Bug #69447 [NEW]: Return-by-ref / yield-by-ref confusion in LSP checks

From: nikic Operating system: PHP version: 5.5.23 Package: Scripting Engine problem Bug Type: Bug Bug description:Return-by-ref / yield-by-ref confusion in LSP checks Description: ------------ Split off from bug #69419. Generators use the ampersand normally indicating by-reference returns to signify by-reference yields. Currently the (covariant) LSP checks for by-ref returns does not take this into account. When a generator extends another generator, this behavior results in the correct semantics: class A { public function &gen() { yield; } } class B extends A { public function gen() { yield; } } Here B::gen() is indeed not compatible with A::gen(). However when mixing generators and normal iterators this is not the case: class A { public function &gen() { yield; } } class B extends A { public function gen() { return ArrayIterator([]); } } This code should be allowed (without the strict standards notice), because B::gen() can also be iterated by-reference. The LSP check should be adjusted for the case where the prototype is a generator. -- Edit bug report at https://bugs.php.net/bug.php?id=69447&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=69447&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=69447&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=69447&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=69447&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=69447&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=69447&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=69447&r=needscript Try newer version: https://bugs.php.net/fix.php?id=69447&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=69447&r=support Expected behavior: https://bugs.php.net/fix.php?id=69447&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=69447&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=69447&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=69447&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=69447&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=69447&r=dst IIS Stability: https://bugs.php.net/fix.php?id=69447&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=69447&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=69447&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=69447&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=69447&r=mysqlcfg