add post_type arg to term links (narrow down the query)

functions.php

<?php

add_filter( 'term_link', 'taxonomy_link_for_post_type', 10, 3 );

function taxonomy_link_for_post_type( $termlink, $term, $taxonomy ) {
	
	$tax_obj = get_taxonomy( $taxonomy );
	
	// if this is not a shared taxonomy, bail
	if ( count( $tax_obj->object_type ) == 1 )
		return $termlink;
	
	// cf. https://gist.github.com/sillybean/c725ea4620e9d434e71927ab41879f38
	$post_type = scl_find_post_type();
	
	if ( !isset( $post_type ) || 'any' == $post_type )
		return $termlink;
	
	$termlink = add_query_arg( 'post_type', $post_type, $termlink );
	
	return $termlink;
}