PHP 8.4: allow Traits & Class defining same (compatible) properties

[procodix]

Description

This is considered an error now, but should be possible, the same way it works with methods, so that also the new property hooks would work.

trait TestTrait {
	public int $Var = 1;
	public function Func():int {return 1;}
}

class TestClass {
	use TestTrait;
	
	public int $Var = 2; // this is not allowed
	public function Func():int {return 2;} // this is ok
}

[iluuu1994]

This is very long-standing behavior (https://3v4l.org/6uh6E), and it was part of the RFC.

https://wiki.php.net/rfc/horizontalreuse#handling_of_propertiesstate

Properties are considered incompatible if they differ in their definition. This means, they differ in the applied modifiers (static, public, protected, private) or their initial value.

I don't really see a technical reason why it needs to be this way, but since this was a community decision, changing it will require an RFC.

I understand that with hooks shadowing of trait properties becomes more reasonable. That said, I believe it's a complex enough topic to warrant an RFC. For example, it's unclear whether the shadowing property adopts unlisted hooks from the trait, or whether it needs to repeat the hook in full.

[github-actions]

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