anchor.diff:  //Support "T x in arg" in positional argument lists
   //Note that we don't need to support this yet
   specialArgument
  -    : inferableType memberName (containment | specifier)
  -    -> ^(SPECIAL_ARGUMENT inferableType memberName containment? specifier?)
  +    : unionType memberName (containment | specifier)
  +    -> ^(SPECIAL_ARGUMENT unionType memberName containment? specifier?)
       //| isCondition
       //| existsCondition
       ;
  
positive.code:     ;
  
  typedMethodOrGetterArgument
      : inferableType memberName
      ( 
        (parameters+ memberBody[$inferableType.tree])
      -> ^(METHOD_ARGUMENT inferableType memberName parameters+ memberBody)
      | memberBody[$inferableType.tree]
      -> ^(ATTRIBUTE_ARGUMENT inferableType memberName memberBody)      
      )
      ;
  
  namedSpecifiedArgument
  
negative.code:     ;
  
  typedMethodOrAttributeDeclaration
      : FUNCTION_MODIFIER memberName methodParameters?
        ( 
          block
        -> ^(METHOD_DEFINITION FUNCTION_MODIFIER memberName methodParameters? block)
        | specifier? ';'
        -> ^(METHOD_DECLARATION FUNCTION_MODIFIER memberName methodParameters? specifier?)
         )
      | VALUE_MODIFIER memberName
        ( 
          (specifier | initializer)? ';'
          -> ^(ATTRIBUTE_DECLARATION VALUE_MODIFIER memberName specifier? initializer?)
          | block
          -> ^(ATTRIBUTE_GETTER_DEFINITION VALUE_MODIFIER memberName block)
        )
      | unionType memberName
        ( 
          methodParameters 
          ( 
            memberBody[$unionType.tree] 
          -> ^(METHOD_DEFINITION unionType memberName methodParameters memberBody)
          | specifier? ';'
          -> ^(METHOD_DECLARATION unionType memberName methodParameters specifier?)
          )
        | (specifier | initializer)? ';'
        -> ^(ATTRIBUTE_DECLARATION unionType memberName specifier? initializer?)
        | memberBody[$unionType.tree]
        -> ^(ATTRIBUTE_GETTER_DEFINITION unionType memberName memberBody)      
        )
      ;
  
  interfaceDeclaration
  