[GHC] #11371: Bogus in-scope set in substitutions

[GHC]

#11371: Bogus in-scope set in substitutions
-------------------------------------+-------------------------------------
        Reporter:  simonpj           |                Owner:  niteria
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11360            |  Differential Rev(s):  phab:D1792,
       Wiki Page:                    |  phab:D1801, phab:D1802
-------------------------------------+-------------------------------------

Comment (by thomie):

 Some of the following `validate --slow` failures are probably also caused
 by this patch: https://phabricator.haskell.org/D1652#53187

 To reproduce, in `testsuite/tests`, run:

 `make TEST="conc014 T3279 conc012 print029 print025 print022 print006
 print005 print003 print008 break018 T2740 hist001 break017 break010
 break011 break012 dynbrk002 print032 print030 print031 print010 print018
 print019 break027 break026 break021 break020 break009 break006 break005
 break003 break028 break001 result001 tcrun028 T8119 T7653 exceptionsrun001
 break022 tc180 T4969 tc152 tc187 tc126 tc125 Vta1 Vta2
 overloadedlabelsghci01 T11351 T3023 tcfail093 T10728 T7332 T6015 T11248
 T6015a T6068 VtaParse dynamic-paper haddock.Cabal" CLEANUP=1 slow`

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11371#comment:9>
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