1 files changed, 50 insertions, 0 deletions
diff --git a/tools/eslint/lib/rules/no-catch-shadow.js b/tools/eslint/lib/rules/no-catch-shadow.js
new file mode 100644
index 0000000000..af07c46292
--- /dev/null
+++ b/tools/eslint/lib/rules/no-catch-shadow.js
@@ -0,0 +1,50 @@
+/**
+ * @fileoverview Rule to flag variable leak in CatchClauses in IE 8 and earlier
+ * @author Ian Christian Myers
+ */
+
+"use strict";
+
+//------------------------------------------------------------------------------
+// Rule Definition
+//------------------------------------------------------------------------------
+
+module.exports = function(context) {
+
+    //--------------------------------------------------------------------------
+    // Helpers
+    //--------------------------------------------------------------------------
+
+    function paramIsShadowing(scope, name) {
+        var found = scope.variables.some(function(variable) {
+            return variable.name === name;
+        });
+
+        if (found) {
+            return true;
+        }
+
+        if (scope.upper) {
+            return paramIsShadowing(scope.upper, name);
+        }
+
+        return false;
+    }
+
+    //--------------------------------------------------------------------------
+    // Public API
+    //--------------------------------------------------------------------------
+
+    return {
+
+        "CatchClause": function(node) {
+            var scope = context.getScope();
+
+            if (paramIsShadowing(scope, node.param.name)) {
+                context.report(node, "Value of '{{name}}' may be overwritten in IE 8 and earlier.",
+                        { name: node.param.name });
+            }
+        }
+    };
+
+};