[GHC] #9739: GHC 7.8 chokes on recursive classes

[GHC]

#9739: GHC 7.8 chokes on recursive classes
-------------------------------------+-------------------------------------
              Reporter:  bitonic     |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.9
  (Type checker)                     |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  Compile-    |  Related Tickets:
  time crash                         |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by dfeuer):

 Replying to [comment:4 bitonic]:
 > Aaaand with only two classes:
 >
 > {{{#!hs
 > module Foo where
 >
 > class Class2 a => Class1 a where
 >   class3 :: (Class2 a) => b
 >
 > class (Class1 a) => Class2 a where
 > }}}

 The two-class version doesn't loop in 7.9; it just gets an error as it
 should.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9739#comment:6>
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