Bug #77562 [Opn->Nab]: Inheritance signature checking for void return type

Edit report at https://bugs.php.net/bug.php?id=77562&edit=1 ID: 77562 Updated by: nikic@php.net Reported by: danack@php.net Summary: Inheritance signature checking for void return type -Status: Open +Status: Not a bug Type: Bug Package: Scripting Engine problem PHP Version: 7.2.14 Block user comment: N Private report: N New Comment: Dropping the *parameter* types is allowed, not the return types. Dropping parameter types is legal because parameters are contravariant. Dropping return types would violate LSP, because they are covariant. Previous Comments: ------------------------------------------------------------------------ [2019-02-04 06:50:20] danack@php.net Description: ------------ From PHP 7.2 dropping the return type for methods in child classes is meant to be allowed on method signature checks: https://wiki.php.net/rfc/parameter-no-type-variance Test script: --------------- class Foo{ function method (): void {} } // This should work in php 7.2+ class Bar extends Foo { function method () {} } Expected result: ---------------- No error. Actual result: -------------- Fatal error: Declaration of Bar::method() must be compatible with Foo::method(): void in /in/3E70o on line 11 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77562&edit=1