PossiblyNullReference when using assert and mutation free

[digilist]

Please take a look at this example: https://psalm.dev/r/ec2ee79823

It gives the following error:

ERROR: PossiblyNullReference - 22:49 - Cannot call method isNotNull on possibly null value

By removing the @psalm-mutation-free annotation on the isNotNull function the code is valid and does not detect any error. I think that's a bug, flagging the method as non mutable invalidates the assert clause.

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/ec2ee79823

<?php

class A {
    private ?A $other = null;
    
    public function setVar(A $other): void
    {
        $this->other = $other;
    }
    
    /**
     * @psalm-mutation-free
     * @psalm-assert !null $this->other
     */
    public function isNotNull(): bool
    {
        return $this->other !== null;
    }
    
    public function doSomething(): void
    {
        if ($this->isNotNull() && $this->other->isNotNull()) {
        }
    }
}

Psalm output (using commit 06ee1b7):

ERROR: PossiblyNullReference - 22:49 - Cannot call method isNotNull on possibly null value

[weirdan]

Actually you want @psalm-assert-if-true there: https://psalm.dev/r/e6a7d153e3

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/e6a7d153e3

<?php

class A {
    private ?A $other = null;
    
    public function setVar(A $other): void
    {
        $this->other = $other;
    }
    
    /**
     * @psalm-mutation-free
     * @psalm-assert-if-true !null $this->other
     */
    public function isNotNull(): bool
    {
        return $this->other !== null;
    }
    
    public function doSomething(): void
    {
        if ($this->isNotNull() && $this->other->isNotNull()) {
        }
    }
}

Psalm output (using commit 06ee1b7):

No issues!

[weirdan]

Still looks like a bug: it appears non-conditional assertions are not in effect for the rest of the expression. However they are properly accounted for outside of that if: https://psalm.dev/r/e540bcbd7a

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/e540bcbd7a

<?php

class A {
    private ?A $other = null;
    
    public function setVar(A $other): void
    {
        $this->other = $other;
    }
    
    /**
     * @psalm-mutation-free
     * @psalm-assert !null $this->other
     */
    public function isNotNull(): bool
    {
        if ($this->other === null) { 
            throw new RuntimeException('oops');
        }
        return true;
    }
    
    public function doSomething(): void
    {
        // is_null() below is redundant, Psalm fails to notice this
        if ($this->isNotNull() && is_null($this->other)) {}
        
        // does not complain below because assertion worked as expected
        if ($this->other->isNotNull()) {}  
    }

}

Psalm output (using commit 06ee1b7):

No issues!