diff --git a/lib/6to5/transformation/file.js b/lib/6to5/transformation/file.js
index 127e047521..87086b3ff3 100644
--- a/lib/6to5/transformation/file.js
+++ b/lib/6to5/transformation/file.js
@@ -460,7 +460,7 @@ File.prototype.generateUid = function (name, scope) {
 File.prototype.generateUidIdentifier = function (name, scope) {
   scope = scope || this.scope;
   var id = t.identifier(this.generateUid(name, scope));
-  scope.addBindingToFunctionScope("var", id);
+  scope.addBindingToFunctionScope(id);
   return id;
 };
 
diff --git a/lib/6to5/traversal/scope.js b/lib/6to5/traversal/scope.js
index 49ec6b3959..147e96ed17 100644
--- a/lib/6to5/traversal/scope.js
+++ b/lib/6to5/traversal/scope.js
@@ -134,7 +134,10 @@ Scope.prototype.generateTempBasedOnNode = function (node) {
   return id;
 };
 
-Scope.prototype.checkBlockScopedCollisions = function (key, id) {
+Scope.prototype.checkBlockScopedCollisions = function (kind, key, id) {
+  if (kind === "param") return;
+  if (kind === "hoisted" && this.bindingKinds["let"][key]) return;
+
   if (this.bindingKinds["let"][key] || this.bindingKinds["const"][key]) {
     throw this.file.errorWithNode(id, "Duplicate declaration " + key, TypeError);
   }
@@ -195,9 +198,7 @@ Scope.prototype.register = function (node, reference, kind) {
   for (var key in ids) {
     var id = ids[key];
 
-    if (kind !== "hoisted" && kind !== "param") {
-      this.checkBlockScopedCollisions(key, id);
-    }
+    this.checkBlockScopedCollisions(kind, key, id);
 
     this.registerType(key, id, node);
     this.bindings[key] = id;
@@ -245,6 +246,8 @@ var programReferenceVisitor = {
   enter: function (node, parent, scope, state) {
     if (t.isReferencedIdentifier(node, parent) && !scope.hasReference(node.name)) {
       state.register(node, true);
+    } else if (t.isLabelStatemented(node)) {
+      state.register(node.label, true);
     }
   }
 };
@@ -393,20 +396,18 @@ Scope.prototype.push = function (opts) {
  * Walk up the scope tree until we hit a `Function` and then
  * push our `node` to it's references.
  *
- * @param {String} kind
  * @param {Object} node
+ * @param {String} [kind]
  */
 
-Scope.prototype.addBindingToFunctionScope = function (kind, node) {
+Scope.prototype.addBindingToFunctionScope = function (node, kind) {
   var scope = this.getFunctionParent();
   var ids   = t.getBindingIdentifiers(node);
 
   extend(scope.bindings, ids);
   extend(scope.references, ids);
 
-  // this ignores the duplicate declaration logic specified in `getInfo`
-  // but it doesn't really matter
-  extend(scope.bindingKinds[kind], ids);
+  if (kind) extend(scope.bindingKinds[kind], ids)
 };
 
 /**