[GHC] #1382: Monad GHC.Prim.Any1 gets derived in a context

[GHC]

#1382: Monad GHC.Prim.Any1  gets derived in a context
--------------------------------------------+-------------------------------
    Reporter:  iampure at gmail.comguest       |        Owner:  simonpj
        Type:  bug                          |       Status:  new    
    Priority:  high                         |    Milestone:         
   Component:  Compiler (Type checker)      |      Version:  6.7    
    Severity:  critical                     |   Resolution:         
    Keywords:  Any1 context type-inference  |   Difficulty:  Unknown
          Os:  Unknown                      |     Testcase:         
Architecture:  Unknown                      |  
--------------------------------------------+-------------------------------
Comment (by simonpj):

 You program really is ambiguous (see message above).  Nevertheless, it's
 definitely a bug that GHC HEAD infers a type with a stupid Any in the
 context.  I've boiled it down a lot more:
 {{{
 data Something d e = Something{ bar::  d, initializer::e   }

 foo :: (Monad m) => Something (m Bool) n
 foo = undefined

 wog x = foo{bar = return True}
 }}}
 Look at `wog`'s type.  No time to fix today, but this is at least a nice
 small case.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1382>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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