[GHC] #13320: Unfortunate compiler loop when creating type loop (with UndecidableInstances)

[GHC]

#13320: Unfortunate compiler loop when creating type loop (with
UndecidableInstances)
-------------------------------------+-------------------------------------
        Reporter:  Ptival            |                Owner:  dfeuer
            Type:  bug               |               Status:  new
        Priority:  low               |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
                                     |  UndecidableInstances loop
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by David Feuer <David.Feuer@…>):

 In [changeset:"cb850e01560adf12e83fcf85f479636be17d017c/ghc" cb850e0/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="cb850e01560adf12e83fcf85f479636be17d017c"
 Add test for #13320

 Reviewers: austin, bgamari

 Reviewed By: bgamari

 Subscribers: rwbarton, thomie

 GHC Trac Issues: #13320

 Differential Revision: https://phabricator.haskell.org/D3532
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13320#comment:6>
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