diff --git a/core/interfaces/i_movable.js b/core/interfaces/i_movable.js
index bc0c3bf9f..25a92d6bb 100644
--- a/core/interfaces/i_movable.js
+++ b/core/interfaces/i_movable.js
@@ -11,17 +11,20 @@
 
 'use strict';
 
-goog.provide('Blockly.IMovable');
+goog.module('Blockly.IMovable');
+goog.module.declareLegacyNamespace();
 
 
 /**
  * The interface for an object that is movable.
  * @interface
  */
-Blockly.IMovable = function() {};
+const IMovable = function() {};
 
 /**
  * Get whether this is movable or not.
  * @return {boolean} True if movable.
  */
-Blockly.IMovable.prototype.isMovable;
+IMovable.prototype.isMovable;
+
+exports = IMovable;
diff --git a/tests/deps.js b/tests/deps.js
index 230083d23..3ce0457fb 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -88,7 +88,7 @@ goog.addDependency('../../core/interfaces/i_drag_target.js', ['Blockly.IDragTarg
 goog.addDependency('../../core/interfaces/i_draggable.js', ['Blockly.IDraggable'], ['Blockly.IDeletable'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/interfaces/i_flyout.js', ['Blockly.IFlyout'], []);
 goog.addDependency('../../core/interfaces/i_metrics_manager.js', ['Blockly.IMetricsManager'], []);
-goog.addDependency('../../core/interfaces/i_movable.js', ['Blockly.IMovable'], []);
+goog.addDependency('../../core/interfaces/i_movable.js', ['Blockly.IMovable'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/interfaces/i_positionable.js', ['Blockly.IPositionable'], ['Blockly.IComponent']);
 goog.addDependency('../../core/interfaces/i_registrable.js', ['Blockly.IRegistrable'], []);
 goog.addDependency('../../core/interfaces/i_registrable_field.js', ['Blockly.IRegistrableField'], []);