Bug #72755 [Opn->Nab]: Signature mismatch during inheritance

Edit report at https://bugs.php.net/bug.php?id=72755&edit=1 ID: 72755 Updated by: cmb@php.net Reported by: pawzar at gmail dot com Summary: Signature mismatch during inheritance -Status: Open +Status: Not a bug Type: Bug Package: Scripting Engine problem Operating System: Linux 4.4.0-31-generic PHP Version: 5.6.24 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: PHP does not support covariant parameter types. For now only invariant parameter types are supported (i.e. the parameter types of overriden methods must be identical to the inherited methods). Sometime, contravariant parameter types might be supported, but most likely never covariant parameter types, as these break the Liskov substitution principle. Previous Comments: ------------------------------------------------------------------------ [2016-08-04 13:11:14] pawzar at gmail dot com Description: ------------ I am trying to adjst some code to E_STRICT standards but I am getting a "Signature mismatch during inheritance" error, when it seems that there sould be none. What is more bizarre is that this error only occurs when I am trying to implement SomeInterface in the extendig class. Test script: --------------- interface SomeInterface { } abstract class FooClass { } abstract class FooBarClass extends FooClass { } abstract class LightAbstract { public function returnArgument(FooClass $arg) { return $arg; } } // OK class RedLight extends LightAbstract { public function returnArgument(FooBarClass $arg) { return parent::returnArgument($arg); } } // Outputs an error (E_STRICT) class BlueLight extends LightAbstract implements SomeInterface { public function returnArgument(FooBarClass $arg) { return parent::returnArgument($arg); } } ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=72755&edit=1