[GHC] #9922: Partial type signatures + extensions panic

[GHC]

#9922: Partial type signatures + extensions panic
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        Reporter:  monoidal          |                   Owner:  thomasw
            Type:  bug               |                  Status:  patch
        Priority:  normal            |               Milestone:  7.10.1
       Component:  Compiler (Type    |                 Version:  7.9
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  Compile-time      |               Test Case:
  crash                              |                Blocking:
      Blocked By:                    |  Differential Revisions:  Phab:D595
 Related Tickets:                    |
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Comment (by thomasw):

 Replying to [comment:5 simonpj]:
 > Thomas: I'm not very happy with the way that wild-card error reporting
 is done.

 I agree. I have thought about it too. An "opt-in to wildcards" approach
 would be much better than my current "opt-out" approach, which was bound
 to be incomplete.

 > I think we discussed this before, but left it on one side until it was
 all working.  Which it now is.  What I suggest is this:
 > ..
 > Does this make sense?  Might you do it?  (To HEAD, of course.)

 Looks like a good plan. I think your suggestion to provide a separate
 `rnLHsTypeWithWildCards` will help me overcome many of the problems I had
 when I last tried to refactor the renaming of wildcards.

 I'll start working on it as soon as the holidays are over, i.e. next week.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9922#comment:6>
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