[GHC] #11663: GHC 8.0 type assignment in arguments of lambda working without Scoped Type Variables

[GHC]

#11663: GHC 8.0 type assignment in arguments of lambda working without Scoped Type
Variables
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        Reporter:  bitemyapp         |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.0.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D2054
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"d5d6804d37960ece2652196f3661604a70c12ffc/ghc"
 d5d6804d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="d5d6804d37960ece2652196f3661604a70c12ffc"
 rename: Disallow type signatures in patterns in plain Haskell

 This should require -XScopedTypeVariables. It seems this was previously
 handled by RnTypes.rnHsBndrSig which called RnTypes.badKindSigErr but
 this was broken in Simon's refactor of wildcards,
 1e041b7382b6aa329e4ad9625439f811e0f27232. Here we re-introduce a check
 in RnPat. See #11663.

 Test Plan: Validate with `T11663`

 Reviewers: austin, simonpj

 Reviewed By: austin

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2054

 GHC Trac Issues: #11663
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11663#comment:6>
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