More strict null checks (#60565)

src/tsconfig.strictNullChecks.json

@@ -358,6 +358,7 @@
 		"./vs/editor/standalone/browser/toggleHighContrast/toggleHighContrast.ts",
 		"./vs/editor/standalone/common/monarch/monarchCommon.ts",
 		"./vs/editor/standalone/common/monarch/monarchCompile.ts",
+		"./vs/editor/standalone/common/monarch/monarchLexer.ts",
 		"./vs/editor/standalone/common/monarch/monarchTypes.ts",
 		"./vs/editor/standalone/common/standaloneThemeService.ts",
 		"./vs/editor/standalone/common/themes.ts",
@@ -565,8 +566,10 @@
 		"./vs/workbench/parts/codeEditor/browser/menuPreventer.ts",
 		"./vs/workbench/parts/codeEditor/browser/simpleEditorOptions.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/accessibility.ts",
+		"./vs/workbench/parts/codeEditor/electron-browser/languageConfiguration/languageConfigurationExtensionPoint.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/largeFileOptimizations.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/selectionClipboard.ts",
+		"./vs/workbench/parts/codeEditor/electron-browser/textMate/inspectTMScopes.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/toggleMinimap.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/toggleMultiCursorModifier.ts",
 		"./vs/workbench/parts/codeEditor/electron-browser/toggleRenderControlCharacter.ts",
@@ -661,6 +664,7 @@
 		"./vs/workbench/services/extensions/electron-browser/inactiveExtensionUrlHandler.ts",
 		"./vs/workbench/services/extensions/node/extensionDescriptionRegistry.ts",
 		"./vs/workbench/services/extensions/node/extensionManagementServerService.ts",
+		"./vs/workbench/services/extensions/node/extensionPoints.ts",
 		"./vs/workbench/services/extensions/node/lazyPromise.ts",
 		"./vs/workbench/services/extensions/node/proxyIdentifier.ts",
 		"./vs/workbench/services/extensions/node/rpcProtocol.ts",
@@ -713,6 +717,7 @@
 		"./vs/workbench/services/search/test/node/textSearchManager.test.ts",
 		"./vs/workbench/services/textMate/electron-browser/TMGrammars.ts",
 		"./vs/workbench/services/textMate/electron-browser/TMHelper.ts",
+		"./vs/workbench/services/textMate/electron-browser/TMSyntax.ts",
 		"./vs/workbench/services/textMate/electron-browser/textMateService.ts",
 		"./vs/workbench/services/textfile/electron-browser/textResourcePropertiesService.ts",
 		"./vs/workbench/services/themes/common/colorExtensionPoint.ts",

src/typings/vscode-textmate.d.ts

@@ -30,7 +30,7 @@ declare module "vscode-textmate" {
 	 */
 	export interface RegistryOptions {
 		theme?: IRawTheme;
-		loadGrammar(scopeName: string): Thenable<IRawGrammar>;
+		loadGrammar(scopeName: string): Thenable<IRawGrammar | null> | null;
 		getInjections?(scopeName: string): string[];
 		getOnigLib?(): Thenable<IOnigLib>;
 	}
@@ -102,7 +102,7 @@ declare module "vscode-textmate" {
 		/**
 		 * Tokenize `lineText` using previous line state `prevState`.
 		 */
-		tokenizeLine(lineText: string, prevState: StackElement): ITokenizeLineResult;
+		tokenizeLine(lineText: string, prevState: StackElement | null): ITokenizeLineResult;
 		/**
 		 * Tokenize `lineText` using previous line state `prevState`.
 		 * The result contains the tokens in binary format, resolved with the following information:
@@ -113,7 +113,7 @@ declare module "vscode-textmate" {
 		 *  - background color
 		 * e.g. for getting the languageId: `(metadata & MetadataConsts.LANGUAGEID_MASK) >>> MetadataConsts.LANGUAGEID_OFFSET`
 		 */
-		tokenizeLine2(lineText: string, prevState: StackElement): ITokenizeLineResult2;
+		tokenizeLine2(lineText: string, prevState: StackElement | null): ITokenizeLineResult2;
 	}
 	export interface ITokenizeLineResult {
 		readonly tokens: IToken[];

src/vs/base/common/htmlContent.ts

@@ -43,7 +43,7 @@ export class MarkdownString implements IMarkdownString {
 	}
 }
 
-export function isEmptyMarkdownString(oneOrMany: IMarkdownString | IMarkdownString[]): boolean {
+export function isEmptyMarkdownString(oneOrMany: IMarkdownString | IMarkdownString[] | null | undefined): boolean {
 	if (isMarkdownString(oneOrMany)) {
 		return !oneOrMany.value;
 	} else if (Array.isArray(oneOrMany)) {

src/vs/editor/common/modes/languageConfiguration.ts

@@ -96,11 +96,11 @@ export interface IndentationRule {
 	/**
 	 * If a line matches this pattern, then **only the next line** after it should be indented once.
 	 */
-	indentNextLinePattern?: RegExp;
+	indentNextLinePattern?: RegExp | null;
 	/**
 	 * If a line matches this pattern, then its indentation should not be changed and it should not be evaluated against the other rules.
 	 */
-	unIndentedLinePattern?: RegExp;
+	unIndentedLinePattern?: RegExp | null;
 
 }
 

src/vs/editor/common/modes/tokenizationRegistry.ts

@@ -5,7 +5,7 @@
 
 import { Color } from 'vs/base/common/color';
 import { Emitter, Event } from 'vs/base/common/event';
-import { IDisposable, toDisposable } from 'vs/base/common/lifecycle';
+import { IDisposable, toDisposable, Disposable } from 'vs/base/common/lifecycle';
 import { ColorId, ITokenizationRegistry, ITokenizationSupport, ITokenizationSupportChangedEvent } from 'vs/editor/common/modes';
 
 export class TokenizationRegistryImpl implements ITokenizationRegistry {
@@ -43,10 +43,14 @@ export class TokenizationRegistryImpl implements ITokenizationRegistry {
 		});
 	}
 
-	public registerPromise(language: string, supportPromise: Thenable<ITokenizationSupport>): Thenable<IDisposable> {
+	public registerPromise(language: string, supportPromise: Thenable<ITokenizationSupport | null>): Thenable<IDisposable> {
 		const promise = this._promises[language] = supportPromise.then(support => {
 			delete this._promises[language];
-			return this.register(language, support);
+			if (support) {
+				return this.register(language, support);
+			} else {
+				return Disposable.None;
+			}
 		});
 		return promise;
 	}

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

@@ -58,10 +58,10 @@ export class HoverOperation<Result> {
 	private _asyncComputationPromiseDone: boolean;
 
 	private _completeCallback: (r: Result) => void;
-	private _errorCallback?: (err: any) => void;
+	private _errorCallback: ((err: any) => void) | null | undefined;
 	private _progressCallback: (progress: any) => void;
 
-	constructor(computer: IHoverComputer<Result>, success: (r: Result) => void, error: undefined | ((err: any) => void), progress: (progress: any) => void, hoverTime: number) {
+	constructor(computer: IHoverComputer<Result>, success: (r: Result) => void, error: ((err: any) => void) | null | undefined, progress: (progress: any) => void, hoverTime: number) {
 		this._computer = computer;
 		this._state = ComputeHoverOperationState.IDLE;
 		this._hoverTime = hoverTime;

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

@@ -40,7 +40,7 @@ class ModesContentComputer implements IHoverComputer<HoverPart[]> {
 
 	private _editor: ICodeEditor;
 	private _result: HoverPart[];
-	private _range: Range;
+	private _range: Range | null;
 
 	constructor(editor: ICodeEditor) {
 		this._editor = editor;
@@ -57,10 +57,14 @@ class ModesContentComputer implements IHoverComputer<HoverPart[]> {
 	}
 
 	computeAsync(token: CancellationToken): Promise<HoverPart[]> {
+		if (!this._editor.hasModel() || !this._range) {
+			return Promise.resolve([]);
+		}
+
 		const model = this._editor.getModel();
 
 		if (!HoverProviderRegistry.has(model)) {
-			return Promise.resolve(null);
+			return Promise.resolve([]);
 		}
 
 		return getHover(model, new Position(
@@ -70,6 +74,10 @@ class ModesContentComputer implements IHoverComputer<HoverPart[]> {
 	}
 
 	computeSync(): HoverPart[] {
+		if (!this._editor.hasModel() || !this._range) {
+			return [];
+		}
+
 		const lineNumber = this._range.startLineNumber;
 
 		if (lineNumber > this._editor.getModel().getLineCount()) {
@@ -157,14 +165,14 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 	static readonly ID = 'editor.contrib.modesContentHoverWidget';
 
 	private _messages: HoverPart[];
-	private _lastRange: Range;
+	private _lastRange: Range | null;
 	private _computer: ModesContentComputer;
 	private _hoverOperation: HoverOperation<HoverPart[]>;
 	private _highlightDecorations: string[];
 	private _isChangingDecorations: boolean;
 	private _markdownRenderer: MarkdownRenderer;
 	private _shouldFocus: boolean;
-	private _colorPicker: ColorPickerWidget;
+	private _colorPicker: ColorPickerWidget | null;
 
 	private renderDisposable: IDisposable = Disposable.None;
 
@@ -175,6 +183,8 @@ export class ModesContentHoverWidget extends ContentHoverWidget {
 	) {
 		super(ModesContentHoverWidget.ID, editor);
 
+		this._messages = [];
+		this._lastRange = null;
 		this._computer = new ModesContentComputer(this._editor);
 		this._highlightDecorations = [];
 		this._isChangingDecorations = false;

src/vs/editor/standalone/common/monarch/monarchLexer.ts

@@ -260,7 +260,7 @@ class MonarchClassicTokensCollector implements IMonarchTokensCollector {
 		}
 		this._lastTokenType = type;
 		this._lastTokenLanguage = this._language;
-		this._tokens.push(new Token(startOffset, type, this._language));
+		this._tokens.push(new Token(startOffset, type, this._language!));
 	}
 
 	public nestedModeTokenize(embeddedModeLine: string, embeddedModeData: EmbeddedModeData, offsetDelta: number): modes.IState {
@@ -306,7 +306,7 @@ class MonarchModernTokensCollector implements IMonarchTokensCollector {
 	}
 
 	public enterMode(startOffset: number, modeId: string): void {
-		this._currentLanguageId = this._modeService.getLanguageIdentifier(modeId).id;
+		this._currentLanguageId = this._modeService.getLanguageIdentifier(modeId)!.id;
 	}
 
 	public emit(startOffset: number, type: string): void {
@@ -417,7 +417,7 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 	}
 
 	public getInitialState(): modes.IState {
-		let rootState = MonarchStackElementFactory.create(null, this._lexer.start);
+		let rootState = MonarchStackElementFactory.create(null, this._lexer.start!);
 		return MonarchLineStateFactory.create(rootState, null);
 	}
 
@@ -506,6 +506,13 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 		return this._myTokenize(restOfTheLine, lineState, offsetDelta + popOffset, tokensCollector);
 	}
 
+	private _safeRuleName(rule: monarchCommon.IRule | null): string {
+		if (rule) {
+			return rule.name;
+		}
+		return '(unknown)';
+	}
+
 	private _myTokenize(line: string, lineState: MonarchLineState, offsetDelta: number, tokensCollector: IMonarchTokensCollector): MonarchLineState {
 		tokensCollector.enterMode(offsetDelta, this._modeId);
 
@@ -519,7 +526,7 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 		// these never need cloning or equality since they are only used within a line match
 		interface GroupMatching {
 			matches: string[];
-			rule: monarchCommon.IRule;
+			rule: monarchCommon.IRule | null;
 			groups: { action: monarchCommon.FuzzyAction; matched: string; }[];
 		}
 		let groupMatching: GroupMatching | null = null;
@@ -599,6 +606,11 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 				action = this._lexer.defaultToken;
 			}
 
+			if (!matched) {
+				// should never happen, needed for strict null checking
+				break;
+			}
+
 			// advance stream
 			pos += matched.length;
 
@@ -647,7 +659,7 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 						nextState = nextState.substr(1); // peel off starting '@'
 					}
 					if (!monarchCommon.findRules(this._lexer, nextState)) {
-						throw monarchCommon.createError(this._lexer, 'trying to switch to a state \'' + nextState + '\' that is undefined in rule: ' + rule.name);
+						throw monarchCommon.createError(this._lexer, 'trying to switch to a state \'' + nextState + '\' that is undefined in rule: ' + this._safeRuleName(rule));
 					} else {
 						stack = stack.switchTo(nextState);
 					}
@@ -657,15 +669,15 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 					if (action.next === '@push') {
 						if (stack.depth >= this._lexer.maxStack) {
 							throw monarchCommon.createError(this._lexer, 'maximum tokenizer stack size reached: [' +
-								stack.state + ',' + stack.parent.state + ',...]');
+								stack.state + ',' + stack.parent!.state + ',...]');
 						} else {
 							stack = stack.push(state);
 						}
 					} else if (action.next === '@pop') {
 						if (stack.depth <= 1) {
-							throw monarchCommon.createError(this._lexer, 'trying to pop an empty stack in rule: ' + rule.name);
+							throw monarchCommon.createError(this._lexer, 'trying to pop an empty stack in rule: ' + this._safeRuleName(rule));
 						} else {
-							stack = stack.pop();
+							stack = stack.pop()!;
 						}
 					} else if (action.next === '@popall') {
 						stack = stack.popall();
@@ -676,7 +688,7 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 						}
 
 						if (!monarchCommon.findRules(this._lexer, nextState)) {
-							throw monarchCommon.createError(this._lexer, 'trying to set a next state \'' + nextState + '\' that is undefined in rule: ' + rule.name);
+							throw monarchCommon.createError(this._lexer, 'trying to set a next state \'' + nextState + '\' that is undefined in rule: ' + this._safeRuleName(rule));
 						} else {
 							stack = stack.push(nextState);
 						}
@@ -690,23 +702,23 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 
 			// check result
 			if (result === null) {
-				throw monarchCommon.createError(this._lexer, 'lexer rule has no well-defined action in rule: ' + rule.name);
+				throw monarchCommon.createError(this._lexer, 'lexer rule has no well-defined action in rule: ' + this._safeRuleName(rule));
 			}
 
 			// is the result a group match?
 			if (Array.isArray(result)) {
 				if (groupMatching && groupMatching.groups.length > 0) {
-					throw monarchCommon.createError(this._lexer, 'groups cannot be nested: ' + rule.name);
+					throw monarchCommon.createError(this._lexer, 'groups cannot be nested: ' + this._safeRuleName(rule));
 				}
 				if (matches.length !== result.length + 1) {
-					throw monarchCommon.createError(this._lexer, 'matched number of groups does not match the number of actions in rule: ' + rule.name);
+					throw monarchCommon.createError(this._lexer, 'matched number of groups does not match the number of actions in rule: ' + this._safeRuleName(rule));
 				}
 				let totalLen = 0;
 				for (let i = 1; i < matches.length; i++) {
 					totalLen += matches[i].length;
 				}
 				if (totalLen !== matched.length) {
-					throw monarchCommon.createError(this._lexer, 'with groups, all characters should be matched in consecutive groups in rule: ' + rule.name);
+					throw monarchCommon.createError(this._lexer, 'with groups, all characters should be matched in consecutive groups in rule: ' + this._safeRuleName(rule));
 				}
 
 				groupMatching = {
@@ -740,7 +752,7 @@ class MonarchTokenizer implements modes.ITokenizationSupport {
 					if (stackLen0 !== stack.depth || state !== stack.state || (!groupMatching ? 0 : groupMatching.groups.length) !== groupLen0) {
 						continue;
 					} else {
-						throw monarchCommon.createError(this._lexer, 'no progress in tokenizer in rule: ' + rule.name);
+						throw monarchCommon.createError(this._lexer, 'no progress in tokenizer in rule: ' + this._safeRuleName(rule));
 						pos = lineLength; // must make progress or editor loops
 					}
 				}

src/vs/workbench/parts/codeEditor/electron-browser/languageConfiguration/languageConfigurationExtensionPoint.ts

@@ -41,7 +41,7 @@ interface ILanguageConfiguration {
 	autoCloseBefore?: string;
 }
 
-function isStringArr(something: string[]): boolean {
+function isStringArr(something: string[] | null): something is string[] {
 	if (!Array.isArray(something)) {
 		return false;
 	}
@@ -54,7 +54,7 @@ function isStringArr(something: string[]): boolean {
 
 }
 
-function isCharacterPair(something: CharacterPair): boolean {
+function isCharacterPair(something: CharacterPair | null): boolean {
 	return (
 		isStringArr(something)
 		&& something.length === 2
@@ -82,7 +82,7 @@ export class LanguageConfigurationFileHandler {
 			});
 		});
 		textMateService.onDidEncounterLanguage((languageId) => {
-			this._loadConfigurationsForMode(this._modeService.getLanguageIdentifier(languageId));
+			this._loadConfigurationsForMode(this._modeService.getLanguageIdentifier(languageId)!);
 		});
 	}
 
@@ -109,7 +109,7 @@ export class LanguageConfigurationFileHandler {
 		});
 	}
 
-	private _extractValidCommentRule(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): CommentRule {
+	private _extractValidCommentRule(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): CommentRule | null {
 		const source = configuration.comments;
 		if (typeof source === 'undefined') {
 			return null;
@@ -139,7 +139,7 @@ export class LanguageConfigurationFileHandler {
 		return result;
 	}
 
-	private _extractValidBrackets(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): CharacterPair[] {
+	private _extractValidBrackets(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): CharacterPair[] | null {
 		const source = configuration.brackets;
 		if (typeof source === 'undefined') {
 			return null;
@@ -163,7 +163,7 @@ export class LanguageConfigurationFileHandler {
 		return result;
 	}
 
-	private _extractValidAutoClosingPairs(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): IAutoClosingPairConditional[] {
+	private _extractValidAutoClosingPairs(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): IAutoClosingPairConditional[] | null {
 		const source = configuration.autoClosingPairs;
 		if (typeof source === 'undefined') {
 			return null;
@@ -209,7 +209,7 @@ export class LanguageConfigurationFileHandler {
 		return result;
 	}
 
-	private _extractValidSurroundingPairs(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): IAutoClosingPair[] {
+	private _extractValidSurroundingPairs(languageIdentifier: LanguageIdentifier, configuration: ILanguageConfiguration): IAutoClosingPair[] | null {
 		const source = configuration.surroundingPairs;
 		if (typeof source === 'undefined') {
 			return null;
@@ -327,7 +327,7 @@ export class LanguageConfigurationFileHandler {
 		return null;
 	}
 
-	private _mapIndentationRules(indentationRules: IIndentationRules): IndentationRule {
+	private _mapIndentationRules(indentationRules: IIndentationRules): IndentationRule | null {
 		try {
 			let increaseIndentPattern = this._parseRegex(indentationRules.increaseIndentPattern);
 			let decreaseIndentPattern = this._parseRegex(indentationRules.decreaseIndentPattern);

src/vs/workbench/parts/codeEditor/electron-browser/textMate/inspectTMScopes.ts

@@ -116,7 +116,7 @@ class InspectTMScopes extends EditorAction {
 }
 
 interface ICompleteLineTokenization {
-	startState: StackElement;
+	startState: StackElement | null;
 	tokens1: IToken[];
 	tokens2: Uint32Array;
 	endState: StackElement;
@@ -347,7 +347,7 @@ class InspectTMScopesWidget extends Disposable implements IContentWidget {
 		};
 	}
 
-	private _getStateBeforeLine(grammar: IGrammar, lineNumber: number): StackElement {
+	private _getStateBeforeLine(grammar: IGrammar, lineNumber: number): StackElement | null {
 		let state: StackElement | null = null;
 
 		for (let i = 1; i < lineNumber; i++) {

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

@@ -7,6 +7,7 @@ import * as nls from 'vs/nls';
 import * as path from 'path';
 import * as semver from 'semver';
 import * as json from 'vs/base/common/json';
+import * as arrays from 'vs/base/common/arrays';
 import { getParseErrorMessage } from 'vs/base/common/jsonErrorMessages';
 import * as types from 'vs/base/common/types';
 import { URI } from 'vs/base/common/uri';
@@ -125,11 +126,11 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 		}
 
 		interface LocalizedMessages {
-			values: MessageBag;
-			default: string;
+			values: MessageBag | undefined;
+			default: string | null;
 		}
 
-		const reportErrors = (localized: string, errors: json.ParseError[]): void => {
+		const reportErrors = (localized: string | null, errors: json.ParseError[]): void => {
 			errors.forEach((error) => {
 				this._log.error(this._absoluteFolderPath, nls.localize('jsonsParseReportErrors', "Failed to parse {0}: {1}.", localized, getParseErrorMessage(error.error)));
 			});
@@ -140,7 +141,7 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 
 		const translationId = `${extensionDescription.publisher}.${extensionDescription.name}`;
 		let translationPath = this._nlsConfig.translations[translationId];
-		let localizedMessages: Promise<LocalizedMessages>;
+		let localizedMessages: Promise<LocalizedMessages | undefined>;
 		if (translationPath) {
 			localizedMessages = pfs.readFile(translationPath, 'utf8').then<LocalizedMessages, LocalizedMessages>((content) => {
 				let errors: json.ParseError[] = [];
@@ -156,7 +157,7 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 				return { values: undefined, default: `${basename}.nls.json` };
 			});
 		} else {
-			localizedMessages = pfs.fileExists(basename + '.nls' + extension).then<LocalizedMessages, undefined | LocalizedMessages>(exists => {
+			localizedMessages = pfs.fileExists(basename + '.nls' + extension).then<LocalizedMessages | undefined, LocalizedMessages | undefined>(exists => {
 				if (!exists) {
 					return undefined;
 				}
@@ -204,8 +205,8 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 	/**
 	 * Parses original message bundle, returns null if the original message bundle is null.
 	 */
-	private static resolveOriginalMessageBundle(originalMessageBundle: string, errors: json.ParseError[]) {
-		return new Promise<{ [key: string]: string; }>((c, e) => {
+	private static resolveOriginalMessageBundle(originalMessageBundle: string | null, errors: json.ParseError[]) {
+		return new Promise<{ [key: string]: string; } | null>((c, e) => {
 			if (originalMessageBundle) {
 				pfs.readFile(originalMessageBundle).then(originalBundleContent => {
 					c(json.parse(originalBundleContent.toString(), errors));
@@ -222,8 +223,8 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 	 * Finds localized message bundle and the original (unlocalized) one.
 	 * If the localized file is not present, returns null for the original and marks original as localized.
 	 */
-	private static findMessageBundles(nlsConfig: NlsConfiguration, basename: string): Promise<{ localized: string, original: string }> {
-		return new Promise<{ localized: string, original: string }>((c, e) => {
+	private static findMessageBundles(nlsConfig: NlsConfiguration, basename: string): Promise<{ localized: string; original: string | null; }> {
+		return new Promise<{ localized: string; original: string | null; }>((c, e) => {
 			function loop(basename: string, locale: string): void {
 				let toCheck = `${basename}.nls.${locale}.json`;
 				pfs.fileExists(toCheck).then(exists => {
@@ -251,7 +252,7 @@ class ExtensionManifestNLSReplacer extends ExtensionManifestHandler {
 	 * This routine makes the following assumptions:
 	 * The root element is an object literal
 	 */
-	private static _replaceNLStrings<T>(nlsConfig: NlsConfiguration, literal: T, messages: { [key: string]: string; }, originalMessages: { [key: string]: string }, log: ILog, messageScope: string): void {
+	private static _replaceNLStrings<T>(nlsConfig: NlsConfiguration, literal: T, messages: { [key: string]: string; }, originalMessages: { [key: string]: string } | null, log: ILog, messageScope: string): void {
 		function processEntry(obj: any, key: string | number, command?: boolean) {
 			let value = obj[key];
 			if (types.isString(value)) {
@@ -313,7 +314,7 @@ export interface IRelaxedExtensionDescription {
 }
 
 class ExtensionManifestValidator extends ExtensionManifestHandler {
-	validate(_extensionDescription: IExtensionDescription): IExtensionDescription {
+	validate(_extensionDescription: IExtensionDescription): IExtensionDescription | null {
 		let extensionDescription = <IRelaxedExtensionDescription>_extensionDescription;
 		extensionDescription.isBuiltin = this._isBuiltin;
 		extensionDescription.isUnderDevelopment = this._isUnderDevelopment;
@@ -502,11 +503,11 @@ export class ExtensionScanner {
 	/**
 	 * Read the extension defined in `absoluteFolderPath`
 	 */
-	public static scanExtension(version: string, log: ILog, absoluteFolderPath: string, isBuiltin: boolean, isUnderDevelopment: boolean, nlsConfig: NlsConfiguration): Promise<IExtensionDescription> {
+	public static scanExtension(version: string, log: ILog, absoluteFolderPath: string, isBuiltin: boolean, isUnderDevelopment: boolean, nlsConfig: NlsConfiguration): Promise<IExtensionDescription | null> {
 		absoluteFolderPath = path.normalize(absoluteFolderPath);
 
 		let parser = new ExtensionManifestParser(version, log, absoluteFolderPath, isBuiltin, isUnderDevelopment);
-		return parser.parse().then((extensionDescription) => {
+		return parser.parse().then<IExtensionDescription | null>((extensionDescription) => {
 			if (extensionDescription === null) {
 				return null;
 			}
@@ -570,7 +571,8 @@ export class ExtensionScanner {
 			}
 
 			const nlsConfig = ExtensionScannerInput.createNLSConfig(input);
-			let extensionDescriptions = await Promise.all(refs.map(r => this.scanExtension(input.ourVersion, log, r.path, isBuiltin, isUnderDevelopment, nlsConfig)));
+			let _extensionDescriptions = await Promise.all(refs.map(r => this.scanExtension(input.ourVersion, log, r.path, isBuiltin, isUnderDevelopment, nlsConfig)));
+			let extensionDescriptions = arrays.coalesce(_extensionDescriptions);
 			extensionDescriptions = extensionDescriptions.filter(item => item !== null && !obsolete[getLocalExtensionId(getGalleryExtensionId(item.publisher, item.name), item.version)]);
 
 			if (!isBuiltin) {

src/vs/workbench/services/textMate/electron-browser/TMSyntax.ts

@@ -57,7 +57,7 @@ export class TMScopeRegistry {
 		return this._scopeNameToLanguageRegistration[scopeName] || null;
 	}
 
-	public getGrammarLocation(scopeName: string): URI {
+	public getGrammarLocation(scopeName: string): URI | null {
 		let data = this.getLanguageRegistration(scopeName);
 		return data ? data.grammarLocation : null;
 	}
@@ -81,7 +81,7 @@ export class TMLanguageRegistration {
 	readonly embeddedLanguages: IEmbeddedLanguagesMap;
 	readonly tokenTypes: ITokenTypeMap;
 
-	constructor(scopeName: string, grammarLocation: URI, embeddedLanguages: IEmbeddedLanguagesMap, tokenTypes: TokenTypesContribution | undefined) {
+	constructor(scopeName: string, grammarLocation: URI, embeddedLanguages: IEmbeddedLanguagesMap | undefined, tokenTypes: TokenTypesContribution | undefined) {
 		this.scopeName = scopeName;
 		this.grammarLocation = grammarLocation;
 
@@ -135,7 +135,7 @@ interface ICreateGrammarResult {
 export class TextMateService implements ITextMateService {
 	public _serviceBrand: any;
 
-	private _grammarRegistry: Promise<[Registry, StackElement]>;
+	private _grammarRegistry: Promise<[Registry, StackElement]> | null;
 	private _modeService: IModeService;
 	private _themeService: IWorkbenchThemeService;
 	private _fileService: IFileService;
@@ -199,7 +199,7 @@ export class TextMateService implements ITextMateService {
 				}
 			}
 		}
-		TokenizationRegistry.setColorMap([null, defaultForeground, defaultBackground]);
+		TokenizationRegistry.setColorMap([null!, defaultForeground, defaultBackground]);
 
 		this._modeService.onDidCreateMode((mode) => {
 			let modeId = mode.getId();
@@ -249,7 +249,7 @@ export class TextMateService implements ITextMateService {
 	}
 
 	private static _toColorMap(colorMap: string[]): Color[] {
-		let result: Color[] = [null];
+		let result: Color[] = [null!];
 		for (let i = 1, len = colorMap.length; i < len; i++) {
 			result[i] = Color.fromHex(colorMap[i]);
 		}
@@ -390,7 +390,7 @@ export class TextMateService implements ITextMateService {
 			}
 		}
 
-		let languageId = this._modeService.getLanguageIdentifier(modeId).id;
+		let languageId = this._modeService.getLanguageIdentifier(modeId)!.id;
 		let containsEmbeddedLanguages = (Object.keys(embeddedLanguages).length > 0);
 		return this._getOrCreateGrammarRegistry().then((_res) => {
 			const [grammarRegistry, initialState] = _res;