anchor.diff:  selectionSet
       :   '{' selection (','? selection)* '}'
       ;
  -
   
   operationType
       :   'query'
  
positive.code: 
  */
  
  
  
  grammar GraphQl;
  
  document
  
negative.code: directive
      :   '@' NAME ':' valueOrVariable
      |   '@' NAME
      |   '@' NAME '(' argument ')'
      ;
  
  typeCondition
  