Return types not checked

[momala454]

Describe the bug It doesn't verify that the return type of a function inside an if is correct

To Reproduce

class TestBug {
    public int $test;
}

function testBug(): TestBug {
    if (1) {
        return [];
    }
    return new TestBug();
}

No error is shown on the line return []; while it's incorrect

If i put return [] on the last line, it detects the error however. So the detection doesn't work inside if

Expected behavior It must detect that the return type is invalid inside the if (1)

Screenshots If applicable, add screenshots to help explain your problem.

Platform and version windows intelephense 1.7.1

[PythooonUser]

Hey :wave:

Your screenshot is a bit misleading. As the error message is not the correct one that you actually want to show.

You cannot create an instance of an array, like new []. Instead it is either new TestBug() or just [].

[momala454]

sorry, i updated my post to fix the screenshot (which was just as reference as the screenshot wasn't the error itself). I've also added a new screenshot that shows no error while it should detect the mismatch

[PythooonUser]

That is not entirely true. When you are using different types for the return statement, you can see it does the type checking somehow in the background nonetheless.

However, it does not report it. Probably, because it is not smart enough to evaluate that if(1) always terminates the function in this case. Like, the final return statement is also not reported to be unreachable.

[momala454]

is it possible to have a return that doesn't terminate the function ? I don't understand why it doesn't report an error if any of the "return" statement is incorrect

[PythooonUser]

It seems to just report the one that is last.

[momala454]

to prevent errors i think it's best to check all of them, because I almost missed an error in my code due to one return having a wrong return type

[momala454]

it doesn't show any error as soon as one return is correct, even if it's not the last one :

function testHelloWorld(): string
{
    return 10;
    return "bla";
    return 10;
}

[beeradmoore]

Just discovered this as well. We thought match may be broken.

function test1(bool $var) : GdImage
{
    return match ($var)
    {
        true => 'a',
        false => new GdImage(),
        default => null,
    };
}

this does not report any issues but if you comment out false => new GdImage(), you now get

Expected type 'GdImage'. Found 'string|null'.`

I was then able to replicate this with if/elseif/else statements.

function test2(bool $var) : GdImage
{
    // Force this to be true
    $var = true;

    if ($var == true)
    {
        return 'a';
    }
    else if ($var == false)
    {
        return new GdImage();
    }
    else 
    {
        return [1];
    }

    return 8;
}

This is fine, but again if you comment out return new GdImage(); you now get

Expected type 'GdImage'. Found 'string|int[]|int'.

It's almost like if the method can return the correct type at some point it is fine with returning other things.