diff --git a/core/input.js b/core/input.js
index 443bfc83f..afa7a3358 100644
--- a/core/input.js
+++ b/core/input.js
@@ -10,31 +10,36 @@
  */
 'use strict';
 
-goog.provide('Blockly.Input');
+goog.module('Blockly.Input');
+goog.module.declareLegacyNamespace();
 
-goog.require('Blockly.Connection');
-goog.require('Blockly.fieldRegistry');
+/* eslint-disable-next-line no-unused-vars */
+const Block = goog.requireType('Blockly.Block');
+/* eslint-disable-next-line no-unused-vars */
+const BlockSvg = goog.requireType('Blockly.BlockSvg');
+/* eslint-disable-next-line no-unused-vars */
+const Connection = goog.require('Blockly.Connection');
+/* eslint-disable-next-line no-unused-vars */
+const Field = goog.requireType('Blockly.Field');
+/* eslint-disable-next-line no-unused-vars */
+const RenderedConnection = goog.requireType('Blockly.RenderedConnection');
+const constants = goog.require('Blockly.constants');
+const fieldRegistry = goog.require('Blockly.fieldRegistry');
+const inputTypes = goog.require('Blockly.inputTypes');
 /** @suppress {extraRequire} */
 goog.require('Blockly.FieldLabel');
-goog.require('Blockly.inputTypes');
-
-goog.requireType('Blockly.Block');
-goog.requireType('Blockly.BlockSvg');
-goog.requireType('Blockly.Field');
-goog.requireType('Blockly.RenderedConnection');
-
 
 /**
  * Class for an input with an optional field.
  * @param {number} type The type of the input.
  * @param {string} name Language-neutral identifier which may used to find this
  *     input again.
- * @param {!Blockly.Block} block The block containing this input.
- * @param {Blockly.Connection} connection Optional connection for this input.
+ * @param {!Block} block The block containing this input.
+ * @param {Connection} connection Optional connection for this input.
  * @constructor
  */
-Blockly.Input = function(type, name, block, connection) {
-  if (type != Blockly.inputTypes.DUMMY && !name) {
+const Input = function(type, name, block, connection) {
+  if (type != inputTypes.DUMMY && !name) {
     throw Error('Value inputs and statement inputs must have non-empty name.');
   }
   /** @type {number} */
@@ -42,13 +47,13 @@ Blockly.Input = function(type, name, block, connection) {
   /** @type {string} */
   this.name = name;
   /**
-   * @type {!Blockly.Block}
+   * @type {!Block}
    * @private
    */
   this.sourceBlock_ = block;
-  /** @type {Blockly.Connection} */
+  /** @type {Connection} */
   this.connection = connection;
-  /** @type {!Array<!Blockly.Field>} */
+  /** @type {!Array<!Field>} */
   this.fieldRow = [];
 };
 
@@ -56,32 +61,32 @@ Blockly.Input = function(type, name, block, connection) {
  * Alignment of input's fields (left, right or centre).
  * @type {number}
  */
-Blockly.Input.prototype.align = Blockly.constants.ALIGN.LEFT;
+Input.prototype.align = constants.ALIGN.LEFT;
 
 /**
  * Is the input visible?
  * @type {boolean}
  * @private
  */
-Blockly.Input.prototype.visible_ = true;
+Input.prototype.visible_ = true;
 
 /**
  * Get the source block for this input.
- * @return {?Blockly.Block} The source block, or null if there is none.
+ * @return {?Block} The source block, or null if there is none.
  */
-Blockly.Input.prototype.getSourceBlock = function() {
+Input.prototype.getSourceBlock = function() {
   return this.sourceBlock_;
 };
 
 /**
  * Add a field (or label from string), and all prefix and suffix fields, to the
  * end of the input's field row.
- * @param {string|!Blockly.Field} field Something to add as a field.
+ * @param {string|!Field} field Something to add as a field.
  * @param {string=} opt_name Language-neutral identifier which may used to find
  *     this field again.  Should be unique to the host block.
- * @return {!Blockly.Input} The input being append to (to allow chaining).
+ * @return {!Input} The input being append to (to allow chaining).
  */
-Blockly.Input.prototype.appendField = function(field, opt_name) {
+Input.prototype.appendField = function(field, opt_name) {
   this.insertFieldAt(this.fieldRow.length, field, opt_name);
   return this;
 };
@@ -90,12 +95,12 @@ Blockly.Input.prototype.appendField = function(field, opt_name) {
  * Inserts a field (or label from string), and all prefix and suffix fields, at
  * the location of the input's field row.
  * @param {number} index The index at which to insert field.
- * @param {string|!Blockly.Field} field Something to add as a field.
+ * @param {string|!Field} field Something to add as a field.
  * @param {string=} opt_name Language-neutral identifier which may used to find
  *     this field again.  Should be unique to the host block.
  * @return {number} The index following the last inserted field.
  */
-Blockly.Input.prototype.insertFieldAt = function(index, field, opt_name) {
+Input.prototype.insertFieldAt = function(index, field, opt_name) {
   if (index < 0 || index > this.fieldRow.length) {
     throw Error('index ' + index + ' out of bounds.');
   }
@@ -107,7 +112,7 @@ Blockly.Input.prototype.insertFieldAt = function(index, field, opt_name) {
 
   // Generate a FieldLabel when given a plain text field.
   if (typeof field == 'string') {
-    field = /** @type {!Blockly.Field} **/ (Blockly.fieldRegistry.fromJson({
+    field = /** @type {!Field} **/ (fieldRegistry.fromJson({
       'type': 'field_label',
       'text': field,
     }));
@@ -134,7 +139,7 @@ Blockly.Input.prototype.insertFieldAt = function(index, field, opt_name) {
   }
 
   if (this.sourceBlock_.rendered) {
-    this.sourceBlock_ = /** @type {!Blockly.BlockSvg} */ (this.sourceBlock_);
+    this.sourceBlock_ = /** @type {!BlockSvg} */ (this.sourceBlock_);
     this.sourceBlock_.render();
     // Adding a field will cause the block to change shape.
     this.sourceBlock_.bumpNeighbours();
@@ -150,13 +155,13 @@ Blockly.Input.prototype.insertFieldAt = function(index, field, opt_name) {
  *     and opt_quiet is true.
  * @throws {Error} if the field is not present and opt_quiet is false.
  */
-Blockly.Input.prototype.removeField = function(name, opt_quiet) {
-  for (var i = 0, field; (field = this.fieldRow[i]); i++) {
+Input.prototype.removeField = function(name, opt_quiet) {
+  for (let i = 0, field; (field = this.fieldRow[i]); i++) {
     if (field.name === name) {
       field.dispose();
       this.fieldRow.splice(i, 1);
       if (this.sourceBlock_.rendered) {
-        this.sourceBlock_ = /** @type {!Blockly.BlockSvg} */ (this.sourceBlock_);
+        this.sourceBlock_ = /** @type {!BlockSvg} */ (this.sourceBlock_);
         this.sourceBlock_.render();
         // Removing a field will cause the block to change shape.
         this.sourceBlock_.bumpNeighbours();
@@ -174,7 +179,7 @@ Blockly.Input.prototype.removeField = function(name, opt_quiet) {
  * Gets whether this input is visible or not.
  * @return {boolean} True if visible.
  */
-Blockly.Input.prototype.isVisible = function() {
+Input.prototype.isVisible = function() {
   return this.visible_;
 };
 
@@ -182,32 +187,32 @@ Blockly.Input.prototype.isVisible = function() {
  * Sets whether this input is visible or not.
  * Should only be used to collapse/uncollapse a block.
  * @param {boolean} visible True if visible.
- * @return {!Array<!Blockly.BlockSvg>} List of blocks to render.
+ * @return {!Array<!BlockSvg>} List of blocks to render.
  * @package
  */
-Blockly.Input.prototype.setVisible = function(visible) {
+Input.prototype.setVisible = function(visible) {
   // Note: Currently there are only unit tests for block.setCollapsed()
   // because this function is package. If this function goes back to being a
   // public API tests (lots of tests) should be added.
-  var renderList = [];
+  let renderList = [];
   if (this.visible_ == visible) {
     return renderList;
   }
   this.visible_ = visible;
 
-  for (var y = 0, field; (field = this.fieldRow[y]); y++) {
+  for (let y = 0, field; (field = this.fieldRow[y]); y++) {
     field.setVisible(visible);
   }
   if (this.connection) {
     this.connection =
-      /** @type {!Blockly.RenderedConnection} */ (this.connection);
+        /** @type {!RenderedConnection} */ (this.connection);
     // Has a connection.
     if (visible) {
       renderList = this.connection.startTrackingAll();
     } else {
       this.connection.stopTrackingAll();
     }
-    var child = this.connection.targetBlock();
+    const child = this.connection.targetBlock();
     if (child) {
       child.getSvgRoot().style.display = visible ? 'block' : 'none';
     }
@@ -219,8 +224,8 @@ Blockly.Input.prototype.setVisible = function(visible) {
  * Mark all fields on this input as dirty.
  * @package
  */
-Blockly.Input.prototype.markDirty = function() {
-  for (var y = 0, field; (field = this.fieldRow[y]); y++) {
+Input.prototype.markDirty = function() {
+  for (let y = 0, field; (field = this.fieldRow[y]); y++) {
     field.markDirty();
   }
 };
@@ -229,9 +234,9 @@ Blockly.Input.prototype.markDirty = function() {
  * Change a connection's compatibility.
  * @param {string|Array<string>|null} check Compatible value type or
  *     list of value types.  Null if all types are compatible.
- * @return {!Blockly.Input} The input being modified (to allow chaining).
+ * @return {!Input} The input being modified (to allow chaining).
  */
-Blockly.Input.prototype.setCheck = function(check) {
+Input.prototype.setCheck = function(check) {
   if (!this.connection) {
     throw Error('This input does not have a connection.');
   }
@@ -241,14 +246,14 @@ Blockly.Input.prototype.setCheck = function(check) {
 
 /**
  * Change the alignment of the connection's field(s).
- * @param {number} align One of the values of Blockly.constants.ALIGN.
+ * @param {number} align One of the values of constants.ALIGN.
  *   In RTL mode directions are reversed, and ALIGN.RIGHT aligns to the left.
- * @return {!Blockly.Input} The input being modified (to allow chaining).
+ * @return {!Input} The input being modified (to allow chaining).
  */
-Blockly.Input.prototype.setAlign = function(align) {
+Input.prototype.setAlign = function(align) {
   this.align = align;
   if (this.sourceBlock_.rendered) {
-    this.sourceBlock_ = /** @type {!Blockly.BlockSvg} */ (this.sourceBlock_);
+    this.sourceBlock_ = /** @type {!BlockSvg} */ (this.sourceBlock_);
     this.sourceBlock_.render();
   }
   return this;
@@ -257,9 +262,9 @@ Blockly.Input.prototype.setAlign = function(align) {
 /**
  * Changes the connection's shadow block.
  * @param {?Element} shadow DOM representation of a block or null.
- * @return {!Blockly.Input} The input being modified (to allow chaining).
+ * @return {!Input} The input being modified (to allow chaining).
  */
-Blockly.Input.prototype.setShadowDom = function(shadow) {
+Input.prototype.setShadowDom = function(shadow) {
   if (!this.connection) {
     throw Error('This input does not have a connection.');
   }
@@ -271,7 +276,7 @@ Blockly.Input.prototype.setShadowDom = function(shadow) {
  * Returns the XML representation of the connection's shadow block.
  * @return {?Element} Shadow DOM representation of a block or null.
  */
-Blockly.Input.prototype.getShadowDom = function() {
+Input.prototype.getShadowDom = function() {
   if (!this.connection) {
     throw Error('This input does not have a connection.');
   }
@@ -281,11 +286,11 @@ Blockly.Input.prototype.getShadowDom = function() {
 /**
  * Initialize the fields on this input.
  */
-Blockly.Input.prototype.init = function() {
+Input.prototype.init = function() {
   if (!this.sourceBlock_.workspace.rendered) {
     return;  // Headless blocks don't need fields initialized.
   }
-  for (var i = 0; i < this.fieldRow.length; i++) {
+  for (let i = 0; i < this.fieldRow.length; i++) {
     this.fieldRow[i].init();
   }
 };
@@ -294,8 +299,8 @@ Blockly.Input.prototype.init = function() {
  * Sever all links to this input.
  * @suppress {checkTypes}
  */
-Blockly.Input.prototype.dispose = function() {
-  for (var i = 0, field; (field = this.fieldRow[i]); i++) {
+Input.prototype.dispose = function() {
+  for (let i = 0, field; (field = this.fieldRow[i]); i++) {
     field.dispose();
   }
   if (this.connection) {
@@ -303,3 +308,5 @@ Blockly.Input.prototype.dispose = function() {
   }
   this.sourceBlock_ = null;
 };
+
+exports = Input;
diff --git a/tests/deps.js b/tests/deps.js
index de575339f..eff657b4f 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -70,7 +70,7 @@ goog.addDependency('../../core/gesture.js', ['Blockly.Gesture'], ['Blockly.Block
 goog.addDependency('../../core/grid.js', ['Blockly.Grid'], ['Blockly.utils.Svg', 'Blockly.utils.dom', 'Blockly.utils.userAgent'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/icon.js', ['Blockly.Icon'], ['Blockly.browserEvents', 'Blockly.utils', 'Blockly.utils.Coordinate', 'Blockly.utils.Size', 'Blockly.utils.Svg', 'Blockly.utils.dom'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/inject.js', ['Blockly.inject'], ['Blockly.BlockDragSurfaceSvg', 'Blockly.Css', 'Blockly.DropDownDiv', 'Blockly.Events', 'Blockly.Grid', 'Blockly.Msg', 'Blockly.Options', 'Blockly.ScrollbarPair', 'Blockly.Tooltip', 'Blockly.WidgetDiv', 'Blockly.Workspace', 'Blockly.WorkspaceDragSurfaceSvg', 'Blockly.WorkspaceSvg', 'Blockly.browserEvents', 'Blockly.utils', 'Blockly.utils.Svg', 'Blockly.utils.aria', 'Blockly.utils.dom', 'Blockly.utils.math', 'Blockly.utils.userAgent']);
-goog.addDependency('../../core/input.js', ['Blockly.Input'], ['Blockly.Connection', 'Blockly.FieldLabel', 'Blockly.fieldRegistry', 'Blockly.inputTypes'], {'lang': 'es5'});
+goog.addDependency('../../core/input.js', ['Blockly.Input'], ['Blockly.Connection', 'Blockly.FieldLabel', 'Blockly.constants', 'Blockly.fieldRegistry', 'Blockly.inputTypes'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/input_types.js', ['Blockly.inputTypes'], ['Blockly.connectionTypes']);
 goog.addDependency('../../core/insertion_marker_manager.js', ['Blockly.InsertionMarkerManager'], ['Blockly.ComponentManager', 'Blockly.Events', 'Blockly.blockAnimations', 'Blockly.connectionTypes', 'Blockly.internalConstants'], {'lang': 'es5'});
 goog.addDependency('../../core/interfaces/i_ast_node_location.js', ['Blockly.IASTNodeLocation'], [], {'lang': 'es6', 'module': 'goog'});