diff --git a/core/renderers/block_rendering_rewrite/block_render_draw.js b/core/renderers/block_rendering_rewrite/block_render_draw.js
index ca70dc058..2e80b5d98 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw.js
@@ -101,7 +101,7 @@ Blockly.blockRendering.Drawer.prototype.recordSizeOnBlock_ = function() {
  * @private
  */
 Blockly.blockRendering.Drawer.prototype.hideHiddenIcons_ = function() {
-  for (var i = 0, iconInfo; iconInfo = this.info_.hiddenIcons[i]; i++) {
+  for (var i = 0, iconInfo; (iconInfo = this.info_.hiddenIcons[i]); i++) {
     iconInfo.icon.iconGroup_.setAttribute('display', 'none');
   }
 };
@@ -145,7 +145,7 @@ Blockly.blockRendering.Drawer.prototype.drawTop_ = function() {
   this.positionPreviousConnection_();
   this.outlinePath_ +=
       Blockly.utils.svgPaths.moveBy(topRow.xPos, this.info_.startY);
-  for (var i = 0, elem; elem = elements[i]; i++) {
+  for (var i = 0, elem; (elem = elements[i]); i++) {
     if (elem.type == 'round corner') {
       this.outlinePath_ +=
           Blockly.blockRendering.constants.OUTSIDE_CORNERS.topLeft;
@@ -262,8 +262,7 @@ Blockly.blockRendering.Drawer.prototype.drawBottom_ = function() {
   this.outlinePath_ +=
     Blockly.utils.svgPaths.lineOnAxis('v', bottomRow.height - bottomRow.overhangY);
 
-  for (var i = elems.length - 1; i >= 0; i--) {
-    var elem = elems[i];
+  for (var i = elems.length - 1, elem; (elem = elems[i]); i--) {
     if (elem.isNextConnection()) {
       this.outlinePath_ += bottomRow.notchShape.pathRight;
     } else if (elem.isSquareCorner()) {
@@ -308,8 +307,8 @@ Blockly.blockRendering.Drawer.prototype.drawLeft_ = function() {
  * @private
  */
 Blockly.blockRendering.Drawer.prototype.drawInternals_ = function() {
-  for (var i = 0, row; row = this.info_.rows[i]; i++) {
-    for (var j = 0, elem; elem = row.elements[j]; j++) {
+  for (var i = 0, row; (row = this.info_.rows[i]); i++) {
+    for (var j = 0, elem; (elem = row.elements[j]); j++) {
       if (elem.isInlineInput()) {
         this.drawInlineInput_(elem);
       } else if (elem.isIcon() || elem.isField()) {
diff --git a/core/renderers/block_rendering_rewrite/block_render_draw_debug.js b/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
index 1278ac3eb..d278db03f 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw_debug.js
@@ -76,7 +76,7 @@ Blockly.blockRendering.Debug = function() {
  * @package
  */
 Blockly.blockRendering.Debug.prototype.clearElems = function() {
-  for (var i = 0, elem; elem = this.debugElements_[i]; i++) {
+  for (var i = 0, elem; (elem = this.debugElements_[i]); i++) {
     Blockly.utils.dom.removeNode(elem);
   }
 
@@ -258,7 +258,7 @@ Blockly.blockRendering.Debug.prototype.drawRenderedRow = function(row, cursorY,
  * @package
  */
 Blockly.blockRendering.Debug.prototype.drawRowWithElements = function(row, cursorY, isRtl) {
-  for (var i = 0, elem; elem = row.elements[i]; i++) {
+  for (var i = 0, elem; (elem = row.elements[i]); i++) {
     if (elem.isSpacer()) {
       this.drawSpacerElem(elem, row.height, isRtl);
     } else {
@@ -325,7 +325,7 @@ Blockly.blockRendering.Debug.prototype.drawDebug = function(block, info) {
   this.randomColour_ = '#' + Math.floor(Math.random() * 16777215).toString(16);
 
   var cursorY = 0;
-  for (var i = 0, row; row = info.rows[i]; i++) {
+  for (var i = 0, row; (row = info.rows[i]); i++) {
     if (row.type == 'between-row spacer') {
       this.drawSpacerRow(row, cursorY, info.RTL);
     } else {
diff --git a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
index 8a6b5ba4c..b2ee1664d 100644
--- a/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
+++ b/core/renderers/block_rendering_rewrite/block_render_draw_highlight.js
@@ -81,7 +81,7 @@ Blockly.blockRendering.Highlighter = function(info, pathObject) {
 Blockly.blockRendering.Highlighter.prototype.drawTopCorner = function(row) {
   this.steps_.push(
       Blockly.utils.svgPaths.moveBy(row.xPos, this.info_.startY));
-  for (var i = 0, elem; elem = row.elements[i]; i++) {
+  for (var i = 0, elem; (elem = row.elements[i]); i++) {
     if (elem.type == 'square corner') {
       this.steps_.push(Blockly.blockRendering.highlightConstants.START_POINT);
     } else if (elem.type == 'round corner') {
diff --git a/core/renderers/block_rendering_rewrite/block_render_info.js b/core/renderers/block_rendering_rewrite/block_render_info.js
index 8f6823331..9565e57ac 100644
--- a/core/renderers/block_rendering_rewrite/block_render_info.js
+++ b/core/renderers/block_rendering_rewrite/block_render_info.js
@@ -177,7 +177,7 @@ Blockly.blockRendering.RenderInfo.prototype.createRows_ = function() {
   // Icons always go on the first row, before anything else.
   var icons = this.block_.getIcons();
   if (icons.length) {
-    for (var i = 0, icon; icon = icons[i]; i++) {
+    for (var i = 0, icon; (icon = icons[i]); i++) {
       var iconInfo = new Blockly.blockRendering.Icon(icon);
       if (this.isCollapsed && icon.collapseHidden) {
         this.hiddenIcons.push(iconInfo);
@@ -190,7 +190,7 @@ Blockly.blockRendering.RenderInfo.prototype.createRows_ = function() {
   var lastInput = undefined;
   // Loop across all of the inputs on the block, creating objects for anything
   // that needs to be rendered and breaking the block up into visual rows.
-  for (var i = 0, input; input = this.block_.inputList[i]; i++) {
+  for (var i = 0, input; (input = this.block_.inputList[i]); i++) {
     if (!input.isVisible()) {
       continue;
     }
@@ -201,7 +201,7 @@ Blockly.blockRendering.RenderInfo.prototype.createRows_ = function() {
     }
 
     // All of the fields in an input go on the same row.
-    for (var j = 0, field; field = input.fieldRow[j]; j++) {
+    for (var j = 0, field; (field = input.fieldRow[j]); j++) {
       activeRow.elements.push(new Blockly.blockRendering.Field(field, input));
     }
     this.addInput_(input, activeRow);
@@ -275,7 +275,7 @@ Blockly.blockRendering.RenderInfo.prototype.shouldStartNewRow_ = function(input,
  * @private
  */
 Blockly.blockRendering.RenderInfo.prototype.addElemSpacing_ = function() {
-  for (var i = 0, row; row = this.rows[i]; i++) {
+  for (var i = 0, row; (row = this.rows[i]); i++) {
     var oldElems = row.elements;
     row.elements = [];
     // No spacing needed before the corner on the top row or the bottom row.
@@ -449,7 +449,7 @@ Blockly.blockRendering.RenderInfo.prototype.computeBounds_ = function() {
   var widestStatementRowFields = 0;
   var blockWidth = 0;
   var widestRowWithConnectedBlocks = 0;
-  for (var i = 0, row; row = this.rows[i]; i++) {
+  for (var i = 0, row; (row = this.rows[i]); i++) {
     row.measure();
     blockWidth = Math.max(blockWidth, row.width);
     if (row.hasStatement) {
@@ -466,7 +466,7 @@ Blockly.blockRendering.RenderInfo.prototype.computeBounds_ = function() {
 
   this.width = blockWidth;
 
-  for (var i = 0, row; row = this.rows[i]; i++) {
+  for (var i = 0, row; (row = this.rows[i]); i++) {
     if (row.hasStatement) {
       row.statementEdge = this.statementEdge;
     }
@@ -488,7 +488,7 @@ Blockly.blockRendering.RenderInfo.prototype.computeBounds_ = function() {
  * @private
  */
 Blockly.blockRendering.RenderInfo.prototype.alignRowElements_ = function() {
-  for (var i = 0, row; row = this.rows[i]; i++) {
+  for (var i = 0, row; (row = this.rows[i]); i++) {
     if (!row.hasInlineInput) {
       if (row.hasStatement) {
         var statementInput = row.getLastInput();
@@ -663,7 +663,7 @@ Blockly.blockRendering.RenderInfo.prototype.finalize_ = function() {
   // accesses and sets properties that already exist on the objects.
   var widestRowWithConnectedBlocks = 0;
   var yCursor = 0;
-  for (var i = 0, row; row = this.rows[i]; i++) {
+  for (var i = 0, row; (row = this.rows[i]); i++) {
     row.yPos = yCursor;
     row.xPos = this.startX;
     yCursor += row.height;
@@ -680,7 +680,7 @@ Blockly.blockRendering.RenderInfo.prototype.finalize_ = function() {
       yCursor += diff;
     }
     var xCursor = row.xPos;
-    for (var j = 0, elem; elem = row.elements[j]; j++) {
+    for (var j = 0, elem; (elem = row.elements[j]); j++) {
       elem.xPos = xCursor;
       elem.centerline = this.getElemCenterline_(row, elem);
       xCursor += elem.width;
diff --git a/core/renderers/measurables/rows.js b/core/renderers/measurables/rows.js
index c023226ed..5d432fbdd 100644
--- a/core/renderers/measurables/rows.js
+++ b/core/renderers/measurables/rows.js
@@ -170,8 +170,7 @@ Blockly.blockRendering.Row.prototype.measure = function() {
  * @package
  */
 Blockly.blockRendering.Row.prototype.getLastInput = function() {
-  for (var i = this.elements.length - 1; i >= 0; i--) {
-    var elem = this.elements[i];
+  for (var i = this.elements.length - 1, elem; (elem = this.elements[i]); i--) {
     if (elem.isSpacer()) {
       continue;
     }
@@ -191,7 +190,7 @@ Blockly.blockRendering.Row.prototype.getLastInput = function() {
  * @package
  */
 Blockly.blockRendering.Row.prototype.getFirstSpacer = function() {
-  for (var i = 0, elem; elem = this.elements[i]; i++) {
+  for (var i = 0, elem; (elem = this.elements[i]); i++) {
     if (elem.isSpacer) {
       return /** @type {Blockly.blockRendering.InRowSpacer} */ (elem);
     }
@@ -206,7 +205,7 @@ Blockly.blockRendering.Row.prototype.getFirstSpacer = function() {
  * @package
  */
 Blockly.blockRendering.Row.prototype.getLastSpacer = function() {
-  for (var i = this.elements.length - 1, elem; elem = this.elements[i]; i--) {
+  for (var i = this.elements.length - 1, elem; (elem = this.elements[i]); i--) {
     if (elem.isSpacer) {
       return /** @type {Blockly.blockRendering.InRowSpacer} */ (elem);
     }
@@ -303,8 +302,7 @@ Blockly.blockRendering.TopRow.prototype.populate = function(block) {
 Blockly.blockRendering.TopRow.prototype.measure = function() {
   this.width = this.minWidth;
   this.height = this.minHeight;
-  for (var e = 0; e < this.elements.length; e++) {
-    var elem = this.elements[e];
+  for (var e = 0, elem; (elem = this.elements[e]); e++) {
     this.width += elem.width;
     if (!(elem.isSpacer())) {
       if (elem.type == 'hat') {
@@ -403,8 +401,7 @@ Blockly.blockRendering.BottomRow.prototype.populate = function(block) {
 Blockly.blockRendering.BottomRow.prototype.measure = function() {
   this.width = this.minWidth;
   this.height = this.minHeight;
-  for (var e = 0; e < this.elements.length; e++) {
-    var elem = this.elements[e];
+  for (var e = 0, elem; (elem = this.elements[e]); e++) {
     this.width += elem.width;
     if (!(elem.isSpacer())) {
       if (elem.type == 'next connection') {
@@ -463,8 +460,7 @@ Blockly.blockRendering.InputRow.prototype.measure = function() {
   this.width = this.minWidth;
   this.height = this.minHeight;
   var connectedBlockWidths = 0;
-  for (var e = 0; e < this.elements.length; e++) {
-    var elem = this.elements[e];
+  for (var e = 0, elem; (elem = this.elements[e]); e++) {
     this.width += elem.width;
     if (elem.isInput) {
       if (elem.type == 'statement input') {