Bug #69317 [Opn]: Incorrect LSP check when extending multiple interfaces

Edit report at https://bugs.php.net/bug.php?id=69317&edit=1 ID: 69317 Updated by: nikic@php.net Reported by: nikic@php.net Summary: Incorrect LSP check when extending multiple interfaces Status: Open Type: Bug Package: Scripting Engine problem PHP Version: master-Git-2015-03-27 (Git) Block user comment: N Private report: N New Comment: This problems still exists. It's also not clear how to fix it, especially with covariance in PHP 7.4. We no longer have a way to just pick the "more specific" method, because variance might be unresolved at the time. Previous Comments: ------------------------------------------------------------------------ [2015-03-27 14:01:04] nikic@php.net Description: ------------ <?php class X {} interface A extends IteratorAggregate { function getIterator() : X; } interface B extends IteratorAggregate, A { } Fatal error: Declaration of IteratorAggregate::getIterator() must be compatible with A::getIterator(): X in /home/nikic/php-src/t030.php on line 9 This happens because we first inherit the IteratorAggregate::getIterator() method and then check it against the A::getIterator() method - which is of course wrong. This is a problem with return types, because they are not fully invariant - not sure if it might also be a problem for some things before PHP 7. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=69317&edit=1