More strict null checks (#60565)

src/tsconfig.strictNullChecks.json

@@ -188,6 +188,7 @@
 		"./vs/editor/contrib/comment/comment.ts",
 		"./vs/editor/contrib/comment/lineCommentCommand.ts",
 		"./vs/editor/contrib/comment/test/blockCommentCommand.test.ts",
+		"./vs/editor/contrib/contextmenu/contextmenu.ts",
 		"./vs/editor/contrib/cursorUndo/cursorUndo.ts",
 		"./vs/editor/contrib/dnd/dnd.ts",
 		"./vs/editor/contrib/dnd/dragAndDropCommand.ts",
@@ -225,8 +226,10 @@
 		"./vs/editor/contrib/gotoError/gotoError.ts",
 		"./vs/editor/contrib/gotoError/gotoErrorWidget.ts",
 		"./vs/editor/contrib/hover/getHover.ts",
+		"./vs/editor/contrib/hover/hover.ts",
 		"./vs/editor/contrib/hover/hoverOperation.ts",
 		"./vs/editor/contrib/hover/hoverWidgets.ts",
+		"./vs/editor/contrib/hover/modesContentHover.ts",
 		"./vs/editor/contrib/hover/modesGlyphHover.ts",
 		"./vs/editor/contrib/inPlaceReplace/inPlaceReplace.ts",
 		"./vs/editor/contrib/inPlaceReplace/inPlaceReplaceCommand.ts",
@@ -245,6 +248,7 @@
 		"./vs/editor/contrib/links/links.ts",
 		"./vs/editor/contrib/markdown/markdownRenderer.ts",
 		"./vs/editor/contrib/message/messageController.ts",
+		"./vs/editor/contrib/multicursor/multicursor.ts",
 		"./vs/editor/contrib/parameterHints/parameterHints.ts",
 		"./vs/editor/contrib/parameterHints/parameterHintsWidget.ts",
 		"./vs/editor/contrib/parameterHints/provideSignatureHelp.ts",
@@ -269,10 +273,12 @@
 		"./vs/editor/contrib/wordPartOperations/wordPartOperations.ts",
 		"./vs/editor/contrib/zoneWidget/zoneWidget.ts",
 		"./vs/editor/editor.worker.ts",
+		"./vs/editor/standalone/browser/accessibilityHelp/accessibilityHelp.ts",
 		"./vs/editor/standalone/browser/colorizer.ts",
 		"./vs/editor/standalone/browser/iPadShowKeyboard/iPadShowKeyboard.ts",
 		"./vs/editor/standalone/browser/inspectTokens/inspectTokens.ts",
 		"./vs/editor/standalone/browser/simpleServices.ts",
+		"./vs/editor/standalone/browser/standaloneCodeEditor.ts",
 		"./vs/editor/standalone/browser/standaloneCodeServiceImpl.ts",
 		"./vs/editor/standalone/browser/standaloneThemeServiceImpl.ts",
 		"./vs/editor/standalone/browser/toggleHighContrast/toggleHighContrast.ts",

src/vs/base/browser/ui/actionbar/actionbar.ts

@@ -228,7 +228,7 @@ export class Separator extends Action {
 export interface IActionItemOptions extends IBaseActionItemOptions {
 	icon?: boolean;
 	label?: boolean;
-	keybinding?: string;
+	keybinding?: string | null;
 }
 
 export class ActionItem extends BaseActionItem {

src/vs/editor/contrib/contextmenu/contextmenu.ts

@@ -20,6 +20,7 @@ import { IContextKeyService } from 'vs/platform/contextkey/common/contextkey';
 import { IContextMenuService, IContextViewService } from 'vs/platform/contextview/browser/contextView';
 import { IKeybindingService } from 'vs/platform/keybinding/common/keybinding';
 import { KeybindingWeight } from 'vs/platform/keybinding/common/keybindingsRegistry';
+import { ITextModel } from 'vs/editor/common/model';
 
 export class ContextMenuController implements IEditorContribution {
 
@@ -60,6 +61,10 @@ export class ContextMenuController implements IEditorContribution {
 	}
 
 	private _onContextMenu(e: IEditorMouseEvent): void {
+		if (!this._editor.hasModel()) {
+			return;
+		}
+
 		if (!this._editor.getConfiguration().contribInfo.contextmenu) {
 			this._editor.focus();
 			// Ensure the cursor is at the position of the mouse click
@@ -88,7 +93,7 @@ export class ContextMenuController implements IEditorContribution {
 		}
 
 		// Unless the user triggerd the context menu through Shift+F10, use the mouse position as menu position
-		let anchor: IAnchor;
+		let anchor: IAnchor | null = null;
 		if (e.target.type !== MouseTargetType.TEXTAREA) {
 			anchor = { x: e.event.posx - 1, width: 2, y: e.event.posy - 1, height: 2 };
 		}
@@ -97,10 +102,13 @@ export class ContextMenuController implements IEditorContribution {
 		this.showContextMenu(anchor);
 	}
 
-	public showContextMenu(anchor?: IAnchor): void {
+	public showContextMenu(anchor?: IAnchor | null): void {
 		if (!this._editor.getConfiguration().contribInfo.contextmenu) {
 			return; // Context menu is turned off through configuration
 		}
+		if (!this._editor.hasModel()) {
+			return;
+		}
 
 		if (!this._contextMenuService) {
 			this._editor.focus();
@@ -108,7 +116,7 @@ export class ContextMenuController implements IEditorContribution {
 		}
 
 		// Find actions available for menu
-		const menuActions = this._getMenuActions();
+		const menuActions = this._getMenuActions(this._editor.getModel());
 
 		// Show menu if we have actions to show
 		if (menuActions.length > 0) {
@@ -116,11 +124,11 @@ export class ContextMenuController implements IEditorContribution {
 		}
 	}
 
-	private _getMenuActions(): IAction[] {
+	private _getMenuActions(model: ITextModel): IAction[] {
 		const result: IAction[] = [];
 
 		let contextMenu = this._menuService.createMenu(MenuId.EditorContext, this._contextKeyService);
-		const groups = contextMenu.getActions({ arg: this._editor.getModel().uri });
+		const groups = contextMenu.getActions({ arg: model.uri });
 		contextMenu.dispose();
 
 		for (let group of groups) {
@@ -133,6 +141,9 @@ export class ContextMenuController implements IEditorContribution {
 	}
 
 	private _doShowContextMenu(actions: IAction[], anchor: IAnchor | null = null): void {
+		if (!this._editor.hasModel()) {
+			return;
+		}
 
 		// Disable hover
 		const oldHoverSetting = this._editor.getConfiguration().contribInfo.hover;
@@ -160,7 +171,7 @@ export class ContextMenuController implements IEditorContribution {
 		// Show menu
 		this._contextMenuIsBeingShownCount++;
 		this._contextMenuService.showContextMenu({
-			getAnchor: () => anchor,
+			getAnchor: () => anchor!,
 
 			getActions: () => actions,
 
@@ -178,7 +189,7 @@ export class ContextMenuController implements IEditorContribution {
 				return new ActionItem(action, action, { icon: true, label: true, isMenu: true });
 			},
 
-			getKeyBinding: (action): ResolvedKeybinding => {
+			getKeyBinding: (action): ResolvedKeybinding | null => {
 				return this._keybindingFor(action);
 			},
 
@@ -192,7 +203,7 @@ export class ContextMenuController implements IEditorContribution {
 		});
 	}
 
-	private _keybindingFor(action: IAction): ResolvedKeybinding {
+	private _keybindingFor(action: IAction): ResolvedKeybinding | null {
 		return this._keybindingService.lookupKeybinding(action.id);
 	}
 

src/vs/editor/contrib/hover/hover.ts

@@ -174,13 +174,13 @@ export class ModesHoverController implements IEditorContribution {
 		if (targetType === MouseTargetType.CONTENT_TEXT) {
 			this.glyphWidget.hide();
 
-			if (this._isHoverEnabled) {
+			if (this._isHoverEnabled && mouseEvent.target.range) {
 				this.contentWidget.startShowingAt(mouseEvent.target.range, HoverStartMode.Delayed, false);
 			}
 		} else if (targetType === MouseTargetType.GUTTER_GLYPH_MARGIN) {
 			this.contentWidget.hide();
 
-			if (this._isHoverEnabled) {
+			if (this._isHoverEnabled && mouseEvent.target.position) {
 				this.glyphWidget.startShowingAt(mouseEvent.target.position.lineNumber);
 			}
 		} else {
@@ -224,11 +224,9 @@ export class ModesHoverController implements IEditorContribution {
 
 		if (this._glyphWidget) {
 			this._glyphWidget.dispose();
-			this._glyphWidget = null;
 		}
 		if (this._contentWidget) {
 			this._contentWidget.dispose();
-			this._contentWidget = null;
 		}
 	}
 }
@@ -256,6 +254,9 @@ class ShowHoverAction extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor): void {
+		if (!editor.hasModel()) {
+			return;
+		}
 		let controller = ModesHoverController.get(editor);
 		if (!controller) {
 			return;

src/vs/editor/contrib/hover/hoverWidgets.ts

@@ -84,7 +84,7 @@ export class ContentHoverWidget extends Widget implements editorBrowser.IContent
 		return this._containerDomNode;
 	}
 
-	public showAt(position: Position, range: Range, focus: boolean): void {
+	public showAt(position: Position, range: Range | null, focus: boolean): void {
 		// Position has changed
 		this._showAtPosition = position;
 		this._showAtRange = range;

src/vs/editor/contrib/hover/modesContentHover.ts

@@ -314,7 +314,7 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 
 		// update column from which to show
 		let renderColumn = Number.MAX_VALUE;
-		let highlightRange = Range.lift(messages[0].range);
+		let highlightRange: Range | null = messages[0].range ? Range.lift(messages[0].range) : null;
 		let fragment = document.createDocumentFragment();
 		let isEmptyHoverContent = true;
 
@@ -326,7 +326,7 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 			}
 
 			renderColumn = Math.min(renderColumn, msg.range.startColumn);
-			highlightRange = Range.plusRange(highlightRange, msg.range);
+			highlightRange = highlightRange ? Range.plusRange(highlightRange, msg.range) : Range.lift(msg.range);
 
 			if (!(msg instanceof ColorHover)) {
 				msg.contents
@@ -357,7 +357,11 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 				const widget = new ColorPickerWidget(fragment, model, this._editor.getConfiguration().pixelRatio, this._themeService);
 
 				getColorPresentations(editorModel, colorInfo, msg.provider, CancellationToken.None).then(colorPresentations => {
-					model.colorPresentations = colorPresentations;
+					model.colorPresentations = colorPresentations || [];
+					if (!this._editor.hasModel()) {
+						// gone...
+						return;
+					}
 					const originalText = this._editor.getModel().getValueInRange(msg.range);
 					model.guessColorPresentation(color, originalText);
 
@@ -400,7 +404,7 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 								alpha: color.rgba.a
 							}
 						}, msg.provider, CancellationToken.None).then((colorPresentations) => {
-							model.colorPresentations = colorPresentations;
+							model.colorPresentations = colorPresentations || [];
 						});
 					};
 
@@ -427,10 +431,10 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 		}
 
 		this._isChangingDecorations = true;
-		this._highlightDecorations = this._editor.deltaDecorations(this._highlightDecorations, [{
+		this._highlightDecorations = this._editor.deltaDecorations(this._highlightDecorations, highlightRange ? [{
 			range: highlightRange,
 			options: ModesContentHoverWidget._DECORATION_OPTIONS
-		}]);
+		}] : []);
 		this._isChangingDecorations = false;
 	}
 

src/vs/editor/contrib/multicursor/multicursor.ts

@@ -54,6 +54,10 @@ export class InsertCursorAbove extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor, args: any): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
 		const useLogicalLine = (args && args.logicalLine === true);
 		const cursors = editor._getCursors();
 		const context = cursors.context;
@@ -99,6 +103,10 @@ export class InsertCursorBelow extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor, args: any): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
 		const useLogicalLine = (args && args.logicalLine === true);
 		const cursors = editor._getCursors();
 		const context = cursors.context;
@@ -154,6 +162,10 @@ class InsertCursorAtEndOfEachLineSelected extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
 		const model = editor.getModel();
 		const selections = editor.getSelections();
 		let newSelections: Selection[] = [];
@@ -177,10 +189,14 @@ class InsertCursorAtEndOfLineSelected extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
 		const selections = editor.getSelections();
 		const lineCount = editor.getModel().getLineCount();
 
-		let newSelections = [];
+		let newSelections: Selection[] = [];
 		for (let i = selections[0].startLineNumber; i <= lineCount; i++) {
 			newSelections.push(new Selection(i, selections[0].startColumn, i, selections[0].endColumn));
 		}
@@ -203,9 +219,13 @@ class InsertCursorAtTopOfLineSelected extends EditorAction {
 	}
 
 	public run(accessor: ServicesAccessor, editor: ICodeEditor): void {
+		if (!editor.hasModel()) {
+			return;
+		}
+
 		const selections = editor.getSelections();
 
-		let newSelections = [];
+		let newSelections: Selection[] = [];
 		for (let i = selections[0].startLineNumber; i >= 1; i--) {
 			newSelections.push(new Selection(i, selections[0].startColumn, i, selections[0].endColumn));
 		}
@@ -226,7 +246,10 @@ export class MultiCursorSessionResult {
 
 export class MultiCursorSession {
 
-	public static create(editor: ICodeEditor, findController: CommonFindController): MultiCursorSession {
+	public static create(editor: ICodeEditor, findController: CommonFindController): MultiCursorSession | null {
+		if (!editor.hasModel()) {
+			return null;
+		}
 		const findState = findController.getState();
 
 		// Find widget owns entirely what we search for if:
@@ -281,10 +304,14 @@ export class MultiCursorSession {
 		public readonly searchText: string,
 		public readonly wholeWord: boolean,
 		public readonly matchCase: boolean,
-		public currentMatch: Selection
+		public currentMatch: Selection | null
 	) { }
 
-	public addSelectionToNextFindMatch(): MultiCursorSessionResult {
+	public addSelectionToNextFindMatch(): MultiCursorSessionResult | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		const nextMatch = this._getNextMatch();
 		if (!nextMatch) {
 			return null;
@@ -294,7 +321,11 @@ export class MultiCursorSession {
 		return new MultiCursorSessionResult(allSelections.concat(nextMatch), nextMatch, ScrollType.Smooth);
 	}
 
-	public moveSelectionToNextFindMatch(): MultiCursorSessionResult {
+	public moveSelectionToNextFindMatch(): MultiCursorSessionResult | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		const nextMatch = this._getNextMatch();
 		if (!nextMatch) {
 			return null;
@@ -304,7 +335,11 @@ export class MultiCursorSession {
 		return new MultiCursorSessionResult(allSelections.slice(0, allSelections.length - 1).concat(nextMatch), nextMatch, ScrollType.Smooth);
 	}
 
-	private _getNextMatch(): Selection {
+	private _getNextMatch(): Selection | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		if (this.currentMatch) {
 			const result = this.currentMatch;
 			this.currentMatch = null;
@@ -323,7 +358,11 @@ export class MultiCursorSession {
 		return new Selection(nextMatch.range.startLineNumber, nextMatch.range.startColumn, nextMatch.range.endLineNumber, nextMatch.range.endColumn);
 	}
 
-	public addSelectionToPreviousFindMatch(): MultiCursorSessionResult {
+	public addSelectionToPreviousFindMatch(): MultiCursorSessionResult | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		const previousMatch = this._getPreviousMatch();
 		if (!previousMatch) {
 			return null;
@@ -333,7 +372,11 @@ export class MultiCursorSession {
 		return new MultiCursorSessionResult(allSelections.concat(previousMatch), previousMatch, ScrollType.Smooth);
 	}
 
-	public moveSelectionToPreviousFindMatch(): MultiCursorSessionResult {
+	public moveSelectionToPreviousFindMatch(): MultiCursorSessionResult | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		const previousMatch = this._getPreviousMatch();
 		if (!previousMatch) {
 			return null;
@@ -343,7 +386,11 @@ export class MultiCursorSession {
 		return new MultiCursorSessionResult(allSelections.slice(0, allSelections.length - 1).concat(previousMatch), previousMatch, ScrollType.Smooth);
 	}
 
-	private _getPreviousMatch(): Selection {
+	private _getPreviousMatch(): Selection | null {
+		if (!this._editor.hasModel()) {
+			return null;
+		}
+
 		if (this.currentMatch) {
 			const result = this.currentMatch;
 			this.currentMatch = null;
@@ -363,6 +410,10 @@ export class MultiCursorSession {
 	}
 
 	public selectAll(): FindMatch[] {
+		if (!this._editor.hasModel()) {
+			return [];
+		}
+
 		this.findController.highlightFindOptions();
 
 		return this._editor.getModel().findMatches(this.searchText, true, false, this.matchCase, this.wholeWord ? this._editor.getConfiguration().wordSeparators : null, false, Constants.MAX_SAFE_SMALL_INTEGER);
@@ -375,7 +426,7 @@ export class MultiCursorSelectionController extends Disposable implements IEdito
 
 	private readonly _editor: ICodeEditor;
 	private _ignoreSelectionChange: boolean;
-	private _session: MultiCursorSession;
+	private _session: MultiCursorSession | null;
 	private _sessionDispose: IDisposable[];
 
 	public static get(editor: ICodeEditor): MultiCursorSelectionController {
@@ -466,7 +517,7 @@ export class MultiCursorSelectionController extends Disposable implements IEdito
 		return new Selection(selection.startLineNumber, word.startColumn, selection.startLineNumber, word.endColumn);
 	}
 
-	private _applySessionResult(result: MultiCursorSessionResult): void {
+	private _applySessionResult(result: MultiCursorSessionResult | null): void {
 		if (!result) {
 			return;
 		}
@@ -476,11 +527,14 @@ export class MultiCursorSelectionController extends Disposable implements IEdito
 		}
 	}
 
-	public getSession(findController: CommonFindController): MultiCursorSession {
+	public getSession(findController: CommonFindController): MultiCursorSession | null {
 		return this._session;
 	}
 
 	public addSelectionToNextFindMatch(findController: CommonFindController): void {
+		if (!this._editor.hasModel()) {
+			return;
+		}
 		if (!this._session) {
 			// If there are multiple cursors, handle the case where they do not all select the same text.
 			const allSelections = this._editor.getSelections();
@@ -527,6 +581,10 @@ export class MultiCursorSelectionController extends Disposable implements IEdito
 	}
 
 	public selectAll(findController: CommonFindController): void {
+		if (!this._editor.hasModel()) {
+			return;
+		}
+
 		let matches: FindMatch[] | null = null;
 
 		const findState = findController.getState();
@@ -578,7 +636,7 @@ export abstract class MultiCursorSelectionControllerAction extends EditorAction
 		}
 		const findController = CommonFindController.get(editor);
 		if (!findController) {
-			return null;
+			return;
 		}
 		this._run(multiCursorController, findController);
 	}
@@ -715,9 +773,9 @@ export class CompatChangeAll extends MultiCursorSelectionControllerAction {
 class SelectionHighlighterState {
 	public readonly searchText: string;
 	public readonly matchCase: boolean;
-	public readonly wordSeparators: string;
+	public readonly wordSeparators: string | null;
 
-	constructor(searchText: string, matchCase: boolean, wordSeparators: string) {
+	constructor(searchText: string, matchCase: boolean, wordSeparators: string | null) {
 		this.searchText = searchText;
 		this.matchCase = matchCase;
 		this.wordSeparators = wordSeparators;
@@ -726,7 +784,7 @@ class SelectionHighlighterState {
 	/**
 	 * Everything equals except for `lastWordUnderCursor`
 	 */
-	public static softEquals(a: SelectionHighlighterState, b: SelectionHighlighterState): boolean {
+	public static softEquals(a: SelectionHighlighterState | null, b: SelectionHighlighterState | null): boolean {
 		if (!a && !b) {
 			return true;
 		}
@@ -748,7 +806,7 @@ export class SelectionHighlighter extends Disposable implements IEditorContribut
 	private _isEnabled: boolean;
 	private decorations: string[];
 	private updateSoon: RunOnceScheduler;
-	private state: SelectionHighlighterState;
+	private state: SelectionHighlighterState | null;
 
 	constructor(editor: ICodeEditor) {
 		super();
@@ -800,12 +858,11 @@ export class SelectionHighlighter extends Disposable implements IEditorContribut
 		this._setState(SelectionHighlighter._createState(this._isEnabled, this.editor));
 	}
 
-	private static _createState(isEnabled: boolean, editor: ICodeEditor): SelectionHighlighterState {
+	private static _createState(isEnabled: boolean, editor: ICodeEditor): SelectionHighlighterState | null {
 		if (!isEnabled) {
 			return null;
 		}
-		const model = editor.getModel();
-		if (!model) {
+		if (!editor.hasModel()) {
 			return null;
 		}
 		const s = editor.getSelection();
@@ -877,7 +934,7 @@ export class SelectionHighlighter extends Disposable implements IEditorContribut
 		return new SelectionHighlighterState(r.searchText, r.matchCase, r.wholeWord ? editor.getConfiguration().wordSeparators : null);
 	}
 
-	private _setState(state: SelectionHighlighterState): void {
+	private _setState(state: SelectionHighlighterState | null): void {
 		if (SelectionHighlighterState.softEquals(this.state, state)) {
 			this.state = state;
 			return;
@@ -889,6 +946,10 @@ export class SelectionHighlighter extends Disposable implements IEditorContribut
 			return;
 		}
 
+		if (!this.editor.hasModel()) {
+			return;
+		}
+
 		const model = this.editor.getModel();
 		if (model.isTooLargeForTokenization()) {
 			// the file is too large, so searching word under cursor in the whole document takes is blocking the UI.

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

@@ -77,7 +77,7 @@ const nlsSingleSelection = nls.localize("singleSelection", "Line {0}, Column {1}
 const nlsMultiSelectionRange = nls.localize("multiSelectionRange", "{0} selections ({1} characters selected)");
 const nlsMultiSelection = nls.localize("multiSelection", "{0} selections");
 
-function getSelectionLabel(selections: Selection[] | null, charactersSelected: number): string | null {
+function getSelectionLabel(selections: Selection[] | null, charactersSelected: number): string {
 	if (!selections || selections.length === 0) {
 		return nlsNoSelection;
 	}
@@ -98,7 +98,7 @@ function getSelectionLabel(selections: Selection[] | null, charactersSelected: n
 		return strings.format(nlsMultiSelection, selections.length);
 	}
 
-	return null;
+	return '';
 }
 
 class AccessibilityHelpWidget extends Widget implements IOverlayWidget {

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

@@ -360,7 +360,7 @@ export class StandaloneDiffEditor extends DiffEditorWidget implements IStandalon
 
 	constructor(
 		domElement: HTMLElement,
-		options: IDiffEditorConstructionOptions,
+		options: IDiffEditorConstructionOptions | undefined,
 		toDispose: IDisposable,
 		@IInstantiationService instantiationService: IInstantiationService,
 		@IContextKeyService contextKeyService: IContextKeyService,

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

@@ -100,7 +100,7 @@ export function onDidCreateEditor(listener: (codeEditor: ICodeEditor) => void):
  * The editor will read the size of `domElement`.
  */
 export function createDiffEditor(domElement: HTMLElement, options?: IDiffEditorConstructionOptions, override?: IEditorOverrideServices): IStandaloneDiffEditor {
-	return withAllStandaloneServices(domElement, override, (services) => {
+	return withAllStandaloneServices(domElement, override || {}, (services) => {
 		return new StandaloneDiffEditor(
 			domElement,
 			options,

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

@@ -53,12 +53,12 @@ export module StaticServices {
 
 	export class LazyStaticService<T> {
 		private _serviceId: ServiceIdentifier<T>;
-		private _factory: (overrides: IEditorOverrideServices) => T;
-		private _value: T;
+		private _factory: (overrides?: IEditorOverrideServices) => T;
+		private _value: T | null;
 
 		public get id() { return this._serviceId; }
 
-		constructor(serviceId: ServiceIdentifier<T>, factory: (overrides: IEditorOverrideServices) => T) {
+		constructor(serviceId: ServiceIdentifier<T>, factory: (overrides?: IEditorOverrideServices) => T) {
 			this._serviceId = serviceId;
 			this._factory = factory;
 			this._value = null;