[GHC] #16127: Panic: piResultTys1 in compiler/types/Type.hs:1022:5

[GHC]

#16127: Panic: piResultTys1 in compiler/types/Type.hs:1022:5
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        Reporter:  _deepfire         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.6.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by _deepfire):

 ..and the following is what hints at the cause (kind polymoprhism mismatch
 between `.hs` and `.hs-boot`):
 {{{
 $ git diff HEAD~1..
 diff --git a/src/Holo/Widget2.hs-boot b/src/Holo/Widget2.hs-boot
 index d63c757..13ed889 100644
 --- a/src/Holo/Widget2.hs-boot
 +++ b/src/Holo/Widget2.hs-boot
 @@ -3,6 +3,7 @@ where

  import           Data.Kind                                (Type)
  import qualified Data.TypeMap.Dynamic              as TM
 +import           GHC.Types                                (Constraint)
  import           Generics.SOP                             (Top)
  import           Generics.SOP.Monadic                     (Result)
  import           Reflex                                   (Dynamic)
 @@ -15,7 +16,7 @@ import {-# SOURCE #-}

  data Definition i a

 -newtype Vocab i c = Vocab (TM.TypeMap (HoloTag i))
 +newtype Vocab (i ∷ Type) (c ∷ Type → Constraint) = Vocab (TM.TypeMap
 (HoloTag i))
  data                                   HoloTag i

  type Blank   i     = Item Top PBlank
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16127#comment:3>
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