diff --git a/src/babel/transformation/transformers/es6/constants.js b/src/babel/transformation/transformers/es6/constants.js
index 4125b68d10..518ee38609 100644
--- a/src/babel/transformation/transformers/es6/constants.js
+++ b/src/babel/transformation/transformers/es6/constants.js
@@ -1,44 +1,31 @@
 import * as messages from "../../../messages";
 import * as t from "../../../types";
 
-var visitor = {
-  enter(node, parent, scope, state) {
-    if (this.isAssignmentExpression() || this.isUpdateExpression()) {
-      var ids = this.getBindingIdentifiers();
+export function AssignmentExpression(node, parent, scope, file) {
+  var ids = this.getBindingIdentifiers();
 
-      for (var name in ids) {
-        var id = ids[name];
+  for (var name in ids) {
+    var id = ids[name];
 
-        var constant = state.constants[name];
+    var binding = scope.getBinding(name);
 
-        // no constant exists
-        if (!constant) continue;
+    // no binding exists
+    if (!binding) continue;
 
-        var constantIdentifier = constant.identifier;
+    // not a constant
+    if (binding.kind !== "const" && binding.kind !== "module") continue;
 
-        // check if the assignment id matches the constant declaration id
-        // if it does then it was the id used to initially declare the
-        // constant so we can just ignore it
-        if (id === constantIdentifier) continue;
+    // check if the assignment id matches the constant declaration id
+    // if it does then it was the id used to initially declare the
+    // constant so we can just ignore it
+    if (binding.identifier === id) continue;
 
-        // check if there's been a local binding that shadows this constant
-        if (!scope.bindingIdentifierEquals(name, constantIdentifier)) continue;
-
-        throw state.file.errorWithNode(id, messages.get("readOnly", name));
-      }
-    } else if (this.isScope()) {
-      this.skip();
-    }
+    throw file.errorWithNode(id, messages.get("readOnly", name));
   }
-};
-
-export function Scopable(node, parent, scope, file) {
-  this.traverse(visitor, {
-    constants: scope.getAllBindingsOfKind("const", "module"),
-    file:      file
-  });
 }
 
+export { AssignmentExpression as UpdateExpression };
+
 export function VariableDeclaration(node) {
   if (node.kind === "const") node.kind = "let";
 }