anchor.diff:       ;
          
   typeDeclaration
  -    : classDeclaration -> ^(CLASS_DECL classDeclaration)
  -    | interfaceDeclaration -> ^(INTERFACE_DECL interfaceDeclaration)
  -    | aliasDeclaration -> ^(ALIAS_DECL aliasDeclaration)
  +    : classDeclaration
  +    -> ^(CLASS_DECL classDeclaration)
  +    | interfaceDeclaration
  +    -> ^(INTERFACE_DECL interfaceDeclaration)
  +    | aliasDeclaration
  +    -> ^(ALIAS_DECL aliasDeclaration)
       ;
   
   importDeclaration  
  
positive.code:     ;
  
  annotation
      : declarationModifier -> ^(ANNOTATION declarationModifier) 
      | userAnnotation
      ;
  
  
negative.code:     ;
  
  directive
      : return | throw | break | retry
      ;
  
  return
      : 'return' assignable?
      -> ^(RET_STMT assignable?)
      ;
  
  throw
      : 'throw' expression?
      -> ^(THROW_STMT expression?)
      ;
  
  break
      : 'break' expression?
      -> ^(BREAK_STMT expression?)
      ;
      
  retry
      : 'retry'
      -> ^(RETRY_STMT)
      ;
  
  abstractMemberDeclaration
  