[GHC] #8306: NegativeLiterals allows negative type-level integers

[GHC]

#8306: NegativeLiterals allows negative type-level integers
-------------------------------------+-------------------------------------
       Reporter:  monoidal           |             Owner:
           Type:  bug                |            Status:  new
       Priority:  normal             |         Milestone:
      Component:  Compiler           |           Version:  7.7
       Keywords:                     |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple   |   Type of failure:  GHC accepts
     Difficulty:  Easy (less than 1  |  invalid program
  hour)                              |         Test Case:
     Blocked By:                     |          Blocking:
Related Tickets:                     |
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 With NegativeLiterals extension it is possible to write negative type-
 level "naturals"

 {{{
 type T = -1
 }}}

 while the current solver assumes everything is nonnegative and claims 0 <=
 -1.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8306>
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