anchor.diff:  
   setterDeclaration returns [AttributeSetterDefinition declaration]
       : ASSIGN 
  -      { $declaration = new AttributeSetterDefinition($ASSIGN); }
  +      { $declaration = new AttributeSetterDefinition($ASSIGN); 
  +        $declaration.setType( new VoidModifier(null) ); }
         memberName 
         { $declaration.setIdentifier($memberName.identifier); }
         block
  
positive.code: namedArgument returns [NamedArgument namedArgument]
      : namedSpecifiedArgument
        { $namedArgument = $namedSpecifiedArgument.specifiedArgument; }
      //| namedArgumentDeclaration
      ;
  
  namedSpecifiedArgument returns [SpecifiedArgument specifiedArgument]
  
negative.code:     SEMICOLON
      ;
  
  namedArgumentDeclaration returns [NamedArgument namedArgument]
      : objectDeclaration
      | typedMethodOrAttributeDeclaration
      | voidOrInferredMethodDeclaration
      | inferredAttributeDeclaration
      ;
  
  //special rule for syntactic predicate
  //to distinguish between a named argument
  //and a sequenced argument
  namedArgumentStart
      : specificationStart 
      | declarationStart
      ;
  
  //special rule for syntactic predicates
  