[GHC] #9415: Superclass cycle with ambiguous type causes loop

[GHC]

#9415: Superclass cycle with ambiguous type causes loop
-------------------------------------+-------------------------------------
              Reporter:  goldfire    |            Owner:  goldfire
                  Type:  bug         |           Status:  merge
              Priority:  normal      |        Milestone:  7.8.4
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
  typecheck/should_fail/T9415        |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Changes (by goldfire):

 * status:  new => merge
 * testcase:   => typecheck/should_fail/T9415
 * version:  7.9 => 7.8.3
 * milestone:   => 7.8.4


Comment:

 This is a proper bug with a simple fix and should be merged if we do
 7.8.4.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9415#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler