Index: src/wp-includes/taxonomy.php
===================================================================
--- src/wp-includes/taxonomy.php	(revision 28441)
+++ src/wp-includes/taxonomy.php	(working copy)
@@ -2033,10 +2033,9 @@
 	}
 
 	$args = wp_parse_args($args, $defaults);
-	extract($args, EXTR_SKIP);
 
-	if ( isset( $default ) ) {
-		$default = (int) $default;
+	if ( isset( $args['default'] ) ) {
+		$default = (int) $args['default'];
 		if ( ! term_exists($default, $taxonomy) )
 			unset($default);
 	}
@@ -2078,7 +2077,7 @@
 			$terms = array($default);
 		} else {
 			$terms = array_diff($terms, array($term));
-			if (isset($default) && isset($force_default) && $force_default)
+			if (isset($default) && isset( $args['force_default'] ) && $args['force_default'] )
 				$terms = array_merge($terms, array($default));
 		}
 		$terms = array_map('intval', $terms);