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References: <55b798d4-dcd7-4d81-852b-b78294cdc39d@email.android.com> <1a980468-c5f3-485b-9e8b-8c97d6ac4802@bastelstu.be>
In-Reply-To: <1a980468-c5f3-485b-9e8b-8c97d6ac4802@bastelstu.be>
Date: Tue, 4 Mar 2025 23:08:36 +0100
Message-ID: <CAAwdEzD7x=HccDQ9ckz+v=1nBm9NCY1i4GPizLoZsUZQ7FDFEA@mail.gmail.com>
Subject: Re: [PHP-DEV] Re: RFC: Marking return values as important (#[\NoDiscard])
To: =?UTF-8?Q?Tim_D=C3=BCsterhus?= <tim@bastelstu.be>
Cc: "Marc B." <marc@mabe.berlin>, Volker Dusch <volker@tideways-gmbh.com>, 
	php internals <internals@lists.php.net>
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From: drealecs@gmail.com (=?UTF-8?Q?Alexandru_P=C4=83tr=C4=83nescu?=)

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Hi Tim,

On Tue, Mar 4, 2025, 22:16 Tim D=C3=BCsterhus <tim@bastelstu.be> wrote:

> Hi Marc
>
> Should the `(void)` cast not be accepted, we will only special case the
> assignment to `$_` to not be elided, even if OPcache knows that the
> function will never return an object. The behavior for other variables
> will remain unchanged.

X


Just asking, as my engine knowledge is a bit limited,
Wouldn't it be possible that when OPcache would optimize away the unused
variable assigned to a function, it could detect that that function have
the NoDiscard attribute and also remove the attribute effect (warning
triggering).
Or identify that the function has the NoDiscard attribute and based on that
do not optimize away the variable?

--
Alex

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<div dir=3D"auto"><div>Hi Tim,<br><br><div class=3D"gmail_quote gmail_quote=
_container"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, Mar 4, 2025, 22:1=
6 Tim D=C3=BCsterhus &lt;<a href=3D"mailto:tim@bastelstu.be">tim@bastelstu.=
be</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margi=
n:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Marc<br><br>
Should the `(void)` cast not be accepted, we will only special case the <br=
>
assignment to `$_` to not be elided, even if OPcache knows that the <br>
function will never return an object. The behavior for other variables <br>
will remain unchanged.</blockquote></div></div><div dir=3D"auto"><div class=
=3D"gmail_quote gmail_quote_container"><blockquote class=3D"gmail_quote" st=
yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">X</bl=
ockquote></div></div><div dir=3D"auto"><br></div><div dir=3D"auto">Just ask=
ing, as my engine knowledge is a bit limited,</div><div dir=3D"auto">Wouldn=
&#39;t it be possible that when OPcache would optimize away the unused vari=
able assigned to a function, it could detect that that function have the No=
Discard attribute and also remove the attribute effect (warning triggering)=
.</div><div dir=3D"auto">Or identify that the function has the NoDiscard at=
tribute and based on that do not optimize away the variable?</div><div dir=
=3D"auto"><br></div><div dir=3D"auto">--</div><div dir=3D"auto">Alex</div><=
div dir=3D"auto"></div></div>

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