PhanTypeInvalidDimOffset for local variable in closure

[Daimona]

While switching MediaWiki to Phan 1.2.4, I noticed what I think is a false positive. For this code, Phan emits the following:
includes/AbuseFilterHooks.php:460 PhanTypeInvalidDimOffset Invalid offset "af_enabled" of array type array{afa_consequence:'tag',af_deleted:false}
I tried to find a simplified version of this code reporting the same issue, but I couldn't find one. All I can say is that moving those 4 lines before the function call at line 450 makes the error disappear. So I guessed that this is somehow related to the code being inside a closure.
I also tried different variable and key naming, just in case, but that doesn't make any difference.

This is our phan config file, and I must also say that I only tried it on 1.2.4 (so not on master) due to troubles with my PC. And I also couldn't find any similar bug report.

[TysonAndre]

I can reproduce this with this simpler example as well:

<?php

class AbuseFilterHooks {

    /**
     * @param array $tags
     * @param bool $enabled
     */
    private static function fetchAllTags( array &$tags, $enabled ) {
        // Function that derives the new key value
        return function () {
            // This is a pretty awful hack.

            $where = [ 'afa_consequence' => 'tag', 'af_deleted' => false ];
            $where['af_enabled'] = true;
        };
    }

    /**
     * @param string[] &$tags
     */
    public static function onListDefinedTags( array &$tags ) {
        self::fetchAllTags( $tags, false );
    }

}

[TysonAndre]

Probably need to update PhanAnnotationAdder to recurse into closures as well - It adds FLAG_IGNORE_NULLABLE_AND_UNDEF to the left hand side of assignments

// in PostOrderAnalysisVisitor
        if ($node->flags & PhanAnnotationAdder::FLAG_IGNORE_NULLABLE_AND_UNDEF) {
            return $context;
        }
        // Check the array type to trigger TypeArraySuspicious
        try {
            /* $array_type = */
            UnionTypeVisitor::unionTypeFromNode(
                $code_base,
                $context,
                $node,
                false
            );
            // TODO: check if array_type has array but not ArrayAccess.
            // If that is true, then assert that $dim_type can cast to `int|string`
        } catch (IssueException $_) {
            // Detect this elsewhere, e.g. want to detect PhanUndeclaredVariableDim but not PhanUndeclaredVariable
        }
        return $context;
    }

[TysonAndre]

Thanks!