parameter.notVariadic

Code example

<?php declare(strict_types = 1);

interface Handler
{
	public function handle(string ...$args): void;
}

class MyHandler implements Handler
{
	public function handle(string $args): void
	{
	}
}

Why is it reported?

A method parameter is declared as non-variadic, but the corresponding parameter in the parent method or interface is variadic. This violates the Liskov Substitution Principle -- code that calls the parent method with multiple arguments would fail when the overriding method is called instead.

In the example above, Handler::handle() accepts any number of string arguments, but MyHandler::handle() accepts only one.

How to fix it

Make the parameter variadic to match the parent declaration:

 class MyHandler implements Handler
 {
-	public function handle(string $args): void
+	public function handle(string ...$args): void
 	{
 	}
 }