Simplify property memoization for Flyweight pattern by replacing it with ??=

[zonuexe]

Now that PHP 7.2 has been dropped, this pattern can be replaced.

[ondrejmirtes]

Would be great to have an auto-fixable rule that would enforce this under https://github.com/phpstan/phpstan-src/tree/2.1.x/build/PHPStan/Build. Do you think it'd be easy for you to implement that? And verify it by actually using it to make these changes. And compare it to your manual changes 😊

(Yeah, RuleErrorBuilder has fixNode method on 2.1.x, a few rules already use it.)

[zonuexe]

I hadn't noticed that they added RuleErrorBuilder::fixNode() yet, but this is very interesting! It probably looks very easy, so I'll give it a try.

[ondrejmirtes]

Yeah, just detect if === null and assignment to the same thing in the only statement.

[phpstan-bot]

This pull request has been marked as ready for review.

[phpstan-bot]

This pull request has been marked as ready for review.

[zonuexe]

@ondrejmirtes
I think this PR now works perfectly, applying the rules replaced all the things I had missed.

The refactoring feature integrated into PHPStan is a game changer. 🎉

[staabm]

I think you can do the same for StaticPropertyFetch

[zonuexe]

Thanks for the suggestion, I implemented it.

[ondrejmirtes]

I described the logic as following:

Yeah, just detect if === null and assignment to the same thing in the only statement.

So even if there's if in the middle of a function body, this rule could detect and change it.

It doesn't matter if there's $this->foo = $foo; or return $this->foo = $foo;. The rule should be able to handle both.

[ondrejmirtes]

I think the rule should apply to If_, not to a method body.

[zonuexe]

Ok, it has been reflected in the rule.