Bug #70722 [NEW]: self return type in interface does not behave as expected

From: eric at ericstern dot com Operating system: OS X PHP version: 7.0.0RC5 Package: Compile Failure Bug Type: Bug Bug description:self return type in interface does not behave as expected Description: ------------ When implementing an interface where a method is typehinted to return self, the return type in the implementing class must explicitly name the interface, rather than being allowed to use self as the typehint in the implementing class. While the RFC (https://wiki.php.net/rfc/return_types) calls out hinting a child class as invalid, self on an implementing class seems like it should be valid, as self in the implementing class will, by definition, be an instance of the interface which is being implemented. Also, in practice, it makes writing out the code to implement the interface very tedious. Test script: --------------- // Does not work, unexpected: <?php interface Chainable { public function something(): self; } class MyChainable implements Chainable { public function something(): self { return $this; } } $x = new MyChainable(); print_r($x->something()); // Currently works (expected) <?php interface Chainable { public function something(): self; } class MyChainable implements Chainable { public function something(): Chainable{ return $this; } } $x = new MyChainable(); print_r($x->something()); Expected result: ---------------- MyChainable Object ( ) Actual result: -------------- PHP Fatal error: Declaration of MyChainable::something(): MyChainable must be compatible with Chainable::something(): Chainable in /Users/firehed/dev/7/ret.php on line 9 -- Edit bug report at https://bugs.php.net/bug.php?id=70722&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=70722&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=70722&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=70722&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=70722&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=70722&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=70722&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=70722&r=needscript Try newer version: https://bugs.php.net/fix.php?id=70722&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=70722&r=support Expected behavior: https://bugs.php.net/fix.php?id=70722&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=70722&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=70722&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=70722&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70722&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=70722&r=dst IIS Stability: https://bugs.php.net/fix.php?id=70722&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=70722&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=70722&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=70722&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=70722&r=mysqlcfg