Description:
------------
A case where the error-control operator @ does NOT work, despite of what the manual says.

Reproduce code:
---------------
---
From manual page: language.operators.errorcontrol
---
The manual says:
"A simple rule of thumb is: if you can take the value of something, you can prepend the @ operator to it."

This is not always true.

As shown by the example given, this works, assuming $cache IS AN ARRAY:
<?php
$value = @$cache[$key]; 
// will not issue a notice if the index $key doesn't exist.
?>

But it does not work if $cache IS A STRING, and $key is an integer higher than strlen($cache)-1. in other words:
<?php
$str='abc';
$value=@$str[5];
// will issue the notice "Uninitialized string offset 5 in...".
?>