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

Edit report at https://bugs.php.net/bug.php?id=69447&edit=1 ID: 69447 Comment by: Theend1973 at hotmail dot com Reported by: nikic@php.net Summary: Return-by-ref / yield-by-ref confusion in LSP checks Status: Assigned Type: Bug Package: Scripting Engine problem PHP Version: 5.5.23 Assigned To: nikic Block user comment: N Private report: N New Comment: I have a new challenge but I think I can get it right Previous Comments: ------------------------------------------------------------------------ [2015-04-14 14:53:10] nikic@php.net 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 this bug report at https://bugs.php.net/bug.php?id=69447&edit=1