[GHC] #14180: Strange/bad error message binding unboxed type variable

[GHC]

#14180: Strange/bad error message binding unboxed type variable
-------------------------------------+-------------------------------------
        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.2
       Component:  Compiler (Type    |              Version:  8.3
  checker)                           |
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by dfeuer):

 Replying to [comment:2 simonpj]:
 > What do you expect to happen here?  We just don't have unboxed ints at
 the type level.   Doubtless the error message could be improved.

 Well, a message to that effect would be much better than what we get now!
 But I don't have a sufficiently clear sense of exactly what is and is not
 allowed to write it myself. Something about variables bound in type
 families not being able to have kinds of kind `TYPE r` unless `r ~
 PtrRepLifted`, perhaps?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14180#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler