[GHC] #13943: Compiler infinite loop with GHC-8.2

[GHC]

#13943: Compiler infinite loop with GHC-8.2
-------------------------------------+-------------------------------------
        Reporter:  vagarenko         |                Owner:  dfeuer
            Type:  bug               |               Status:  closed
        Priority:  high              |            Milestone:  8.2.3
       Component:  Compiler          |              Version:  8.2.1-rc3
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_compile/T13943
      Blocked By:                    |             Blocking:
 Related Tickets:  #12791            |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by simonpj):

 * status:  new => closed
 * testcase:   => typecheck/should_compile/T13943
 * resolution:   => fixed


Comment:

 > I think it's basically wrong for the specializer to select a top-level
 instance that might be overlapped by one that's given

 Yes; and it doesn't, in fact.  There was just an outright bug, as in the
 commit message above.

 Simon

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13943#comment:13>
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