[GHC] #13774: Singletons code fails to typecheck when type signature involving type family is added

[GHC]

#13774: Singletons code fails to typecheck when type signature involving type
family is added
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.0.1
  checker)                           |             Keywords:  FunDeps,
      Resolution:  invalid           |  TypeFamilies
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by RyanGlScott):

 Urgh. I'd like to feign ignorance and claim that I would have never
 thought in a million years to put in a kind ascription, but this isn't
 even the first time that this bug has bit me (#11275). So I should
 probably know better by now... but thanks for patiently explaining to me
 again anyways :)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13774#comment:5>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler