[GHC] #12742: Instantiation of invisible type family arguments is too eager

[GHC]

#12742: Instantiation of invisible type family arguments is too eager
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        Reporter:  goldfire          |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"c813d8c9776b2c57ec90ab29e1cc0b687fbb9c34/ghc"
 c813d8c9/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="c813d8c9776b2c57ec90ab29e1cc0b687fbb9c34"
 Regression test for #12742

 Location: dependent/should_compile/T12742
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12742#comment:3>
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