diff --git a/src/vs/editor/contrib/gotoSymbol/goToSymbol.ts b/src/vs/editor/contrib/gotoSymbol/goToSymbol.ts
index d478c783204ad..e3e7ec687d567 100644
--- a/src/vs/editor/contrib/gotoSymbol/goToSymbol.ts
+++ b/src/vs/editor/contrib/gotoSymbol/goToSymbol.ts
@@ -3,7 +3,6 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { flatten, coalesce } from 'vs/base/common/arrays';
 import { CancellationToken } from 'vs/base/common/cancellation';
 import { onUnexpectedExternalError } from 'vs/base/common/errors';
 import { registerModelAndPositionCommand } from 'vs/editor/browser/editorExtensions';
@@ -28,9 +27,18 @@ function getLocationLinks<T>(
 			return undefined;
 		});
 	});
-	return Promise.all(promises)
-		.then(flatten)
-		.then(coalesce);
+
+	return Promise.all(promises).then(values => {
+		const result: LocationLink[] = [];
+		for (let value of values) {
+			if (Array.isArray(value)) {
+				result.push(...value);
+			} else if (value) {
+				result.push(value);
+			}
+		}
+		return result;
+	});
 }
 
 
diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index 0a0db394fa543..01e6949541c07 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -484,10 +484,10 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			showErrorMessage(message: string, first: vscode.MessageOptions | string | vscode.MessageItem, ...rest: Array<string | vscode.MessageItem>) {
 				return extHostMessageService.showMessage(extension, Severity.Error, message, first, rest);
 			},
-			showQuickPick(items: any, options: vscode.QuickPickOptions, token?: vscode.CancellationToken): any {
+			showQuickPick(items: any, options?: vscode.QuickPickOptions, token?: vscode.CancellationToken): any {
 				return extHostQuickOpen.showQuickPick(items, !!extension.enableProposedApi, options, token);
 			},
-			showWorkspaceFolderPick(options: vscode.WorkspaceFolderPickOptions) {
+			showWorkspaceFolderPick(options?: vscode.WorkspaceFolderPickOptions) {
 				return extHostQuickOpen.showWorkspaceFolderPick(options);
 			},
 			showInputBox(options?: vscode.InputBoxOptions, token?: vscode.CancellationToken) {
@@ -536,7 +536,7 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 			createWebviewPanel(viewType: string, title: string, showOptions: vscode.ViewColumn | { viewColumn: vscode.ViewColumn, preserveFocus?: boolean }, options: vscode.WebviewPanelOptions & vscode.WebviewOptions): vscode.WebviewPanel {
 				return extHostWebviews.createWebviewPanel(extension, viewType, title, showOptions, options);
 			},
-			createWebviewTextEditorInset(editor: vscode.TextEditor, line: number, height: number, options: vscode.WebviewOptions): vscode.WebviewEditorInset {
+			createWebviewTextEditorInset(editor: vscode.TextEditor, line: number, height: number, options?: vscode.WebviewOptions): vscode.WebviewEditorInset {
 				checkProposedApiEnabled(extension);
 				return extHostEditorInsets.createWebviewEditorInset(editor, line, height, options, extension);
 			},
diff --git a/src/vs/workbench/api/common/extHostApiCommands.ts b/src/vs/workbench/api/common/extHostApiCommands.ts
index a8b6923f8fb1e..ab21443e9c401 100644
--- a/src/vs/workbench/api/common/extHostApiCommands.ts
+++ b/src/vs/workbench/api/common/extHostApiCommands.ts
@@ -9,7 +9,6 @@ import type * as vscode from 'vscode';
 import * as typeConverters from 'vs/workbench/api/common/extHostTypeConverters';
 import * as types from 'vs/workbench/api/common/extHostTypes';
 import { IRawColorInfo, IWorkspaceEditDto, ICallHierarchyItemDto, IIncomingCallDto, IOutgoingCallDto } from 'vs/workbench/api/common/extHost.protocol';
-import { ISingleEditOperation } from 'vs/editor/common/model';
 import * as modes from 'vs/editor/common/modes';
 import * as search from 'vs/workbench/contrib/search/common/search';
 import { ICommandHandlerDescription } from 'vs/platform/commands/common/commands';
@@ -128,17 +127,17 @@ const newCommands: ApiCommand[] = [
 	new ApiCommand(
 		'vscode.executeFormatDocumentProvider', '_executeFormatDocumentProvider', 'Execute document format provider.',
 		[ApiCommandArgument.Uri, new ApiCommandArgument('options', 'Formatting options', _ => true, v => v)],
-		new ApiCommandResult<ISingleEditOperation[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
+		new ApiCommandResult<modes.TextEdit[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
 	),
 	new ApiCommand(
 		'vscode.executeFormatRangeProvider', '_executeFormatRangeProvider', 'Execute range format provider.',
 		[ApiCommandArgument.Uri, ApiCommandArgument.Range, new ApiCommandArgument('options', 'Formatting options', _ => true, v => v)],
-		new ApiCommandResult<ISingleEditOperation[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
+		new ApiCommandResult<modes.TextEdit[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
 	),
 	new ApiCommand(
 		'vscode.executeFormatOnTypeProvider', '_executeFormatOnTypeProvider', 'Execute format on type provider.',
 		[ApiCommandArgument.Uri, ApiCommandArgument.Position, new ApiCommandArgument('ch', 'Trigger character', v => typeof v === 'string', v => v), new ApiCommandArgument('options', 'Formatting options', _ => true, v => v)],
-		new ApiCommandResult<ISingleEditOperation[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
+		new ApiCommandResult<modes.TextEdit[], types.TextEdit[] | undefined>('A promise that resolves to an array of TextEdits.', tryMapWith(typeConverters.TextEdit.to))
 	),
 	// -- go to symbol (definition, type definition, declaration, impl, references)
 	new ApiCommand(
diff --git a/src/vs/workbench/api/common/extHostFileSystemEventService.ts b/src/vs/workbench/api/common/extHostFileSystemEventService.ts
index 234432210e946..f81141921023c 100644
--- a/src/vs/workbench/api/common/extHostFileSystemEventService.ts
+++ b/src/vs/workbench/api/common/extHostFileSystemEventService.ts
@@ -199,7 +199,7 @@ export class ExtHostFileSystemEventService implements ExtHostFileSystemEventServ
 
 		const edits: WorkspaceEdit[] = [];
 
-		await emitter.fireAsync(data, token, async (thenable, listener: IExtensionListener<E>) => {
+		await emitter.fireAsync(data, token, async (thenable, listener) => {
 			// ignore all results except for WorkspaceEdits. Those are stored in an array.
 			const now = Date.now();
 			const result = await Promise.resolve(thenable);
@@ -208,7 +208,7 @@ export class ExtHostFileSystemEventService implements ExtHostFileSystemEventServ
 			}
 
 			if (Date.now() - now > timeout) {
-				this._logService.warn('SLOW file-participant', listener.extension?.identifier);
+				this._logService.warn('SLOW file-participant', (<IExtensionListener<E>>listener).extension?.identifier);
 			}
 		});