[GHC] #15666: Dependent type synonym in recursive type family causes GHC to panic

[GHC]

#15666: Dependent type synonym in recursive type family causes GHC to panic
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        Reporter:  tydeu             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15380            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:   => #15380


Comment:

 Ah, the commit that fixed this is 59f38587d44efd00b10a6d98f6a7a1b22e87f13a
 (`Remove the type-checking knot.`) That being said, the program in this
 ticket is rather different from the one in #15380 (which that commit
 fixed), since this ticket's program actually does compile. I'll add a
 separate regression test for this one.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15666#comment:7>
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