Code Modernization: Rename parameters that use reserved keywords in wp-includes/query.php.

While using reserved PHP keywords as parameter name labels is allowed, in the context of function calls using named parameters in PHP 8.0+, this will easily lead to confusion. To avoid that, it is recommended not to use reserved keywords as function parameter names.

This commit:
* Renames the `$var` and `$default` parameters to `$query_var` and `$default_value` in `get_query_var()`.
* Renames the `$var` parameter to `$query_var` in `set_query_var()`.

Follow-up to [52946], [52996], [52997], [52998], [53003], [53014], [53029], [53039], [53116], [53117], [53137], [53174], [53184], [53185], [53192], [53193], [53198], [53203], [53207], [53215], [53216], [53220], [53230], [53232], [53236], [53239], [53240], [53242], [53243], [53245], [53246], [53257], [53269], [53270], [53271], [53272], [53273], [53274], [53275], [53276], [53277], [53281], [53283], [53284], [53285], [53287], [53364], [53365], [54927], [54929], [54930], [54931], [54932], [54933], [54938], [54943], [54944], [54945], [54946], [54947], [54948], [54950], [54951], [54952], [54956], [54959], [54960], [54961].

Props jrf, aristath, poena, justinahinon, SergeyBiryukov.
See #56788.

git-svn-id: https://develop.svn.wordpress.org/trunk@54962 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/class-wp-query.php

@@ -1779,7 +1779,8 @@ public function set_404() {
 	 * @since 3.9.0 The `$default_value` argument was introduced.
 	 *
 	 * @param string $query_var     Query variable key.
-	 * @param mixed  $default_value Optional. Value to return if the query variable is not set. Default empty string.
+	 * @param mixed  $default_value Optional. Value to return if the query variable is not set.
+	 *                              Default empty string.
 	 * @return mixed Contents of the query variable.
 	 */
 	public function get( $query_var, $default_value = '' ) {

src/wp-includes/query.php

@@ -15,17 +15,18 @@
  * Retrieves the value of a query variable in the WP_Query class.
  *
  * @since 1.5.0
- * @since 3.9.0 The `$default` argument was introduced.
+ * @since 3.9.0 The `$default_value` argument was introduced.
  *
  * @global WP_Query $wp_query WordPress Query object.
  *
- * @param string $var       The variable key to retrieve.
- * @param mixed  $default   Optional. Value to return if the query variable is not set. Default empty.
+ * @param string $query_var     The variable key to retrieve.
+ * @param mixed  $default_value Optional. Value to return if the query variable is not set.
+ *                              Default empty string.
  * @return mixed Contents of the query variable.
  */
-function get_query_var( $var, $default = '' ) {
+function get_query_var( $query_var, $default_value = '' ) {
 	global $wp_query;
-	return $wp_query->get( $var, $default );
+	return $wp_query->get( $query_var, $default_value );
 }
 
 /**
@@ -67,12 +68,12 @@ function get_queried_object_id() {
  *
  * @global WP_Query $wp_query WordPress Query object.
  *
- * @param string $var   Query variable key.
- * @param mixed  $value Query variable value.
+ * @param string $query_var Query variable key.
+ * @param mixed  $value     Query variable value.
  */
-function set_query_var( $var, $value ) {
+function set_query_var( $query_var, $value ) {
 	global $wp_query;
-	$wp_query->set( $var, $value );
+	$wp_query->set( $query_var, $value );
 }
 
 /**