Bug #65576 [NEW]: Constructor from trait conflicts with inherited constructor

From: krewecherl at gmail dot com Operating system: * PHP version: 5.4.19 Package: Class/Object related Bug Type: Bug Bug description:Constructor from trait conflicts with inherited constructor Description: ------------ Given: - a trait T containing a __construct method - a base class A with a __construct method (directly, inherited or via traits) - a class B exending A and using trait T Compilation fails with the fatal error "B has colliding constructor definitions coming from traits". Any other method (including magic methods like __set) works fine in this scenario, with the constructor being the only exception. It should be possible to use a constructor from a trait in a derived class, even if the base class already has a constructor. The collision can be resolved by prioritizing the constructor from the trait over the inherited constructor. This problem is the result of a bugfix in zend_compile.c related to issue #55554 (Trait methods overriding legacy constructors): https://github.com/php/php-src/commit/e14354af21c9188582ef454696163cf68c7677ce I understand the problem, but think that the given combination should still be made to work. If there are insurmountable technical difficulties, the special exception for constructors needs to be documented in the manual. Test script: --------------- trait T { public function __construct () {} } class A { public function __construct () {} } class B extends A { use T; } Expected result: ---------------- Class B uses the constructor included via trait T, overriding base class A's original constructor. Actual result: -------------- Fatal error "B has colliding constructor definitions coming from traits". -- Edit bug report at https://bugs.php.net/bug.php?id=65576&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=65576&r=trysnapshot54 Try a snapshot (PHP 5.3): https://bugs.php.net/fix.php?id=65576&r=trysnapshot53 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=65576&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=65576&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=65576&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=65576&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=65576&r=needscript Try newer version: https://bugs.php.net/fix.php?id=65576&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=65576&r=support Expected behavior: https://bugs.php.net/fix.php?id=65576&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=65576&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=65576&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=65576&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=65576&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=65576&r=dst IIS Stability: https://bugs.php.net/fix.php?id=65576&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=65576&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=65576&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=65576&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=65576&r=mysqlcfg