GraphQL\Validator\Messages::fieldsConflictMessage PHP Method

    static function fieldsConflictMessage($responseName, $reason)
    {
        $reasonMessage = self::reasonMessage($reason);
        return "Fields {$responseName} conflict because {$reasonMessage}.";
    }

 public function __invoke(ValidationContext $context)
 {
     $comparedSet = new PairSet();
     return [Node::SELECTION_SET => ['leave' => function (SelectionSet $selectionSet) use($context, $comparedSet) {
         $fieldMap = $this->collectFieldASTsAndDefs($context, $context->getType(), $selectionSet);
         $conflicts = $this->findConflicts($fieldMap, $context, $comparedSet);
         if (!empty($conflicts)) {
             return array_map(function ($conflict) {
                 $responseName = $conflict[0][0];
                 $reason = $conflict[0][1];
                 $blameNodes = $conflict[1];
                 return new Error(Messages::fieldsConflictMessage($responseName, $reason), $blameNodes);
             }, $conflicts);
         }
     }]];
 }