CODEWITHSUNDEEP
haskellghc
Francisco Pizarro
Francisco Pizarro

Reputation: 45

GHC warnings are suppressed unless intermediate files are deleted

I'm compiling my program as: ghc -Wall foo.hs and I get some helpful warnings:

foo.hs:14:1: Warning:
    Top-level binding with no type signature: main :: IO ()

Now, if I immediately re-run ghc -Wall foo.hs, I get no warnings. If I delete the intermediate files foo.o and foo.hi, then run ghc -Wall foo.hs, the warnings reappear.

Is this intended behaviour? Can I make it so warnings are always displayed without having to delete intermediate files?

Upvotes: 0

Views: 80

Answers (1)

Tom Ellis
Tom Ellis

Reputation: 9414

If the results of compilation (.hi and .o) already exist then GHC will not recompile the .hs. GHC only emits the warning when it compiles (or typechecks) the .hs.

Perhaps you could use ghc -fforce-recomp foo.hs to force recompiling. (If you just want to typecheck then it's quicker to useghc -fforce-recomp -fno-code foo.hs but there are some warnings that -fno-code doesn't catch.)

Upvotes: 2

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