[GHC] #11405: Incorrect failure of type-level skolem escape check

[GHC]

#11405: Incorrect failure of type-level skolem escape check
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        Reporter:  goldfire          |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.0.1-rc1
      Resolution:                    |             Keywords:  TypeInType
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 Richard Eisenberg <eir@…>):

 In [changeset:"3c6635ef4561ab53e51d7187c966b628a972b261/ghc"
 3c6635ef/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="3c6635ef4561ab53e51d7187c966b628a972b261"
 Fix #11405.

 This adds a new variant of AbsBinds that is used solely for bindings
 with a type signature. This allows for a simpler desugaring that
 does not produce the bogus output that tripped up Core Lint in
 ticket #11405. Should make other desugarings simpler, too.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11405#comment:10>
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