Blocking dependency on ghc-mod

[orome]

I may have this wrong, but it appears there's no way to use this with recent GHC, because ghc-mod doesn't work with GHC 8.2.2 (DanielG/ghc-mod#900).

Is there a way to get an ghc-mod executable that works with GHC 8.2.2?

[bgamari]

Not currently I'm afraid. Help on DanielG/ghc-mod#900 would be appreciated though.

[orome]

@bgamari What do you recommend for folks who are using GHC 8.2.X? Should we disable/remove ghc-mod?

[orome]

Any news on this?

[carymrobbins]

@orome Sadly I don't think so. I'd track that ghc-mod ticket for progress, but currently, there doesn't appear to be any.

[orome]

@carymrobbins Will do. Thx.

[orome]

Just to confirm that I understand the error I'm seeing. Is the issue that the GHC used to compile ghc-mod doesn't match the GHC that's set as the one used as the "Haskell Compiler" in the IDE? If so, why do these need to match at all? Shouldn't it be possible to lint/format the code using executables compiled with arbitrary GHC?

I ask because it seems like one way around this would simply be not to care what GHC has been specified elsewhere or is being used globally on the command line (if that's were the incompatibility arises), or to provide an additional setting to point to a matching GHC (e.g. off the path somewhere).

(And for that matter, if I'm building with stack, why is the "Haskell Compiler" setting for GHC relevant at all: I could be using any GHC, as specified in my stack.yaml?)

[carymrobbins]

Shouldn't it be possible to lint/format the code using executables compiled with arbitrary GHC?

Yes, that part is possible and doesn't need ghc-mod, you can do that with hlint and/or your formatter directly.

Also, I just recently discovered that there are working ghc-mod builds for GHC >= 8.2 available in this fork - https://github.com/alanz/ghc-mod/tree/ghc-8.4-hie

I'm currently using the GHC 8.4 build and it seems to be working pretty well.

[orome]

I don't see any linting or formatting inspections at all. How can I confirm that it's working? (I do get some auto-completion though). I have no entry for ghc-mod or ghc-modi, since that's not compatible, but have the other tools configured.

[carymrobbins]

@orome Check the Haskell Tools Console. It should show you the output for your configured tools.

If you don't see it, it might have to do with the checking for Haskell modules and the way you created the project. If you are using stack and imported the project using HaskForce's stack project import wizard, it should "just work". Otherwise, you might need to explicitly import the module as a Haskell Module from the Project Structure menu. Ideally though it could better detect that you have tools configured, so it should just show the console regardless.

[carymrobbins]

@orome Just to double check, you do have hlint configured in the Haskell Tools, correct?

[orome]

Yes. It's setup there. I see hlint output on the Haskell Tools Console, but I don't see any inspections or highlighting in the IDE editor window.

My package is listed under modules in the Project Structure. Are there other setting there that need to be just so (e.g., I don't have a project SDK configured, just Haskell as a module SDK, whatever that means).

[carymrobbins]

@orome Do you see the Haskell Tools Console at the bottom of your IDE?

[orome]

Yes.

[carymrobbins]

Ok, so then do you see the output from hlint there?

[orome]

Yes, see above. But I see nothing in the IDE editor window. Should I?

[carymrobbins]

That seems strange. Maybe copy/paste the output you see from hlint into a gist and link here?

[orome]

I get, for example:

Using working directory: /Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/.idea
/Users/Rax/.local/bin/hlint --no-exit-code --version
Using working directory: /Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/.idea
/Users/Rax/.local/bin/hlint --no-exit-code /Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs --json
[{"module":["Crypto.Enigma"],"decl":["stages"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":238,"startColumn":17,"endLine":238,"endColumn":43,"from":"(length $ components ec) - 1","to":"length (components ec) - 1","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 238, startCol = 17, endLine = 238, endCol = 41}, subts = [(\"a\",SrcSpan {startLine = 238, startCol = 18, endLine = 238, endCol = 24}),(\"b\",SrcSpan {startLine = 238, startCol = 27, endLine = 238, endCol = 40})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":["step"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":275,"startColumn":29,"endLine":275,"endColumn":70,"from":"(mod (positions ec !! i + di - 1) 26) + 1","to":"mod (positions ec !! i + di - 1) 26 + 1","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 275, startCol = 29, endLine = 275, endCol = 66}, subts = [(\"x\",SrcSpan {startLine = 275, startCol = 30, endLine = 275, endCol = 65})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["windows"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":296,"startColumn":36,"endLine":296,"endColumn":67,"from":"windowLetter ec <$> (stages ec)","to":"windowLetter ec <$> stages ec","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 296, startCol = 56, endLine = 296, endCol = 67}, subts = [(\"x\",SrcSpan {startLine = 296, startCol = 57, endLine = 296, endCol = 66})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":324,"startColumn":23,"endLine":324,"endColumn":47,"from":"(== (length components'))","to":"(== length components')","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 324, startCol = 26, endLine = 324, endCol = 46}, subts = [(\"x\",SrcSpan {startLine = 324, startCol = 27, endLine = 324, endCol = 45})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":328,"startColumn":25,"endLine":330,"endColumn":67,"from":"(and $ (== 2) . length <$> splitOn \".\" plug) &&\n  (and $ (`elem` letters) <$> filter (/= '.') plug) &&\n    ((\\ s -> s == nub s) $ filter (/= '.') plug)","to":"and ((== 2) . length <$> splitOn \".\" plug) &&\n  (and $ (`elem` letters) <$> filter (/= '.') plug) &&\n    ((\\ s -> s == nub s) $ filter (/= '.') plug)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 328, startCol = 25, endLine = 328, endCol = 66}, subts = [(\"a\",SrcSpan {startLine = 328, startCol = 26, endLine = 328, endCol = 29}),(\"b\",SrcSpan {startLine = 328, startCol = 32, endLine = 328, endCol = 65})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":329,"startColumn":25,"endLine":330,"endColumn":67,"from":"(and $ (`elem` letters) <$> filter (/= '.') plug) &&\n  ((\\ s -> s == nub s) $ filter (/= '.') plug)","to":"(and $ (`elem` letters) <$> filter (/= '.') plug) &&\n  (\\ s -> s == nub s) (filter (/= '.') plug)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 330, startCol = 25, endLine = 330, endCol = 67}, subts = [(\"a\",SrcSpan {startLine = 330, startCol = 26, endLine = 330, endCol = 44}),(\"b\",SrcSpan {startLine = 330, startCol = 47, endLine = 330, endCol = 66})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":329,"startColumn":25,"endLine":330,"endColumn":67,"from":"(and $ (`elem` letters) <$> filter (/= '.') plug) &&\n  ((\\ s -> s == nub s) $ filter (/= '.') plug)","to":"and ((`elem` letters) <$> filter (/= '.') plug) &&\n  ((\\ s -> s == nub s) $ filter (/= '.') plug)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 329, startCol = 25, endLine = 329, endCol = 73}, subts = [(\"a\",SrcSpan {startLine = 329, startCol = 26, endLine = 329, endCol = 29}),(\"b\",SrcSpan {startLine = 329, startCol = 32, endLine = 329, endCol = 72})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":335,"startColumn":46,"endLine":335,"endColumn":76,"from":"(mod (numA0 w - r + 1) 26) + 1","to":"mod (numA0 w - r + 1) 26 + 1","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 335, startCol = 46, endLine = 335, endCol = 72}, subts = [(\"x\",SrcSpan {startLine = 335, startCol = 47, endLine = 335, endCol = 71})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Error","hint":"Redundant $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":341,"startColumn":17,"endLine":341,"endColumn":85,"from":"reverse $\n  (read <$> (splitOn \".\" $ \"01.\" ++ rngs ++ \".01\") :: [Int])","to":"reverse (read <$> (splitOn \".\" $ \"01.\" ++ rngs ++ \".01\") :: [Int])","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 341, startCol = 17, endLine = 341, endCol = 85}, subts = [(\"a\",SrcSpan {startLine = 341, startCol = 17, endLine = 341, endCol = 24}),(\"b\",SrcSpan {startLine = 341, startCol = 27, endLine = 341, endCol = 85})], orig = \"a b\"}]"}
,{"module":["Crypto.Enigma"],"decl":["configEnigmaExcept"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":341,"startColumn":28,"endLine":341,"endColumn":75,"from":"read <$> (splitOn \".\" $ \"01.\" ++ rngs ++ \".01\")","to":"read <$> splitOn \".\" (\"01.\" ++ rngs ++ \".01\")","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 341, startCol = 37, endLine = 341, endCol = 75}, subts = [(\"a\",SrcSpan {startLine = 341, startCol = 38, endLine = 341, endCol = 49}),(\"b\",SrcSpan {startLine = 341, startCol = 52, endLine = 341, endCol = 74})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":[],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":383,"startColumn":66,"endLine":383,"endColumn":96,"from":"(printf \"%02d\") <$> (rings ec)","to":"printf \"%02d\" <$> (rings ec)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 383, startCol = 66, endLine = 383, endCol = 81}, subts = [(\"x\",SrcSpan {startLine = 383, startCol = 67, endLine = 383, endCol = 80})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":[],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":383,"startColumn":66,"endLine":383,"endColumn":96,"from":"(printf \"%02d\") <$> (rings ec)","to":"(printf \"%02d\") <$> rings ec","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 383, startCol = 86, endLine = 383, endCol = 96}, subts = [(\"x\",SrcSpan {startLine = 383, startCol = 87, endLine = 383, endCol = 95})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["componentMapping"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":435,"startColumn":28,"endLine":435,"endColumn":62,"from":"rotMap (1 - p) letters !! (numA0 ch)","to":"rotMap (1 - p) letters !! numA0 ch","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 435, startCol = 52, endLine = 435, endCol = 62}, subts = [(\"x\",SrcSpan {startLine = 435, startCol = 53, endLine = 435, endCol = 61})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["componentMapping"],"severity":"Suggestion","hint":"Move brackets to avoid $","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":436,"startColumn":16,"endLine":436,"endColumn":63,"from":"chrA0 <$> (ordering $ componentMapping Fwd c p)","to":"chrA0 <$> ordering (componentMapping Fwd c p)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 436, startCol = 26, endLine = 436, endCol = 63}, subts = [(\"a\",SrcSpan {startLine = 436, startCol = 27, endLine = 436, endCol = 35}),(\"b\",SrcSpan {startLine = 436, startCol = 38, endLine = 436, endCol = 62})], orig = \"a (b)\"}]"}
,{"module":["Crypto.Enigma"],"decl":["componentMapping"],"severity":"Warning","hint":"Eta reduce","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":439,"startColumn":9,"endLine":439,"endColumn":59,"from":"rotMap o w = take 26 . drop (mod o 26) . cycle $ w","to":"rotMap o = take 26 . drop (mod o 26) . cycle","note":[],"refactorings":"[]"}
,{"module":["Crypto.Enigma"],"decl":["stageMappingList"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":473,"startColumn":23,"endLine":473,"endColumn":47,"from":"((stageMapping Fwd) <$>)","to":"(stageMapping Fwd <$>)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 473, startCol = 24, endLine = 473, endCol = 42}, subts = [(\"x\",SrcSpan {startLine = 473, startCol = 25, endLine = 473, endCol = 41})], orig = \"x\"}]"}
,{"module":["Crypto.Enigma"],"decl":["stageMappingList"],"severity":"Suggestion","hint":"Redundant bracket","file":"/Users/Rax/Documents/Projects/Coding/Haskell/crypto-enigma/Crypto/Enigma.hs","startLine":473,"startColumn":51,"endLine":473,"endColumn":75,"from":"((stageMapping Rev) <$>)","to":"(stageMapping Rev <$>)","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 473, startCol = 52, endLine = 473, endCol = 70}, subts = [(\"x\",SrcSpan {startLine = 473, startCol = 53, endLine = 473, endCol = 69})], orig = \"x\"}]"}]

And this changes as expected in response to annotations or specs in .hlint.yaml — but nothing in the IDE editor window.

[carymrobbins]

And I assume you are looking for lint warnings in crypto-enigma/Crypto/Enigma.hs ? If so, maybe open up the IntelliJ log (Help > Show Log) and look for log entries or stack traces with haskforce in them.

% grep -i haskforce /Users/Rax/Library/Logs/IntelliJIdea2018.2/idea.log

[orome]

Here's what the command above produces.

[carymrobbins]

@orome Ah ok, I think that's a bug introduced by hlint >= 2.1.5 where the JSON format changed. I have fixed it in commit 9a8612e; however, I haven't released it. I have a few bug fixes that are probably ready to be released as well as an experimental auto-import feature, so I'll get those packaged up and released in the next couple of days.

In the meantime, you can probably build HaskForce from source, which is pretty straight forward.

[orome]

Is there any way to also add a feature that allows picking a GHC to use with the executables (ghc-mod, etc.)? As it now stands this GHC has to be (I think) the system GHC (or is it the project GHC), which means that if that's been updated beyond 8.0.2, ghc-mod can't be used.

[carymrobbins]

If you are using stack, it should use your resolver's ghc. Otherwise, ghc is configurable under

Project Preferences > Build, Execution, Deployment > Compiler > Haskell Compiler

[orome]

Exactly; and those affect my builds, meaning that I'd have to limit them to 8.0.2 just to use ghc-mod. Shouldn't it be possible for Haskforce to use its own GHC, independent of the one used to build the project?

[carymrobbins]

The GHC version of ghc-mod has to match your project, otherwise it won't work.

[orome]

Ah, so ghc-mod can't be used with any project built for GHC>8.0.2 then.

[carymrobbins]

@orome Actually no, I am using it with GHC 8.4.3. See my previous comment here.

[carymrobbins]

This seems mostly resolved so long as you're not using GHC 8.2 (which I believe is the only GHC that ghc-mod doesn't support).

[orome]

But ghc-mod can't be built with base>=4.10, right? So I can't use it with a project that uses the latest GHC or LTS.

[carymrobbins]

Actually no, I'm currently using LTS 13.x and ghc-mod works. I have some steps outlined here that might help - http://caryrobbins.com/dev/installing-ghc-mod/

Ideally, we should get something like this workflow packaged up to make it easier for folks to install and configure ghc-mod (which is related to #304).