Description:
------------
Return type of the child must match the parent:

This code leads to "Fatal error: Declaration of B::test(): string must be compatible with A::test(): int"

<?php

class A
{
	function test(): int 
	{}
}

class B extends A
{
	function test(): string
	{}
}
?>

But it's okay, if I add interface:

<?php

interface I
{
	function test();
}

class A implements I
{
	function test(): int 
	{}
}

class B extends A
{
	function test(): string
	{}
}
?>

Expected result:
----------------
Fatal error: Declaration of B::test(): string must be compatible with A::test(): int

Actual result:
--------------
no error