Strict null work on main thread

src/vs/editor/browser/services/bulkEditService.ts

@@ -23,6 +23,6 @@ export interface IBulkEditResult {
 export interface IBulkEditService {
 	_serviceBrand: any;
 
-	apply(edit: WorkspaceEdit, options: IBulkEditOptions): Promise<IBulkEditResult>;
+	apply(edit: WorkspaceEdit, options?: IBulkEditOptions): Promise<IBulkEditResult>;
 }
 

src/vs/editor/standalone/browser/simpleServices.ts

@@ -576,7 +576,7 @@ export class SimpleBulkEditService implements IBulkEditService {
 		//
 	}
 
-	apply(workspaceEdit: WorkspaceEdit, options: IBulkEditOptions): Promise<IBulkEditResult> {
+	apply(workspaceEdit: WorkspaceEdit, options?: IBulkEditOptions): Promise<IBulkEditResult> {
 
 		let edits = new Map<ITextModel, TextEdit[]>();
 

src/vs/platform/files/common/files.ts

@@ -419,7 +419,7 @@ export interface IBaseStat {
 	 * A unique identifier thet represents the
 	 * current state of the file or directory.
 	 */
-	etag: string;
+	etag?: string;
 
 	/**
 	 * The resource is readonly.

src/vs/workbench/api/electron-browser/mainThreadDecorations.ts

@@ -109,13 +109,17 @@ export class MainThreadDecorations implements MainThreadDecorationsShape {
 	}
 
 	$onDidChange(handle: number, resources: UriComponents[]): void {
-		const [emitter] = this._provider.get(handle);
-		emitter.fire(resources && resources.map(URI.revive));
+		const provider = this._provider.get(handle);
+		if (provider) {
+			const [emitter] = provider;
+			emitter.fire(resources && resources.map(URI.revive));
+		}
 	}
 
 	$unregisterDecorationProvider(handle: number): void {
-		if (this._provider.has(handle)) {
-			dispose(this._provider.get(handle));
+		const provider = this._provider.get(handle);
+		if (provider) {
+			dispose(provider);
 			this._provider.delete(handle);
 		}
 	}

src/vs/workbench/api/electron-browser/mainThreadDocuments.ts

@@ -130,14 +130,14 @@ export class MainThreadDocuments implements MainThreadDocumentsShape {
 
 	private _shouldHandleFileEvent(e: TextFileModelChangeEvent): boolean {
 		const model = this._modelService.getModel(e.resource);
-		return model && shouldSynchronizeModel(model);
+		return !!model && shouldSynchronizeModel(model);
 	}
 
 	private _onModelAdded(model: ITextModel): void {
 		// Same filter as in mainThreadEditorsTracker
 		if (!shouldSynchronizeModel(model)) {
 			// don't synchronize too large models
-			return null;
+			return;
 		}
 		let modelUrl = model.uri;
 		this._modelIsSynced[modelUrl.toString()] = true;

src/vs/workbench/api/electron-browser/mainThreadDocumentsAndEditors.ts

@@ -7,7 +7,7 @@ import { Emitter, Event } from 'vs/base/common/event';
 import { IDisposable, combinedDisposable, dispose } from 'vs/base/common/lifecycle';
 import { values } from 'vs/base/common/map';
 import { URI } from 'vs/base/common/uri';
-import { ICodeEditor, isCodeEditor, isDiffEditor } from 'vs/editor/browser/editorBrowser';
+import { ICodeEditor, isCodeEditor, isDiffEditor, IActiveCodeEditor } from 'vs/editor/browser/editorBrowser';
 import { IBulkEditService } from 'vs/editor/browser/services/bulkEditService';
 import { ICodeEditorService } from 'vs/editor/browser/services/codeEditorService';
 import { IEditor } from 'vs/editor/common/editorCommon';
@@ -70,7 +70,7 @@ class TextEditorSnapshot {
 	readonly id: string;
 
 	constructor(
-		readonly editor: ICodeEditor,
+		readonly editor: IActiveCodeEditor,
 	) {
 		this.id = `${editor.getId()},${editor.getModel().id}`;
 	}
@@ -85,8 +85,8 @@ class DocumentAndEditorStateDelta {
 		readonly addedDocuments: ITextModel[],
 		readonly removedEditors: TextEditorSnapshot[],
 		readonly addedEditors: TextEditorSnapshot[],
-		readonly oldActiveEditor: string,
-		readonly newActiveEditor: string,
+		readonly oldActiveEditor: string | undefined,
+		readonly newActiveEditor: string | undefined,
 	) {
 		this.isEmpty = this.removedDocuments.length === 0
 			&& this.addedDocuments.length === 0
@@ -131,7 +131,7 @@ class DocumentAndEditorState {
 	constructor(
 		readonly documents: Set<ITextModel>,
 		readonly textEditors: Map<string, TextEditorSnapshot>,
-		readonly activeEditor: string,
+		readonly activeEditor: string | undefined,
 	) {
 		//
 	}
@@ -230,14 +230,14 @@ class MainThreadDocumentAndEditorStateComputer {
 
 		// editor: only take those that have a not too large model
 		const editors = new Map<string, TextEditorSnapshot>();
-		let activeEditor: string | null = null;
+		let activeEditor: string | undefined = undefined;
 
 		for (const editor of this._codeEditorService.listCodeEditors()) {
 			if (editor.isSimpleWidget) {
 				continue;
 			}
 			const model = editor.getModel();
-			if (model && shouldSynchronizeModel(model)
+			if (editor.hasModel() && model && shouldSynchronizeModel(model)
 				&& !model.isDisposed() // model disposed
 				&& Boolean(this._modelService.getModel(model.uri)) // model disposing, the flag didn't flip yet but the model service already removed it
 			) {
@@ -282,7 +282,7 @@ class MainThreadDocumentAndEditorStateComputer {
 		}
 	}
 
-	private _getActiveEditorFromPanel(): IEditor {
+	private _getActiveEditorFromPanel(): IEditor | undefined {
 		let panel = this._panelService.getActivePanel();
 		if (panel instanceof BaseTextEditor && isCodeEditor(panel.getControl())) {
 			return panel.getControl();
@@ -444,8 +444,8 @@ export class MainThreadDocumentsAndEditors {
 		};
 	}
 
-	private _findEditorPosition(editor: MainThreadTextEditor): EditorViewColumn {
-		for (let workbenchEditor of this._editorService.visibleControls) {
+	private _findEditorPosition(editor: MainThreadTextEditor): EditorViewColumn | undefined {
+		for (const workbenchEditor of this._editorService.visibleControls) {
 			if (editor.matches(workbenchEditor)) {
 				return editorGroupToViewColumn(this._editorGroupService, workbenchEditor.group);
 			}
@@ -453,8 +453,8 @@ export class MainThreadDocumentsAndEditors {
 		return undefined;
 	}
 
-	findTextEditorIdFor(editor: IWorkbenchEditor): string {
-		for (let id in this._textEditors) {
+	findTextEditorIdFor(editor: IWorkbenchEditor): string | undefined {
+		for (const id in this._textEditors) {
 			if (this._textEditors[id].matches(editor)) {
 				return id;
 			}

src/vs/workbench/api/electron-browser/mainThreadEditor.ts

@@ -187,7 +187,7 @@ export class MainThreadTextEditor {
 	private _focusTracker: IFocusTracker;
 	private _codeEditorListeners: IDisposable[];
 
-	private _properties: MainThreadTextEditorProperties | null;
+	private _properties: MainThreadTextEditorProperties;
 	private readonly _onPropertiesChanged: Emitter<IEditorPropertiesChangeData>;
 
 	constructor(
@@ -204,7 +204,6 @@ export class MainThreadTextEditor {
 		this._modelService = modelService;
 		this._codeEditorListeners = [];
 
-		this._properties = null;
 		this._onPropertiesChanged = new Emitter<IEditorPropertiesChangeData>();
 
 		this._modelListeners = [];
@@ -300,7 +299,7 @@ export class MainThreadTextEditor {
 		return !!this._codeEditor;
 	}
 
-	public getProperties(): MainThreadTextEditorProperties | null {
+	public getProperties(): MainThreadTextEditorProperties {
 		return this._properties;
 	}
 
@@ -316,7 +315,7 @@ export class MainThreadTextEditor {
 
 		const newSelections = selections.map(Selection.liftSelection);
 		this._setProperties(
-			new MainThreadTextEditorProperties(newSelections, this._properties!.options, this._properties!.visibleRanges),
+			new MainThreadTextEditorProperties(newSelections, this._properties.options, this._properties.visibleRanges),
 			null
 		);
 	}

src/vs/workbench/api/electron-browser/mainThreadEditors.ts

@@ -36,7 +36,7 @@ export class MainThreadTextEditors implements MainThreadTextEditorsShape {
 	private _documentsAndEditors: MainThreadDocumentsAndEditors;
 	private _toDispose: IDisposable[];
 	private _textEditorsListenersMap: { [editorId: string]: IDisposable[]; };
-	private _editorPositionData: ITextEditorPositionData;
+	private _editorPositionData: ITextEditorPositionData | null;
 	private _registeredDecorationTypes: { [decorationType: string]: boolean; };
 
 	constructor(
@@ -145,7 +145,7 @@ export class MainThreadTextEditors implements MainThreadTextEditorsShape {
 				options: { preserveFocus: false }
 			}, viewColumnToEditorGroup(this._editorGroupService, position)).then(() => { return; });
 		}
-		return undefined;
+		return Promise.resolve();
 	}
 
 	$tryHideEditor(id: string): Promise<void> {
@@ -158,7 +158,7 @@ export class MainThreadTextEditors implements MainThreadTextEditorsShape {
 				}
 			}
 		}
-		return undefined;
+		return Promise.resolve();
 	}
 
 	$trySetSelections(id: string, selections: ISelection[]): Promise<void> {
@@ -192,7 +192,7 @@ export class MainThreadTextEditors implements MainThreadTextEditorsShape {
 			return Promise.reject(disposed(`TextEditor(${id})`));
 		}
 		this._documentsAndEditors.getEditor(id).revealRange(range, revealType);
-		return undefined;
+		return Promise.resolve();
 	}
 
 	$trySetOptions(id: string, options: ITextEditorConfigurationUpdate): Promise<void> {

src/vs/workbench/api/electron-browser/mainThreadLanguageFeatures.ts

@@ -198,7 +198,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 
 	$registerHoverProvider(handle: number, selector: ISerializedDocumentFilter[]): void {
 		this._registrations[handle] = modes.HoverProviderRegistry.register(typeConverters.LanguageSelector.from(selector), <modes.HoverProvider>{
-			provideHover: (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.Hover> => {
+			provideHover: (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.Hover | undefined> => {
 				return this._proxy.$provideHover(handle, model.uri, position, token);
 			}
 		});
@@ -208,7 +208,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 
 	$registerDocumentHighlightProvider(handle: number, selector: ISerializedDocumentFilter[]): void {
 		this._registrations[handle] = modes.DocumentHighlightProviderRegistry.register(typeConverters.LanguageSelector.from(selector), <modes.DocumentHighlightProvider>{
-			provideDocumentHighlights: (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.DocumentHighlight[]> => {
+			provideDocumentHighlights: (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.DocumentHighlight[] | undefined> => {
 				return this._proxy.$provideDocumentHighlights(handle, model.uri, position, token);
 			}
 		});
@@ -243,7 +243,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 	$registerDocumentFormattingSupport(handle: number, selector: ISerializedDocumentFilter[], displayName: string): void {
 		this._registrations[handle] = modes.DocumentFormattingEditProviderRegistry.register(typeConverters.LanguageSelector.from(selector), <modes.DocumentFormattingEditProvider>{
 			displayName,
-			provideDocumentFormattingEdits: (model: ITextModel, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[]> => {
+			provideDocumentFormattingEdits: (model: ITextModel, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[] | undefined> => {
 				return this._proxy.$provideDocumentFormattingEdits(handle, model.uri, options, token);
 			}
 		});
@@ -252,7 +252,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 	$registerRangeFormattingSupport(handle: number, selector: ISerializedDocumentFilter[], displayName: string): void {
 		this._registrations[handle] = modes.DocumentRangeFormattingEditProviderRegistry.register(typeConverters.LanguageSelector.from(selector), <modes.DocumentRangeFormattingEditProvider>{
 			displayName,
-			provideDocumentRangeFormattingEdits: (model: ITextModel, range: EditorRange, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[]> => {
+			provideDocumentRangeFormattingEdits: (model: ITextModel, range: EditorRange, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[] | undefined> => {
 				return this._proxy.$provideDocumentRangeFormattingEdits(handle, model.uri, range, options, token);
 			}
 		});
@@ -263,7 +263,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 
 			autoFormatTriggerCharacters,
 
-			provideOnTypeFormattingEdits: (model: ITextModel, position: EditorPosition, ch: string, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[]> => {
+			provideOnTypeFormattingEdits: (model: ITextModel, position: EditorPosition, ch: string, options: modes.FormattingOptions, token: CancellationToken): Promise<ISingleEditOperation[] | undefined> => {
 				return this._proxy.$provideOnTypeFormattingEdits(handle, model.uri, position, ch, options, token);
 			}
 		});
@@ -272,7 +272,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 	// --- navigate type
 
 	$registerNavigateTypeSupport(handle: number): void {
-		let lastResultId: number;
+		let lastResultId: number | undefined;
 		this._registrations[handle] = search.WorkspaceSymbolProviderRegistry.register(<search.IWorkspaceSymbolProvider>{
 			provideWorkspaceSymbols: (search: string, token: CancellationToken): Promise<search.IWorkspaceSymbol[]> => {
 				return this._proxy.$provideWorkspaceSymbols(handle, search, token).then(result => {
@@ -298,7 +298,7 @@ export class MainThreadLanguageFeatures implements MainThreadLanguageFeaturesSha
 				return this._proxy.$provideRenameEdits(handle, model.uri, position, newName, token).then(reviveWorkspaceEditDto);
 			},
 			resolveRenameLocation: supportResolveLocation
-				? (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.RenameLocation> => this._proxy.$resolveRenameLocation(handle, model.uri, position, token)
+				? (model: ITextModel, position: EditorPosition, token: CancellationToken): Promise<modes.RenameLocation | undefined> => this._proxy.$resolveRenameLocation(handle, model.uri, position, token)
 				: undefined
 		});
 	}

src/vs/workbench/api/electron-browser/mainThreadTreeViews.ts

@@ -45,7 +45,10 @@ export class MainThreadTreeViews extends Disposable implements MainThreadTreeVie
 		return this.viewsService.openView(treeViewId, options.focus)
 			.then(() => {
 				const viewer = this.getTreeView(treeViewId);
-				return this.reveal(viewer, this._dataProviders.get(treeViewId), item, parentChain, options);
+				if (viewer) {
+					return this.reveal(viewer, this._dataProviders.get(treeViewId)!, item, parentChain, options);
+				}
+				return undefined;
 			});
 	}
 
@@ -56,7 +59,7 @@ export class MainThreadTreeViews extends Disposable implements MainThreadTreeVie
 			const itemsToRefresh = dataProvider.getItemsToRefresh(itemsToRefreshByHandle);
 			return viewer.refresh(itemsToRefresh.length ? itemsToRefresh : undefined);
 		}
-		return null;
+		return Promise.resolve();
 	}
 
 	$setMessage(treeViewId: string, message: string | IMarkdownString): void {

src/vs/workbench/api/electron-browser/mainThreadWebview.ts

@@ -68,14 +68,14 @@ export class MainThreadWebviews implements MainThreadWebviewsShape, WebviewReviv
 		handle: WebviewPanelHandle,
 		viewType: string,
 		title: string,
-		showOptions: { viewColumn: EditorViewColumn | null, preserveFocus: boolean },
+		showOptions: { viewColumn?: EditorViewColumn, preserveFocus?: boolean },
 		options: WebviewInputOptions,
 		extensionId: ExtensionIdentifier,
 		extensionLocation: UriComponents
 	): void {
 		const mainThreadShowOptions: ICreateWebViewShowOptions = Object.create(null);
 		if (showOptions) {
-			mainThreadShowOptions.preserveFocus = showOptions.preserveFocus;
+			mainThreadShowOptions.preserveFocus = !!showOptions.preserveFocus;
 			mainThreadShowOptions.group = viewColumnToEditorGroup(this._editorGroupService, showOptions.viewColumn);
 		}
 
@@ -129,7 +129,7 @@ export class MainThreadWebviews implements MainThreadWebviewsShape, WebviewReviv
 
 		const targetGroup = this._editorGroupService.getGroup(viewColumnToEditorGroup(this._editorGroupService, showOptions.viewColumn));
 
-		this._webviewService.revealWebview(webview, targetGroup || this._editorGroupService.activeGroup, showOptions.preserveFocus);
+		this._webviewService.revealWebview(webview, targetGroup || this._editorGroupService.activeGroup, !!showOptions.preserveFocus);
 	}
 
 	public $postMessage(handle: WebviewPanelHandle, message: any): Promise<boolean> {
@@ -137,7 +137,7 @@ export class MainThreadWebviews implements MainThreadWebviewsShape, WebviewReviv
 		const editors = this._editorService.visibleControls
 			.filter(e => e instanceof WebviewEditor)
 			.map(e => e as WebviewEditor)
-			.filter(e => e.input.matches(webview));
+			.filter(e => e.input!.matches(webview));
 
 		for (const editor of editors) {
 			editor.sendMessage(message);
@@ -216,7 +216,7 @@ export class MainThreadWebviews implements MainThreadWebviewsShape, WebviewReviv
 		let newActiveWebview: { input: WebviewEditorInput, handle: WebviewPanelHandle } | undefined = undefined;
 		if (activeEditor && activeEditor.input instanceof WebviewEditorInput) {
 			for (const handle of map.keys(this._webviews)) {
-				const input = this._webviews.get(handle);
+				const input = this._webviews.get(handle)!;
 				if (input.matches(activeEditor.input)) {
 					newActiveWebview = { input, handle };
 					break;
@@ -240,7 +240,7 @@ export class MainThreadWebviews implements MainThreadWebviewsShape, WebviewReviv
 			if (oldActiveWebview) {
 				this._proxy.$onDidChangeWebviewPanelViewState(this._activeWebview, {
 					active: false,
-					visible: this._editorService.visibleControls.some(editor => editor.input && editor.input.matches(oldActiveWebview)),
+					visible: this._editorService.visibleControls.some(editor => !!editor.input && editor.input.matches(oldActiveWebview)),
 					position: editorGroupToViewColumn(this._editorGroupService, oldActiveWebview.group),
 				});
 			}

src/vs/workbench/api/node/extHostTypeConverters.ts

@@ -443,7 +443,7 @@ export namespace TextEdit {
 
 	export function to(edit: modes.TextEdit): types.TextEdit {
 		const result = new types.TextEdit(Range.to(edit.range), edit.text);
-		result.newEol = typeof edit.eol === 'undefined' ? undefined : EndOfLine.to(edit.eol);
+		result.newEol = (typeof edit.eol === 'undefined' ? undefined : EndOfLine.to(edit.eol))!;
 		return result;
 	}
 }
@@ -457,7 +457,7 @@ export namespace WorkspaceEdit {
 			const [uri, uriOrEdits] = entry;
 			if (Array.isArray(uriOrEdits)) {
 				// text edits
-				const doc = documents ? documents.getDocument(uri.toString()) : undefined;
+				const doc = documents && uri ? documents.getDocument(uri.toString()) : undefined;
 				result.edits.push(<ResourceTextEditDto>{ resource: uri, modelVersionId: doc && doc.version, edits: uriOrEdits.map(TextEdit.from) });
 			} else {
 				// resource edits
@@ -986,6 +986,9 @@ export namespace GlobPattern {
 
 export namespace LanguageSelector {
 
+	export function from(selector: undefined): undefined;
+	export function from(selector: vscode.DocumentSelector): languageSelector.LanguageSelector;
+	export function from(selector: vscode.DocumentSelector | undefined): languageSelector.LanguageSelector | undefined;
 	export function from(selector: vscode.DocumentSelector | undefined): languageSelector.LanguageSelector | undefined {
 		if (!selector) {
 			return undefined;
@@ -997,7 +1000,7 @@ export namespace LanguageSelector {
 			return <languageSelector.LanguageFilter>{
 				language: selector.language,
 				scheme: selector.scheme,
-				pattern: GlobPattern.from(selector.pattern),
+				pattern: typeof selector.pattern === 'undefined' ? undefined : GlobPattern.from(selector.pattern),
 				exclusive: selector.exclusive
 			};
 		}

src/vs/workbench/api/node/extHostTypes.ts

@@ -948,9 +948,9 @@ export class SymbolInformation {
 	kind: SymbolKind;
 	containerName: string | undefined;
 
-	constructor(name: string, kind: SymbolKind, containerName: string, location: Location);
+	constructor(name: string, kind: SymbolKind, containerName: string | undefined, location: Location);
 	constructor(name: string, kind: SymbolKind, range: Range, uri?: URI, containerName?: string);
-	constructor(name: string, kind: SymbolKind, rangeOrContainer: string | Range, locationOrUri?: Location | URI, containerName?: string) {
+	constructor(name: string, kind: SymbolKind, rangeOrContainer: string | undefined | Range, locationOrUri?: Location | URI, containerName?: string) {
 		this.name = name;
 		this.kind = kind;
 		this.containerName = containerName;

src/vs/workbench/browser/parts/editor/resourceViewer.ts

@@ -27,7 +27,7 @@ export interface IResourceDescriptor {
 	readonly resource: URI;
 	readonly name: string;
 	readonly size: number;
-	readonly etag: string;
+	readonly etag?: string;
 	readonly mime: string;
 }
 

src/vs/workbench/common/editor/binaryEditorModel.ts

@@ -16,7 +16,7 @@ export class BinaryEditorModel extends EditorModel {
 	private name: string;
 	private resource: URI;
 	private size: number;
-	private etag: string;
+	private etag?: string;
 	private mime: string;
 
 	constructor(
@@ -70,7 +70,7 @@ export class BinaryEditorModel extends EditorModel {
 	/**
 	 * The etag of the binary resource if known.
 	 */
-	getETag(): string {
+	getETag(): string | undefined {
 		return this.etag;
 	}
 

src/vs/workbench/services/decorations/browser/decorations.ts

@@ -31,7 +31,7 @@ export interface IDecoration {
 export interface IDecorationsProvider {
 	readonly label: string;
 	readonly onDidChange: Event<URI[]>;
-	provideDecorations(uri: URI, token: CancellationToken): IDecorationData | Promise<IDecorationData> | undefined;
+	provideDecorations(uri: URI, token: CancellationToken): IDecorationData | Promise<IDecorationData | undefined> | undefined;
 }
 
 export interface IResourceDecorationChangeEvent {

src/vs/workbench/services/decorations/browser/decorationsService.ts

@@ -301,7 +301,7 @@ class DecorationProviderWrapper {
 
 		const source = new CancellationTokenSource();
 		const dataOrThenable = this._provider.provideDecorations(uri, source.token);
-		if (!isThenable(dataOrThenable)) {
+		if (!isThenable<IDecorationData | Promise<IDecorationData | undefined> | undefined>(dataOrThenable)) {
 			// sync -> we have a result now
 			return this._keepItem(uri, dataOrThenable);
 

src/vs/workbench/services/extensions/electron-browser/extensionService.ts

@@ -37,13 +37,13 @@ const NO_OP_VOID_PROMISE = Promise.resolve<void>(undefined);
 
 schema.properties.engines.properties.vscode.default = `^${pkg.version}`;
 
-let productAllowProposedApi: Set<string> = null;
+let productAllowProposedApi: Set<string> | null = null;
 function allowProposedApiFromProduct(id: ExtensionIdentifier): boolean {
 	// create set if needed
-	if (productAllowProposedApi === null) {
+	if (!productAllowProposedApi) {
 		productAllowProposedApi = new Set<string>();
 		if (isNonEmptyArray(product.extensionAllowedProposedApi)) {
-			product.extensionAllowedProposedApi.forEach((id) => productAllowProposedApi.add(ExtensionIdentifier.toKey(id)));
+			product.extensionAllowedProposedApi.forEach((id) => productAllowProposedApi!.add(ExtensionIdentifier.toKey(id)));
 		}
 	}
 	return productAllowProposedApi.has(ExtensionIdentifier.toKey(id));
@@ -167,7 +167,7 @@ export class ExtensionService extends Disposable implements IExtensionService {
 		}
 
 		while (this._deltaExtensionsQueue.length > 0) {
-			const item = this._deltaExtensionsQueue.shift();
+			const item = this._deltaExtensionsQueue.shift()!;
 			try {
 				this._inHandleDeltaExtensions = true;
 				await this._deltaExtensions(item.toAdd, item.toRemove);
@@ -856,7 +856,7 @@ export class ExtensionService extends Disposable implements IExtensionService {
 		if (!this._extensionsMessages.has(extensionKey)) {
 			this._extensionsMessages.set(extensionKey, []);
 		}
-		this._extensionsMessages.get(extensionKey).push({
+		this._extensionsMessages.get(extensionKey)!.push({
 			type: severity,
 			message: message,
 			extensionId: null,

src/vs/workbench/services/extensions/node/extensionDescriptionRegistry.ts

@@ -189,8 +189,8 @@ export class ExtensionDescriptionRegistry {
 		return this._extensionsArr.slice(0);
 	}
 
-	public getExtensionDescription(extensionId: ExtensionIdentifier | string): IExtensionDescription | null {
+	public getExtensionDescription(extensionId: ExtensionIdentifier | string): IExtensionDescription | undefined {
 		const extension = this._extensionsMap.get(ExtensionIdentifier.toKey(extensionId));
-		return extension ? extension : null;
+		return extension ? extension : undefined;
 	}
 }