[GHC] #11621: GHC doesn't see () as a Constraint in type family

[GHC]

#11621: GHC doesn't see () as a Constraint in type family
-------------------------------------+-------------------------------------
        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.10.1
  checker)                           |             Keywords:
      Resolution:                    |  ConstraintKinds
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11715, #13742    |  Differential Rev(s):  Phab:D5413
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by RyanGlScott):

 Good catch. Alas, I had a feeling this was too good to be true.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11621#comment:9>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler