Odd PhanEmptyFQSENInClasslike error when an intersection type is the object in an array callable

[anomiex]

Phan version: 5.4.3, v5.x-dev 790e4f7

Reproduction

1. Create the following file:

    <?php
   
    interface A {}
    interface B {}
   
    function foo( A&B $var ): bool {
        return is_callable( [ $var, 'func' ] );
    }

2. Do phan --init, then run phan on the file.

Expected results

No issues reported. Or possibly one about method "func" not being known to exist on any of the types involved.

Actual results

This strange issue is reported.

test.php:7 PhanEmptyFQSENInClasslike Possible use of a classlike '\' with an empty FQSEN.

Other notes

This also happens if the types are declared via phpdoc or by @phan-var.

If you instead do like

$var2 = [ $var, 'func' ];
is_callable( $var2 );

it doesn't report the unexpected PhanEmptyFQSENInClasslike issue. But I think that may be because it's not really checking $var2 at all rather than that it's doing the right thing with it.