I read that `get_template_part()` should only used by themes not plugins, I don't know if using it inside a widget function (created by the theme) is considered as a plugin or not.

Anyway, I'm trying to pass that widget variables ($myvar) to the template ('loop.php' in my case), but it doesn't fetch it even with using `global $myvar;` inside the template.

Here's my widget function code:

```
function widget($args, $instance) {
    extract( $args );
    $title = apply_filters('widget_title', $instance['title']);
    echo $before_widget;
    if ($title) { echo $before_title.$title.$after_title; }
    $myvar = 'start';
    get_template_part('loop'); ?>
    echo $after_widget;
}

```