How to supress warnings for on-save build?

[adnelson]

I want SublimeHaskell to check my files when I do a save, but there are a lot of things that the linter grabs up, for example, a top-level declaration without a type signature, or shadowing a variable, that I often don't care about. Then, when there is a legitimate error, like a type error, it's hidden in a sea of trivial warnings which makes it more convenient to simply compile it in GHC/i to see the error rather than looking at SublimeHaskell's output. Further, it's kind of annoying to have the console pop up every time I save, much less with Build FAILED, especially if there aren't any errors.

I was able to disable the checking entirely with "enable_ghc_mod": false, but I don't want to turn off everything. How can I choose which warnings to disable, or failing that, simply kill off the warnings and only have it show errors?

Looking through the source, I can see that these things are being called in autobuild.py, but I can only trace it as far as view.window().run_command('sublime_haskell_ghc_mod_check_and_lint'), and I don't know how that works, since a text search for sublime_haskell_ghc_mod_check_and_lint only returns 2 results, neither of which are a definition of that command.

[nh2]

are a lot of things that the linter grabs up

Just to not to confuse the two: It's not the linter (like our hlint support), it's just ghc warnings.

Anyway, that is not what you asked.

How can I choose which warnings to disable, or failing that, simply kill off the warnings and only have it show errors?

Have you seen the auto_build_mode in the settings?

    // How to build the cabal project in order to obtain error messages.
    // This option exists because `cabal build` is slow and cannot re-print
    // warnings of already compiled modules.
    // (Also see https://github.com/haskell/cabal/issues/1179, cabal 1.16).
    //
    // Possible values:
    // - "normal"
    //   Uses a full `cabal build`, generating object files and binaries.
    //   If this takes too long for you, look at the other options.
    // - "normal-then-warnings"
    //   Like "normal", but afterwards also collects project-wide warnings with
    //   `cabal build --ghc-options="-fforce-recomp -Wall -fno-code"`
    //   (this recompiles everything, but skips code generation for speed).
    // - "typecheck"
    //   Performs a type check of the whole project, trying to not do any more
    //   than that in order to give faster feedback (that "normal").
    //   Currently uses `cabal build --ghc-options="-c"` to skip linking.
    // - "typecheck-then-warnings"
    //   Like "typecheck", but afterwards collects warnings like
    //   "normal-then-warnings".
    //
    // Please note that it is currently impossible to properly use a `-fno-code`
    // build on a cabal project that links a shared library; it errors too early.
    // (https://github.com/haskell/cabal/issues/1176, cabal 1.16).
    "auto_build_mode": "normal-then-warnings",

I think "auto_build_mode": "normal", is what you are looking for.

Could you check if that is it?

[adnelson]

Ah, thanks for the clarification. Hmm, unfortunately it didn't help. I've so far tried it on normal and typecheck, to no effect.

[mvoidex]

I don't know how that works, since a text search for sublime_haskell_ghc_mod_check_and_lint only returns 2 results, neither of which are a definition of that command

SublimeText has mixed name convention for commands. Command named FooBar[Command] in python will be seen as foo_bar in SublimeText. So in your case there is SublimeHaskellGhcModCheckAndLint class at ghcmod.py:43

[nh2]

Hmm, unfortunately it didn't help.

Ah, I think the reason is that this setting is only for building and getting error messages/warnings with cabal. You only want to use ghc-mod, without cabal, is that correct?

In that case, adding a setting that would control the warning level for ghc-mod would be a useful addition!

[bzdzb]

You can prevent these warnings by putting OPTIONS_GHC pragmas at the top of your source files. E.g. {-# OPTIONS_GHC -fno-warn-type-defaults #-}.

Or, you can add the following to your SublimeHaskell.sublime-settings config: "ghc_opts": ["-fno-warn-type-defaults"],