Doc #55038 [Opn->Nab]: inconsistent error-handling for $this with closure

Edit report at https://bugs.php.net/bug.php?id=55038&edit=1 ID: 55038 Updated by: cmb@php.net Reported by: rasmus at mindplay dot dk Summary: inconsistent error-handling for $this with closure -Status: Open +Status: Not a bug Type: Documentation Problem Package: Class/Object related Operating System: Win7 PHP Version: 5.3.6 -Assigned To: +Assigned To: cmb Block user comment: N Private report: N New Comment: As dexen dot devries has already shown, this behavior is not particularly related to closures, but rather stems from the fact that $this is a special pseudo-variable that is (only) available when a method is called from within an object context, see <http://php.net/manual/en/language.oop5.basic.php>. The inconsistency will be fixed as of PHP 7.1.0, due to <https://wiki.php.net/rfc/this_var>. For anonymous functions $this is already forbidden as parameter as of PHP 7.0.7, to solve bug #71737. Previous Comments: ------------------------------------------------------------------------ [2014-07-15 11:22:00] yohgaki@php.net Closure is implemented by class. Therefore, this is limitation. If this is not documented, it should be written somewhere. ------------------------------------------------------------------------ [2012-09-06 10:27:28] dexen dot devries at gmali dot com Note, the closure and creation of another object instance are irrelevant. Two simpler reproduction scripts -- one uses anonymous function, the other plain function. <?php $foo = function($this) { var_dump($this); // this will work! var_dump($this->bar); // this will blow up }; $foo(new stdclass); ?> <?php function bar($this) { var_dump($this); // this will work! var_dump($this->bar); // this will blow up } bar(new stdclass); ?> Expected result: both uses of $this and $this->bar behave in similar way. Actual result: PHP complains only on $this->bar. ------------------------------------------------------------------------ [2011-06-12 03:53:57] rasmus at mindplay dot dk Description: ------------ $this is not generally allowed outside an object context, but sometimes it is. I discovered this while trying to write a cheeky little base-class that would allow you to decorate objects with new methods, at run-time. I would have gotten away with it, too - and I still could of course, only I would have to break from the convention of $this, and naming the context-object something else, which kind of sucks. Test script: --------------- <?php $foo = function($this) { var_dump($this); // this will work! }; $foo('bar'); // now an object: class Test { public $foo = 'bar'; } $test = new Test; // and another closure: $ouch = function($this) { var_dump($this->bar); // this will blow up }; $ouch($test); Expected result: ---------------- The two examples should either fail consistently, or succeed consistently. From my point of view, why should I not be allowed to have a local variable named $this if I wanted to? There's nothing special or magical about this variable, besides the fact that it gets automatically assigned on call. Actual result: -------------- The second example fails. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=55038&edit=1