anchor.diff:     ;
   
   enum_type
  -   : KW_ENUM ID LEFT_BRACE enumerator (COMA enumerator)* RIGHT_BRACE
  +   : KW_ENUM ID LEFT_BRACE enumerator (COMMA enumerator)* RIGHT_BRACE
      ;
   
   enumerator
  
positive.code:    ;
  
  interface_inheritance_spec
     : COLON interface_name (COMA interface_name)*
     ;
  
  interface_name
  
negative.code: 
  attr_declarator
     : simple_declarator attr_raises_expr
     | simple_declarator (COMMA simple_declarator)*
     ;
  
  attr_raises_expr
  