[GHC] #16059: checkValidType is defeated by a type synonym

[GHC]

#16059: checkValidType is defeated by a type synonym
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler (Type    |              Version:  8.7
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC accepts       |  Unknown/Multiple
  invalid program                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by goldfire):

 Silly me. I looked quickly and assumed that the problem was the lack of a
 `-XQuantifiedConstraints`. This is clearly wrong.

 Bah. I guess I take back my comment:5 then, as I can't see any better way
 out of this mess other than to implement kind-level constraints, which, in
 turn, requires dependent types.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16059#comment:7>
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