Doc #78677 [Opn]: Parameter Type Widening not properly documented

Edit report at https://bugs.php.net/bug.php?id=78677&edit=1 ID: 78677 Updated by: cmb@php.net Reported by: pavel at bunaev dot ru Summary: Parameter Type Widening not properly documented Status: Open Type: Documentation Problem Package: Class/Object related Operating System: 18.04.1-Ubuntu PHP Version: 7.2.23 Block user comment: N Private report: N New Comment: Well, there is a note in the Interfaces section[1], but this is only correct for PHP 7.2 and up (and even too general for 7.2), and it doesn't cater to inheritance in general. It seems to me that this should be documented in the Inheritance section[2]; we could link to that section from other parts of the manual where appropriate. [1] <https://www.php.net/manual/en/language.oop5.interfaces.php> [2] <https://www.php.net/manual/en/language.oop5.inheritance.php> Previous Comments: ------------------------------------------------------------------------ [2019-10-17 08:05:43] sjon@php.net @cmb shouldn't this functionality also be documented on https://www.php.net/manual/en/functions.arguments.php#functions.arguments.type-declaration ? ------------------------------------------------------------------------ [2019-10-17 08:04:01] sjon@php.net While this might be documented better, this is definitely not a bug, see https://wiki.php.net/rfc/parameter-no-type-variance ------------------------------------------------------------------------ [2019-10-17 08:02:40] cmb@php.net Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php See <https://www.php.net/manual/en/migration72.new-features.php#migration72.new-features.param-type-widening>. ------------------------------------------------------------------------ [2019-10-17 07:41:20] pavel at bunaev dot ru Description: ------------ The interface allows you to change the type of variable in an incompatible direction. In versions php 7.0+ and 7.1-, we could specify in the interface with what types of data we will work in the method. And at the kernel level, be sure that by implementing the interface the signature will not change. In version php 7.2+ and 7.3+, this has changed and there was no announcement .. We can create an interface and expect in the signature that the method will work with certain arguments but in fact we can transfer anything OS linux version php 7.2+ version php 7.1- is ok Test script: --------------- <?php interface IBaz {}; interface IFoo { public function simple(IBaz $a); } class CFoo implements IFoo { public function simple($a){ var_dump($a); } } $cFoo = new CFoo(); $cFoo->simple('vbvc'); Expected result: ---------------- <br /> <b>Fatal error</b>: Declaration of CFoo::simple($a) must be compatible with IFoo::simple(IBaz $a) in <b>[...][...]</b> on line <b>7</b><br /> Actual result: -------------- string(4) "vbvc" ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=78677&edit=1