[GHC] #14732: -fdefer-typed-holes breaks a correct program

[GHC]

#14732: -fdefer-typed-holes breaks a correct program
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        Reporter:  MitchellSalad     |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
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 Simon Peyton Jones <simonpj@…>):

 In [changeset:"e9ae0cae9eb6a340473b339b5711ae76c6bdd045/ghc" e9ae0ca/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="e9ae0cae9eb6a340473b339b5711ae76c6bdd045"
 Look inside implications in simplifyRule

 Trac #14732 was a perpelexing bug in which -fdefer-typed-holes
 caused a mysterious type error in a RULE.  This turned out to
 be because we are more aggressive about creating implications
 when deferring (see TcUnify.implicationNeeded), and the rule
 mechanism hadn't caught up.

 This fixes it.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14732#comment:5>
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