[GHC] #4385: Type-level natural numbers

[GHC]

#4385: Type-level natural numbers
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    Reporter:  diatchki                 |       Owner:  diatchki        
        Type:  feature request          |      Status:  new             
    Priority:  normal                   |   Milestone:  7.6.2           
   Component:  Compiler (Type checker)  |     Version:                  
    Keywords:                           |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple         |     Failure:  None/Unknown    
  Difficulty:                           |    Testcase:                  
   Blockedby:                           |    Blocking:                  
     Related:                           |  
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Comment(by maltem):

 I'm trying out the type-nats branch and the wiki says to complain when the
 solver cannot solve something, so here we go:

 {{{
 Bug.hs:22:29:
     Could not deduce ((2 * n) ~ ((2 * n1) + 2))
     from the context (n ~ (n1 + 1))
 }}}

 The code is attached. I'd welcome a hint how I can work around the error
 (the wiki mentions that this should typically be possible, but I don't
 understand how).

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4385#comment:58>
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