[GHC] #7788: Recursive type family causes <<loop>>

[GHC]

#7788: Recursive type family causes <<loop>>
-------------------------------------+-------------------------------------
        Reporter:  shachaf           |                   Owner:  goldfire
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.10.1
       Component:  Compiler (Type    |                 Version:  7.6.2
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  Incorrect result  |               Test Case:
  at runtime                         |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:  #8550             |
-------------------------------------+-------------------------------------
Changes (by goldfire):

 * owner:  simonpj => goldfire
 * related:   => #8550
 * milestone:  7.12.1 => 7.10.1


Comment:

 I just noticed that I had been asked to do this, and I think it would be
 nice in 7.10.

 However, the fix would potentially be user-facing: A type-family-heavy
 program that compiles on 7.10.1RC2 might need to set `-ftype-function-
 depth` after the fix. Is that acceptable at this point?

 Also, time is very precious for me before Feb. 27. I can get right on this
 Mar. 2.

 (See also #8550, which is probably a dup of this bug.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7788#comment:12>
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