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diff --git a/tools/eslint/lib/rules/no-mixed-spaces-and-tabs.js b/tools/eslint/lib/rules/no-mixed-spaces-and-tabs.js
new file mode 100644
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+++ b/tools/eslint/lib/rules/no-mixed-spaces-and-tabs.js
@@ -0,0 +1,68 @@
+/**
+ * @fileoverview Disallow mixed spaces and tabs for indentation
+ * @author Jary Niebur
+ * @copyright 2014 Nicholas C. Zakas. All rights reserved.
+ * @copyright 2014 Jary Niebur. All rights reserved.
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+    var smartTabs;
+
+    switch (context.options[0]) {
+        case true: // Support old syntax, maybe add deprecation warning here
+        case "smart-tabs":
+            smartTabs = true;
+            break;
+        default:
+            smartTabs = false;
+    }
+
+    var COMMENT_START = /^\s*\/\*/,
+        MAYBE_COMMENT = /^\s*\*/;
+
+    //--------------------------------------------------------------------------
+    // Public
+    //--------------------------------------------------------------------------
+
+    return {
+
+        "Program": function(node) {
+            /*
+             * At least one space followed by a tab
+             * or the reverse before non-tab/-space
+             * characters begin.
+             */
+            var regex = /^(?=[\t ]*(\t | \t))/,
+                match,
+                lines = context.getSourceLines();
+
+            if (smartTabs) {
+                /*
+                 * At least one space followed by a tab
+                 * before non-tab/-space characters begin.
+                 */
+                regex = /^(?=[\t ]* \t)/;
+            }
+
+            lines.forEach(function(line, i) {
+                match = regex.exec(line);
+
+                if (match) {
+
+                    if (!MAYBE_COMMENT.test(line) && !COMMENT_START.test(lines[i - 1])) {
+                        context.report(node, { line: i + 1, column: match.index + 1 }, "Mixed spaces and tabs.");
+                    }
+
+                }
+            });
+        }
+
+    };
+
+};