diff --git a/src/vs/base/common/lifecycle.ts b/src/vs/base/common/lifecycle.ts
index 3a3f196619d..e82f147d322 100644
--- a/src/vs/base/common/lifecycle.ts
+++ b/src/vs/base/common/lifecycle.ts
@@ -23,7 +23,7 @@ function markTracked<T extends IDisposable>(x: T): void {
 
 	if (x && x !== Disposable.None) {
 		try {
-			x[__is_disposable_tracked__] = true;
+			(x as any)[__is_disposable_tracked__] = true;
 		} catch {
 			// noop
 		}
@@ -37,7 +37,7 @@ function trackDisposable<T extends IDisposable>(x: T): T {
 
 	const stack = new Error().stack!;
 	setTimeout(() => {
-		if (!x[__is_disposable_tracked__]) {
+		if (!(x as any)[__is_disposable_tracked__]) {
 			console.log(stack);
 		}
 	}, 3000);
diff --git a/src/vs/code/electron-main/window.ts b/src/vs/code/electron-main/window.ts
index e791fc73a9d..37f1ee30537 100644
--- a/src/vs/code/electron-main/window.ts
+++ b/src/vs/code/electron-main/window.ts
@@ -316,7 +316,7 @@ export class CodeWindow extends Disposable implements ICodeWindow {
 		const urls = ['https://marketplace.visualstudio.com/*', 'https://*.vsassets.io/*'];
 		this._win.webContents.session.webRequest.onBeforeSendHeaders({ urls }, (details, cb) => {
 			this.marketplaceHeadersPromise.then(headers => {
-				const requestHeaders = objects.assign(details.requestHeaders, headers);
+				const requestHeaders = objects.assign(details.requestHeaders, headers) as { [key: string]: string | undefined };
 				if (!this.configurationService.getValue('extensions.disableExperimentalAzureSearch')) {
 					requestHeaders['Cookie'] = `${requestHeaders['Cookie'] ? requestHeaders['Cookie'] + ';' : ''}EnableExternalSearchForVSCode=true`;
 				}
diff --git a/src/vs/platform/instantiation/common/instantiation.ts b/src/vs/platform/instantiation/common/instantiation.ts
index df147f419c3..918cd9bb808 100644
--- a/src/vs/platform/instantiation/common/instantiation.ts
+++ b/src/vs/platform/instantiation/common/instantiation.ts
@@ -114,11 +114,11 @@ export interface ServiceIdentifier<T> {
 }
 
 function storeServiceDependency(id: Function, target: Function, index: number, optional: boolean): void {
-	if (target[_util.DI_TARGET] === target) {
-		target[_util.DI_DEPENDENCIES].push({ id, index, optional });
+	if ((target as any)[_util.DI_TARGET] === target) {
+		(target as any)[_util.DI_DEPENDENCIES].push({ id, index, optional });
 	} else {
-		target[_util.DI_DEPENDENCIES] = [{ id, index, optional }];
-		target[_util.DI_TARGET] = target;
+		(target as any)[_util.DI_DEPENDENCIES] = [{ id, index, optional }];
+		(target as any)[_util.DI_TARGET] = target;
 	}
 }
 
diff --git a/src/vs/platform/windows/common/windows.ts b/src/vs/platform/windows/common/windows.ts
index 75677e6beae..1f64adccc5b 100644
--- a/src/vs/platform/windows/common/windows.ts
+++ b/src/vs/platform/windows/common/windows.ts
@@ -206,15 +206,15 @@ export interface IFileToOpen {
 }
 
 export function isWorkspaceToOpen(uriToOpen: IURIToOpen): uriToOpen is IWorkspaceToOpen {
-	return !!uriToOpen['workspaceUri'];
+	return !!(uriToOpen as IWorkspaceToOpen)['workspaceUri'];
 }
 
 export function isFolderToOpen(uriToOpen: IURIToOpen): uriToOpen is IFolderToOpen {
-	return !!uriToOpen['folderUri'];
+	return !!(uriToOpen as IFolderToOpen)['folderUri'];
 }
 
 export function isFileToOpen(uriToOpen: IURIToOpen): uriToOpen is IFileToOpen {
-	return !!uriToOpen['fileUri'];
+	return !!(uriToOpen as IFileToOpen)['fileUri'];
 }
 
 
diff --git a/src/vs/workbench/contrib/webview/common/mimeTypes.ts b/src/vs/workbench/contrib/webview/common/mimeTypes.ts
index a34d61f10b3..0f1f583d451 100644
--- a/src/vs/workbench/contrib/webview/common/mimeTypes.ts
+++ b/src/vs/workbench/contrib/webview/common/mimeTypes.ts
@@ -7,20 +7,20 @@ import { getMediaMime, MIME_UNKNOWN } from 'vs/base/common/mime';
 import { extname } from 'vs/base/common/path';
 import { URI } from 'vs/base/common/uri';
 
-const webviewMimeTypes = {
-	'.svg': 'image/svg+xml',
-	'.txt': 'text/plain',
-	'.css': 'text/css',
-	'.js': 'application/javascript',
-	'.json': 'application/json',
-	'.html': 'text/html',
-	'.htm': 'text/html',
-	'.xhtml': 'application/xhtml+xml',
-	'.oft': 'font/otf',
-	'.xml': 'application/xml',
-};
+const webviewMimeTypes = new Map([
+	['.svg', 'image/svg+xml'],
+	['.txt', 'text/plain'],
+	['.css', 'text/css'],
+	['.js', 'application/javascript'],
+	['.json', 'application/json'],
+	['.html', 'text/html'],
+	['.htm', 'text/html'],
+	['.xhtml', 'application/xhtml+xml'],
+	['.oft', 'font/otf'],
+	['.xml', 'application/xml'],
+]);
 
 export function getWebviewContentMimeType(normalizedPath: URI): string {
 	const ext = extname(normalizedPath.fsPath).toLowerCase();
-	return webviewMimeTypes[ext] || getMediaMime(normalizedPath.fsPath) || MIME_UNKNOWN;
+	return webviewMimeTypes.get(ext) || getMediaMime(normalizedPath.fsPath) || MIME_UNKNOWN;
 }
diff --git a/src/vs/workbench/contrib/webview/electron-browser/webviewElement.ts b/src/vs/workbench/contrib/webview/electron-browser/webviewElement.ts
index 67ca21ee160..32d4b8d25f0 100644
--- a/src/vs/workbench/contrib/webview/electron-browser/webviewElement.ts
+++ b/src/vs/workbench/contrib/webview/electron-browser/webviewElement.ts
@@ -181,7 +181,8 @@ class SvgBlocker extends Disposable {
 		});
 
 		session.onHeadersReceived((details) => {
-			const contentType: string[] = details.responseHeaders['content-type'] || details.responseHeaders['Content-Type'];
+			const headers: any = details.responseHeaders;
+			const contentType: string[] = headers['content-type'] || headers['Content-Type'];
 			if (contentType && Array.isArray(contentType) && contentType.some(x => x.toLowerCase().indexOf('image/svg') >= 0)) {
 				const uri = URI.parse(details.url);
 				if (uri && !this.isAllowedSvg(uri)) {
diff --git a/src/vs/workbench/services/textfile/common/textFileEditorModel.ts b/src/vs/workbench/services/textfile/common/textFileEditorModel.ts
index 9a70fd94b6a..0640812db20 100644
--- a/src/vs/workbench/services/textfile/common/textFileEditorModel.ts
+++ b/src/vs/workbench/services/textfile/common/textFileEditorModel.ts
@@ -816,7 +816,8 @@ export class TextFileEditorModel extends BaseTextEditorModel implements ITextFil
 			mimeType: guessMimeTypes(this.resource).join(', '),
 			ext,
 			path: hash(path),
-			reason
+			reason,
+			whitelistedjson: undefined as string | undefined
 		};
 
 		if (ext === '.json' && TextFileEditorModel.WHITELIST_JSON.indexOf(fileName) > -1) {