[GHC] #14498: GHC internal error: "not in scope during TC but it passed the renamer"

[GHC]

#14498: GHC internal error: "not in scope during TC but it passed the renamer"
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.2.1
  checker)                           |             Keywords:
      Resolution:  fixed             |  PatternSynonyms
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Compile-time      |            Test Case:
  crash or panic                     |  patsyn/should_fail/T14498
      Blocked By:                    |             Blocking:
 Related Tickets:  #14288            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by simonpj):

 * status:  new => closed
 * testcase:   => patsyn/should_fail/T14498
 * resolution:   => fixed


Comment:

 OK good.  Fixed by
 {{{
 commit f1fe5b4adf6a4094ecc600a28f64f7628903d017
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Mon Dec 18 12:03:33 2017 +0000

     Fix scoping of pattern-synonym existentials

     This patch fixes Trac #14998, where we eventually decided that
     the existential type variables of the signature of a pattern
     synonym should not scope over the pattern synonym.

     See Note [Pattern synonym existentials do not scope] in TcPatSyn.
 }}}

 Sorry about mis-typing the ticket number in the commit message!

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14498#comment:19>
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