[GHC] #11305: Type checker regression introduced by visible type-application

[GHC]

#11305: Type checker regression introduced by visible type-application
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        Reporter:  hvr               |                Owner:  goldfire
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  7.11
  checker)                           |
      Resolution:                    |             Keywords:  regression
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_compile/T11305
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1715
       Wiki Page:                    |
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Comment (by Richard Eisenberg <eir@…>):

 In [changeset:"c06b46d0313cafe05f8250a660b4481d7c1d298f/ghc" c06b46d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="c06b46d0313cafe05f8250a660b4481d7c1d298f"
 Fix #11305.

 Summary:
 In the fallthrough case when doing a subsumption case, we
 need to deeply instantiate to remove any buried foralls in
 the "actual" type.

 Once this validates, please feel free to commit it; I may not
 have the chance to do this on Tuesday. Back in full action on
 Wed.

 Test Plan: ./validate, typecheck/should_compiler/T11305

 Reviewers: austin, bgamari, hvr

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D1715

 GHC Trac Issues: #11305
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11305#comment:5>
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