--TEST--
Bug #71572: String offset assignment from an empty string inserts null byte
--FILE--
<?php

$str = "abc";
var_dump($str[0] = "");
var_dump($str[1] = "");
var_dump($str[3] = "");
var_dump($str[10] = "");
var_dump($str);
?>
--EXPECTF--
Warning: Cannot assign an empty string to a string offset in %s on line %d
NULL

Warning: Cannot assign an empty string to a string offset in %s on line %d
NULL

Warning: Cannot assign an empty string to a string offset in %s on line %d
NULL

Warning: Cannot assign an empty string to a string offset in %s on line %d
NULL
string(3) "abc"