diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index d64abff5ed6..6ca0cac5d39 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -63,13 +63,21 @@ export interface IExtensionApiFactory {
 	(extension: IExtensionDescription): typeof vscode;
 }
 
+export function checkProposedApiEnabled(extension: IExtensionDescription): void {
+	if (!extension.enableProposedApi) {
+		throwProposedApiError(extension);
+	}
+}
+
+function throwProposedApiError(extension: IExtensionDescription): never {
+	throw new Error(`[${extension.id}]: Proposed API is only available when running out of dev or with the following command line switch: --enable-proposed-api ${extension.id}`);
+}
+
 function proposedApiFunction<T>(extension: IExtensionDescription, fn: T): T {
 	if (extension.enableProposedApi) {
 		return fn;
 	} else {
-		return <any>(() => {
-			throw new Error(`[${extension.id}]: Proposed API is only available when running out of dev or with the following command line switch: --enable-proposed-api ${extension.id}`);
-		});
+		return <any>throwProposedApiError;
 	}
 }
 
diff --git a/src/vs/workbench/api/node/extHostExtensionService.ts b/src/vs/workbench/api/node/extHostExtensionService.ts
index 1f0e130df8c..6c64bc0b62d 100644
--- a/src/vs/workbench/api/node/extHostExtensionService.ts
+++ b/src/vs/workbench/api/node/extHostExtensionService.ts
@@ -12,7 +12,7 @@ import { TPromise } from 'vs/base/common/winjs.base';
 import { ExtensionDescriptionRegistry } from 'vs/workbench/services/extensions/node/extensionDescriptionRegistry';
 import { IExtensionDescription } from 'vs/platform/extensions/common/extensions';
 import { ExtHostStorage } from 'vs/workbench/api/node/extHostStorage';
-import { createApiFactory, initializeExtensionApi } from 'vs/workbench/api/node/extHost.api.impl';
+import { createApiFactory, initializeExtensionApi, checkProposedApiEnabled } from 'vs/workbench/api/node/extHost.api.impl';
 import { MainContext, MainThreadExtensionServiceShape, IWorkspaceData, IEnvironment, IInitData, ExtHostExtensionServiceShape, MainThreadTelemetryShape, IExtHostContext } from './extHost.protocol';
 import { IExtensionMemento, ExtensionsActivator, ActivatedExtension, IExtensionAPI, IExtensionContext, EmptyExtension, IExtensionModule, ExtensionActivationTimesBuilder, ExtensionActivationTimes, ExtensionActivationReason, ExtensionActivatedByEvent } from 'vs/workbench/api/node/extHostExtensionActivator';
 import { ExtHostConfiguration } from 'vs/workbench/api/node/extHostConfiguration';
@@ -344,7 +344,10 @@ export class ExtHostExtensionService implements ExtHostExtensionServiceShape {
 				get extensionPath() { return extensionDescription.extensionFolderPath; },
 				storagePath: this._storagePath.value(extensionDescription),
 				asAbsolutePath: (relativePath: string) => { return join(extensionDescription.extensionFolderPath, relativePath); },
-				get logger() { return that._extHostLogService.getExtLogger(extensionDescription.id); }
+				get logger() {
+					checkProposedApiEnabled(extensionDescription);
+					return that._extHostLogService.getExtLogger(extensionDescription.id);
+				}
 			});
 		});
 	}