diff --git a/src/vs/base/browser/ui/menu/menu.ts b/src/vs/base/browser/ui/menu/menu.ts
index affb18ccbe1..64043f7fb14 100644
--- a/src/vs/base/browser/ui/menu/menu.ts
+++ b/src/vs/base/browser/ui/menu/menu.ts
@@ -6,7 +6,7 @@
 import 'vs/css!./menu';
 import * as nls from 'vs/nls';
 import * as strings from 'vs/base/common/strings';
-import { IActionRunner, IAction, Action } from 'vs/base/common/actions';
+import { IActionRunner, IAction, Action, IActionViewItem } from 'vs/base/common/actions';
 import { ActionBar, IActionViewItemProvider, ActionsOrientation, Separator, ActionViewItem, IActionViewItemOptions, BaseActionViewItem } from 'vs/base/browser/ui/actionbar/actionbar';
 import { ResolvedKeybinding, KeyCode } from 'vs/base/common/keyCodes';
 import { addClass, EventType, EventHelper, EventLike, removeTabIndexAndUpdateFocus, isAncestor, hasClass, addDisposableListener, removeClass, append, $, addClasses, removeClasses } from 'vs/base/browser/dom';
@@ -205,8 +205,8 @@ export class Menu extends ActionBar {
 		container.appendChild(this.scrollableElement.getDomNode());
 		this.scrollableElement.scanDomNode();
 
-		this.viewItems.filter(item => !(item instanceof MenuSeparatorActionViewItem)).forEach((item: BaseMenuActionViewItem, index: number, array: any[]) => {
-			item.updatePositionInSet(index + 1, array.length);
+		this.viewItems.filter(item => !(item instanceof MenuSeparatorActionViewItem)).forEach((item: IActionViewItem, index: number, array: any[]) => {
+			(item as BaseMenuActionViewItem).updatePositionInSet(index + 1, array.length);
 		});
 	}
 
diff --git a/src/vs/base/browser/ui/toolbar/toolbar.ts b/src/vs/base/browser/ui/toolbar/toolbar.ts
index 3e13d9ce66d..846e156dfa3 100644
--- a/src/vs/base/browser/ui/toolbar/toolbar.ts
+++ b/src/vs/base/browser/ui/toolbar/toolbar.ts
@@ -52,7 +52,7 @@ export class ToolBar extends Disposable {
 			orientation: options.orientation,
 			ariaLabel: options.ariaLabel,
 			actionRunner: options.actionRunner,
-			actionViewItemProvider: (action: Action) => {
+			actionViewItemProvider: (action: IAction) => {
 
 				// Return special action item for the toggle menu action
 				if (action.id === ToggleMenuAction.ID) {
diff --git a/src/vs/base/common/iterator.ts b/src/vs/base/common/iterator.ts
index f44cbd236b8..3ea4bc94e32 100644
--- a/src/vs/base/common/iterator.ts
+++ b/src/vs/base/common/iterator.ts
@@ -271,7 +271,7 @@ export interface INavigator<T> extends INextIterator<T> {
 
 export class MappedNavigator<T, R> extends MappedIterator<T, R> implements INavigator<R> {
 
-	constructor(protected navigator: INavigator<T>, fn: (item: T) => R) {
+	constructor(protected navigator: INavigator<T>, fn: (item: T | null) => R) {
 		super(navigator, fn);
 	}
 
diff --git a/src/vs/base/parts/ipc/common/ipc.ts b/src/vs/base/parts/ipc/common/ipc.ts
index 48f75577206..603414de3aa 100644
--- a/src/vs/base/parts/ipc/common/ipc.ts
+++ b/src/vs/base/parts/ipc/common/ipc.ts
@@ -553,7 +553,7 @@ export class ChannelClient implements IChannelClient, IDisposable {
 			}
 		});
 
-		const handler: IHandler = (res: IRawEventFireResponse) => emitter.fire(res.data);
+		const handler: IHandler = (res: IRawResponse) => emitter.fire((res as IRawEventFireResponse).data);
 		this.handlers.set(id, handler);
 
 		return emitter.event;
diff --git a/src/vs/base/parts/storage/test/node/storage.test.ts b/src/vs/base/parts/storage/test/node/storage.test.ts
index 92992e494b0..83e99a94551 100644
--- a/src/vs/base/parts/storage/test/node/storage.test.ts
+++ b/src/vs/base/parts/storage/test/node/storage.test.ts
@@ -294,7 +294,7 @@ suite('SQLite Storage Library', () => {
 		return set;
 	}
 
-	async function testDBBasics(path: string, logError?: (error: Error) => void) {
+	async function testDBBasics(path: string, logError?: (error: Error | string) => void) {
 		let options!: ISQLiteStorageDatabaseOptions;
 		if (logError) {
 			options = {
diff --git a/src/vs/editor/browser/editorExtensions.ts b/src/vs/editor/browser/editorExtensions.ts
index 18bd6370f27..6855f9882d7 100644
--- a/src/vs/editor/browser/editorExtensions.ts
+++ b/src/vs/editor/browser/editorExtensions.ts
@@ -377,7 +377,7 @@ class EditorContributionRegistry {
 	}
 
 	public registerEditorContribution<Services extends BrandedService[]>(id: string, ctor: { new(editor: ICodeEditor, ...services: Services): IEditorContribution }): void {
-		this.editorContributions.push({ id, ctor });
+		this.editorContributions.push({ id, ctor: ctor as IEditorContributionCtor });
 	}
 
 	public getEditorContributions(): IEditorContributionDescription[] {
@@ -385,7 +385,7 @@ class EditorContributionRegistry {
 	}
 
 	public registerDiffEditorContribution<Services extends BrandedService[]>(id: string, ctor: { new(editor: IDiffEditor, ...services: Services): IEditorContribution }): void {
-		this.diffEditorContributions.push({ id, ctor });
+		this.diffEditorContributions.push({ id, ctor: ctor as IDiffEditorContributionCtor });
 	}
 
 	public getDiffEditorContributions(): IDiffEditorContributionDescription[] {