Fix missing properties for UnitEnum and BackedEnum interfaces

[ondrejmirtes]

Phew, interfaces with properties...

This one actually fixes a couple of problems:

1. When reflecting UnitEnum and BackedEnum, which aren't actually enums, just plain interfaces, BackedEnum didn't know about the "name" property because ReflectionClass code didn't inherit properties from interfaces (understandably).
2. jetbrains/phpstorm-stubs 2021.3 have several bugs in enum stubs - the properties aren't readonly, and the BackedEnum value property has wrong type. Relevant PRs: BackedEnum value is int|string JetBrains/phpstorm-stubs#1316 + [phpstorm-stubs] WI-62762 mark enums properties readonly JetBrains/phpstorm-stubs#1278

[Ocramius]

May I add: what the fuck?

[ondrejmirtes]

Original issue from here :) phpstan/phpstan#6385

[ondrejmirtes]

The CI fails because you need this commit :) ondrejmirtes@b5d9ca3

It's about updating phpstorm-stubs so that in earlier PHP versions classes and interfaces don't implement/extend things from newer PHP versions.

I think I'm gonna leave that to @kukulich because it needs some more work :)

[Ocramius]

@ondrejmirtes does #972 cover the missing details needed for this one?

[Ocramius]

@kukulich some agreement needed for #972: should it land on 5.0.x as a bugfix, or 5.1.x as improvement?

I'm tempted to move this one to 5.1.x and cut 5.1.0 once ready

[ondrejmirtes]

AFAIK #972 fixes PhpStormStubsSourceStubber which is currently buggy - you ask for some class reflection, ask for its parent class and it crashes because it extends something it doesn't exist yet. So it can land in 5.0.x.

[kukulich]

I agree with @ondrejmirtes, eg. SimpleXMLIterator implements Stringable (PHP 8.0 only) so it cannot be reflected on PHP < 8.0, hence I think it's bug.

[Ocramius]

If anyone can rebase this one, we can 🚢

[ondrejmirtes]

Looks like it's going to be green :)

[Ocramius]

LGTM 👍

[Ocramius]

Thanks @ondrejmirtes!