Interface %s cannot implement itself

Description

An interface can extend another interface, to expand its list of methods. It cannot extends itself, as it is useless.

Example

<?php

interface I extends I {}

?>

Literal Examples

• Interface I cannot implement itself

Alternatives

• Extend another interface.
• Do not extend the current interface.

In more recent PHP versions, this error message is now :ref:interface-"%s"-not-found.