Fix #1536 - pattern used in bootstrap is causing a recursion error

lib/less/tree/mixin.js

@@ -41,6 +41,7 @@ tree.mixin.Call.prototype = {
                             try {
                                 if (!(mixin instanceof tree.mixin.Definition)) {
                                     mixin = new tree.mixin.Definition("", [], mixin.rules, null, false);
+                                    mixin.originalRuleset = mixins[m].originalRuleset || mixins[m];
                                 }
                                 Array.prototype.push.apply(
                                       rules, mixin.eval(env, args, this.important).rules);
@@ -203,9 +204,9 @@ tree.mixin.Definition.prototype = {
         rules = important ?
             this.parent.makeImportant.apply(this).rules : this.rules.slice(0);
 
-        ruleset = new(tree.Ruleset)(null, rules).eval(new(tree.evalEnv)(env,
-                                                    [this, frame].concat(mixinFrames)));
+        ruleset = new(tree.Ruleset)(null, rules);
         ruleset.originalRuleset = this;
+        ruleset = ruleset.eval(new(tree.evalEnv)(env, [this, frame].concat(mixinFrames)));
         return ruleset;
     },
     matchCondition: function (args, env) {

test/less/mixins.less

@@ -112,3 +112,12 @@ h3 { .margin_between(15px, 5px); }
 
     &.large { .paddingFloat(((10em * 2) * 2)); }
 }
+.clearfix() {
+  // ...
+}
+.clearfix {
+  .clearfix();
+}
+.foo {
+  .clearfix();
+}