ReturnTypeWillChange Is For All

<?php

interface i {
    function foo(): int;
}

class x implements i {
    #[Returntypewillchange]
    function foo() : int { return 'abc'; }
}

ReturnTypeWillChange is an attribute that tells PHP that the return type of the related method is different from the defined by the PHP native methods. In fact, this attribute may also be used on custom interfaces, to skip the type checks.

The method signature must be compatible with the interface definition, but, with the attribute, it may actually return anything else. This also means that types may only be trusted after checking for attributes.

See Also

• ReturnTypeWillChange (PHP manual)
• this function never returns [Try me]

PHP Error Messages

• Declaration of x::foo() must be compatible with i::foo(): int

PHP Features

• attribute
• php-attribute
• custom
• returntypewillchange

Last updated: 10 September 2026