Revert "Revert "Merge from vscode ada4bddb8edc69eea6ebaaa0e88c5f903cbd43d8 (#5529)" (#5553)" (#5562)

This reverts commit c9a4f8f664.

src/vs/editor/browser/controller/coreCommands.ts

@@ -301,13 +301,13 @@ export namespace CoreNavigationCommands {
 	export const MoveTo: CoreEditorCommand = registerEditorCommand(new BaseMoveToCommand({
 		id: '_moveTo',
 		inSelectionMode: false,
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const MoveToSelect: CoreEditorCommand = registerEditorCommand(new BaseMoveToCommand({
 		id: '_moveToSelect',
 		inSelectionMode: true,
-		precondition: null
+		precondition: undefined
 	}));
 
 	abstract class ColumnSelectCommand extends CoreEditorCommand {
@@ -330,7 +330,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'columnSelect',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -354,7 +354,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'cursorColumnSelectLeft',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -373,7 +373,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'cursorColumnSelectRight',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -405,7 +405,7 @@ export namespace CoreNavigationCommands {
 	export const CursorColumnSelectUp: CoreEditorCommand = registerEditorCommand(new ColumnSelectUpCommand({
 		isPaged: false,
 		id: 'cursorColumnSelectUp',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -417,7 +417,7 @@ export namespace CoreNavigationCommands {
 	export const CursorColumnSelectPageUp: CoreEditorCommand = registerEditorCommand(new ColumnSelectUpCommand({
 		isPaged: true,
 		id: 'cursorColumnSelectPageUp',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -443,7 +443,7 @@ export namespace CoreNavigationCommands {
 	export const CursorColumnSelectDown: CoreEditorCommand = registerEditorCommand(new ColumnSelectDownCommand({
 		isPaged: false,
 		id: 'cursorColumnSelectDown',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -455,7 +455,7 @@ export namespace CoreNavigationCommands {
 	export const CursorColumnSelectPageDown: CoreEditorCommand = registerEditorCommand(new ColumnSelectDownCommand({
 		isPaged: true,
 		id: 'cursorColumnSelectPageDown',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -468,7 +468,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'cursorMove',
-				precondition: null,
+				precondition: undefined,
 				description: CursorMove_.description
 			});
 		}
@@ -531,7 +531,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorLeft',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -548,7 +548,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorLeftSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -564,7 +564,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorRight',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -581,7 +581,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorRightSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -597,7 +597,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorUp',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -614,7 +614,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorUpSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -633,7 +633,7 @@ export namespace CoreNavigationCommands {
 			value: Constants.PAGE_SIZE_MARKER
 		},
 		id: 'cursorPageUp',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -649,7 +649,7 @@ export namespace CoreNavigationCommands {
 			value: Constants.PAGE_SIZE_MARKER
 		},
 		id: 'cursorPageUpSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -665,7 +665,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorDown',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -682,7 +682,7 @@ export namespace CoreNavigationCommands {
 			value: 1
 		},
 		id: 'cursorDownSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -701,7 +701,7 @@ export namespace CoreNavigationCommands {
 			value: Constants.PAGE_SIZE_MARKER
 		},
 		id: 'cursorPageDown',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -717,7 +717,7 @@ export namespace CoreNavigationCommands {
 			value: Constants.PAGE_SIZE_MARKER
 		},
 		id: 'cursorPageDownSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -729,7 +729,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'createCursor',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -790,7 +790,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: '_lastCursorMoveToSelect',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -835,7 +835,7 @@ export namespace CoreNavigationCommands {
 	export const CursorHome: CoreEditorCommand = registerEditorCommand(new HomeCommand({
 		inSelectionMode: false,
 		id: 'cursorHome',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -847,7 +847,7 @@ export namespace CoreNavigationCommands {
 	export const CursorHomeSelect: CoreEditorCommand = registerEditorCommand(new HomeCommand({
 		inSelectionMode: true,
 		id: 'cursorHomeSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -860,7 +860,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'cursorLineStart',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -914,7 +914,7 @@ export namespace CoreNavigationCommands {
 	export const CursorEnd: CoreEditorCommand = registerEditorCommand(new EndCommand({
 		inSelectionMode: false,
 		id: 'cursorEnd',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -926,7 +926,7 @@ export namespace CoreNavigationCommands {
 	export const CursorEndSelect: CoreEditorCommand = registerEditorCommand(new EndCommand({
 		inSelectionMode: true,
 		id: 'cursorEndSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -939,7 +939,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'cursorLineEnd',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -994,7 +994,7 @@ export namespace CoreNavigationCommands {
 	export const CursorTop: CoreEditorCommand = registerEditorCommand(new TopCommand({
 		inSelectionMode: false,
 		id: 'cursorTop',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -1006,7 +1006,7 @@ export namespace CoreNavigationCommands {
 	export const CursorTopSelect: CoreEditorCommand = registerEditorCommand(new TopCommand({
 		inSelectionMode: true,
 		id: 'cursorTopSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -1038,7 +1038,7 @@ export namespace CoreNavigationCommands {
 	export const CursorBottom: CoreEditorCommand = registerEditorCommand(new BottomCommand({
 		inSelectionMode: false,
 		id: 'cursorBottom',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -1050,7 +1050,7 @@ export namespace CoreNavigationCommands {
 	export const CursorBottomSelect: CoreEditorCommand = registerEditorCommand(new BottomCommand({
 		inSelectionMode: true,
 		id: 'cursorBottomSelect',
-		precondition: null,
+		precondition: undefined,
 		kbOpts: {
 			weight: CORE_WEIGHT,
 			kbExpr: EditorContextKeys.textInputFocus,
@@ -1063,7 +1063,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'editorScroll',
-				precondition: null,
+				precondition: undefined,
 				description: EditorScroll_.description
 			});
 		}
@@ -1134,7 +1134,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'scrollLineUp',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -1159,7 +1159,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'scrollPageUp',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -1185,7 +1185,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'scrollLineDown',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -1210,7 +1210,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'scrollPageDown',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -1257,20 +1257,20 @@ export namespace CoreNavigationCommands {
 	export const WordSelect: CoreEditorCommand = registerEditorCommand(new WordCommand({
 		inSelectionMode: false,
 		id: '_wordSelect',
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const WordSelectDrag: CoreEditorCommand = registerEditorCommand(new WordCommand({
 		inSelectionMode: true,
 		id: '_wordSelectDrag',
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const LastCursorWordSelect: CoreEditorCommand = registerEditorCommand(new class extends CoreEditorCommand {
 		constructor() {
 			super({
 				id: 'lastCursorWordSelect',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -1317,13 +1317,13 @@ export namespace CoreNavigationCommands {
 	export const LineSelect: CoreEditorCommand = registerEditorCommand(new LineCommand({
 		inSelectionMode: false,
 		id: '_lineSelect',
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const LineSelectDrag: CoreEditorCommand = registerEditorCommand(new LineCommand({
 		inSelectionMode: true,
 		id: '_lineSelectDrag',
-		precondition: null
+		precondition: undefined
 	}));
 
 	class LastCursorLineCommand extends CoreEditorCommand {
@@ -1353,20 +1353,20 @@ export namespace CoreNavigationCommands {
 	export const LastCursorLineSelect: CoreEditorCommand = registerEditorCommand(new LastCursorLineCommand({
 		inSelectionMode: false,
 		id: 'lastCursorLineSelect',
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const LastCursorLineSelectDrag: CoreEditorCommand = registerEditorCommand(new LastCursorLineCommand({
 		inSelectionMode: true,
 		id: 'lastCursorLineSelectDrag',
-		precondition: null
+		precondition: undefined
 	}));
 
 	export const ExpandLineSelection: CoreEditorCommand = registerEditorCommand(new class extends CoreEditorCommand {
 		constructor() {
 			super({
 				id: 'expandLineSelection',
-				precondition: null,
+				precondition: undefined,
 				kbOpts: {
 					weight: CORE_WEIGHT,
 					kbExpr: EditorContextKeys.textInputFocus,
@@ -1445,7 +1445,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'revealLine',
-				precondition: null,
+				precondition: undefined,
 				description: RevealLine_.description
 			});
 		}
@@ -1493,7 +1493,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'selectAll',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -1513,7 +1513,7 @@ export namespace CoreNavigationCommands {
 		constructor() {
 			super({
 				id: 'setSelection',
-				precondition: null
+				precondition: undefined
 			});
 		}
 
@@ -1728,7 +1728,7 @@ class EditorHandlerCommand extends Command {
 	constructor(id: string, handlerId: string, description?: ICommandHandlerDescription) {
 		super({
 			id: id,
-			precondition: null,
+			precondition: undefined,
 			description: description
 		});
 		this._handlerId = handlerId;

src/vs/editor/browser/editorExtensions.ts

@@ -40,17 +40,17 @@ export interface ICommandMenubarOptions {
 }
 export interface ICommandOptions {
 	id: string;
-	precondition: ContextKeyExpr | null;
-	kbOpts?: ICommandKeybindingsOptions | null;
+	precondition: ContextKeyExpr | undefined;
+	kbOpts?: ICommandKeybindingsOptions;
 	description?: ICommandHandlerDescription;
 	menubarOpts?: ICommandMenubarOptions;
 }
 export abstract class Command {
 	public readonly id: string;
-	public readonly precondition: ContextKeyExpr | null;
-	private readonly _kbOpts: ICommandKeybindingsOptions | null | undefined;
-	private readonly _menubarOpts: ICommandMenubarOptions | null | undefined;
-	private readonly _description: ICommandHandlerDescription | null | undefined;
+	public readonly precondition: ContextKeyExpr | undefined;
+	private readonly _kbOpts: ICommandKeybindingsOptions | undefined;
+	private readonly _menubarOpts: ICommandMenubarOptions | undefined;
+	private readonly _description: ICommandHandlerDescription | undefined;
 
 	constructor(opts: ICommandOptions) {
 		this.id = opts.id;

src/vs/editor/common/services/getIconClasses.ts

@@ -19,14 +19,11 @@ export function getIconClasses(modelService: IModelService, modeService: IModeSe
 
 		// Get the path and name of the resource. For data-URIs, we need to parse specially
 		let name: string | undefined;
-		let path: string | undefined;
 		if (resource.scheme === Schemas.data) {
 			const metadata = DataUri.parseMetaData(resource);
 			name = metadata.get(DataUri.META_DATA_LABEL);
-			path = name;
 		} else {
 			name = cssEscape(basenameOrAuthority(resource).toLowerCase());
-			path = resource.path.toLowerCase();
 		}
 
 		// Folders
@@ -47,46 +44,60 @@ export function getIconClasses(modelService: IModelService, modeService: IModeSe
 				classes.push(`ext-file-icon`); // extra segment to increase file-ext score
 			}
 
-			// Configured Language
-			let configuredLangId: string | null = getConfiguredLangId(modelService, modeService, resource);
-			configuredLangId = configuredLangId || (path ? modeService.getModeIdByFilepathOrFirstLine(path) : null);
-			if (configuredLangId) {
-				classes.push(`${cssEscape(configuredLangId)}-lang-file-icon`);
+			// Detected Mode
+			const detectedModeId = detectModeId(modelService, modeService, resource);
+			if (detectedModeId) {
+				classes.push(`${cssEscape(detectedModeId)}-lang-file-icon`);
 			}
 		}
 	}
 	return classes;
 }
 
-export function getConfiguredLangId(modelService: IModelService, modeService: IModeService, resource: uri): string | null {
-	let configuredLangId: string | null = null;
-	if (resource) {
-		let modeId: string | null = null;
+export function detectModeId(modelService: IModelService, modeService: IModeService, resource: uri): string | null {
+	if (!resource) {
+		return null; // we need a resource at least
+	}
 
-		// Data URI: check for encoded metadata
-		if (resource.scheme === Schemas.data) {
-			const metadata = DataUri.parseMetaData(resource);
-			const mime = metadata.get(DataUri.META_DATA_MIME);
+	let modeId: string | null = null;
 
-			if (mime) {
-				modeId = modeService.getModeId(mime);
-			}
-		}
+	// Data URI: check for encoded metadata
+	if (resource.scheme === Schemas.data) {
+		const metadata = DataUri.parseMetaData(resource);
+		const mime = metadata.get(DataUri.META_DATA_MIME);
 
-		// Any other URI: check for model if existing
-		else {
-			const model = modelService.getModel(resource);
-			if (model) {
-				modeId = model.getLanguageIdentifier().language;
-			}
-		}
-
-		if (modeId && modeId !== PLAINTEXT_MODE_ID) {
-			configuredLangId = modeId; // only take if the mode is specific (aka no just plain text)
+		if (mime) {
+			modeId = modeService.getModeId(mime);
 		}
 	}
 
-	return configuredLangId;
+	// Any other URI: check for model if existing
+	else {
+		const model = modelService.getModel(resource);
+		if (model) {
+			modeId = model.getModeId();
+		}
+	}
+
+	// only take if the mode is specific (aka no just plain text)
+	if (modeId && modeId !== PLAINTEXT_MODE_ID) {
+		return modeId;
+	}
+
+	// otherwise fallback to path based detection
+	let path: string | undefined;
+	if (resource.scheme === Schemas.data) {
+		const metadata = DataUri.parseMetaData(resource);
+		path = metadata.get(DataUri.META_DATA_LABEL);
+	} else {
+		path = resource.path.toLowerCase();
+	}
+
+	if (path) {
+		return modeService.getModeIdByFilepathOrFirstLine(path);
+	}
+
+	return null; // finally - we do not know the mode id
 }
 
 export function cssEscape(val: string): string {

src/vs/editor/common/services/resolverService.ts

@@ -5,7 +5,7 @@
 
 import { IDisposable, IReference } from 'vs/base/common/lifecycle';
 import { URI } from 'vs/base/common/uri';
-import { ITextModel } from 'vs/editor/common/model';
+import { ITextModel, ITextSnapshot } from 'vs/editor/common/model';
 import { IEditorModel } from 'vs/platform/editor/common/editor';
 import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
 
@@ -46,6 +46,12 @@ export interface ITextEditorModel extends IEditorModel {
 	 */
 	readonly textEditorModel: ITextModel | null;
 
+	/**
+	 * Creates a snapshot of the model's contents.
+	 */
+	createSnapshot(this: IResolvedTextEditorModel): ITextSnapshot;
+	createSnapshot(this: ITextEditorModel): ITextSnapshot | null;
+
 	isReadonly(): boolean;
 }
 

src/vs/editor/contrib/bracketMatching/bracketMatching.ts

@@ -31,7 +31,7 @@ class JumpToBracketAction extends EditorAction {
 			id: 'editor.action.jumpToBracket',
 			label: nls.localize('smartSelect.jumpBracket', "Go to Bracket"),
 			alias: 'Go to Bracket',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.US_BACKSLASH,
@@ -55,7 +55,7 @@ class SelectToBracketAction extends EditorAction {
 			id: 'editor.action.selectToBracket',
 			label: nls.localize('smartSelect.selectToBracket', "Select to Bracket"),
 			alias: 'Select to Bracket',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/contrib/clipboard/clipboard.ts

@@ -59,7 +59,7 @@ abstract class ExecCommandAction extends EditorAction {
 class ExecCommandCutAction extends ExecCommandAction {
 
 	constructor() {
-		let kbOpts: ICommandKeybindingsOptions | null = {
+		let kbOpts: ICommandKeybindingsOptions | undefined = {
 			kbExpr: EditorContextKeys.textInputFocus,
 			primary: KeyMod.CtrlCmd | KeyCode.KEY_X,
 			win: { primary: KeyMod.CtrlCmd | KeyCode.KEY_X, secondary: [KeyMod.Shift | KeyCode.Delete] },
@@ -68,7 +68,7 @@ class ExecCommandCutAction extends ExecCommandAction {
 		// Do not bind cut keybindings in the browser,
 		// since browsers do that for us and it avoids security prompts
 		if (!platform.isNative) {
-			kbOpts = null;
+			kbOpts = undefined;
 		}
 		super('cut', {
 			id: 'editor.action.clipboardCutAction',
@@ -107,7 +107,7 @@ class ExecCommandCutAction extends ExecCommandAction {
 class ExecCommandCopyAction extends ExecCommandAction {
 
 	constructor() {
-		let kbOpts: ICommandKeybindingsOptions | null = {
+		let kbOpts: ICommandKeybindingsOptions | undefined = {
 			kbExpr: EditorContextKeys.textInputFocus,
 			primary: KeyMod.CtrlCmd | KeyCode.KEY_C,
 			win: { primary: KeyMod.CtrlCmd | KeyCode.KEY_C, secondary: [KeyMod.CtrlCmd | KeyCode.Insert] },
@@ -116,14 +116,14 @@ class ExecCommandCopyAction extends ExecCommandAction {
 		// Do not bind copy keybindings in the browser,
 		// since browsers do that for us and it avoids security prompts
 		if (!platform.isNative) {
-			kbOpts = null;
+			kbOpts = undefined;
 		}
 
 		super('copy', {
 			id: 'editor.action.clipboardCopyAction',
 			label: nls.localize('actions.clipboard.copyLabel', "Copy"),
 			alias: 'Copy',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: kbOpts,
 			menuOpts: {
 				group: CLIPBOARD_CONTEXT_MENU_GROUP,
@@ -162,7 +162,7 @@ class ExecCommandCopyAction extends ExecCommandAction {
 class ExecCommandPasteAction extends ExecCommandAction {
 
 	constructor() {
-		let kbOpts: ICommandKeybindingsOptions | null = {
+		let kbOpts: ICommandKeybindingsOptions | undefined = {
 			kbExpr: EditorContextKeys.textInputFocus,
 			primary: KeyMod.CtrlCmd | KeyCode.KEY_V,
 			win: { primary: KeyMod.CtrlCmd | KeyCode.KEY_V, secondary: [KeyMod.Shift | KeyCode.Insert] },
@@ -171,7 +171,7 @@ class ExecCommandPasteAction extends ExecCommandAction {
 		// Do not bind paste keybindings in the browser,
 		// since browsers do that for us and it avoids security prompts
 		if (!platform.isNative) {
-			kbOpts = null;
+			kbOpts = undefined;
 		}
 
 		super('paste', {
@@ -201,7 +201,7 @@ class ExecCommandCopyWithSyntaxHighlightingAction extends ExecCommandAction {
 			id: 'editor.action.clipboardCopyWithSyntaxHighlightingAction',
 			label: nls.localize('actions.clipboard.copyWithSyntaxHighlightingLabel', "Copy With Syntax Highlighting"),
 			alias: 'Copy With Syntax Highlighting',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: 0,

src/vs/editor/contrib/codeAction/codeAction.ts

@@ -34,8 +34,8 @@ export class CodeActionSet {
 
 	public readonly actions: readonly CodeAction[];
 
-	public constructor(actions: CodeAction[]) {
-		this.actions = mergeSort(actions, CodeActionSet.codeActionsComparator);
+	public constructor(actions: readonly CodeAction[]) {
+		this.actions = mergeSort([...actions], CodeActionSet.codeActionsComparator);
 	}
 
 	public get hasAutoFix() {

src/vs/editor/contrib/codeAction/codeActionCommands.ts

@@ -176,6 +176,7 @@ function showCodeActionsForEditorSelection(
 		return;
 	}
 
+	MessageController.get(editor).closeMessage();
 	const pos = editor.getPosition();
 	controller.triggerFromEditorSelection(filter, autoApply).then(codeActions => {
 		if (!codeActions || !codeActions.actions.length) {

src/vs/editor/contrib/codeAction/codeActionTrigger.ts

@@ -20,8 +20,12 @@ export class CodeActionKind {
 		public readonly value: string
 	) { }
 
+	public equals(other: CodeActionKind): boolean {
+		return this.value === other.value;
+	}
+
 	public contains(other: CodeActionKind): boolean {
-		return this.value === other.value || startsWith(other.value, this.value + CodeActionKind.sep);
+		return this.equals(other) || startsWith(other.value, this.value + CodeActionKind.sep);
 	}
 
 	public intersects(other: CodeActionKind): boolean {

src/vs/editor/contrib/colorPicker/colorDetector.ts

@@ -76,9 +76,9 @@ export class ColorDetector implements IEditorContribution {
 		}
 		const languageId = model.getLanguageIdentifier();
 		// handle deprecated settings. [languageId].colorDecorators.enable
-		let deprecatedConfig = this._configurationService.getValue(languageId.language);
+		const deprecatedConfig = this._configurationService.getValue<{}>(languageId.language);
 		if (deprecatedConfig) {
-			let colorDecorators = deprecatedConfig['colorDecorators']; // deprecatedConfig.valueOf('.colorDecorators.enable');
+			const colorDecorators = deprecatedConfig['colorDecorators']; // deprecatedConfig.valueOf('.colorDecorators.enable');
 			if (colorDecorators && colorDecorators['enable'] !== undefined && !colorDecorators['enable']) {
 				return colorDecorators['enable'];
 			}

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

@@ -6,7 +6,7 @@
 import * as nls from 'vs/nls';
 import * as dom from 'vs/base/browser/dom';
 import { IKeyboardEvent } from 'vs/base/browser/keyboardEvent';
-import { ActionItem, Separator } from 'vs/base/browser/ui/actionbar/actionbar';
+import { ActionViewItem, Separator } from 'vs/base/browser/ui/actionbar/actionbar';
 import { IAnchor } from 'vs/base/browser/ui/contextview/contextview';
 import { IAction } from 'vs/base/common/actions';
 import { KeyCode, KeyMod, ResolvedKeybinding } from 'vs/base/common/keyCodes';
@@ -176,18 +176,18 @@ export class ContextMenuController implements IEditorContribution {
 
 			getActions: () => actions,
 
-			getActionItem: (action) => {
+			getActionViewItem: (action) => {
 				const keybinding = this._keybindingFor(action);
 				if (keybinding) {
-					return new ActionItem(action, action, { label: true, keybinding: keybinding.getLabel(), isMenu: true });
+					return new ActionViewItem(action, action, { label: true, keybinding: keybinding.getLabel(), isMenu: true });
 				}
 
-				const customActionItem = <any>action;
-				if (typeof customActionItem.getActionItem === 'function') {
-					return customActionItem.getActionItem();
+				const customActionViewItem = <any>action;
+				if (typeof customActionViewItem.getActionViewItem === 'function') {
+					return customActionViewItem.getActionViewItem();
 				}
 
-				return new ActionItem(action, action, { icon: true, label: true, isMenu: true });
+				return new ActionViewItem(action, action, { icon: true, label: true, isMenu: true });
 			},
 
 			getKeyBinding: (action): ResolvedKeybinding | undefined => {
@@ -228,7 +228,7 @@ class ShowContextMenu extends EditorAction {
 			id: 'editor.action.showContextMenu',
 			label: nls.localize('action.showContextMenu.label', "Show Editor Context Menu"),
 			alias: 'Show Editor Context Menu',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.Shift | KeyCode.F10,

src/vs/editor/contrib/cursorUndo/cursorUndo.ts

@@ -119,7 +119,7 @@ export class CursorUndo extends EditorAction {
 			id: 'cursorUndo',
 			label: nls.localize('cursor.undo', "Soft Undo"),
 			alias: 'Soft Undo',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_U,

src/vs/editor/contrib/find/findController.ts

@@ -422,7 +422,7 @@ export class StartFindAction extends EditorAction {
 			id: FIND_IDS.StartFindAction,
 			label: nls.localize('startFindAction', "Find"),
 			alias: 'Find',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: null,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_F,
@@ -459,7 +459,7 @@ export class StartFindWithSelectionAction extends EditorAction {
 			id: FIND_IDS.StartFindWithSelection,
 			label: nls.localize('startFindWithSelectionAction', "Find With Selection"),
 			alias: 'Find With Selection',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: null,
 				primary: 0,
@@ -513,7 +513,7 @@ export class NextMatchFindAction extends MatchFindAction {
 			id: FIND_IDS.NextMatchFindAction,
 			label: nls.localize('findNextMatchAction', "Find Next"),
 			alias: 'Find Next',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyCode.F3,
@@ -535,7 +535,7 @@ export class PreviousMatchFindAction extends MatchFindAction {
 			id: FIND_IDS.PreviousMatchFindAction,
 			label: nls.localize('findPreviousMatchAction', "Find Previous"),
 			alias: 'Find Previous',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.Shift | KeyCode.F3,
@@ -583,7 +583,7 @@ export class NextSelectionMatchFindAction extends SelectionMatchFindAction {
 			id: FIND_IDS.NextSelectionMatchFindAction,
 			label: nls.localize('nextSelectionMatchFindAction', "Find Next Selection"),
 			alias: 'Find Next Selection',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.CtrlCmd | KeyCode.F3,
@@ -604,7 +604,7 @@ export class PreviousSelectionMatchFindAction extends SelectionMatchFindAction {
 			id: FIND_IDS.PreviousSelectionMatchFindAction,
 			label: nls.localize('previousSelectionMatchFindAction', "Find Previous Selection"),
 			alias: 'Find Previous Selection',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.F3,
@@ -625,7 +625,7 @@ export class StartFindReplaceAction extends EditorAction {
 			id: FIND_IDS.StartFindReplaceAction,
 			label: nls.localize('startReplace', "Replace"),
 			alias: 'Replace',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: null,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_H,
@@ -704,7 +704,7 @@ registerEditorCommand(new FindCommand({
 
 registerEditorCommand(new FindCommand({
 	id: FIND_IDS.ToggleCaseSensitiveCommand,
-	precondition: null,
+	precondition: undefined,
 	handler: x => x.toggleCaseSensitive(),
 	kbOpts: {
 		weight: KeybindingWeight.EditorContrib + 5,
@@ -718,7 +718,7 @@ registerEditorCommand(new FindCommand({
 
 registerEditorCommand(new FindCommand({
 	id: FIND_IDS.ToggleWholeWordCommand,
-	precondition: null,
+	precondition: undefined,
 	handler: x => x.toggleWholeWords(),
 	kbOpts: {
 		weight: KeybindingWeight.EditorContrib + 5,
@@ -732,7 +732,7 @@ registerEditorCommand(new FindCommand({
 
 registerEditorCommand(new FindCommand({
 	id: FIND_IDS.ToggleRegexCommand,
-	precondition: null,
+	precondition: undefined,
 	handler: x => x.toggleRegex(),
 	kbOpts: {
 		weight: KeybindingWeight.EditorContrib + 5,
@@ -746,7 +746,7 @@ registerEditorCommand(new FindCommand({
 
 registerEditorCommand(new FindCommand({
 	id: FIND_IDS.ToggleSearchScopeCommand,
-	precondition: null,
+	precondition: undefined,
 	handler: x => x.toggleSearchScope(),
 	kbOpts: {
 		weight: KeybindingWeight.EditorContrib + 5,

src/vs/editor/contrib/folding/folding.ts

@@ -503,7 +503,7 @@ class UnfoldAction extends FoldingAction<FoldingArguments> {
 			id: 'editor.unfold',
 			label: nls.localize('unfoldAction.label', "Unfold"),
 			alias: 'Unfold',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.US_CLOSE_SQUARE_BRACKET,
@@ -567,7 +567,7 @@ class UnFoldRecursivelyAction extends FoldingAction<void> {
 			id: 'editor.unfoldRecursively',
 			label: nls.localize('unFoldRecursivelyAction.label', "Unfold Recursively"),
 			alias: 'Unfold Recursively',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.US_CLOSE_SQUARE_BRACKET),
@@ -588,7 +588,7 @@ class FoldAction extends FoldingAction<FoldingArguments> {
 			id: 'editor.fold',
 			label: nls.localize('foldAction.label', "Fold"),
 			alias: 'Fold',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.US_OPEN_SQUARE_BRACKET,
@@ -652,7 +652,7 @@ class FoldRecursivelyAction extends FoldingAction<void> {
 			id: 'editor.foldRecursively',
 			label: nls.localize('foldRecursivelyAction.label', "Fold Recursively"),
 			alias: 'Fold Recursively',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.US_OPEN_SQUARE_BRACKET),
@@ -674,7 +674,7 @@ class FoldAllBlockCommentsAction extends FoldingAction<void> {
 			id: 'editor.foldAllBlockComments',
 			label: nls.localize('foldAllBlockComments.label', "Fold All Block Comments"),
 			alias: 'Fold All Block Comments',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.US_SLASH),
@@ -707,7 +707,7 @@ class FoldAllRegionsAction extends FoldingAction<void> {
 			id: 'editor.foldAllMarkerRegions',
 			label: nls.localize('foldAllMarkerRegions.label', "Fold All Regions"),
 			alias: 'Fold All Regions',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_8),
@@ -740,7 +740,7 @@ class UnfoldAllRegionsAction extends FoldingAction<void> {
 			id: 'editor.unfoldAllMarkerRegions',
 			label: nls.localize('unfoldAllMarkerRegions.label', "Unfold All Regions"),
 			alias: 'Unfold All Regions',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_9),
@@ -773,7 +773,7 @@ class FoldAllAction extends FoldingAction<void> {
 			id: 'editor.foldAll',
 			label: nls.localize('foldAllAction.label', "Fold All"),
 			alias: 'Fold All',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_0),
@@ -794,7 +794,7 @@ class UnfoldAllAction extends FoldingAction<void> {
 			id: 'editor.unfoldAll',
 			label: nls.localize('unfoldAllAction.label', "Unfold All"),
 			alias: 'Unfold All',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_J),
@@ -838,7 +838,7 @@ for (let i = 1; i <= 7; i++) {
 			id: FoldLevelAction.ID(i),
 			label: nls.localize('foldLevelAction.label', "Fold Level {0}", i),
 			alias: `Fold Level ${i}`,
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | (KeyCode.KEY_0 + i)),

src/vs/editor/contrib/fontZoom/fontZoom.ts

@@ -15,7 +15,7 @@ class EditorFontZoomIn extends EditorAction {
 			id: 'editor.action.fontZoomIn',
 			label: nls.localize('EditorFontZoomIn.label', "Editor Font Zoom In"),
 			alias: 'Editor Font Zoom In',
-			precondition: null
+			precondition: undefined
 		});
 	}
 
@@ -31,7 +31,7 @@ class EditorFontZoomOut extends EditorAction {
 			id: 'editor.action.fontZoomOut',
 			label: nls.localize('EditorFontZoomOut.label', "Editor Font Zoom Out"),
 			alias: 'Editor Font Zoom Out',
-			precondition: null
+			precondition: undefined
 		});
 	}
 
@@ -47,7 +47,7 @@ class EditorFontZoomReset extends EditorAction {
 			id: 'editor.action.fontZoomReset',
 			label: nls.localize('EditorFontZoomReset.label', "Editor Font Zoom Reset"),
 			alias: 'Editor Font Zoom Reset',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/contrib/goToDefinition/goToDefinitionMouse.ts

@@ -294,7 +294,7 @@ class GotoDefinitionWithMouseEditorContribution implements editorCommon.IEditorC
 
 	private gotoDefinition(target: IMouseTarget, sideBySide: boolean): Promise<any> {
 		this.editor.setPosition(target.position!);
-		const action = new DefinitionAction(new DefinitionActionConfig(sideBySide, false, true, false), { alias: '', label: '', id: '', precondition: null });
+		const action = new DefinitionAction(new DefinitionActionConfig(sideBySide, false, true, false), { alias: '', label: '', id: '', precondition: undefined });
 		return this.editor.invokeWithinContext(accessor => action.run(accessor, this.editor));
 	}
 

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

@@ -251,7 +251,7 @@ class ShowHoverAction extends EditorAction {
 				]
 			}, "Show Hover"),
 			alias: 'Show Hover',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_I),

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

@@ -40,7 +40,6 @@ import { applyCodeAction, QuickFixAction } from 'vs/editor/contrib/codeAction/co
 import { Action } from 'vs/base/common/actions';
 import { CodeActionKind } from 'vs/editor/contrib/codeAction/codeActionTrigger';
 import { IModeService } from 'vs/editor/common/services/modeService';
-import { withNullAsUndefined } from 'vs/base/common/types';
 import { IIdentifiedSingleEditOperation } from 'vs/editor/common/model';
 
 const $ = dom.$;
@@ -68,14 +67,13 @@ class ModesContentComputer implements IHoverComputer<HoverPart[]> {
 
 	private readonly _editor: ICodeEditor;
 	private _result: HoverPart[];
-	private _range: Range | null;
+	private _range?: Range;
 
 	constructor(
 		editor: ICodeEditor,
 		private readonly _markerDecorationsService: IMarkerDecorationsService
 	) {
 		this._editor = editor;
-		this._range = null;
 	}
 
 	setRange(range: Range): void {
@@ -183,7 +181,7 @@ class ModesContentComputer implements IHoverComputer<HoverPart[]> {
 
 	private _getLoadingMessage(): HoverPart {
 		return {
-			range: withNullAsUndefined(this._range),
+			range: this._range,
 			contents: [new MarkdownString().appendText(nls.localize('modesContentHover.loading', "Loading..."))]
 		};
 	}

src/vs/editor/contrib/indentation/indentation.ts

@@ -253,7 +253,7 @@ export class IndentUsingTabs extends ChangeIndentationSizeAction {
 			id: IndentUsingTabs.ID,
 			label: nls.localize('indentUsingTabs', "Indent Using Tabs"),
 			alias: 'Indent Using Tabs',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -267,7 +267,7 @@ export class IndentUsingSpaces extends ChangeIndentationSizeAction {
 			id: IndentUsingSpaces.ID,
 			label: nls.localize('indentUsingSpaces', "Indent Using Spaces"),
 			alias: 'Indent Using Spaces',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -281,7 +281,7 @@ export class DetectIndentation extends EditorAction {
 			id: DetectIndentation.ID,
 			label: nls.localize('detectIndentation', "Detect Indentation from Content"),
 			alias: 'Detect Indentation from Content',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/contrib/links/links.ts

@@ -410,7 +410,7 @@ class OpenLinkAction extends EditorAction {
 			id: 'editor.action.openLink',
 			label: nls.localize('label', "Open Link"),
 			alias: 'Open Link',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/contrib/message/messageController.ts

@@ -35,7 +35,7 @@ export class MessageController extends Disposable implements editorCommon.IEdito
 
 	private readonly _editor: ICodeEditor;
 	private readonly _visible: IContextKey<boolean>;
-	private _messageWidget: MessageWidget;
+	private _messageWidget?: MessageWidget;
 	private _messageListeners: IDisposable[] = [];
 
 	constructor(
@@ -96,7 +96,9 @@ export class MessageController extends Disposable implements editorCommon.IEdito
 	closeMessage(): void {
 		this._visible.reset();
 		this._messageListeners = dispose(this._messageListeners);
-		this._messageListeners.push(MessageWidget.fadeOut(this._messageWidget));
+		if (this._messageWidget) {
+			this._messageListeners.push(MessageWidget.fadeOut(this._messageWidget));
+		}
 	}
 
 	private _onDidAttemptReadOnlyEdit(): void {

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

@@ -34,7 +34,7 @@ export class InsertCursorAbove extends EditorAction {
 			id: 'editor.action.insertCursorAbove',
 			label: nls.localize('mutlicursor.insertAbove', "Add Cursor Above"),
 			alias: 'Add Cursor Above',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Alt | KeyCode.UpArrow,
@@ -83,7 +83,7 @@ export class InsertCursorBelow extends EditorAction {
 			id: 'editor.action.insertCursorBelow',
 			label: nls.localize('mutlicursor.insertBelow', "Add Cursor Below"),
 			alias: 'Add Cursor Below',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Alt | KeyCode.DownArrow,
@@ -132,7 +132,7 @@ class InsertCursorAtEndOfEachLineSelected extends EditorAction {
 			id: 'editor.action.insertCursorAtEndOfEachLineSelected',
 			label: nls.localize('mutlicursor.insertAtEndOfEachLineSelected', "Add Cursors to Line Ends"),
 			alias: 'Add Cursors to Line Ends',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.Shift | KeyMod.Alt | KeyCode.KEY_I,
@@ -184,7 +184,7 @@ class InsertCursorAtEndOfLineSelected extends EditorAction {
 			id: 'editor.action.addCursorsToBottom',
 			label: nls.localize('mutlicursor.addCursorsToBottom', "Add Cursors To Bottom"),
 			alias: 'Add Cursors To Bottom',
-			precondition: null
+			precondition: undefined
 		});
 	}
 
@@ -214,7 +214,7 @@ class InsertCursorAtTopOfLineSelected extends EditorAction {
 			id: 'editor.action.addCursorsToTop',
 			label: nls.localize('mutlicursor.addCursorsToTop', "Add Cursors To Top"),
 			alias: 'Add Cursors To Top',
-			precondition: null
+			precondition: undefined
 		});
 	}
 
@@ -650,7 +650,7 @@ export class AddSelectionToNextFindMatchAction extends MultiCursorSelectionContr
 			id: 'editor.action.addSelectionToNextFindMatch',
 			label: nls.localize('addSelectionToNextFindMatch', "Add Selection To Next Find Match"),
 			alias: 'Add Selection To Next Find Match',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_D,
@@ -675,7 +675,7 @@ export class AddSelectionToPreviousFindMatchAction extends MultiCursorSelectionC
 			id: 'editor.action.addSelectionToPreviousFindMatch',
 			label: nls.localize('addSelectionToPreviousFindMatch', "Add Selection To Previous Find Match"),
 			alias: 'Add Selection To Previous Find Match',
-			precondition: null,
+			precondition: undefined,
 			menubarOpts: {
 				menuId: MenuId.MenubarSelectionMenu,
 				group: '3_multi',
@@ -695,7 +695,7 @@ export class MoveSelectionToNextFindMatchAction extends MultiCursorSelectionCont
 			id: 'editor.action.moveSelectionToNextFindMatch',
 			label: nls.localize('moveSelectionToNextFindMatch', "Move Last Selection To Next Find Match"),
 			alias: 'Move Last Selection To Next Find Match',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyChord(KeyMod.CtrlCmd | KeyCode.KEY_K, KeyMod.CtrlCmd | KeyCode.KEY_D),
@@ -714,7 +714,7 @@ export class MoveSelectionToPreviousFindMatchAction extends MultiCursorSelection
 			id: 'editor.action.moveSelectionToPreviousFindMatch',
 			label: nls.localize('moveSelectionToPreviousFindMatch', "Move Last Selection To Previous Find Match"),
 			alias: 'Move Last Selection To Previous Find Match',
-			precondition: null
+			precondition: undefined
 		});
 	}
 	protected _run(multiCursorController: MultiCursorSelectionController, findController: CommonFindController): void {
@@ -728,7 +728,7 @@ export class SelectHighlightsAction extends MultiCursorSelectionControllerAction
 			id: 'editor.action.selectHighlights',
 			label: nls.localize('selectAllOccurrencesOfFindMatch', "Select All Occurrences of Find Match"),
 			alias: 'Select All Occurrences of Find Match',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.KEY_L,

src/vs/editor/contrib/smartSelect/smartSelect.ts

@@ -161,7 +161,7 @@ class GrowSelectionAction extends AbstractSmartSelect {
 			id: 'editor.action.smartSelect.expand',
 			label: nls.localize('smartSelect.expand', "Expand Selection"),
 			alias: 'Expand Selection',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.Shift | KeyMod.Alt | KeyCode.RightArrow,
@@ -187,7 +187,7 @@ class ShrinkSelectionAction extends AbstractSmartSelect {
 			id: 'editor.action.smartSelect.shrink',
 			label: nls.localize('smartSelect.shrink', "Shrink Selection"),
 			alias: 'Shrink Selection',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.editorTextFocus,
 				primary: KeyMod.Shift | KeyMod.Alt | KeyCode.LeftArrow,

src/vs/editor/contrib/toggleTabFocusMode/toggleTabFocusMode.ts

@@ -20,7 +20,7 @@ export class ToggleTabFocusModeAction extends EditorAction {
 			id: ToggleTabFocusModeAction.ID,
 			label: nls.localize({ key: 'toggle.tabMovesFocus', comment: ['Turn on/off use of tab key for moving focus around VS Code'] }, "Toggle Tab Key Moves Focus"),
 			alias: 'Toggle Tab Key Moves Focus',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: null,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_M,

src/vs/editor/contrib/tokenization/tokenization.ts

@@ -14,7 +14,7 @@ class ForceRetokenizeAction extends EditorAction {
 			id: 'editor.action.forceRetokenize',
 			label: nls.localize('forceRetokenize', "Developer: Force Retokenize"),
 			alias: 'Developer: Force Retokenize',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/contrib/wordOperations/wordOperations.ts

@@ -98,7 +98,7 @@ export class CursorWordStartLeft extends WordLeftCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordStartLeft',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.CtrlCmd | KeyCode.LeftArrow,
@@ -115,7 +115,7 @@ export class CursorWordEndLeft extends WordLeftCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordEndLeft',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -126,7 +126,7 @@ export class CursorWordLeft extends WordLeftCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordStartFast,
 			id: 'cursorWordLeft',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -137,7 +137,7 @@ export class CursorWordStartLeftSelect extends WordLeftCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordStartLeftSelect',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.LeftArrow,
@@ -154,7 +154,7 @@ export class CursorWordEndLeftSelect extends WordLeftCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordEndLeftSelect',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -165,7 +165,7 @@ export class CursorWordLeftSelect extends WordLeftCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordLeftSelect',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -176,7 +176,7 @@ export class CursorWordStartRight extends WordRightCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordStartRight',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -187,7 +187,7 @@ export class CursorWordEndRight extends WordRightCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordEndRight',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.CtrlCmd | KeyCode.RightArrow,
@@ -204,7 +204,7 @@ export class CursorWordRight extends WordRightCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordRight',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -215,7 +215,7 @@ export class CursorWordStartRightSelect extends WordRightCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordStartRightSelect',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }
@@ -226,7 +226,7 @@ export class CursorWordEndRightSelect extends WordRightCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordEndRightSelect',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: KeyMod.CtrlCmd | KeyMod.Shift | KeyCode.RightArrow,
@@ -243,7 +243,7 @@ export class CursorWordRightSelect extends WordRightCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordRightSelect',
-			precondition: null
+			precondition: undefined
 		});
 	}
 }

src/vs/editor/contrib/wordPartOperations/wordPartOperations.ts

@@ -79,7 +79,7 @@ export class CursorWordPartLeft extends WordPartLeftCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordPartLeft',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: 0,
@@ -98,7 +98,7 @@ export class CursorWordPartLeftSelect extends WordPartLeftCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordStart,
 			id: 'cursorWordPartLeftSelect',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: 0,
@@ -122,7 +122,7 @@ export class CursorWordPartRight extends WordPartRightCommand {
 			inSelectionMode: false,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordPartRight',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: 0,
@@ -138,7 +138,7 @@ export class CursorWordPartRightSelect extends WordPartRightCommand {
 			inSelectionMode: true,
 			wordNavigationType: WordNavigationType.WordEnd,
 			id: 'cursorWordPartRightSelect',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.textInputFocus,
 				primary: 0,

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

@@ -330,7 +330,7 @@ class ShowAccessibilityHelpAction extends EditorAction {
 			id: 'editor.action.showAccessibilityHelp',
 			label: AccessibilityHelpNLS.showAccessibilityHelpAction,
 			alias: 'Show Accessibility Help',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: (browser.isIE ? KeyMod.CtrlCmd | KeyCode.F1 : KeyMod.Alt | KeyCode.F1),

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

@@ -84,7 +84,7 @@ class InspectTokens extends EditorAction {
 			id: 'editor.action.inspectTokens',
 			label: InspectTokensNLS.inspectTokensAction,
 			alias: 'Developer: Inspect Tokens',
-			precondition: null
+			precondition: undefined
 		});
 	}
 

src/vs/editor/standalone/browser/quickOpen/gotoLine.ts

@@ -149,7 +149,7 @@ export class GotoLineAction extends BaseEditorQuickOpenAction {
 			id: 'editor.action.gotoLine',
 			label: GoToLineNLS.gotoLineActionLabel,
 			alias: 'Go to Line...',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: KeyMod.CtrlCmd | KeyCode.KEY_G,

src/vs/editor/standalone/browser/quickOpen/quickCommand.ts

@@ -82,7 +82,7 @@ export class QuickCommandAction extends BaseEditorQuickOpenAction {
 			id: 'editor.action.quickCommand',
 			label: QuickCommandNLS.quickCommandActionLabel,
 			alias: 'Command Palette',
-			precondition: null,
+			precondition: undefined,
 			kbOpts: {
 				kbExpr: EditorContextKeys.focus,
 				primary: (browser.isIE ? KeyMod.Alt | KeyCode.F1 : KeyCode.F1),

src/vs/editor/standalone/browser/quickOpen/quickOutline.ts

@@ -26,12 +26,12 @@ let SCOPE_PREFIX = ':';
 export class SymbolEntry extends QuickOpenEntryGroup {
 	private readonly name: string;
 	private readonly type: string;
-	private readonly description: string | null;
+	private readonly description: string | undefined;
 	private readonly range: Range;
 	private readonly editor: ICodeEditor;
 	private readonly decorator: IDecorator;
 
-	constructor(name: string, type: string, description: string | null, range: Range, highlights: IHighlight[], editor: ICodeEditor, decorator: IDecorator) {
+	constructor(name: string, type: string, description: string | undefined, range: Range, highlights: IHighlight[], editor: ICodeEditor, decorator: IDecorator) {
 		super();
 
 		this.name = name;
@@ -55,7 +55,7 @@ export class SymbolEntry extends QuickOpenEntryGroup {
 		return this.type;
 	}
 
-	public getDescription(): string | null {
+	public getDescription(): string | undefined {
 		return this.description;
 	}
 
@@ -169,7 +169,7 @@ export class QuickOutlineAction extends BaseEditorQuickOpenAction {
 		});
 	}
 
-	private symbolEntry(name: string, type: string, description: string | null, range: IRange, highlights: IHighlight[], editor: ICodeEditor, decorator: IDecorator): SymbolEntry {
+	private symbolEntry(name: string, type: string, description: string | undefined, range: IRange, highlights: IHighlight[], editor: ICodeEditor, decorator: IDecorator): SymbolEntry {
 		return new SymbolEntry(name, type, description, Range.lift(range), highlights, editor, decorator);
 	}
 
@@ -192,7 +192,7 @@ export class QuickOutlineAction extends BaseEditorQuickOpenAction {
 			if (highlights) {
 
 				// Show parent scope as description
-				let description: string | null = null;
+				let description: string | undefined = undefined;
 				if (element.containerName) {
 					description = element.containerName;
 				}

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

@@ -19,7 +19,7 @@ import { EditOperation } from 'vs/editor/common/core/editOperation';
 import { IPosition, Position as Pos } from 'vs/editor/common/core/position';
 import { Range } from 'vs/editor/common/core/range';
 import * as editorCommon from 'vs/editor/common/editorCommon';
-import { ITextModel } from 'vs/editor/common/model';
+import { ITextModel, ITextSnapshot } from 'vs/editor/common/model';
 import { TextEdit, WorkspaceEdit, isResourceTextEdit } from 'vs/editor/common/modes';
 import { IModelService } from 'vs/editor/common/services/modelService';
 import { IResolvedTextEditorModel, ITextModelContentProvider, ITextModelService } from 'vs/editor/common/services/resolverService';
@@ -67,6 +67,10 @@ export class SimpleModel implements IResolvedTextEditorModel {
 		return this.model;
 	}
 
+	public createSnapshot(): ITextSnapshot {
+		return this.model.createSnapshot();
+	}
+
 	public isReadonly(): boolean {
 		return false;
 	}
@@ -348,7 +352,7 @@ export class StandaloneKeybindingService extends AbstractKeybindingService {
 
 			if (!keybinding) {
 				// This might be a removal keybinding item in user settings => accept it
-				result[resultLen++] = new ResolvedKeybindingItem(null, item.command, item.commandArgs, when, isDefault);
+				result[resultLen++] = new ResolvedKeybindingItem(undefined, item.command, item.commandArgs, when, isDefault);
 			} else {
 				const resolvedKeybindings = this.resolveKeybinding(keybinding);
 				for (const resolvedKeybinding of resolvedKeybindings) {

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

@@ -17,7 +17,7 @@ class ToggleHighContrast extends EditorAction {
 			id: 'editor.action.toggleHighContrast',
 			label: ToggleHighContrastNLS.toggleHighContrast,
 			alias: 'Toggle High Contrast Theme',
-			precondition: null
+			precondition: undefined
 		});
 		this._originalThemeName = null;
 	}