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Message-ID: <da3bfcdb-110f-7ec6-2a1f-d081c0b34faa@gmail.com>
Date: Thu, 25 Mar 2021 17:01:52 +0000
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Subject: Re: [PHP-DEV] [RFC] Auto-capture multi-line closures
 andshortfunctions take 2
From: rowan.collins@gmail.com (Rowan Tommins)

On 25/03/2021 16:24, Nuno Maduro wrote:
> Concerning the comments about what's exactly "auto-captured" by the scope
> of a multi-line short closure, we will be just reusing the "auto-capture"
> feature that already exists in one-line short closures. Therefore, this RFC
> doesn't have plans on changing the way "auto-capture" already works in PHP.


This may be technically true, but it's not particularly helpful. I'm not 
sure if the details are actually documented anywhere, and there's an 
awful lot of PHP code that either can't be used in a single-expression 
closure, or is extremely unlikely to be used.

For instance, which of the following will capture $a?

$assignedBeforeUse = fn() {
     $a = 42;
     echo $a;
}

$unreachableUse = fn() {
     if(false) { echo $a; }
     $a = 42;
}

$assignedBeforeUnreachableUse = fn() {
     $a = 42;
     if(false) { echo $a; }
}

$unsetRatherThanWritten = fn() {
     unset($a);
     echo $a;
}

$outerClosure = fn() {
     $nestedClosure = fn() {
         echo $a;
     }
}


Regards,

-- 
Rowan Tommins
[IMSoP]