Bug #72208 [NEW]: Covariant parameter types should be supported

From: mbrowne83 at gmail dot com Operating system: Ubuntu 14.04.4 LTS PHP version: 7.0.6 Package: Class/Object related Bug Type: Bug Bug description:Covariant parameter types should be supported Description: ------------ It seems that PHP does not support covariant parameter types. It should be possible to override a base class method and make its parameter type more specific. In the code example, the warning message is erroneous (or at least arbitrary) because the code does in fact conform to the Liskov Substitution Principle and is valid OOP. Test script: --------------- //example use case from https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)#Covariant_method_return_type class Animal {} class Cat extends Animal {} class AnimalShelter { function putAnimal(Animal $a) {} } class CatShelter extends AnimalShelter { function putAnimal(Cat $c) {} } Expected result: ---------------- No output Actual result: -------------- Warning: Declaration of CatShelter::putAnimal(Cat $c) should be compatible with AnimalShelter::putAnimal(Animal $a) in /vagrant/test.php on line 14 -- Edit bug report at https://bugs.php.net/bug.php?id=72208&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=72208&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=72208&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=72208&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=72208&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=72208&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=72208&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=72208&r=needscript Try newer version: https://bugs.php.net/fix.php?id=72208&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=72208&r=support Expected behavior: https://bugs.php.net/fix.php?id=72208&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=72208&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=72208&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=72208&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=72208&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=72208&r=dst IIS Stability: https://bugs.php.net/fix.php?id=72208&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=72208&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=72208&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=72208&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=72208&r=mysqlcfg