From 972e295df6f73abf47740e689a69e0486934b47a Mon Sep 17 00:00:00 2001
From: David Greenspan <dgreenspan@alum.mit.edu>
Date: Wed, 19 Jun 2013 18:04:20 -0700
Subject: [PATCH] Don't mutate template AST in evaluate.  Fixes #1143

---
 packages/handlebars/evaluate.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/handlebars/evaluate.js b/packages/handlebars/evaluate.js
index 31403fd1a7..fa3df9bcd2 100644
--- a/packages/handlebars/evaluate.js
+++ b/packages/handlebars/evaluate.js
@@ -128,6 +128,7 @@ Handlebars.evaluate = function (ast, data, options) {
     if (id[1] === '') {
       // an empty path segment is our AST's way of encoding
       // the presence of 'this.' at the beginning of the path.
+      id = id.slice();
       id.splice(1, 1); // remove the ''
       scopedToContext = true;
     }