AllowDynamicProperties validation should error on enums

[DanielEScherzer]

Description

The following code:

<?php

#[AllowDynamicProperties]
enum Example {
    case MyCase;
}

$c = Example::MyCase;
$c->prop = 'foo';

Resulted in this output:

Fatal error: Uncaught Error: Cannot create dynamic property Example::$prop in /in/Aqipu:9
Stack trace:
#0 {main}
  thrown in /in/Aqipu on line 9

Process exited with code 255.

But I expected this output instead:

Fatal error: Cannot apply #[AllowDynamicProperties] to enum in /in/Aqipu on line 4

Process exited with code 255.

PHP Version

PHP 8.2

Operating System

No response

[DanielEScherzer]

See 3v4l https://3v4l.org/Aqipu - if enumerations can never have dynamic properties (as per https://www.php.net/manual/en/language.enumerations.object-differences.php) then we should prevent the dynamic properties attribute from being applied, since its presence generally indicates that it is safe to use dynamic properties

[devnexen]

seems fair point (and easy enough to fix) @iluuu1994 your thoughts ?

[kocsismate]

I've already shared my POV in the relevant PR:

The change looks good on its own but I'm wondering whether it isn't an oversight of the enum RFC that attributes targeting classes are allowed for enums? It looks like to me that we should(n't have) allow(ed) this, so the best course of action would be to add a new target for enums, and only allow the usage if it's set.

#15733 (comment)

[DanielEScherzer]

@devnexen should this be added to NEWS or UPGRADING since previously the attribute would be allowed, just not useful?

[devnexen]

can you make a PR ? I ll merge it.