@@ -18,13 +18,14 @@
   var HAS_SYMBOLS = typeof Object.getOwnPropertySymbols === 'function';
 
   function makeSuper (_super, old, name, fn) {
+    var isFunction = typeof old === 'function';
     var newMethod = function () {
       var tmp = this._super;
 
       // Add a new ._super() method that is the same method
       // but either pointing to the prototype method
       // or to the overwritten method
-      this._super = (typeof old === 'function') ? old : _super[name];
+      this._super = isFunction ? old : _super[name];
 
       // The method only need to be bound temporarily, so we
       // remove it when we're done executing
@@ -35,9 +36,11 @@
       return ret;
     };
 
-    Object.getOwnPropertySymbols(old).forEach(function (name) {
-      newMethod[name] = old[name];
-    });
+    if (isFunction) {
+      Object.getOwnPropertySymbols(old).forEach(function (name) {
+        newMethod[name] = old[name];
+      });
+    }
 
     return newMethod;
   }
 
@@ -48,12 +48,16 @@ describe('UberProto', function () {
     Obj.mixin({
       test: function () {
         return this._super() + ' mixed in';
+      },
+      otherTest: function () {
+        return typeof this._super === 'function';
       }
     });
 
     assert.equal(inst.test(), 'Tester mixed in');
     assert.ok(Obj.test[testProp], 'Symbol conserved on method (Obj)');
     assert.ok(inst.test[testProp], 'Symbol conserved on method (inst)');
+    assert.ok(!inst.otherTest());
   });
 
   it('creates a new object', function () {