diff --git a/lib/less/tree/mixin.js b/lib/less/tree/mixin.js
index ecc6c16..0516f3d 100644
--- a/lib/less/tree/mixin.js
+++ b/lib/less/tree/mixin.js
@@ -54,9 +54,11 @@ tree.mixin.Definition = function (name, params, rules) {
 };
 tree.mixin.Definition.prototype = {
     toCSS: function () { return "" },
-    variable: function (name) { return tree.Ruleset.prototype.variable.call(this, name) },
-    find: function () { return tree.Ruleset.prototype.find.apply(this, arguments) },
-    rulesets: function () { return tree.Ruleset.prototype.rulesets.apply(this) },
+
+    parent:   tree.Ruleset.prototype,
+    variable: function (name) { return this.parent.variable.call(this, name) },
+    find:     function ()     { return this.parent.find.apply(this, arguments) },
+    rulesets: function ()     { return this.parent.rulesets.apply(this) },
 
     eval: function (args, env) {
         var frame = new(tree.Ruleset)(null, []), context;