Re: [GHC] #14326: Panic on COMPLETE pragma with mismatched type variable order

5 Oct 2017

      #14326: Panic on COMPLETE pragma with mismatched type variable order
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        Reporter:  dailectic         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dailectic):

 Replying to [comment:1 RyanGlScott]:
...
I feel like you're leaving out some important information here. I tried
 loading this file (I had to add some language extensions that you left
 out):
{{{#!hs
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE ScopedTypeVariables #-}
module Bug where
data E a b = L' a | R b
pattern L :: forall b a. a -> E a b
pattern L a = L' a
{-# COMPLETE L, R #-}
}}}
I compiled this with 8.2.1, but it did not panic. What am I missing?
Thanks, I was mistaken and the source seems to be in interaction with
 nested pattern matches rather than just the declaration. I've edited the
 ticket to reflect this.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14326#comment:4
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