GHC and GHCi dumps "panic!" ("initTc: unsolved constraints")

changed weight to 5

ghci says below line if I replace Main.hs (but it was defined)

https://gist.github.com/a57b9f85e7927c1327450183faa81620

*Control.Exception.Throwable.TH Data.Text Data.Char Language.Haskell.TH T TIO> :reload
[7 of 9] Compiling Maru.Main        ( /home/aiya000/Repository/hs-zuramaru/src/Maru/Main.hs, interpreted )

/home/aiya000/Repository/hs-zuramaru/src/Maru/Main.hs:44:1: error:
    Variable not in scope: makeLensesA :: Name -> DecsQ
Failed, modules loaded: Control.Exception.Throwable.TH, Maru.Eval, Maru.Parser, Maru.Type, Maru.Type.Parser, Maru.Type.SExpr.

changed title from GHCi dumps "panic!" ("initTc: unsolved constraints") to GHC and GHCi dumps "panic!" ("initTc: unsolved constraints")

Trac metadata

Trac field	Value
TypeOfFailure	GhciCrash → CompileTimeCrash

added compiler crash label and removed GHCi label

I use makeLensesFor instead of my makeLensesA.

Is this microlens's problem ?

https://github.com/aiya000/hs-zuramaru/commit/3980ea2833fa346592745d1bf15f86f6bb444d88

closed

Thanks for the bug report.

This is a duplicate of #13106 (closed), and has been fixed in GHC 8.2.

For what it's worth, this panic sometimes happens when you have out-of-scope identifiers. Here's the error message you get on GHC 8.2:

[6 of 6] Compiling Maru.Main        ( src/Maru/Main.hs, interpreted )

src/Maru/Main.hs:42:15: error:
    • Variable not in scope:
        makeLensesWith :: t1 -> String -> Name -> DecsQ
    • Perhaps you meant ‘makeLensesA’ (line 42)
      Perhaps you want to add ‘makeLensesWith’ to the import list
      in the import of ‘Lens.Micro.TH’ (src/Maru/Main.hs:26:1-45).
   |
42 | makeLensesA = makeLensesWith (lensRules & lensField .~ addSuffix)
   |               ^^^^^^^^^^^^^^

src/Maru/Main.hs:42:31: error:
    • Variable not in scope: lensRules
    • Perhaps you want to add ‘lensRules’ to the import list
      in the import of ‘Lens.Micro.TH’ (src/Maru/Main.hs:26:1-45).
   |
42 | makeLensesA = makeLensesWith (lensRules & lensField .~ addSuffix)
   |                               ^^^^^^^^^

src/Maru/Main.hs:42:41: error:
    Variable not in scope:
      (&)
        :: t5
           -> (((Name -> [Name] -> Name -> [DefName])
                -> f0 (Name -> [Name] -> Name -> [DefName]))
               -> Lens.Micro.TH.LensRules -> f0 Lens.Micro.TH.LensRules)
           -> t3
   |
42 | makeLensesA = makeLensesWith (lensRules & lensField .~ addSuffix)
   |                                         ^

src/Maru/Main.hs:42:53: error:
    • Variable not in scope:
        (.~) :: t3 -> (Name -> [Name] -> Name -> [DefName]) -> t1
    • Perhaps you meant ‘.’ (imported from Prelude)
   |
42 | makeLensesA = makeLensesWith (lensRules & lensField .~ addSuffix)
   |                                                     ^^

src/Maru/Main.hs:54:1: error:
    GHC stage restriction:
      ‘makeLensesA’ is used in a top-level splice, quasi-quote, or annotation,
      and must be imported, not defined locally
   |
54 | makeLensesA ''CliOptions
   | ^^^^^^^^^^^

So ultimately, the root of the issue is that you're trying to use things which aren't imported (e.g., makeLensesWith).

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedDuplicate
Related	- → #13106 (closed)

Thanks ! and sorry x)

I could avoiding this problem :D

And ghc problem is fixed.

Problems is nothing xD

added GHCi label

added Pnormal label

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	GhciCrash
Priority	normal
Resolution	Unresolved
Component	Compiler
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GHC and GHCi dumps "panic!" ("initTc: unsolved constraints")

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