diff --git a/closure/goog/base.js b/closure/goog/base.js
index 73db18742..52a15dbcb 100644
--- a/closure/goog/base.js
+++ b/closure/goog/base.js
@@ -250,6 +250,28 @@ goog.require = function(namespace) {
   return null;
 };
 
+/**
+ * Requires a symbol for its type information. This is an indication to the
+ * compiler that the symbol may appear in type annotations, yet it is not
+ * referenced at runtime.
+ *
+ * When called within a goog.module or ES6 module file, the return value may be
+ * assigned to or destructured into a variable, but it may not be otherwise used
+ * in code outside of a type annotation.
+ *
+ * Note that all calls to goog.requireType will be stripped by the compiler.
+ *
+ * @param {string} namespace Namespace (as was given in goog.provide,
+ *     goog.module, or goog.declareModuleId) in the form
+ *     "goog.package.part".
+ * @return {?}
+ */
+goog.requireType = function(namespace) {
+  // Return an empty object so that single-level destructuring of the return
+  // value doesn't crash at runtime when using the debug loader. Multi-level
+  // destructuring isn't supported.
+  return {};
+};
 
 /**
  * Path for included scripts.
diff --git a/core/block_svg.js b/core/block_svg.js
index bfc5c7bb7..9d18f68ed 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -100,6 +100,13 @@ Blockly.BlockSvg = function(workspace, prototypeName, opt_id) {
   /** @type {!Blockly.WorkspaceSvg} */
   this.workspace = workspace;
 
+  /** @type {Blockly.RenderedConnection} */
+  this.outputConnection = null;
+  /** @type {Blockly.RenderedConnection} */
+  this.nextConnection = null;
+  /** @type {Blockly.RenderedConnection} */
+  this.previousConnection = null;
+
   /**
    * Whether to move the block to the drag surface when it is dragged.
    * True if it should move, false if it should be translated directly.
@@ -239,6 +246,13 @@ Blockly.BlockSvg.prototype.decompose;
  */
 Blockly.BlockSvg.prototype.compose;
 
+/**
+ * An property used internally to reference the block's rendering debugger.
+ * @type {?Blockly.blockRendering.Debug}
+ * @package
+ */
+Blockly.BlockSvg.prototype.renderingDebugger;
+
 /**
  * Create and initialize the SVG representation of the block.
  * May be called more than once.
diff --git a/core/renderers/common/debugger.js b/core/renderers/common/debugger.js
index a405fc650..fbc876f0d 100644
--- a/core/renderers/common/debugger.js
+++ b/core/renderers/common/debugger.js
@@ -42,6 +42,7 @@ Blockly.blockRendering.Debug = function() {
   /**
    * An array of SVG elements that have been created by this object.
    * @type {Array.<!SVGElement>}
+   * @private
    */
   this.debugElements_ = [];
 
@@ -49,6 +50,7 @@ Blockly.blockRendering.Debug = function() {
    * The SVG root of the block that is being rendered.  Debug elements will
    * be attached to this root.
    * @type {SVGElement}
+   * @private
    */
   this.svgRoot_ = null;
 };
@@ -178,6 +180,8 @@ Blockly.blockRendering.Debug.prototype.drawRenderedElem = function(elem, isRtl)
  * share the same colours, as do previous and next.  When positioned correctly
  * a connected pair will look like a bullseye.
  * @param {Blockly.RenderedConnection} conn The connection to circle.
+ * @suppress {visibility} Suppress visibility of conn.offsetInBlock_ since this
+ *     is a debug module.
  * @package
  */
 Blockly.blockRendering.Debug.prototype.drawConnection = function(conn) {
@@ -273,7 +277,7 @@ Blockly.blockRendering.Debug.prototype.drawRowWithElements = function(row, curso
   for (var i = 0, elem; (elem = row.elements[i]); i++) {
     if (Blockly.blockRendering.Types.isSpacer(elem)) {
       this.drawSpacerElem(
-          /** @type {Blockly.blockRendering.InRowSpacer} */ (elem),
+          /** @type {!Blockly.blockRendering.InRowSpacer} */ (elem),
           row.height, isRtl);
     } else {
       this.drawRenderedElem(elem, isRtl);
diff --git a/core/renderers/common/info.js b/core/renderers/common/info.js
index f39cc9187..ccd046978 100644
--- a/core/renderers/common/info.js
+++ b/core/renderers/common/info.js
@@ -654,7 +654,7 @@ Blockly.blockRendering.RenderInfo.prototype.getElemCenterline_ = function(row,
  * Record final position information on elements on the given row, for use in
  * drawing.  At minimum this records xPos and centerline on each element.
  * @param {!Blockly.blockRendering.Row} row The row containing the elements.
- * @private
+ * @protected
  */
 Blockly.blockRendering.RenderInfo.prototype.recordElemPositions_ = function(
     row) {
diff --git a/core/renderers/common/path_object.js b/core/renderers/common/path_object.js
index 81370fcdf..07b1aa343 100644
--- a/core/renderers/common/path_object.js
+++ b/core/renderers/common/path_object.js
@@ -32,7 +32,6 @@ goog.require('Blockly.utils.dom');
  * An interface for a block's path object.
  * @param {!SVGElement} _root The root SVG element.
  * @interface
- * @package
  */
 Blockly.blockRendering.IPathObject = function(_root) {};
 
diff --git a/core/renderers/common/renderer.js b/core/renderers/common/renderer.js
index bd16cef4d..49a83943a 100644
--- a/core/renderers/common/renderer.js
+++ b/core/renderers/common/renderer.js
@@ -30,6 +30,8 @@ goog.require('Blockly.blockRendering.PathObject');
 goog.require('Blockly.blockRendering.RenderInfo');
 goog.require('Blockly.CursorSvg');
 
+goog.requireType('Blockly.blockRendering.Debug');
+
 
 /**
  * The base class for a block renderer.
@@ -89,6 +91,7 @@ Blockly.blockRendering.Renderer.prototype.makeDrawer_ = function(block, info) {
 /**
  * Create a new instance of the renderer's debugger.
  * @return {!Blockly.blockRendering.Debug} The renderer debugger.
+ * @suppress {strictModuleDepCheck} Debug renderer only included in playground.
  * @protected
  */
 Blockly.blockRendering.Renderer.prototype.makeDebugger_ = function() {
diff --git a/core/renderers/geras/measurables/inputs.js b/core/renderers/geras/measurables/inputs.js
index 441b7550f..de7254f10 100644
--- a/core/renderers/geras/measurables/inputs.js
+++ b/core/renderers/geras/measurables/inputs.js
@@ -37,7 +37,7 @@ goog.require('Blockly.utils.object');
  *     information for.
  * @package
  * @constructor
- * @extends {Blockly.blockRendering.InputConnection}
+ * @extends {Blockly.blockRendering.InlineInput}
  */
 Blockly.geras.InlineInput = function(constants, input) {
   Blockly.geras.InlineInput.superClass_.constructor.call(
@@ -62,7 +62,7 @@ Blockly.utils.object.inherits(Blockly.geras.InlineInput,
  *     information for.
  * @package
  * @constructor
- * @extends {Blockly.blockRendering.InputConnection}
+ * @extends {Blockly.blockRendering.StatementInput}
  */
 Blockly.geras.StatementInput = function(constants, input) {
   Blockly.geras.StatementInput.superClass_.constructor.call(
diff --git a/core/renderers/measurables/connections.js b/core/renderers/measurables/connections.js
index d514a6439..ca81f5c30 100644
--- a/core/renderers/measurables/connections.js
+++ b/core/renderers/measurables/connections.js
@@ -36,7 +36,7 @@ goog.require('Blockly.utils.object');
  * the block.
  * @param {!Blockly.blockRendering.ConstantProvider} constants The rendering
  *   constants provider.
- * @param {Blockly.RenderedConnection} connectionModel The connection object on
+ * @param {!Blockly.RenderedConnection} connectionModel The connection object on
  *     the block that this represents.
  * @package
  * @constructor
diff --git a/core/renderers/measurables/types.js b/core/renderers/measurables/types.js
index 02c3c48f6..d31ea79ba 100644
--- a/core/renderers/measurables/types.js
+++ b/core/renderers/measurables/types.js
@@ -28,7 +28,6 @@ goog.provide('Blockly.blockRendering.Types');
 /**
  * Types of rendering elements.
  * @enum {number}
- * @package
  */
 Blockly.blockRendering.Types = {
   NONE: 0, // None