anchor.diff:      ;
   
   typeBound
  -    :   type ('&' type)*
  +    :   typeType ('&' typeType)*
       ;
   
   enumDeclaration
  
positive.code:     |   expression '[' expression ']'
      |   expression '(' expressionList? ')'
      |   'new' creator
      |   '(' type ')' expression
      |   expression ('++' | '--')
      |   ('+'|'-'|'++'|'--') expression
      |   ('~'|'!') expression
  
negative.code:     :   Identifier
      ;
  
  typeType
      :   classOrInterfaceType ('[' ']')*
      |   primitiveType ('[' ']')*
      ;
  