[GHC] #8155: Defaulting bug or unfortunate error message with closed type families

[GHC]

#8155: Defaulting bug or unfortunate error message with closed type families
--------------------------+------------------------------------------------
        Reporter:  nh2    |         Owner:
            Type:  bug    |        Status:  closed
        Priority:         |     Milestone:
  normal                  |
       Component:         |       Version:  7.6.3
  Compiler                |
      Resolution:  fixed  |      Keywords:
Operating System:         |  Architecture:  Unknown/Multiple
  Unknown/Multiple        |
 Type of failure:         |     Test Case:  indexed_types/should_fail/T8155
  None/Unknown            |
      Blocked By:         |      Blocking:
 Related Tickets:         |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"a94b484715d3caf445a7069377d5311e0e50f66e/ghc"
 a94b4847/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="a94b484715d3caf445a7069377d5311e0e50f66e"
 Back-pedal the fix for Trac #8155

 I implemented a rather elaborate fix for #8155 ages ago, which
 which turns out to be
   a) unnecesssary in this particular case
   b) harmful to the defaulting story; see comment:15 of #12923.

 So this patch reverts the elaborate bit. The bit I removed is
 described in "Historical note" under Note [approximateWC].
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8155#comment:8>
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