PrefixAllGlobals/GlobalVariablesOverride: detect variables being set via list()

[jrfnl]

Bug Description

Variables being assigned a value via the list() construct - including PHP 7.1 short list syntax - are not recognized as variable assignments for the purposes of the GlobalVariablesOverride and the PrefixAllGlobals sniffs.

This causes false negatives.

Minimal Code Snippet

The below code doesn't produce any errors for the above mentioned sniffs, while it should.

// PREFIX ALL GLOBALS.
// Detect variables being set via the list() construct.
list( $var1, $var2 )                 = $array; // Bad x 2.
list( $acronym_var1, $acronym_var2 ) = $array;

[ $var1, $var2 ]                 = $array; // Bad x 2.
[ $acronym_var1, $acronym_var2 ] = $array;

/**
 * GLOBAL VARS OVERRIDE.
 * Detect var override via list construct.
 */
function acronym_prepare_items() {
	global $wp_query, $post_mime_types, $avail_post_mime_types, $mode;
	list( $post_mime_types, $avail_post_mime_types ) = get_an_array(); // Bad x2.
	[ $post_mime_types, $avail_post_mime_types ]     = get_an_array(); // PHP 7.1 short list syntax, bad x2.
}

Tested Against develop branch?

• I have verified the issue still exists in the develop branch of WPCS.