Bug #75385 [NEW]: Fatal error after overriding method and returning subclass of what parent do

From: carlos at wfmh dot org dot pl Operating system: Ubuntu PHP version: 7.2.0RC4 Package: PHP Language Specification Bug Type: Bug Bug description:Fatal error after overriding method and returning subclass of what parent do Description: ------------ Having script like that <?php class ModelBase {} class ModelChild extends ModelBase {} class A { public function test(): ModelBase {} } class B extends A { public function test(): ModelChild {} } ordinary php file.php throws PHP Fatal error: Declaration of B::test(): ModelChild must be compatible with A::test(): ModelBase in file.php on line 13 PHP 7.2.0RC3 (cli) (built: Sep 28 2017 16:28:37) ( NTS ) Copyright (c) 1997-2017 The PHP Group Test script: --------------- <?php class ModelBase {} class ModelChild extends ModelBase {} class A { public function test(): ModelBase {} } class B extends A { public function test(): ModelChild {} } Expected result: ---------------- As ModelChild extends ModelBase, methods expected to return ModelBase should be allowed to be overriden and return its subclass (ModelChild) as it is allowed in any other language that follows OOP principles. Actual result: -------------- PHP Fatal error: Declaration of B::test(): ModelChild must be compatible with A::test(): ModelBase in file.php on line 13 -- Edit bug report at https://bugs.php.net/bug.php?id=75385&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75385&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75385&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75385&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75385&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75385&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75385&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75385&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75385&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75385&r=support Expected behavior: https://bugs.php.net/fix.php?id=75385&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75385&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75385&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75385&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75385&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75385&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75385&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75385&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75385&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75385&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75385&r=mysqlcfg