[GHC] #15664: Core Lint error

[GHC]

#15664: Core Lint error
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1-beta1
      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 Simon Peyton Jones <simonpj@…>):

 In [changeset:"4bdb10ca7ba14f00dd62270eadab4f93238227bc/ghc"
 4bdb10ca/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="4bdb10ca7ba14f00dd62270eadab4f93238227bc"
 Fix Lint of unsaturated type families

 GHC allows types to have unsaturated type synonyms and type families,
 provided they /are/ saturated if you expand all type synonyms.

 TcValidity carefully checked this; see check_syn_tc_app.  But
 Lint only did half the job, adn that led to Trac #15664.

 This patch just teaches Core Lint to be as clever as TcValidity.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15664#comment:3>
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