diff --git a/lib/6to5/transformers/constants.js b/lib/6to5/transformers/constants.js
index b3c604fd9c..3150f86c62 100644
--- a/lib/6to5/transformers/constants.js
+++ b/lib/6to5/transformers/constants.js
@@ -9,17 +9,19 @@ exports.ForOfStatement =
 exports.ForStatement = function (node, parent, file) {
   var constants = [];
 
-  var check = function (node, name) {
-    if (constants.indexOf(name) >= 0) {
-      throw file.errorWithNode(node, name + " is read-only");
-    }
+  var check = function (node, names) {
+    _.each(names, function (name) {
+      if (constants.indexOf(name) >= 0) {
+        throw file.errorWithNode(node, name + " is read-only");
+      }
+    });
   };
 
   _.each(node.body, function (child) {
     if (child && t.isVariableDeclaration(child) && child.kind === "const") {
       _.each(child.declarations, function (declar) {
         _.each(t.getIds(declar.id), function (name) {
-          check(declar, name);
+          check(declar, [name]);
           constants.push(name);
         });
 
@@ -34,10 +36,8 @@ exports.ForStatement = function (node, parent, file) {
   traverse(node, function (child) {
     if (child._ignoreConstant) return;
 
-    if (t.isVariableDeclarator(child) || t.isFunctionDeclaration(child) || t.isClassDeclaration(child)) {
-      check(child, child.id.name);
-    } else if (t.isAssignmentExpression(child)) {
-      check(child, child.left.name);
+    if (t.isVariableDeclarator(child) || t.isFunctionDeclaration(child) || t.isClassDeclaration(child) || t.isAssignmentExpression(child)) {
+      check(child, t.getIds(child));
     }
   });
 };