Bug #73220 [Opn->Nab]: Classes implementing an interface can violate its method's signatures

Edit report at https://bugs.php.net/bug.php?id=73220&edit=1 ID: 73220 Updated by: rasmus@php.net Reported by: phansys at gmail dot com Summary: Classes implementing an interface can violate its method's signatures -Status: Open +Status: Not a bug Type: Bug Package: PHP Language Specification Operating System: any PHP Version: 7.0.11 Block user comment: N Private report: N New Comment: Adding additional default values does not violate LSP (Liskov Substitution Principle) in that in your example, B can be used in place of any other class that implements A and as such it is entirely compatible with A and there should be no error. Previous Comments: ------------------------------------------------------------------------ [2016-10-01 19:53:14] phansys at gmail dot com Description: ------------ Classes implementing an interface can violate its method's signatures by adding more arguments with a default value. Test script: --------------- interface A { public function test($one = null); } class B implements A { public function test($one = null, $two = null) { var_dump($one, $two); } } Expected result: ---------------- Fatal error: Declaration of B::test($one, $two) must be compatible with A::test($one = NULL) Actual result: -------------- No error. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=73220&edit=1