diff --git a/core/block_animations.ts b/core/block_animations.ts
index 5db01dd3b..68b8d7582 100644
--- a/core/block_animations.ts
+++ b/core/block_animations.ts
@@ -26,7 +26,7 @@ interface CloneRect {
 }
 
 /** PID of disconnect UI animation.  There can only be one at a time. */
-let disconnectPid: AnyDuringMigration = 0;
+let disconnectPid: ReturnType<typeof setTimeout>|null = null;
 
 /** SVG group of wobbling block.  There can only be one at a time. */
 let disconnectGroup: SVGElement|null = null;
@@ -199,7 +199,9 @@ function disconnectUiStep(group: SVGElement, magnitude: number, start: Date) {
  */
 export function disconnectUiStop() {
   if (disconnectGroup) {
-    clearTimeout(disconnectPid);
+    if (disconnectPid) {
+      clearTimeout(disconnectPid);
+    }
     disconnectGroup.setAttribute('transform', '');
     disconnectGroup = null;
   }
diff --git a/core/common.ts b/core/common.ts
index 342dc935d..18f255d3f 100644
--- a/core/common.ts
+++ b/core/common.ts
@@ -204,7 +204,7 @@ export const draggingConnections: Connection[] = [];
  * @alias Blockly.common.getBlockTypeCounts
  */
 export function getBlockTypeCounts(
-    block: Block, opt_stripFollowing?: boolean): AnyDuringMigration {
+    block: Block, opt_stripFollowing?: boolean): {[key: string]: number} {
   const typeCountsMap = Object.create(null);
   const descendants = block.getDescendants(true);
   if (opt_stripFollowing) {
diff --git a/core/dropdowndiv.ts b/core/dropdowndiv.ts
index 6158b73ca..6bc2a9106 100644
--- a/core/dropdowndiv.ts
+++ b/core/dropdowndiv.ts
@@ -52,7 +52,7 @@ export const ANIMATION_TIME = 0.25;
  * Timer for animation out, to be cleared if we need to immediately hide
  * without disrupting new shows.
  */
-let animateOutTimer: AnyDuringMigration = null;
+let animateOutTimer: ReturnType<typeof setTimeout>|null = null;
 
 /** Callback for when the drop-down is hidden. */
 let onHide: Function|null = null;
diff --git a/core/extensions.ts b/core/extensions.ts
index ae9e3cc39..99ffa809a 100644
--- a/core/extensions.ts
+++ b/core/extensions.ts
@@ -352,7 +352,7 @@ function mutatorPropertiesMatch(
  * @throws Error Will throw if no global document can be found (e.g., Node.js).
  * @internal
  */
-export function runAfterPageLoad(fn: () => AnyDuringMigration) {
+export function runAfterPageLoad(fn: () => void) {
   if (typeof document !== 'object') {
     throw Error('runAfterPageLoad() requires browser document.');
   }
diff --git a/core/flyout_base.ts b/core/flyout_base.ts
index c315d9a71..223d930da 100644
--- a/core/flyout_base.ts
+++ b/core/flyout_base.ts
@@ -158,7 +158,7 @@ export abstract class Flyout extends DeleteArea implements IFlyout {
   /**
    * List of event listeners.
    */
-  private listeners_: AnyDuringMigration[][] = [];
+  private listeners_: browserEvents.Data[] = [];
 
   /**
    * List of blocks that should always be disabled.
diff --git a/core/flyout_metrics_manager.ts b/core/flyout_metrics_manager.ts
index c52a008f6..38dd32daa 100644
--- a/core/flyout_metrics_manager.ts
+++ b/core/flyout_metrics_manager.ts
@@ -73,8 +73,7 @@ export class FlyoutMetricsManager extends MetricsManager {
       opt_getWorkspaceCoordinates?: boolean, opt_viewMetrics?: ContainerRegion,
       opt_contentMetrics?: ContainerRegion) {
     // AnyDuringMigration because:  Expected 1 arguments, but got 0.
-    const contentMetrics =
-        opt_contentMetrics || (this.getContentMetrics as AnyDuringMigration)();
+    const contentMetrics = opt_contentMetrics || this.getContentMetrics();
     const margin = this.flyout_.MARGIN * this.workspace_.scale;
     const scale = opt_getWorkspaceCoordinates ? this.workspace_.scale : 1;
 
diff --git a/core/generator.ts b/core/generator.ts
index 53c5ca74d..62d884daf 100644
--- a/core/generator.ts
+++ b/core/generator.ts
@@ -27,7 +27,7 @@ import type {Workspace} from './workspace.js';
  * @alias Blockly.Generator
  */
 export class Generator {
-  name_: AnyDuringMigration;
+  name_: string;
 
   /**
    * This is used as a placeholder in functions defined using
@@ -36,7 +36,7 @@ export class Generator {
    * not confuse the regular expression parser.
    */
   protected FUNCTION_NAME_PLACEHOLDER_ = '{leCUI8hutHZI4480Dc}';
-  FUNCTION_NAME_PLACEHOLDER_REGEXP_: AnyDuringMigration;
+  FUNCTION_NAME_PLACEHOLDER_REGEXP_: RegExp;
 
   /**
    * Arbitrary code to inject into locations that risk causing infinite loops.
@@ -86,13 +86,13 @@ export class Generator {
   protected RESERVED_WORDS_ = '';
 
   /** A dictionary of definitions to be printed before the code. */
-  protected definitions_?: AnyDuringMigration = undefined;
+  protected definitions_: {[key: string]: string} = Object.create(null);
 
   /**
    * A dictionary mapping desired function names in definitions_ to actual
    * function names (to avoid collisions with user functions).
    */
-  protected functionNames_?: AnyDuringMigration = undefined;
+  protected functionNames_: {[key: string]: string} = Object.create(null);
 
   /** A database of variable and procedure names. */
   protected nameDB_?: Names = undefined;
@@ -118,7 +118,7 @@ export class Generator {
           'No workspace specified in workspaceToCode call.  Guessing.');
       workspace = common.getMainWorkspace();
     }
-    let code = [];
+    const code = [];
     this.init(workspace);
     const blocks = workspace.getTopBlocks(true);
     for (let i = 0, block; block = blocks[i]; i++) {
@@ -132,9 +132,7 @@ export class Generator {
         if (block.outputConnection) {
           // This block is a naked value.  Ask the language's code generator if
           // it wants to append a semicolon, or something.
-          // AnyDuringMigration because:  Argument of type 'string | any[]' is
-          // not assignable to parameter of type 'string'.
-          line = this.scrubNakedValue(line as AnyDuringMigration);
+          line = this.scrubNakedValue(line);
           if (this.STATEMENT_PREFIX && !block.suppressPrefixSuffix) {
             line = this.injectId(this.STATEMENT_PREFIX, block) + line;
           }
@@ -145,21 +143,14 @@ export class Generator {
         code.push(line);
       }
     }
-    // AnyDuringMigration because:  Type 'string' is not assignable to type
-    // 'any[]'.
     // Blank line between each section.
-    code = code.join('\n') as AnyDuringMigration;
-    // AnyDuringMigration because:  Argument of type 'any[]' is not assignable
-    // to parameter of type 'string'. AnyDuringMigration because:  Type 'string'
-    // is not assignable to type 'any[]'.
-    code = this.finish(code as AnyDuringMigration) as AnyDuringMigration;
+    let codeString = code.join('\n');
+    codeString = this.finish(codeString);
     // Final scrubbing of whitespace.
-    // AnyDuringMigration because:  Property 'replace' does not exist on type
-    // 'any[]'.
-    code = (code as AnyDuringMigration).replace(/^\s+\n/, '');
-    code = code.replace(/\n\s+$/, '\n');
-    code = code.replace(/[ \t]+\n/g, '\n');
-    return code;
+    codeString = codeString.replace(/^\s+\n/, '');
+    codeString = codeString.replace(/\n\s+$/, '\n');
+    codeString = codeString.replace(/[ \t]+\n/g, '\n');
+    return codeString;
   }
 
   // The following are some helpful functions which can be used by multiple
@@ -211,7 +202,7 @@ export class Generator {
    * operator order value.  Returns '' if block is null.
    */
   blockToCode(block: Block|null, opt_thisOnly?: boolean): string
-      |AnyDuringMigration[] {
+      |[string, number] {
     if (this.isInitialized === false) {
       console.warn(
           'Generator init was not called before blockToCode was called.');
@@ -228,7 +219,7 @@ export class Generator {
       return opt_thisOnly ? '' : this.blockToCode(block.getChildren(false)[0]);
     }
 
-    const func = (this as AnyDuringMigration)[block.type];
+    const func = (this as any)[block.type];
     if (typeof func !== 'function') {
       throw Error(
           'Language "' + this.name_ + '" does not know how to generate ' +
@@ -503,8 +494,8 @@ export class Generator {
   finish(code: string): string {
     // Optionally override
     // Clean up temporary data.
-    delete this.definitions_;
-    delete this.functionNames_;
+    this.definitions_ = Object.create(null);
+    this.functionNames_ = Object.create(null);
     return code;
   }
 
@@ -531,8 +522,6 @@ Object.defineProperties(Generator.prototype, {
    * @deprecated 'variableDB_' was renamed to 'nameDB_' (May 2021).
    * @suppress {checkTypes}
    */
-  // AnyDuringMigration because:  Type 'Names | undefined' is not assignable to
-  // type 'PropertyDescriptor'.
   variableDB_: ({
     /** @returns Name database. */
     get(this: Generator): Names |
diff --git a/core/keyboard_nav/basic_cursor.ts b/core/keyboard_nav/basic_cursor.ts
index 434784587..648158fc6 100644
--- a/core/keyboard_nav/basic_cursor.ts
+++ b/core/keyboard_nav/basic_cursor.ts
@@ -120,9 +120,7 @@ export class BasicCursor extends Cursor {
       return this.getNextNode_(newNode, isValid);
     }
     const siblingOrParent = this.findSiblingOrParent_(node.out());
-    // AnyDuringMigration because:  Argument of type 'ASTNode | null' is not
-    // assignable to parameter of type 'ASTNode'.
-    if (isValid(siblingOrParent as AnyDuringMigration)) {
+    if (isValid(siblingOrParent)) {
       return siblingOrParent;
     } else if (siblingOrParent) {
       return this.getNextNode_(siblingOrParent, isValid);
diff --git a/core/menu.ts b/core/menu.ts
index 1dc5d7dea..f5c46e076 100644
--- a/core/menu.ts
+++ b/core/menu.ts
@@ -123,7 +123,7 @@ export class Menu {
    * @returns The DOM element.
    * @internal
    */
-  getElement(): Element|null {
+  getElement(): HTMLDivElement|null {
     return this.element_;
   }
 
@@ -135,9 +135,7 @@ export class Menu {
   focus() {
     const el = this.getElement();
     if (el) {
-      // AnyDuringMigration because:  Property 'focus' does not exist on type
-      // 'Element'.
-      (el as AnyDuringMigration).focus({preventScroll: true});
+      el.focus({preventScroll: true});
       dom.addClass(el, 'blocklyFocused');
     }
   }
@@ -146,9 +144,7 @@ export class Menu {
   private blur_() {
     const el = this.getElement();
     if (el) {
-      // AnyDuringMigration because:  Property 'blur' does not exist on type
-      // 'Element'.
-      (el as AnyDuringMigration).blur();
+      el.blur();
       dom.removeClass(el, 'blocklyFocused');
     }
   }
@@ -209,8 +205,9 @@ export class Menu {
     // a menu item's div, or some element within the menu item.
     // Walk up parents until one meets either the menu's root element, or
     // a menu item's div.
-    while (elem && elem !== menuElem) {
-      if (dom.hasClass(elem, 'blocklyMenuItem')) {
+    let currentElement: Element|null = elem;
+    while (currentElement && currentElement !== menuElem) {
+      if (dom.hasClass(currentElement, 'blocklyMenuItem')) {
         // Having found a menu item's div, locate that menu item in this menu.
         for (let i = 0, menuItem; menuItem = this.menuItems_[i]; i++) {
           if (menuItem.getElement() === elem) {
@@ -218,9 +215,7 @@ export class Menu {
           }
         }
       }
-      // AnyDuringMigration because:  Type 'HTMLElement | null' is not
-      // assignable to type 'Element'.
-      elem = elem.parentElement as AnyDuringMigration;
+      currentElement = currentElement.parentElement;
     }
     return null;
   }
@@ -258,10 +253,9 @@ export class Menu {
    * @internal
    */
   highlightNext() {
-    // AnyDuringMigration because:  Argument of type 'MenuItem | null' is not
-    // assignable to parameter of type 'MenuItem'.
-    const index =
-        this.menuItems_.indexOf(this.highlightedItem_ as AnyDuringMigration);
+    const index = this.highlightedItem_ ?
+        this.menuItems_.indexOf(this.highlightedItem_) :
+        -1;
     this.highlightHelper_(index, 1);
   }
 
@@ -272,10 +266,9 @@ export class Menu {
    * @internal
    */
   highlightPrevious() {
-    // AnyDuringMigration because:  Argument of type 'MenuItem | null' is not
-    // assignable to parameter of type 'MenuItem'.
-    const index =
-        this.menuItems_.indexOf(this.highlightedItem_ as AnyDuringMigration);
+    const index = this.highlightedItem_ ?
+        this.menuItems_.indexOf(this.highlightedItem_) :
+        -1;
     this.highlightHelper_(index < 0 ? this.menuItems_.length : index, -1);
   }
 
diff --git a/core/menuitem.ts b/core/menuitem.ts
index 6af0ff84e..3eec5ac69 100644
--- a/core/menuitem.ts
+++ b/core/menuitem.ts
@@ -135,8 +135,8 @@ export class MenuItem {
    * @returns value Value associated with the menu item.
    * @internal
    */
-  getValue(): AnyDuringMigration {
-    return this.opt_value;
+  getValue(): string|null {
+    return this.opt_value ?? null;
   }
 
   /**
@@ -245,7 +245,7 @@ export class MenuItem {
    * @param obj Used as the 'this' object in fn when called.
    * @internal
    */
-  onAction(fn: (p1: MenuItem) => AnyDuringMigration, obj: AnyDuringMigration) {
+  onAction(fn: (p1: MenuItem) => void, obj: object) {
     this.actionHandler_ = fn.bind(obj);
   }
 }
diff --git a/core/mutator.ts b/core/mutator.ts
index 11843577f..a29520b92 100644
--- a/core/mutator.ts
+++ b/core/mutator.ts
@@ -71,10 +71,10 @@ export class Mutator extends Icon {
   private sourceListener_: Function|null = null;
 
   /**
-   * The PID associated with the updateWorkpace_ timeout, or 0 if no timeout
+   * The PID associated with the updateWorkpace_ timeout, or null if no timeout
    * is currently running.
    */
-  private updateWorkspacePid_: AnyDuringMigration = 0;
+  private updateWorkspacePid_: ReturnType<typeof setTimeout>|null = null;
 
   /** @param quarkNames List of names of sub-blocks for flyout. */
   constructor(block: BlockSvg, quarkNames: string[]) {
@@ -382,7 +382,7 @@ export class Mutator extends Icon {
   private workspaceChanged_(e: Abstract) {
     if (!this.shouldIgnoreMutatorEvent_(e) && !this.updateWorkspacePid_) {
       this.updateWorkspacePid_ = setTimeout(() => {
-        this.updateWorkspacePid_ = 0;
+        this.updateWorkspacePid_ = null;
         this.updateWorkspace_();
       }, 0);
     }
diff --git a/core/procedures.ts b/core/procedures.ts
index fe3cc4016..608ab24bf 100644
--- a/core/procedures.ts
+++ b/core/procedures.ts
@@ -50,6 +50,8 @@ export const CATEGORY_NAME = 'PROCEDURE';
  */
 export const DEFAULT_ARG = 'x';
 
+export type ProcedureTuple = [string, string[], boolean];
+
 /**
  * Procedure block type.
  *
@@ -57,8 +59,8 @@ export const DEFAULT_ARG = 'x';
  */
 export interface ProcedureBlock {
   getProcedureCall: () => string;
-  renameProcedure: (p1: string, p2: string) => AnyDuringMigration;
-  getProcedureDef: () => AnyDuringMigration[];
+  renameProcedure: (p1: string, p2: string) => void;
+  getProcedureDef: () => ProcedureTuple;
 }
 
 /**
@@ -70,7 +72,8 @@ export interface ProcedureBlock {
  *     list of name, parameter list, and return value boolean.
  * @alias Blockly.Procedures.allProcedures
  */
-export function allProcedures(root: Workspace): AnyDuringMigration[][][] {
+export function allProcedures(root: Workspace):
+    [ProcedureTuple[], ProcedureTuple[]] {
   const proceduresNoReturn =
       root.getBlocksByType('procedures_defnoreturn', false)
           .map(function(block) {
@@ -93,8 +96,7 @@ export function allProcedures(root: Workspace): AnyDuringMigration[][][] {
  * @param tb Second tuple.
  * @returns -1, 0, or 1 to signify greater than, equality, or less than.
  */
-function procTupleComparator(
-    ta: AnyDuringMigration[], tb: AnyDuringMigration[]): number {
+function procTupleComparator(ta: ProcedureTuple, tb: ProcedureTuple): number {
   return ta[0].localeCompare(tb[0], undefined, {sensitivity: 'base'});
 }
 
@@ -212,9 +214,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
     // </block>
     const block = utilsXml.createElement('block');
     block.setAttribute('type', 'procedures_defnoreturn');
-    // AnyDuringMigration because:  Argument of type 'number' is not assignable
-    // to parameter of type 'string'.
-    block.setAttribute('gap', 16 as AnyDuringMigration);
+    block.setAttribute('gap', '16');
     const nameField = utilsXml.createElement('field');
     nameField.setAttribute('name', 'NAME');
     nameField.appendChild(
@@ -228,9 +228,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
     // </block>
     const block = utilsXml.createElement('block');
     block.setAttribute('type', 'procedures_defreturn');
-    // AnyDuringMigration because:  Argument of type 'number' is not assignable
-    // to parameter of type 'string'.
-    block.setAttribute('gap', 16 as AnyDuringMigration);
+    block.setAttribute('gap', '16');
     const nameField = utilsXml.createElement('field');
     nameField.setAttribute('name', 'NAME');
     nameField.appendChild(
@@ -242,16 +240,12 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
     // <block type="procedures_ifreturn" gap="16"></block>
     const block = utilsXml.createElement('block');
     block.setAttribute('type', 'procedures_ifreturn');
-    // AnyDuringMigration because:  Argument of type 'number' is not assignable
-    // to parameter of type 'string'.
-    block.setAttribute('gap', 16 as AnyDuringMigration);
+    block.setAttribute('gap', '16');
     xmlList.push(block);
   }
   if (xmlList.length) {
     // Add slightly larger gap between system blocks and user calls.
-    // AnyDuringMigration because:  Argument of type 'number' is not assignable
-    // to parameter of type 'string'.
-    xmlList[xmlList.length - 1].setAttribute('gap', 24 as AnyDuringMigration);
+    xmlList[xmlList.length - 1].setAttribute('gap', '24');
   }
 
   /**
@@ -262,7 +256,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
    * @param templateName The type of the block to generate.
    */
   function populateProcedures(
-      procedureList: AnyDuringMigration[][], templateName: string) {
+      procedureList: ProcedureTuple[], templateName: string) {
     for (let i = 0; i < procedureList.length; i++) {
       const name = procedureList[i][0];
       const args = procedureList[i][1];
@@ -273,9 +267,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
       // </block>
       const block = utilsXml.createElement('block');
       block.setAttribute('type', templateName);
-      // AnyDuringMigration because:  Argument of type 'number' is not
-      // assignable to parameter of type 'string'.
-      block.setAttribute('gap', 16 as AnyDuringMigration);
+      block.setAttribute('gap', '16');
       const mutation = utilsXml.createElement('mutation');
       mutation.setAttribute('name', name);
       block.appendChild(mutation);
@@ -288,9 +280,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
     }
   }
 
-  // AnyDuringMigration because:  Argument of type 'WorkspaceSvg' is not
-  // assignable to parameter of type 'Workspace'.
-  const tuple = allProcedures(workspace as AnyDuringMigration);
+  const tuple = allProcedures(workspace);
   populateProcedures(tuple[0], 'procedures_callnoreturn');
   populateProcedures(tuple[1], 'procedures_callreturn');
   return xmlList;
diff --git a/core/utils.ts b/core/utils.ts
index 25558d400..8a0fd767a 100644
--- a/core/utils.ts
+++ b/core/utils.ts
@@ -76,9 +76,7 @@ export {
  * @alias Blockly.utils.noEvent
  */
 export function noEvent(e: Event) {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn('Blockly.utils.noEvent', 'September 2021', 'September 2022');
+  deprecation.warn('Blockly.utils.noEvent', 'September 2021', 'September 2022');
   // This event has been handled.  No need to bubble up to the document.
   e.preventDefault();
   e.stopPropagation();
@@ -93,11 +91,9 @@ export function noEvent(e: Event) {
  * @alias Blockly.utils.isTargetInput
  */
 export function isTargetInput(e: Event): boolean {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.isTargetInput', 'September 2021', 'September 2022',
-          'Blockly.browserEvents.isTargetInput');
+  deprecation.warn(
+      'Blockly.utils.isTargetInput', 'September 2021', 'September 2022',
+      'Blockly.browserEvents.isTargetInput');
   return browserEvents.isTargetInput(e);
 }
 
@@ -111,14 +107,10 @@ export function isTargetInput(e: Event): boolean {
  * @alias Blockly.utils.getRelativeXY
  */
 export function getRelativeXY(element: Element): Coordinate {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getRelativeXY', 'December 2021', 'December 2022',
-          'Blockly.utils.svgMath.getRelativeXY');
-  // AnyDuringMigration because:  Property 'getRelativeXY' does not exist on
-  // type 'void'.
-  return (svgMath as AnyDuringMigration).getRelativeXY(element);
+  deprecation.warn(
+      'Blockly.utils.getRelativeXY', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.getRelativeXY');
+  return svgMath.getRelativeXY(element);
 }
 
 /**
@@ -132,14 +124,10 @@ export function getRelativeXY(element: Element): Coordinate {
  * @alias Blockly.utils.getInjectionDivXY_
  */
 function getInjectionDivXY(element: Element): Coordinate {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getInjectionDivXY_', 'December 2021', 'December 2022',
-          'Blockly.utils.svgMath.getInjectionDivXY');
-  // AnyDuringMigration because:  Property 'getInjectionDivXY' does not exist on
-  // type 'void'.
-  return (svgMath as AnyDuringMigration).getInjectionDivXY(element);
+  deprecation.warn(
+      'Blockly.utils.getInjectionDivXY_', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.getInjectionDivXY');
+  return svgMath.getInjectionDivXY(element);
 }
 export const getInjectionDivXY_ = getInjectionDivXY;
 
@@ -152,11 +140,9 @@ export const getInjectionDivXY_ = getInjectionDivXY;
  * @alias Blockly.utils.isRightButton
  */
 export function isRightButton(e: Event): boolean {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.isRightButton', 'September 2021', 'September 2022',
-          'Blockly.browserEvents.isRightButton');
+  deprecation.warn(
+      'Blockly.utils.isRightButton', 'September 2021', 'September 2022',
+      'Blockly.browserEvents.isRightButton');
   return browserEvents.isRightButton(e as MouseEvent);
 }
 
@@ -173,11 +159,9 @@ export function isRightButton(e: Event): boolean {
  */
 export function mouseToSvg(
     e: Event, svg: SVGSVGElement, matrix: SVGMatrix|null): SVGPoint {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.mouseToSvg', 'September 2021', 'September 2022',
-          'Blockly.browserEvents.mouseToSvg');
+  deprecation.warn(
+      'Blockly.utils.mouseToSvg', 'September 2021', 'September 2022',
+      'Blockly.browserEvents.mouseToSvg');
   return browserEvents.mouseToSvg(e as MouseEvent, svg, matrix);
 }
 
@@ -190,11 +174,9 @@ export function mouseToSvg(
  * @alias Blockly.utils.getScrollDeltaPixels
  */
 export function getScrollDeltaPixels(e: WheelEvent): {x: number, y: number} {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getScrollDeltaPixels', 'September 2021',
-          'September 2022', 'Blockly.browserEvents.getScrollDeltaPixels');
+  deprecation.warn(
+      'Blockly.utils.getScrollDeltaPixels', 'September 2021', 'September 2022',
+      'Blockly.browserEvents.getScrollDeltaPixels');
   return browserEvents.getScrollDeltaPixels(e);
 }
 
@@ -212,14 +194,10 @@ export function getScrollDeltaPixels(e: WheelEvent): {x: number, y: number} {
  * @alias Blockly.utils.tokenizeInterpolation
  */
 export function tokenizeInterpolation(message: string): Array<string|number> {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.tokenizeInterpolation', 'December 2021',
-          'December 2022', 'Blockly.utils.parsing.tokenizeInterpolation');
-  // AnyDuringMigration because:  Property 'tokenizeInterpolation' does not
-  // exist on type 'void'.
-  return (parsing as AnyDuringMigration).tokenizeInterpolation(message);
+  deprecation.warn(
+      'Blockly.utils.tokenizeInterpolation', 'December 2021', 'December 2022',
+      'Blockly.utils.parsing.tokenizeInterpolation');
+  return parsing.tokenizeInterpolation(message);
 }
 
 /**
@@ -233,16 +211,11 @@ export function tokenizeInterpolation(message: string): Array<string|number> {
  * @deprecated
  * @alias Blockly.utils.replaceMessageReferences
  */
-export function replaceMessageReferences(message: string|
-                                         AnyDuringMigration): string {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.replaceMessageReferences', 'December 2021',
-          'December 2022', 'Blockly.utils.parsing.replaceMessageReferences');
-  // AnyDuringMigration because:  Property 'replaceMessageReferences' does not
-  // exist on type 'void'.
-  return (parsing as AnyDuringMigration).replaceMessageReferences(message);
+export function replaceMessageReferences(message: string|any): string {
+  deprecation.warn(
+      'Blockly.utils.replaceMessageReferences', 'December 2021',
+      'December 2022', 'Blockly.utils.parsing.replaceMessageReferences');
+  return parsing.replaceMessageReferences(message);
 }
 
 /**
@@ -256,14 +229,10 @@ export function replaceMessageReferences(message: string|
  * @alias Blockly.utils.checkMessageReferences
  */
 export function checkMessageReferences(message: string): boolean {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.checkMessageReferences', 'December 2021',
-          'December 2022', 'Blockly.utils.parsing.checkMessageReferences');
-  // AnyDuringMigration because:  Property 'checkMessageReferences' does not
-  // exist on type 'void'.
-  return (parsing as AnyDuringMigration).checkMessageReferences(message);
+  deprecation.warn(
+      'Blockly.utils.checkMessageReferences', 'December 2021', 'December 2022',
+      'Blockly.utils.parsing.checkMessageReferences');
+  return parsing.checkMessageReferences(message);
 }
 
 /**
@@ -274,14 +243,10 @@ export function checkMessageReferences(message: string): boolean {
  * @alias Blockly.utils.genUid
  */
 export function genUid(): string {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.genUid', 'September 2021', 'September 2022',
-          'Blockly.utils.idGenerator.genUid');
-  // AnyDuringMigration because:  Property 'genUid' does not exist on type
-  // 'void'.
-  return (idGenerator as AnyDuringMigration).genUid();
+  deprecation.warn(
+      'Blockly.utils.genUid', 'September 2021', 'September 2022',
+      'Blockly.utils.idGenerator.genUid');
+  return idGenerator.genUid();
 }
 
 /**
@@ -293,14 +258,10 @@ export function genUid(): string {
  * @alias Blockly.utils.is3dSupported
  */
 export function is3dSupported(): boolean {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.is3dSupported', 'December 2021', 'December 2022',
-          'Blockly.utils.svgMath.is3dSupported');
-  // AnyDuringMigration because:  Property 'is3dSupported' does not exist on
-  // type 'void'.
-  return (svgMath as AnyDuringMigration).is3dSupported();
+  deprecation.warn(
+      'Blockly.utils.is3dSupported', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.is3dSupported');
+  return svgMath.is3dSupported();
 }
 
 /**
@@ -314,14 +275,10 @@ export function is3dSupported(): boolean {
  * @internal
  */
 export function getViewportBBox(): Rect {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getViewportBBox', 'December 2021', 'December 2022',
-          'Blockly.utils.svgMath.getViewportBBox');
-  // AnyDuringMigration because:  Property 'getViewportBBox' does not exist on
-  // type 'void'.
-  return (svgMath as AnyDuringMigration).getViewportBBox();
+  deprecation.warn(
+      'Blockly.utils.getViewportBBox', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.getViewportBBox');
+  return svgMath.getViewportBBox();
 }
 
 /**
@@ -334,11 +291,9 @@ export function getViewportBBox(): Rect {
  * @deprecated
  * @internal
  */
-export function arrayRemove(
-    arr: AnyDuringMigration[], value: AnyDuringMigration): boolean {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn('Blockly.utils.arrayRemove', 'December 2021', 'December 2022');
+export function arrayRemove<T>(arr: Array<T>, value: T): boolean {
+  deprecation.warn(
+      'Blockly.utils.arrayRemove', 'December 2021', 'December 2022');
   return arrayUtils.removeElem(arr, value);
 }
 
@@ -351,14 +306,10 @@ export function arrayRemove(
  * @alias Blockly.utils.getDocumentScroll
  */
 export function getDocumentScroll(): Coordinate {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getDocumentScroll', 'December 2021', 'December 2022',
-          'Blockly.utils.svgMath.getDocumentScroll');
-  // AnyDuringMigration because:  Property 'getDocumentScroll' does not exist on
-  // type 'void'.
-  return (svgMath as AnyDuringMigration).getDocumentScroll();
+  deprecation.warn(
+      'Blockly.utils.getDocumentScroll', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.getDocumentScroll');
+  return svgMath.getDocumentScroll();
 }
 
 /**
@@ -373,12 +324,10 @@ export function getDocumentScroll(): Coordinate {
  * @alias Blockly.utils.getBlockTypeCounts
  */
 export function getBlockTypeCounts(
-    block: Block, opt_stripFollowing?: boolean): AnyDuringMigration {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.getBlockTypeCounts', 'December 2021', 'December 2022',
-          'Blockly.common.getBlockTypeCounts');
+    block: Block, opt_stripFollowing?: boolean): {[key: string]: number} {
+  deprecation.warn(
+      'Blockly.utils.getBlockTypeCounts', 'December 2021', 'December 2022',
+      'Blockly.common.getBlockTypeCounts');
   return common.getBlockTypeCounts(block, opt_stripFollowing);
 }
 
@@ -393,15 +342,10 @@ export function getBlockTypeCounts(
  */
 export function screenToWsCoordinates(
     ws: WorkspaceSvg, screenCoordinates: Coordinate): Coordinate {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.screenToWsCoordinates', 'December 2021',
-          'December 2022', 'Blockly.utils.svgMath.screenToWsCoordinates');
-  // AnyDuringMigration because:  Property 'screenToWsCoordinates' does not
-  // exist on type 'void'.
-  return (svgMath as AnyDuringMigration)
-      .screenToWsCoordinates(ws, screenCoordinates);
+  deprecation.warn(
+      'Blockly.utils.screenToWsCoordinates', 'December 2021', 'December 2022',
+      'Blockly.utils.svgMath.screenToWsCoordinates');
+  return svgMath.screenToWsCoordinates(ws, screenCoordinates);
 }
 
 /**
@@ -418,14 +362,10 @@ export function screenToWsCoordinates(
  */
 export function parseBlockColour(colour: number|
                                  string): {hue: number|null, hex: string} {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn(
-          'Blockly.utils.parseBlockColour', 'December 2021', 'December 2022',
-          'Blockly.utils.parsing.parseBlockColour');
-  // AnyDuringMigration because:  Property 'parseBlockColour' does not exist on
-  // type 'void'.
-  return (parsing as AnyDuringMigration).parseBlockColour(colour);
+  deprecation.warn(
+      'Blockly.utils.parseBlockColour', 'December 2021', 'December 2022',
+      'Blockly.utils.parsing.parseBlockColour');
+  return parsing.parseBlockColour(colour);
 }
 
 /**
@@ -436,9 +376,8 @@ export function parseBlockColour(colour: number|
  * @deprecated
  * @alias Blockly.utils.runAfterPageLoad
  */
-export function runAfterPageLoad(fn: () => AnyDuringMigration) {
-  // AnyDuringMigration because:  Property 'warn' does not exist on type 'void'.
-  (deprecation as AnyDuringMigration)
-      .warn('Blockly.utils.runAfterPageLoad', 'December 2021', 'December 2022');
+export function runAfterPageLoad(fn: () => void) {
+  deprecation.warn(
+      'Blockly.utils.runAfterPageLoad', 'December 2021', 'December 2022');
   extensions.runAfterPageLoad(fn);
 }
diff --git a/core/utils/aria.ts b/core/utils/aria.ts
index b0bed04a5..fcacf4da7 100644
--- a/core/utils/aria.ts
+++ b/core/utils/aria.ts
@@ -152,7 +152,5 @@ export function setState(
     value = value.join(' ');
   }
   const attrStateName = ARIA_PREFIX + stateName;
-  // AnyDuringMigration because:  Argument of type 'string | number | boolean'
-  // is not assignable to parameter of type 'string'.
-  element.setAttribute(attrStateName, value as AnyDuringMigration);
+  element.setAttribute(attrStateName, `${value}`);
 }
diff --git a/core/utils/array.ts b/core/utils/array.ts
index 59002188c..26cda7961 100644
--- a/core/utils/array.ts
+++ b/core/utils/array.ts
@@ -18,8 +18,7 @@ goog.declareModuleId('Blockly.utils.array');
  * @alias Blockly.array.removeElem
  * @internal
  */
-export function removeElem(
-    arr: AnyDuringMigration[], value: AnyDuringMigration): boolean {
+export function removeElem<T>(arr: Array<T>, value: T): boolean {
   const i = arr.indexOf(value);
   if (i === -1) {
     return false;
diff --git a/core/utils/idgenerator.ts b/core/utils/idgenerator.ts
index 92b580fc9..4fe0aa67c 100644
--- a/core/utils/idgenerator.ts
+++ b/core/utils/idgenerator.ts
@@ -12,6 +12,15 @@
 import * as goog from '../../closure/goog/goog.js';
 goog.declareModuleId('Blockly.utils.idGenerator');
 
+/**
+ * Legal characters for the universally unique IDs.  Should be all on
+ * a US keyboard.  No characters that conflict with XML or JSON.
+ * Requests to remove additional 'problematic' characters from this
+ * soup will be denied.  That's your failure to properly escape in
+ * your own environment.  Issues #251, #625, #682, #1304.
+ */
+const soup = '!#$%()*+,-./:;=?@[]^_`{|}~' +
+    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
 
 /**
  * Namespace object for internal implementations we want to be able to
@@ -19,7 +28,23 @@ goog.declareModuleId('Blockly.utils.idGenerator');
  *
  * @ignore
  */
-const internal = {};
+const internal = {
+  /**
+   * Generate a random unique ID.  This should be globally unique.
+   * 87 characters ^ 20 length > 128 bits (better than a UUID).
+   *
+   * @returns A globally unique ID string.
+   */
+  genUid: () => {
+    const length = 20;
+    const soupLength = soup.length;
+    const id = [];
+    for (let i = 0; i < length; i++) {
+      id[i] = soup.charAt(Math.random() * soupLength);
+    }
+    return id.join('');
+  },
+};
 export const TEST_ONLY = internal;
 
 /** Next unique ID to use. */
@@ -40,33 +65,6 @@ export function getNextUniqueId(): string {
   return 'blockly-' + (nextId++).toString(36);
 }
 
-/**
- * Legal characters for the universally unique IDs.  Should be all on
- * a US keyboard.  No characters that conflict with XML or JSON.
- * Requests to remove additional 'problematic' characters from this
- * soup will be denied.  That's your failure to properly escape in
- * your own environment.  Issues #251, #625, #682, #1304.
- */
-const soup = '!#$%()*+,-./:;=?@[]^_`{|}~' +
-    'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
-
-/**
- * Generate a random unique ID.  This should be globally unique.
- * 87 characters ^ 20 length > 128 bits (better than a UUID).
- *
- * @returns A globally unique ID string.
- */
-// AnyDuringMigration because:  Property 'genUid' does not exist on type '{}'.
-(internal as AnyDuringMigration).genUid = function(): string {
-  const length = 20;
-  const soupLength = soup.length;
-  const id = [];
-  for (let i = 0; i < length; i++) {
-    id[i] = soup.charAt(Math.random() * soupLength);
-  }
-  return id.join('');
-};
-
 /**
  * Generate a random unique ID.
  *
@@ -75,6 +73,5 @@ const soup = '!#$%()*+,-./:;=?@[]^_`{|}~' +
  * @alias Blockly.utils.idGenerator.genUid
  */
 export function genUid(): string {
-  // AnyDuringMigration because:  Property 'genUid' does not exist on type '{}'.
-  return (internal as AnyDuringMigration).genUid();
+  return internal.genUid();
 }
diff --git a/core/utils/parsing.ts b/core/utils/parsing.ts
index 1034bfa45..36452f0d7 100644
--- a/core/utils/parsing.ts
+++ b/core/utils/parsing.ts
@@ -183,8 +183,7 @@ export function tokenizeInterpolation(message: string): (string|number)[] {
  * @returns String with message references replaced.
  * @alias Blockly.utils.parsing.replaceMessageReferences
  */
-export function replaceMessageReferences(message: string|
-                                         AnyDuringMigration): string {
+export function replaceMessageReferences(message: string|any): string {
   if (typeof message !== 'string') {
     return message;
   }
diff --git a/core/variables.ts b/core/variables.ts
index 166f46d17..16f762b1a 100644
--- a/core/variables.ts
+++ b/core/variables.ts
@@ -82,11 +82,10 @@ export function allDeveloperVariables(workspace: Workspace): string[] {
   const variables = new Set<string>();
   for (let i = 0, block; block = blocks[i]; i++) {
     let getDeveloperVariables = block.getDeveloperVariables;
-    if (!getDeveloperVariables &&
-        (block as AnyDuringMigration).getDeveloperVars) {
+    if (!getDeveloperVariables && (block as any).getDeveloperVars) {
       // August 2018: getDeveloperVars() was deprecated and renamed
       // getDeveloperVariables().
-      getDeveloperVariables = (block as AnyDuringMigration).getDeveloperVars;
+      getDeveloperVariables = (block as any).getDeveloperVars;
       if (!ALL_DEVELOPER_VARS_WARNINGS_BY_BLOCK_TYPE[block.type]) {
         console.warn(
             'Function getDeveloperVars() deprecated. Use ' +
@@ -120,17 +119,12 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
   button.setAttribute('callbackKey', 'CREATE_VARIABLE');
 
   workspace.registerButtonCallback('CREATE_VARIABLE', function(button) {
-    // AnyDuringMigration because:  Argument of type 'WorkspaceSvg' is not
-    // assignable to parameter of type 'Workspace'.
-    createVariableButtonHandler(
-        button.getTargetWorkspace() as AnyDuringMigration);
+    createVariableButtonHandler(button.getTargetWorkspace());
   });
 
   xmlList.push(button);
 
-  // AnyDuringMigration because:  Argument of type 'WorkspaceSvg' is not
-  // assignable to parameter of type 'Workspace'.
-  const blockList = flyoutCategoryBlocks(workspace as AnyDuringMigration);
+  const blockList = flyoutCategoryBlocks(workspace);
   xmlList = xmlList.concat(blockList);
   return xmlList;
 }
@@ -152,27 +146,15 @@ export function flyoutCategoryBlocks(workspace: Workspace): Element[] {
     if (Blocks['variables_set']) {
       const block = utilsXml.createElement('block');
       block.setAttribute('type', 'variables_set');
-      // AnyDuringMigration because:  Argument of type 'number' is not
-      // assignable to parameter of type 'string'.
-      block.setAttribute(
-          'gap', (Blocks['math_change'] ? 8 : 24) as AnyDuringMigration);
-      // AnyDuringMigration because:  Argument of type 'Element | null' is not
-      // assignable to parameter of type 'Node'.
-      block.appendChild(
-          generateVariableFieldDom(mostRecentVariable) as AnyDuringMigration);
+      block.setAttribute('gap', Blocks['math_change'] ? '8' : '24');
+      block.appendChild(generateVariableFieldDom(mostRecentVariable));
       xmlList.push(block);
     }
     if (Blocks['math_change']) {
       const block = utilsXml.createElement('block');
       block.setAttribute('type', 'math_change');
-      // AnyDuringMigration because:  Argument of type 'number' is not
-      // assignable to parameter of type 'string'.
-      block.setAttribute(
-          'gap', (Blocks['variables_get'] ? 20 : 8) as AnyDuringMigration);
-      // AnyDuringMigration because:  Argument of type 'Element | null' is not
-      // assignable to parameter of type 'Node'.
-      block.appendChild(
-          generateVariableFieldDom(mostRecentVariable) as AnyDuringMigration);
+      block.setAttribute('gap', Blocks['variables_get'] ? '20' : '8');
+      block.appendChild(generateVariableFieldDom(mostRecentVariable));
       const value = Xml.textToDom(
           '<value name="DELTA">' +
           '<shadow type="math_number">' +
@@ -188,13 +170,8 @@ export function flyoutCategoryBlocks(workspace: Workspace): Element[] {
       for (let i = 0, variable; variable = variableModelList[i]; i++) {
         const block = utilsXml.createElement('block');
         block.setAttribute('type', 'variables_get');
-        // AnyDuringMigration because:  Argument of type 'number' is not
-        // assignable to parameter of type 'string'.
-        block.setAttribute('gap', 8 as AnyDuringMigration);
-        // AnyDuringMigration because:  Argument of type 'Element | null' is not
-        // assignable to parameter of type 'Node'.
-        block.appendChild(
-            generateVariableFieldDom(variable) as AnyDuringMigration);
+        block.setAttribute('gap', '8');
+        block.appendChild(generateVariableFieldDom(variable));
         xmlList.push(block);
       }
     }
@@ -265,9 +242,7 @@ export function generateUniqueNameFromOptions(
     if (letterIndex === letters.length) {
       // Reached the end of the character sequence so back to 'i'.
       letterIndex = 0;
-      // AnyDuringMigration because:  Type 'number' is not assignable to type
-      // 'string'.
-      suffix = (Number(suffix) + 1) as AnyDuringMigration;
+      suffix = `${Number(suffix) + 1}`;
     }
     potName = letters.charAt(letterIndex) + suffix;
   }
@@ -291,12 +266,11 @@ export function generateUniqueNameFromOptions(
  * @alias Blockly.Variables.createVariableButtonHandler
  */
 export function createVariableButtonHandler(
-    workspace: Workspace,
-    opt_callback?: (p1?: string|null) => AnyDuringMigration,
+    workspace: Workspace, opt_callback?: (p1?: string|null) => void,
     opt_type?: string) {
   const type = opt_type || '';
   // This function needs to be named so it can be called recursively.
-  function promptAndCheckWithAlert(defaultName: AnyDuringMigration) {
+  function promptAndCheckWithAlert(defaultName: string) {
     promptName(Msg['NEW_VARIABLE_TITLE'], defaultName, function(text) {
       if (text) {
         const existing = nameUsedWithAnyType(text, workspace);
@@ -343,9 +317,9 @@ export function createVariableButtonHandler(
  */
 export function renameVariable(
     workspace: Workspace, variable: VariableModel,
-    opt_callback?: (p1?: string|null) => AnyDuringMigration) {
+    opt_callback?: (p1?: string|null) => void) {
   // This function needs to be named so it can be called recursively.
-  function promptAndCheckWithAlert(defaultName: AnyDuringMigration) {
+  function promptAndCheckWithAlert(defaultName: string) {
     const promptText =
         Msg['RENAME_VARIABLE_TITLE'].replace('%1', variable.name);
     promptName(promptText, defaultName, function(newName) {
@@ -381,13 +355,13 @@ export function renameVariable(
  *
  * @param promptText The string of the prompt.
  * @param defaultText The default value to show in the prompt's field.
- * @param callback A callback. It will return the new variable name, or null if
- *     the user picked something illegal.
+ * @param callback A callback. It will be passed the new variable name, or null
+ *     if the user picked something illegal.
  * @alias Blockly.Variables.promptName
  */
 export function promptName(
     promptText: string, defaultText: string,
-    callback: (p1: string|null) => AnyDuringMigration) {
+    callback: (p1: string|null) => void) {
   dialog.prompt(promptText, defaultText, function(newVar) {
     // Merge runs of whitespace.  Strip leading and trailing whitespace.
     // Beyond this, all names are legal.
@@ -452,8 +426,8 @@ export function nameUsedWithAnyType(
  * @returns The generated DOM.
  * @alias Blockly.Variables.generateVariableFieldDom
  */
-export function generateVariableFieldDom(variableModel: VariableModel): Element|
-    null {
+export function generateVariableFieldDom(variableModel: VariableModel):
+    Element {
   /* Generates the following XML:
    * <field name="VAR" id="goKTKmYJ8DhVHpruv" variabletype="int">foo</field>
    */
@@ -556,10 +530,7 @@ function createVariable(
     const ws =
         (workspace.isFlyout ? (workspace as WorkspaceSvg).targetWorkspace :
                               workspace);
-    // Must call version on exports to allow for mocking in tests. See #5321
-    // AnyDuringMigration because:  Argument of type 'Workspace | WorkspaceSvg'
-    // is not assignable to parameter of type 'Workspace'.
-    opt_name = generateUniqueName(ws as AnyDuringMigration);
+    opt_name = generateUniqueName(ws!);
   }
 
   // Create a potential variable if in the flyout.
diff --git a/core/variables_dynamic.ts b/core/variables_dynamic.ts
index 0b00bf328..6191b99d2 100644
--- a/core/variables_dynamic.ts
+++ b/core/variables_dynamic.ts
@@ -19,6 +19,7 @@ import {VariableModel} from './variable_model.js';
 import * as Variables from './variables.js';
 import type {Workspace} from './workspace.js';
 import type {WorkspaceSvg} from './workspace_svg.js';
+import type {FlyoutButton} from './flyout_button.js';
 
 
 /**
@@ -37,7 +38,7 @@ export const CATEGORY_NAME = 'VARIABLE_DYNAMIC';
  *
  * @param button
  */
-function stringButtonClickHandler(button: AnyDuringMigration) {
+function stringButtonClickHandler(button: FlyoutButton) {
   Variables.createVariableButtonHandler(
       button.getTargetWorkspace(), undefined, 'String');
 }
@@ -49,7 +50,7 @@ export const onCreateVariableButtonClick_String = stringButtonClickHandler;
  *
  * @param button
  */
-function numberButtonClickHandler(button: AnyDuringMigration) {
+function numberButtonClickHandler(button: FlyoutButton) {
   Variables.createVariableButtonHandler(
       button.getTargetWorkspace(), undefined, 'Number');
 }
@@ -61,7 +62,7 @@ export const onCreateVariableButtonClick_Number = numberButtonClickHandler;
  *
  * @param button
  */
-function colourButtonClickHandler(button: AnyDuringMigration) {
+function colourButtonClickHandler(button: FlyoutButton) {
   Variables.createVariableButtonHandler(
       button.getTargetWorkspace(), undefined, 'Colour');
 }
@@ -98,9 +99,7 @@ export function flyoutCategory(workspace: WorkspaceSvg): Element[] {
   workspace.registerButtonCallback(
       'CREATE_VARIABLE_COLOUR', colourButtonClickHandler);
 
-  // AnyDuringMigration because:  Argument of type 'WorkspaceSvg' is not
-  // assignable to parameter of type 'Workspace'.
-  const blockList = flyoutCategoryBlocks(workspace as AnyDuringMigration);
+  const blockList = flyoutCategoryBlocks(workspace);
   xmlList = xmlList.concat(blockList);
   return xmlList;
 }
@@ -121,14 +120,8 @@ export function flyoutCategoryBlocks(workspace: Workspace): Element[] {
       const firstVariable = variableModelList[variableModelList.length - 1];
       const block = xml.createElement('block');
       block.setAttribute('type', 'variables_set_dynamic');
-      // AnyDuringMigration because:  Argument of type 'number' is not
-      // assignable to parameter of type 'string'.
-      block.setAttribute('gap', 24 as AnyDuringMigration);
-      // AnyDuringMigration because:  Argument of type 'Element | null' is not
-      // assignable to parameter of type 'Node'.
-      block.appendChild(
-          Variables.generateVariableFieldDom(firstVariable) as
-          AnyDuringMigration);
+      block.setAttribute('gap', '24');
+      block.appendChild(Variables.generateVariableFieldDom(firstVariable));
       xmlList.push(block);
     }
     if (Blocks['variables_get_dynamic']) {
@@ -136,13 +129,8 @@ export function flyoutCategoryBlocks(workspace: Workspace): Element[] {
       for (let i = 0, variable; variable = variableModelList[i]; i++) {
         const block = xml.createElement('block');
         block.setAttribute('type', 'variables_get_dynamic');
-        // AnyDuringMigration because:  Argument of type 'number' is not
-        // assignable to parameter of type 'string'.
-        block.setAttribute('gap', 8 as AnyDuringMigration);
-        // AnyDuringMigration because:  Argument of type 'Element | null' is not
-        // assignable to parameter of type 'Node'.
-        block.appendChild(
-            Variables.generateVariableFieldDom(variable) as AnyDuringMigration);
+        block.setAttribute('gap', '8');
+        block.appendChild(Variables.generateVariableFieldDom(variable));
         xmlList.push(block);
       }
     }