To reproduce "PHP Fatal error: Cannot create references to/from string offsets nor overloaded objects"

string_references.php

<?php
$widgets = array();
$widgets['a'] = 'hello';

print($widgets['a'][0]);  // show 'h'
print("\n");
$o = & $widgets['a'][0];  // Show "Cannot create references to/from string offsets"
//print($o);
?>