Implement AbstractProtectedMethodRule

[staabm]

interfaces cannot contain non-public methods

https://3v4l.org/3VBl2

[ondrejmirtes]

I'd make it clear this is only about interface, both in rule class name, and the error message

[staabm]

I also though about that.

DX wise there are a lot of error situations. I think we need to make sure, that we don't report too much errors at a time.

• methods must be public in interfaces https://3v4l.org/tmQX8
• methods are not allowed to be declared abstract in interfaces https://3v4l.org/rlVKF
• the combination of the 2: private abstract or protected abstract in interfaces https://3v4l.org/LR2DP
• final on abstract is not allowed https://phpstan.org/r/f7056d2d-412e-4698-910f-e5e9439e0648 -> final private abstract

thats also the reason why I did not cover interfaces in AbstractPrivateMethodRule in the first place, as if we use a different error message in this rule here it would be kind of inconsistent to have

interface fooInterface {
	abstract private function sayPrivate() : void; // 'Private method fooInterface::sayPrivate() cannot be abstract.'
	abstract protected function sayProtected() : void; // 'Protected method fooInterface::sayPrivate() cannot be abstract in interface.'
	abstract public function sayPublic() : void;
}

[ondrejmirtes]

I'm fine with saying Protected method fooInterface::sayProtected() cannot be abstract in interface..

[staabm]

I changed the PR to error about method visibility in interfaces (no matter abstract method or not)

[phpstan-bot]

This pull request has been marked as ready for review.

[ondrejmirtes]

Thank you.

[ondrejmirtes]

FYI just noticed a typo in the class name MethodVisibitiliyInInterfaceRule

[staabm]

ohh good catch. do you take care of it, or should I PR a name-change?

[ondrejmirtes]

Please send a PR