[GHC] #16203: Unhelpful names for wildcard type variables

[GHC]

#16203: Unhelpful names for wildcard type variables
-------------------------------------+-------------------------------------
        Reporter:  simonpj           |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
                                     |  PartialTypeSignatures
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 goldfire):

 Suppose we have

 {{{#!hs
 type family F a b where
   F _ _ = Bool
 }}}

 If we reverse the change, I believe we get that GHC reports that the
 equation is `F w1 w2 = Bool`. Perhaps that's better than what we have, but
 someone has to pay the price.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16203#comment:5>
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