Show all posts in sidebar in single.php

Initiating new WP_Query($post) shows all posts. Credit to @Latheesh V M Villa

Add:

$loop_query = new WP_Query($post)

Then change loop values like:

have_posts()

to:

$loop_query->have_posts()

loop.php

<?php $loop_query = new WP_Query($post); if ($loop_query->have_posts()): while ($loop_query->have_posts()) : $loop_query->the_post(); ?>
    <article class="loop-template" id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
        <!-- article content here -->
    </article>
<?php endwhile; ?>
<?php else: ?>
    <article>
        <!-- else content here -->
    </article>
<?php endif; ?>

It appears you can leave everything inside the loop alone such as the_ID() and the_title().

Great article at smashingmagazine here