod: ghc-mod check -g -Wall file.hs.