为什么我会发生eclipse错误，此代码有效还是eclipse错误？

Question

这里的https://github.com/php-fig/http-message/tree/master/src中的代码

当从eclipse中查看php时（最新版本：2018-12（4.10.0）） 线  int $ error = \ UPLOAD_ERR_OK， 突出显示为错误，并显示消息“常量表达式包含无效操作” 从“ \ UPLOAD_ERR_OK”中删除“ \”时，错误会消失，但这不是解决方案。 谁错了？会发生什么？

<?php

namespace Psr\Http\Message;

interface UploadedFileFactoryInterface
{
/**
* Create a new uploaded file.
*
 * If a size is not provided it will be determined by checking the size of
 * the file.
 *
 * @see http://php.net/manual/features.file-upload.post-method.php
 * @see http://php.net/manual/features.file-upload.errors.php
 *
 * @param StreamInterface $stream Underlying stream representing the
 *     uploaded file content.
 * @param int $size in bytes
 * @param int $error PHP file upload error
 * @param string $clientFilename Filename as provided by the client, if any.
 * @param string $clientMediaType Media type as provided by the client, if any.
 *
 * @return UploadedFileInterface
 *
 * @throws \InvalidArgumentException If the file resource is not readable.
 */
public function createUploadedFile(
    StreamInterface $stream,
    int $size = null,
    int $error = \UPLOAD_ERR_OK, // <== ERROR IS HERE
    string $clientFilename = null,
    string $clientMediaType = null
): UploadedFileInterface;
}