Index: jquery/test/unit/core.js
===================================================================
--- jquery/test/unit/core.js	(revision 5939)
+++ jquery/test/unit/core.js	(working copy)
@@ -1360,7 +1360,7 @@
 });
 
 test("removeClass(String) - simple", function() {
-	expect(4);
+	expect(5);
 	
 	var $divs = jQuery('div');
 	
@@ -1384,6 +1384,12 @@
 	var j = jQuery("#nonnodes").contents();
 	j.removeClass("asdf");
 	ok( !j.hasClass("asdf"), "Check node,textnode,comment for removeClass" );
+	
+	reset();
+	
+	$divs.eq(0).addClass("first state-one state-two test last-state last").removeClass(/state/);
+	ok( $divs.eq(0).is('.first.test.last'), "RegExp passed to removeClass" );
+	
 });
 
 test("toggleClass(String)", function() {
Index: jquery/src/core.js
===================================================================
--- jquery/src/core.js	(revision 5939)
+++ jquery/src/core.js	(working copy)
@@ -787,6 +787,7 @@
 
 		// internal only, use hasClass("class")
 		has: function( elem, className ) {
+			if (elem instanceof RegExp) return elem.test(className);
 			return jQuery.inArray( className, (elem.className || elem).toString().split(/\s+/) ) > -1;
 		}
 	},