v2.2.1

lib/compress.js

@@ -1744,7 +1744,7 @@ merge(Compressor.prototype, {
         }
         if (self.operator == "+" && self.right instanceof AST_String
             && self.right.getValue() === "" && self.left instanceof AST_Binary
-            && self.left.operator == "+" && self.left.is_string()) {
+            && self.left.operator == "+" && self.left.is_string(compressor)) {
             return self.left;
         }
         return self;

package.json

@@ -3,7 +3,7 @@
     "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
     "homepage": "http://lisperator.net/uglifyjs",
     "main": "tools/node.js",
-    "version": "2.2.0",
+    "version": "2.2.1",
     "engines": { "node" : ">=0.4.0" },
     "maintainers": [{
         "name": "Mihai Bazon",