Bug #75449 [Opn->Nab]: Ignored return type for abstract methods, defined in traits

From: Date: Tue, 21 Nov 2017 23:17:48 +0000
Subject: Bug #75449 [Opn->Nab]: Ignored return type for abstract methods, defined in traits
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-212670@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=75449&edit=1

 ID:                 75449
 Updated by:         pmmaga@php.net
 Reported by:        alex dot rill at yandex dot ru
 Summary:            Ignored return type for abstract methods, defined in
                     traits
-Status:             Open
+Status:             Not a bug
 Type:               Bug
 Package:            Class/Object related
 Operating System:   Windows
 PHP Version:        7.1.11
 Block user comment: N
 Private report:     N

 New Comment:

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php

This is expected behavior. In your first example, the abstract function from the trait is overriden
by the function declared on your class. No inheritance rules are applied at all. It's not only
about the return value type.

In your second example, you are importing the abstract function to an abstract class. In that case,
the inheritance rules are applied when you are extending from that abstract class.


Previous Comments:
------------------------------------------------------------------------
[2017-10-31 02:12:55] saintatgod at gmail dot com

<?php
trait T {
        abstract static function values(): array;
}

//class B {
//      use T;
//      static function values() {
//              return 'Worked!'; // string, not array
//      }
//}

//echo B::valuesi(); // print: Worked!

abstract class B {
        use T;
        self::values(); // if inheritance trait, must implement abstract function in trait
}

class C extends B {
        static function values() {
                return 'Don\'t worked';
        }
}

echo C::values();

------------------------------------------------------------------------
[2017-10-31 01:43:27] saintatgod at gmail dot com

where is Class D ?

------------------------------------------------------------------------
[2017-10-28 06:25:31] alex dot rill at yandex dot ru

Description:
------------
Dont speak english. All in example code.
---
From manual page: http://www.php.net/language.oop5.traits
---


Test script:
---------------
<?php

trait T {
    abstract static function values(): array;
}

class B {
    use T;
    static function values() {
        return 'Worked!'; // string, not array
    }
}

echo B::values(); // print: Worked!

abstract class B {
    use T;
}

class C extends B {
    static function values() {
        return 'Don\'t worked';
    }
}

echo C::values(); // Fatal Error: Class D contains 1 abstract method and must therefore be declared
abstract or implement the remaining methods (C::values)
?>
Online example: http://sandbox.onlinephpfunctions.com/code/7b26e7237abcf97d15aac6a0868c084241bf8d0c



------------------------------------------------------------------------



--
Edit this bug report at https://bugs.php.net/bug.php?id=75449&edit=1


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