Enable noImplicitOverride and add override keyword to properties/functions that are overridden.

packages/@ember/-internals/glimmer/lib/component-managers/outlet.ts

@@ -226,7 +226,7 @@ export function createRootOutlet(outletView: OutletView): OutletComponentDefinit
         return 'div';
       }
 
-      getCapabilities(): InternalComponentCapabilities {
+      override getCapabilities(): InternalComponentCapabilities {
         return WRAPPED_CAPABILITIES;
       }
 

packages/@ember/-internals/glimmer/lib/component-managers/root.ts

@@ -29,7 +29,7 @@ class RootComponentManager extends CurlyComponentManager {
     this.component = component;
   }
 
-  create(
+  override create(
     _owner: Owner,
     _state: unknown,
     _args: Nullable<VMArguments>,

packages/@ember/-internals/glimmer/lib/component.ts

@@ -843,7 +843,7 @@ class Component<S = unknown>
   declare [IS_DISPATCHING_ATTRS]: boolean;
   declare [DIRTY_TAG]: DirtyableTag;
 
-  init(properties?: object | undefined) {
+  override init(properties?: object | undefined) {
     super.init(properties);
 
     // Handle methods from ViewMixin.
@@ -921,13 +921,13 @@ class Component<S = unknown>
     return this.__dispatcher;
   }
 
-  on<Target>(
+  override on<Target>(
     name: string,
     target: Target,
     method: string | ((this: Target, ...args: any[]) => void)
   ): this;
-  on(name: string, method: ((...args: any[]) => void) | string): this;
-  on(name: string, target: any, method?: any) {
+  override on(name: string, method: ((...args: any[]) => void) | string): this;
+  override on(name: string, target: any, method?: any) {
     this._dispatcher?.setupHandlerForEmberEvent(name);
     // The `on` method here comes from the Evented mixin. Since this mixin
     // is applied to the parent of this class, however, we are still able
@@ -1177,7 +1177,7 @@ class Component<S = unknown>
 
   static isComponentFactory = true;
 
-  static toString() {
+  static override toString() {
     return '@ember/component';
   }
 }

packages/@ember/-internals/glimmer/lib/components/abstract-input.ts

@@ -101,7 +101,7 @@ class ForkedValue implements Value {
 }
 
 export default abstract class AbstractInput extends InternalComponent {
-  validateArguments(): void {
+  override validateArguments(): void {
     assert(
       `The ${this.constructor} component does not take any positional arguments`,
       this.args.positional.length === 0
@@ -159,7 +159,7 @@ export default abstract class AbstractInput extends InternalComponent {
     }
   }
 
-  protected listenerFor(name: string): EventListener {
+  protected override listenerFor(name: string): EventListener {
     let listener = super.listenerFor(name);
 
     if (this.isVirtualEventListener(name, listener)) {

packages/@ember/-internals/glimmer/lib/components/input.ts

@@ -160,14 +160,14 @@ if (hasDOM) {
   @public
 */
 class _Input extends AbstractInput {
-  static toString(): string {
+  static override toString(): string {
     return 'Input';
   }
 
   /**
    * The HTML class attribute.
    */
-  get class(): string {
+  override get class(): string {
     if (this.isCheckbox) {
       return 'ember-checkbox ember-view';
     } else {
@@ -237,15 +237,15 @@ class _Input extends AbstractInput {
     this._checked.set(checked);
   }
 
-  @action change(event: Event): void {
+  @action override change(event: Event): void {
     if (this.isCheckbox) {
       this.checkedDidChange(event);
     } else {
       super.change(event);
     }
   }
 
-  @action input(event: Event): void {
+  @action override input(event: Event): void {
     if (!this.isCheckbox) {
       super.input(event);
     }
@@ -257,7 +257,7 @@ class _Input extends AbstractInput {
     this.checked = element.checked;
   }
 
-  protected isSupportedArgument(name: string): boolean {
+  protected override isSupportedArgument(name: string): boolean {
     let supportedArguments = [
       'type',
       'value',

packages/@ember/-internals/glimmer/lib/components/link-to.ts

@@ -275,13 +275,13 @@ function isQueryParams(value: unknown): value is QueryParams {
 **/
 
 class _LinkTo extends InternalComponent {
-  static toString(): string {
+  static override toString(): string {
     return 'LinkTo';
   }
 
   @service('-routing') private declare routing: RoutingService<Route>;
 
-  validateArguments(): void {
+  override validateArguments(): void {
     assert(
       'You attempted to use the <LinkTo> component within a routeless engine, this is not supported. ' +
         'If you are using the ember-engines addon, use the <LinkToExternal> component instead. ' +
@@ -305,7 +305,7 @@ class _LinkTo extends InternalComponent {
     super.validateArguments();
   }
 
-  get class(): string {
+  override get class(): string {
     let classes = 'ember-view';
 
     if (this.isActive) {
@@ -566,7 +566,7 @@ class _LinkTo extends InternalComponent {
     event.preventDefault();
   }
 
-  protected isSupportedArgument(name: string): boolean {
+  protected override isSupportedArgument(name: string): boolean {
     let supportedArguments = [
       'route',
       'model',

packages/@ember/-internals/glimmer/lib/components/textarea.ts

@@ -141,25 +141,25 @@ import { type OpaqueInternalComponentConstructor, opaquify } from './internal';
   @public
 **/
 class _Textarea extends AbstractInput {
-  static toString(): string {
+  static override toString(): string {
     return 'Textarea';
   }
 
-  get class(): string {
+  override get class(): string {
     return 'ember-text-area ember-view';
   }
 
   // See abstract-input.ts for why these are needed
 
-  @action change(event: Event): void {
+  @action override change(event: Event): void {
     super.change(event);
   }
 
-  @action input(event: Event): void {
+  @action override input(event: Event): void {
     super.input(event);
   }
 
-  protected isSupportedArgument(name: string): boolean {
+  protected override isSupportedArgument(name: string): boolean {
     let supportedArguments = ['type', 'value', 'enter', 'insert-newline', 'escape-press'];
     return supportedArguments.indexOf(name) !== -1 || super.isSupportedArgument(name);
   }

packages/@ember/-internals/glimmer/lib/helper.ts

@@ -128,7 +128,7 @@ export default class Helper<S = unknown> extends FrameworkObject {
   // here to preserve the type param.
   private declare [SIGNATURE]: S;
 
-  init(properties: object | undefined) {
+  override init(properties: object | undefined) {
     super.init(properties);
     this[RECOMPUTE_TAG] = createTag();
 

packages/@ember/-internals/glimmer/lib/utils/iterator.ts

@@ -179,7 +179,7 @@ class ObjectIterator extends BoundedIterator {
     return this.values[position];
   }
 
-  memoFor(position: number): unknown {
+  override memoFor(position: number): unknown {
     return this.keys[position];
   }
 }

packages/@ember/-internals/glimmer/lib/views/outlet.ts

@@ -27,7 +27,7 @@ const TOP_LEVEL_NAME = '-top-level';
 export default class OutletView {
   static extend(injections: any): typeof OutletView {
     return class extends OutletView {
-      static create(options: any) {
+      static override create(options: any) {
         if (options) {
           return super.create(Object.assign({}, injections, options));
         } else {

packages/@ember/-internals/glimmer/tests/integration/application/debug-render-tree-test.ts

@@ -61,7 +61,7 @@ if (ENV._DEBUG_RENDER_TREE) {
         ENV._TEMPLATE_ONLY_GLIMMER_COMPONENTS = true;
       }
 
-      teardown() {
+      override teardown() {
         super.teardown();
         ENV._TEMPLATE_ONLY_GLIMMER_COMPONENTS = this._TEMPLATE_ONLY_GLIMMER_COMPONENTS;
       }
@@ -85,7 +85,7 @@ if (ENV._DEBUG_RENDER_TREE) {
         });
 
         class PassThroughRoute extends Route {
-          model({ model }: { model: string }) {
+          override model({ model }: { model: string }) {
             return model;
           }
         }
@@ -197,9 +197,9 @@ if (ENV._DEBUG_RENDER_TREE) {
           'engine:foo',
           class extends Engine {
             isFooEngine = true;
-            Resolver = ModuleBasedTestResolver;
+            override Resolver = ModuleBasedTestResolver;
 
-            init(properties: object | undefined) {
+            override init(properties: object | undefined) {
               super.init(properties);
               this.register(
                 'template:application',
@@ -222,7 +222,7 @@ if (ENV._DEBUG_RENDER_TREE) {
               );
             }
 
-            buildInstance(options?: EngineInstanceOptions): EngineInstance {
+            override buildInstance(options?: EngineInstanceOptions): EngineInstance {
               let instance: EngineInstance & {
                 isFooEngineInstance?: boolean;
               } = super.buildInstance(options);
@@ -235,9 +235,9 @@ if (ENV._DEBUG_RENDER_TREE) {
         this.add(
           'engine:bar',
           class extends Engine {
-            Resolver = ModuleBasedTestResolver;
+            override Resolver = ModuleBasedTestResolver;
 
-            init(properties: object | undefined) {
+            override init(properties: object | undefined) {
               super.init(properties);
               this.register(
                 'template:application',
@@ -260,7 +260,7 @@ if (ENV._DEBUG_RENDER_TREE) {
               );
             }
 
-            buildInstance(options?: EngineInstanceOptions): EngineInstance {
+            override buildInstance(options?: EngineInstanceOptions): EngineInstance {
               let instance: EngineInstance & {
                 isBarEngineInstance?: boolean;
               } = super.buildInstance(options);
@@ -593,9 +593,9 @@ if (ENV._DEBUG_RENDER_TREE) {
           'engine:foo',
           class extends Engine {
             isFooEngine = true;
-            Resolver = ModuleBasedTestResolver;
+            override Resolver = ModuleBasedTestResolver;
 
-            init(properties: object | undefined) {
+            override init(properties: object | undefined) {
               super.init(properties);
               this.register(
                 'template:application',
@@ -626,7 +626,7 @@ if (ENV._DEBUG_RENDER_TREE) {
               );
             }
 
-            buildInstance(options?: EngineInstanceOptions): EngineInstance {
+            override buildInstance(options?: EngineInstanceOptions): EngineInstance {
               return (instance = super.buildInstance(options));
             }
           }

packages/@ember/-internals/metal/lib/alias.ts

@@ -67,7 +67,7 @@ export class AliasedProperty extends ComputedDescriptor {
     this.altKey = altKey;
   }
 
-  setup(obj: object, keyName: string, propertyDesc: PropertyDescriptor, meta: Meta): void {
+  override setup(obj: object, keyName: string, propertyDesc: PropertyDescriptor, meta: Meta): void {
     assert(`Setting alias '${keyName}' on self`, this.altKey !== keyName);
     super.setup(obj, keyName, propertyDesc, meta);
     CHAIN_PASS_THROUGH.add(this);

packages/@ember/-internals/metal/lib/computed.ts

@@ -319,7 +319,12 @@ export class ComputedProperty extends ComputedDescriptor {
     }
   }
 
-  setup(obj: object, keyName: string, propertyDesc: DecoratorPropertyDescriptor, meta: Meta) {
+  override setup(
+    obj: object,
+    keyName: string,
+    propertyDesc: DecoratorPropertyDescriptor,
+    meta: Meta
+  ) {
     super.setup(obj, keyName, propertyDesc, meta);
 
     assert(
@@ -543,7 +548,7 @@ export class ComputedProperty extends ComputedDescriptor {
   }
 
   /* called before property is overridden */
-  teardown(obj: object, keyName: string, meta: Meta): void {
+  override teardown(obj: object, keyName: string, meta: Meta): void {
     if (meta.revisionFor(keyName) !== undefined) {
       meta.setRevisionFor(keyName, undefined);
       meta.setValueFor(keyName, undefined);
@@ -554,7 +559,7 @@ export class ComputedProperty extends ComputedDescriptor {
 }
 
 class AutoComputedProperty extends ComputedProperty {
-  get(obj: object, keyName: string): unknown {
+  override get(obj: object, keyName: string): unknown {
     let meta = metaFor(obj);
     let tagMeta = tagMetaFor(obj);
 

packages/@ember/-internals/views/lib/system/event_dispatcher.ts

@@ -348,7 +348,7 @@ export default class EventDispatcher extends EmberObject {
     this.lazyEvents.delete(event);
   }
 
-  destroy() {
+  override destroy() {
     if (this._didSetup === false) {
       return;
     }
@@ -368,7 +368,7 @@ export default class EventDispatcher extends EmberObject {
     return this._super(...arguments);
   }
 
-  toString() {
+  override toString() {
     return '(EventDispatcher)';
   }
 }

packages/@ember/-internals/views/lib/views/core_view.ts

@@ -46,7 +46,7 @@ class CoreView extends FrameworkObject.extend(Evented, ActionHandler) {
   */
   declare parentView: View | null;
 
-  init(properties: object | undefined) {
+  override init(properties: object | undefined) {
     super.init(properties);
 
     // Handle methods from Evented