PHPStan thinks static variable can be float

[iluuu1994]

PHPStan 0.11

Summary of a problem or a feature request

I don't understand this one. Making a local static variable makes PHPStan think the variable can be a float when there's really no reason to. Removing the static removes the error.

Code snippet that reproduces the problem

function returnsInt(): int
{
	static $i = 0;
	return ++$i;
}

Function returnsInt() should return int but returns float|int.

https://phpstan.org/r/249d5f01-7caf-406d-bf12-5f6b116c3810

Expected output

No error.

[ondrejmirtes]

It's because any static variable is mixed. mixed++ is float|int. I should fix this by supporting @var above static assignment: https://phpstan.org/r/282b0f74-83b1-4380-b4f3-8074f1b3e426

[iluuu1994]

@ondrejmirtes I see. So basically we assume mixed because tracking the value is hard, right? I guess since this is so rare it's not really worth fixing. @var seems like a pragmatic solution.

[ondrejmirtes]

I'm currently rewriting NodeScopeResolver so the tracking might be worth revisiting :)

[ondrejmirtes]

@var above static is already supported: https://phpstan.org/r/7d2742f1-d521-4767-8723-85a7fbf26f62

[iluuu1994]

And coincidentally, this is correct, int++ also technically results in int|float ^^ https://3v4l.org/9barY
But this edge case is probably worth ignoring.

[phpstan-bot]

@ondrejmirtes PHPStan now reports different result with your code snippet:

@@ @@
-7: Function returnsInt() should return int but returns float|int.
+No errors

[phpstan-bot]

@iluuu1994 After the latest commit in dev-master, PHPStan now reports different result with your code snippet:

@@ @@
-6: Function returnsInt() should return int but returns float|int.
+No errors

[iluuu1994]

Nice 😁 Thanks @ondrejmirtes!

[ondrejmirtes]

I love this bot :) You're welcome!

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