diff --git a/src/vs/workbench/api/common/extHost.api.impl.ts b/src/vs/workbench/api/common/extHost.api.impl.ts
index ac216e9263834f01a38fe392a3ececfab23e3b1a..178d54dd3e05dbc357fd01aaa451258a1499ac6d 100644
--- a/src/vs/workbench/api/common/extHost.api.impl.ts
+++ b/src/vs/workbench/api/common/extHost.api.impl.ts
@@ -113,7 +113,7 @@ export function createApiFactoryAndRegisterActors(accessor: ServicesAccessor): I
 	const extHostEditors = rpcProtocol.set(ExtHostContext.ExtHostEditors, new ExtHostEditors(rpcProtocol, extHostDocumentsAndEditors));
 	const extHostTreeViews = rpcProtocol.set(ExtHostContext.ExtHostTreeViews, new ExtHostTreeViews(rpcProtocol.getProxy(MainContext.MainThreadTreeViews), extHostCommands, extHostLogService));
 	const extHostEditorInsets = rpcProtocol.set(ExtHostContext.ExtHostEditorInsets, new ExtHostEditorInsets(rpcProtocol.getProxy(MainContext.MainThreadEditorInsets), extHostEditors, initData.environment));
-	const extHostDiagnostics = rpcProtocol.set(ExtHostContext.ExtHostDiagnostics, new ExtHostDiagnostics(rpcProtocol));
+	const extHostDiagnostics = rpcProtocol.set(ExtHostContext.ExtHostDiagnostics, new ExtHostDiagnostics(rpcProtocol, extHostLogService));
 	const extHostLanguageFeatures = rpcProtocol.set(ExtHostContext.ExtHostLanguageFeatures, new ExtHostLanguageFeatures(rpcProtocol, uriTransformer, extHostDocuments, extHostCommands, extHostDiagnostics, extHostLogService));
 	const extHostFileSystem = rpcProtocol.set(ExtHostContext.ExtHostFileSystem, new ExtHostFileSystem(rpcProtocol, extHostLanguageFeatures));
 	const extHostFileSystemEvent = rpcProtocol.set(ExtHostContext.ExtHostFileSystemEventService, new ExtHostFileSystemEventService(rpcProtocol, extHostDocumentsAndEditors));
diff --git a/src/vs/workbench/api/common/extHostDiagnostics.ts b/src/vs/workbench/api/common/extHostDiagnostics.ts
index 1455bb030d8abe9c0b8cddae8802940cea6ebf72..e0b6831c5522d2e1f49e14c31fe79548d5a9afd1 100644
--- a/src/vs/workbench/api/common/extHostDiagnostics.ts
+++ b/src/vs/workbench/api/common/extHostDiagnostics.ts
@@ -13,6 +13,7 @@ import * as converter from './extHostTypeConverters';
 import { mergeSort } from 'vs/base/common/arrays';
 import { Event, Emitter } from 'vs/base/common/event';
 import { keys } from 'vs/base/common/map';
+import { ILogService } from 'vs/platform/log/common/log';
 
 export class DiagnosticCollection implements vscode.DiagnosticCollection {
 
@@ -253,7 +254,7 @@ export class ExtHostDiagnostics implements ExtHostDiagnosticsShape {
 
 	readonly onDidChangeDiagnostics: Event<vscode.DiagnosticChangeEvent> = Event.map(Event.debounce(this._onDidChangeDiagnostics.event, ExtHostDiagnostics._debouncer, 50), ExtHostDiagnostics._mapper);
 
-	constructor(mainContext: IMainContext) {
+	constructor(mainContext: IMainContext, @ILogService private readonly _logService: ILogService) {
 		this._proxy = mainContext.getProxy(MainContext.MainThreadDiagnostics);
 	}
 
@@ -266,7 +267,7 @@ export class ExtHostDiagnostics implements ExtHostDiagnosticsShape {
 		} else if (!_collections.has(name)) {
 			owner = name;
 		} else {
-			console.warn(`DiagnosticCollection with name '${name}' does already exist.`);
+			this._logService.warn(`DiagnosticCollection with name '${name}' does already exist.`);
 			do {
 				owner = name + ExtHostDiagnostics._idPool++;
 			} while (_collections.has(owner));
diff --git a/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts b/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
index 20bb18053aeb5dafe52acdbe1b26fdd95b03b6d8..99d627ed5592d9329d786f778977ebdb03991d2a 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostApiCommands.test.ts
@@ -112,7 +112,7 @@ suite('ExtHostLanguageFeatureCommands', function () {
 		rpcProtocol.set(MainContext.MainThreadCommands, inst.createInstance(MainThreadCommands, rpcProtocol));
 		ExtHostApiCommands.register(commands);
 
-		const diagnostics = new ExtHostDiagnostics(rpcProtocol);
+		const diagnostics = new ExtHostDiagnostics(rpcProtocol, new NullLogService());
 		rpcProtocol.set(ExtHostContext.ExtHostDiagnostics, diagnostics);
 
 		extHost = new ExtHostLanguageFeatures(rpcProtocol, null, extHostDocuments, commands, diagnostics, new NullLogService());
diff --git a/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts b/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
index 60181c415f256af51f6baa50a5a345ee256ffab6..43e7087b3be95151f4bcb099da7d87358d06fccc 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostDiagnostics.test.ts
@@ -11,6 +11,7 @@ import { MainThreadDiagnosticsShape, IMainContext } from 'vs/workbench/api/commo
 import { IMarkerData, MarkerSeverity } from 'vs/platform/markers/common/markers';
 import { mock } from 'vs/workbench/test/electron-browser/api/mock';
 import { Emitter, Event } from 'vs/base/common/event';
+import { NullLogService } from 'vs/platform/log/common/log';
 
 suite('ExtHostDiagnostics', () => {
 
@@ -387,7 +388,7 @@ suite('ExtHostDiagnostics', () => {
 			assertRegistered(): void {
 
 			}
-		});
+		}, new NullLogService());
 
 		let collection1 = diags.createDiagnosticCollection('foo');
 		let collection2 = diags.createDiagnosticCollection('foo'); // warns, uses a different owner
@@ -436,7 +437,7 @@ suite('ExtHostDiagnostics', () => {
 			assertRegistered(): void {
 
 			}
-		});
+		}, new NullLogService());
 
 
 		//
diff --git a/src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts b/src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts
index 68cd2940255d894ba39366b27c3387a9ebebdb4d..3793608226f301d4eff1363318d6655b95dfb55f 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts
@@ -102,7 +102,7 @@ suite('ExtHostLanguageFeatures', function () {
 		rpcProtocol.set(ExtHostContext.ExtHostCommands, commands);
 		rpcProtocol.set(MainContext.MainThreadCommands, inst.createInstance(MainThreadCommands, rpcProtocol));
 
-		const diagnostics = new ExtHostDiagnostics(rpcProtocol);
+		const diagnostics = new ExtHostDiagnostics(rpcProtocol, new NullLogService());
 		rpcProtocol.set(ExtHostContext.ExtHostDiagnostics, diagnostics);
 
 		extHost = new ExtHostLanguageFeatures(rpcProtocol, null, extHostDocuments, commands, diagnostics, new NullLogService());