[GHC] #15694: GHC panic from pattern synonym, "Type-correct unfilled coercion hole"

[GHC]

#15694: GHC panic from pattern synonym, "Type-correct unfilled coercion hole"
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:
                                     |  PatternSynonyms
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"7ea714cd8d64dd0a7646d71d45e18c9f6a3527cb/ghc" 7ea714c/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="7ea714cd8d64dd0a7646d71d45e18c9f6a3527cb"
 Solve equalities in a pattern signature

 Trac #15694 showed that we were forgetting to solve
 the equalities of a pattern signature until too late.

 Result: WARNINGs and a panic:
   "Type-correct unfilled coercion hole"
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15694#comment:2>
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