[GHC] #14885: TH breaks the scoping of quoted default method implementations when spliced

[GHC]

#14885: TH breaks the scoping of quoted default method implementations when spliced
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        Reporter:  RyanGlScott       |                Owner:  sighingnow
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Template Haskell  |              Version:  8.2.2
      Resolution:                    |             Keywords:
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:D4469
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"a3986d7fa59d96a77ac0f25bcf1dcf96b8746994/ghc" a3986d7/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="a3986d7fa59d96a77ac0f25bcf1dcf96b8746994"
 Fix scoped type variables in TH for several constructs

 Namely class methods, default signatures and pattern synonyms.

 When scoped type variables occur inside class default methods,
 default signatures and pattern synonyms, avoid re-create explicit
 type variables when represent the type signatures.

 This patch should fix Trac#14885.

 Signed-off-by: HE, Tao <sighingnow at gmail.com>

 Test Plan: make test TEST="T14885a T14885b T14885c"

 Reviewers: goldfire, bgamari, simonpj, RyanGlScott

 Reviewed By: simonpj, RyanGlScott

 Subscribers: rwbarton, thomie, carter

 GHC Trac Issues: #14885

 Differential Revision: https://phabricator.haskell.org/D4469
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14885#comment:5>
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