[GHC] #10748: Associated type families regression

[GHC]

#10748: Associated type families regression
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        Reporter:  slyfox            |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.2
      Resolution:  invalid           |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by slyfox):

 Aha, I see.

 Ported as:
 {{{#!diff
 diff --git a/src/Synthesizer/Causal/Class.hs
 b/src/Synthesizer/Causal/Class.hs
 index 358dd85..89c9c71 100644
 --- a/src/Synthesizer/Causal/Class.hs
 +++ b/src/Synthesizer/Causal/Class.hs
 @@ -12,7 +12,8 @@ import Control.Arrow (Arrow, arr, (<<<), (&&&), )


 +type family ProcessOf (signal :: * -> *) :: * -> * -> *
 +
  class (Arrow process, ProcessOf (SignalOf process) ~ process) => C
 process where
     type SignalOf process :: * -> *
 -   type ProcessOf (signal :: * -> *) :: * -> * -> *
     toSignal :: process () a -> SignalOf process a
     fromSignal :: SignalOf process b -> process a b
 diff --git a/src/Synthesizer/Causal/Process.hs
 b/src/Synthesizer/Causal/Process.hs
 index e64afcd..33027ef 100644
 --- a/src/Synthesizer/Causal/Process.hs
 +++ b/src/Synthesizer/Causal/Process.hs
 @@ -175,8 +175,8 @@ instance ArrowLoop T where
     loop = liftKleisli loop

 +type instance Class.ProcessOf Sig.T = T

  instance Class.C T where
     type SignalOf T = Sig.T
 -   type ProcessOf Sig.T = T
     toSignal = flip applyConst ()
     fromSignal sig = const () ^>> feed sig
 }}}

 Thank you!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10748#comment:2>
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