[5.x]: Typing error when including `_includes/field` without element

[ryssbowh]

What happened?

Description

craft\elements\db\ElementQuery::prepForEagerLoading(): Argument #2 ($sourceElement) must be of type craft\base\ElementInterface, null given, called in /var/www/html/vendor/craftcms/cms/src/fields/BaseRelationField.php on line 779

This was triggered by including the Craft template _includes/field with a null element :

{% set fields = craft.app.entries.getEntryTypeById(1).getFieldLayout().getCustomFields() %}
{% set field = fields|filter(f => f.handle == handle)|first %}

{% if field %}
	{% include "_includes/field" with {
		field: field,
		required: field.required,
		element: element,
	} only %}
{% endif %}

Trace :

#0 /var/www/html/vendor/craftcms/cms/src/fields/BaseRelationField.php(779): craft\elements\db\ElementQuery->prepForEagerLoading()
#1 /var/www/html/vendor/twig/twig/src/Extension/CoreExtension.php(1861): craft\fields\BaseRelationField->normalizeValue()
#2 /var/www/html/vendor/craftcms/cms/src/helpers/Template.php(148): Twig\Extension\CoreExtension::getAttribute()
#3 /var/www/html/storage/runtime/compiled_templates/ce/ced396a1738357a99f7cb71543823dc6.php(55): craft\helpers\Template::attribute()
#4 /var/www/html/vendor/twig/twig/src/Template.php(387): __TwigTemplate_439b60981d16809434267e6211637c09->doDisplay()

Steps to reproduce

1. Include the template _includes/field with a null element and a relation field

Craft CMS version

5.8.18

PHP version

8.3

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

[linear]

CMS-1629

[i-just]

Hi, thanks for reporting! I just raised a PR for this.