[GHC] #13555: Typechecker regression when combining PolyKinds and MonoLocalBinds

[GHC]

#13555: Typechecker regression when combining PolyKinds and MonoLocalBinds
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3472
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"18c3a7ea0f7577514721feadefd9a62c228edb60/ghc" 18c3a7e/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="18c3a7ea0f7577514721feadefd9a62c228edb60"
 Document the kind generalization behavior observed in #13555

 The conclusion of #13555 was that a program which began to fail to
 typecheck (starting in GHC 8.2) was never correct to begin with. Let's
 document why this is the case with respect to `MonoLocalBinds`'
 interaction with kind generalization. Also adds the reported program as
 a `compile_fail` testcase.

 Test Plan: make test TEST=T13555 # Also, read the docs

 Reviewers: goldfire, simonpj, austin, bgamari

 Reviewed By: goldfire, simonpj, bgamari

 Subscribers: rwbarton, thomie

 GHC Trac Issues: #13555

 Differential Revision: https://phabricator.haskell.org/D3472
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13555#comment:10>
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