0|positive-int += $bool : 0 ? 1, should not give a 'does not accept int' error

[HenkPoley]

Bug report

When you declare a class attribute as 0 or higher, and initialise it as 0. Then adding 0 or 1 to it, should not be a problem. It's still 0 or higher.

Code snippet that reproduces the problem

https://phpstan.org/r/4e349804-7493-43ab-81fd-ed54f3f388de

<?php

class Bar {
    /**
     * @var int
     * @psalm-var 0|positive-int
     */
    protected $depth = 0;

    function foo(bool $isRoot): void {
        $this->depth += $isRoot ? 0 : 1;
    }
}

Real world example: https://github.com/FreeDSx/LDAP/blob/7722aea71a840d9cbf133a61ef326fc049b3dd34/src/FreeDSx/Ldap/Search/FilterParser.php#L127

Expected output

No output in particular

[ondrejmirtes]

Root issue: https://phpstan.org/r/c0259855-d15d-4ee3-9816-8e6722179db2

This should still result in positive-int|0. It can be fixed in MutatingScope::resolveType().

[HenkPoley]

Something similar happens further down the 'Real world example' code. Where function parameter int $startAt and $startAt += 2; seems to cause $startAt to be seen as int|null 🤷‍♂️

[phpstan-bot]

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

@@ @@
-11: Property Bar::$depth (int<0, max>) does not accept int.
+No errors

[phpstan-bot]

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

@@ @@
-11: Dumped type: int
+11: Dumped type: int<0, max>

Full report

Line	Error
11	Dumped type: int<0, max>

[staabm]

I think this was fixed with recent commits

• phpstan/phpstan-src@cee5bbe
• phpstan/phpstan-src@65b91aa

[ondrejmirtes]

Fixed by: phpstan/phpstan-src#637

[github-actions]

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