1--TEST-- 2Creating the stream filter object may fail 3--FILE-- 4<?php 5class SampleFilter extends php_user_filter { 6 private $data = \FOO; 7} 8stream_filter_register('sample.filter', SampleFilter::class); 9try { 10 var_dump(file_get_contents('php://filter/read=sample.filter/resource='. __FILE__)); 11} catch (Error $e) { 12 echo $e->getMessage(), "\n"; 13} 14?> 15--EXPECTF-- 16Warning: file_get_contents(): Unable to create or locate filter "sample.filter" in %s on line %d 17 18Warning: file_get_contents(): Unable to create filter (sample.filter) in %s on line %d 19Undefined constant "FOO" 20