Index: tests/phpunit/tests/actions.php
===================================================================
--- tests/phpunit/tests/actions.php	(revision 46550)
+++ tests/phpunit/tests/actions.php	(working copy)
@@ -557,4 +557,23 @@
 		$p1->post_title = 'Bar1';
 		$p2->post_title = 'Bar2';
 	}
+
+	/**
+ 	 * @ticket 48312
+	 *
+	 * Tests PHP 4 notation for calling actions while passing in an object by reference.
+ 	 */
+	function test_action_args_4() {
+		$a   = new MockAction();
+		$tag = __FUNCTION__;
+		$val = new stdClass;
+
+		add_action( $tag, array( &$a, 'action' ) );
+		// call the action with PHP 4 notation for passing object by reference
+		do_action( $tag, [ $val ] );
+
+		$call_count = $a->get_call_count();
+		$argsvar = $a->get_args();
+		$this->assertEquals( array( $val ), array_pop( $argsvar ) );
+	}
 }