diff --git a/src/vs/base/browser/htmlContentRenderer.ts b/src/vs/base/browser/htmlContentRenderer.ts
index fd81c880241..cee63325b9b 100644
--- a/src/vs/base/browser/htmlContentRenderer.ts
+++ b/src/vs/base/browser/htmlContentRenderer.ts
@@ -92,7 +92,7 @@ export function renderMarkdown(markdown: IMarkdownString, options: RenderOptions
 
 	// signal to code-block render that the
 	// element has been created
-	let signalInnerHTML: Function;
+	let signalInnerHTML: () => void;
 	const withInnerHTML = new Promise(c => signalInnerHTML = c);
 
 	const renderer = new marked.Renderer();
diff --git a/src/vs/base/common/async.ts b/src/vs/base/common/async.ts
index ace08b77709..edc2ad5e2db 100644
--- a/src/vs/base/common/async.ts
+++ b/src/vs/base/common/async.ts
@@ -318,7 +318,7 @@ export function timeout(millis: number, token?: CancellationToken): CancelablePr
 	});
 }
 
-export function disposableTimeout(handler: Function, timeout = 0): IDisposable {
+export function disposableTimeout(handler: () => void, timeout = 0): IDisposable {
 	const timer = setTimeout(handler, timeout);
 	return {
 		dispose() {
diff --git a/src/vs/base/common/collections.ts b/src/vs/base/common/collections.ts
index ca40515c99c..f5c5cf5408b 100644
--- a/src/vs/base/common/collections.ts
+++ b/src/vs/base/common/collections.ts
@@ -58,7 +58,7 @@ export function first<T>(from: IStringDictionary<T> | INumberDictionary<T>): T |
  * Iterates over each entry in the provided set. The iterator allows
  * to remove elements and will stop when the callback returns {{false}}.
  */
-export function forEach<T>(from: IStringDictionary<T> | INumberDictionary<T>, callback: (entry: { key: any; value: T; }, remove: Function) => any): void {
+export function forEach<T>(from: IStringDictionary<T> | INumberDictionary<T>, callback: (entry: { key: any; value: T; }, remove: () => void) => any): void {
 	for (let key in from) {
 		if (hasOwnProperty.call(from, key)) {
 			const result = callback({ key: key, value: (from as any)[key] }, function () {
diff --git a/src/vs/base/common/event.ts b/src/vs/base/common/event.ts
index f6b794079cf..493f02d1415 100644
--- a/src/vs/base/common/event.ts
+++ b/src/vs/base/common/event.ts
@@ -732,7 +732,7 @@ export class EventBufferer {
 	}
 
 	bufferEvents<R = void>(fn: () => R): R {
-		const buffer: Function[] = [];
+		const buffer: Array<() => R> = [];
 		this.buffers.push(buffer);
 		const r = fn();
 		this.buffers.pop();
diff --git a/src/vs/base/common/worker/simpleWorker.ts b/src/vs/base/common/worker/simpleWorker.ts
index 08531cd3459..3bb968d34f5 100644
--- a/src/vs/base/common/worker/simpleWorker.ts
+++ b/src/vs/base/common/worker/simpleWorker.ts
@@ -245,11 +245,11 @@ export class SimpleWorkerClient<T> extends Disposable {
 		});
 
 		// Create proxy to loaded code
-		let proxyMethodRequest = (method: string, args: any[]): Promise<any> => {
+		const proxyMethodRequest = (method: string, args: any[]): Promise<any> => {
 			return this._request(method, args);
 		};
 
-		let createProxyMethod = (method: string, proxyMethodRequest: (method: string, args: any[]) => Promise<any>): Function => {
+		const createProxyMethod = (method: string, proxyMethodRequest: (method: string, args: any[]) => Promise<any>): () => Promise<any> => {
 			return function () {
 				let args = Array.prototype.slice.call(arguments, 0);
 				return proxyMethodRequest(method, args);
diff --git a/src/vs/editor/common/services/webWorker.ts b/src/vs/editor/common/services/webWorker.ts
index 07035be7f57..95539535e3a 100644
--- a/src/vs/editor/common/services/webWorker.ts
+++ b/src/vs/editor/common/services/webWorker.ts
@@ -69,13 +69,13 @@ class MonacoWebWorkerImpl<T> extends EditorWorkerClient implements MonacoWebWork
 				return proxy.loadForeignModule(this._foreignModuleId, this._foreignModuleCreateData).then((foreignMethods) => {
 					this._foreignModuleCreateData = null;
 
-					let proxyMethodRequest = (method: string, args: any[]): Promise<any> => {
+					const proxyMethodRequest = (method: string, args: any[]): Promise<any> => {
 						return proxy.fmr(method, args);
 					};
 
-					let createProxyMethod = (method: string, proxyMethodRequest: (method: string, args: any[]) => Promise<any>): Function => {
+					const createProxyMethod = (method: string, proxyMethodRequest: (method: string, args: any[]) => Promise<any>): () => Promise<any> => {
 						return function () {
-							let args = Array.prototype.slice.call(arguments, 0);
+							const args = Array.prototype.slice.call(arguments, 0);
 							return proxyMethodRequest(method, args);
 						};
 					};
diff --git a/src/vs/editor/contrib/rename/renameInputField.ts b/src/vs/editor/contrib/rename/renameInputField.ts
index 5c60267db08..881417ed27f 100644
--- a/src/vs/editor/contrib/rename/renameInputField.ts
+++ b/src/vs/editor/contrib/rename/renameInputField.ts
@@ -128,10 +128,8 @@ export default class RenameInputField implements IContentWidget, IDisposable {
 		this._inputField.setAttribute('selectionEnd', selectionEnd.toString());
 		this._inputField.size = Math.max((where.endColumn - where.startColumn) * 1.1, 20);
 
-		let disposeOnDone: IDisposable[] = [],
-			always: Function;
-
-		always = () => {
+		const disposeOnDone: IDisposable[] = [];
+		const always = () => {
 			dispose(disposeOnDone);
 			this._hide();
 		};
diff --git a/src/vs/workbench/api/electron-browser/mainThreadProgress.ts b/src/vs/workbench/api/electron-browser/mainThreadProgress.ts
index 3ce2237f606..83ef37518c2 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadProgress.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadProgress.ts
@@ -11,7 +11,7 @@ import { extHostNamedCustomer } from 'vs/workbench/api/electron-browser/extHostC
 export class MainThreadProgress implements MainThreadProgressShape {
 
 	private _progressService: IProgressService2;
-	private _progress = new Map<number, { resolve: Function, progress: IProgress<IProgressStep> }>();
+	private _progress = new Map<number, { resolve: () => void, progress: IProgress<IProgressStep> }>();
 	private _proxy: ExtHostProgressShape;
 
 	constructor(
diff --git a/src/vs/workbench/api/node/extHostTypes.ts b/src/vs/workbench/api/node/extHostTypes.ts
index 7c17d8d7ce1..9f7d7eb99f2 100644
--- a/src/vs/workbench/api/node/extHostTypes.ts
+++ b/src/vs/workbench/api/node/extHostTypes.ts
@@ -32,9 +32,9 @@ export class Disposable {
 		});
 	}
 
-	private _callOnDispose?: Function;
+	private _callOnDispose?: () => any;
 
-	constructor(callOnDispose: Function) {
+	constructor(callOnDispose: () => any) {
 		this._callOnDispose = callOnDispose;
 	}
 
diff --git a/src/vs/workbench/services/search/node/fileSearch.ts b/src/vs/workbench/services/search/node/fileSearch.ts
index 9b56487c323..4554f18097d 100644
--- a/src/vs/workbench/services/search/node/fileSearch.ts
+++ b/src/vs/workbench/services/search/node/fileSearch.ts
@@ -176,7 +176,7 @@ export class FileWalker {
 		});
 	}
 
-	private call(fun: Function, that: any, ...args: any[]): void {
+	private call<F extends Function>(fun: F, that: any, ...args: any[]): void {
 		try {
 			fun.apply(that, args);
 		} catch (e) {