diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index e0f283ecc8e..2de312e716f 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -27,7 +27,12 @@ declare module 'vscode' {
 		/**
 		 *
 		 */
-		export function getDiagnostics(resource?: Uri): Diagnostic[];
+		export function getDiagnostics(resource: Uri): Diagnostic[];
+
+		/**
+		 *
+		 */
+		export function getDiagnostics(): [Uri, Diagnostic[]][];
 	}
 
 	//#endregion
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index ac851683c8f..95a283b53b4 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -236,7 +236,7 @@ export function createApiFactory(
 				checkProposedApiEnabled(extension);
 				return extHostDiagnostics.onDidChangeDiagnostics;
 			},
-			getDiagnostics: proposedApiFunction(extension, resource => {
+			getDiagnostics: <any>proposedApiFunction(extension, (resource?) => {
 				return extHostDiagnostics.getDiagnostics(resource);
 			}),
 			getLanguages(): TPromise<string[]> {
diff --git a/src/vs/workbench/api/node/extHostDiagnostics.ts b/src/vs/workbench/api/node/extHostDiagnostics.ts
index 661728303f0..342060762d7 100644
--- a/src/vs/workbench/api/node/extHostDiagnostics.ts
+++ b/src/vs/workbench/api/node/extHostDiagnostics.ts
@@ -261,17 +261,34 @@ export class ExtHostDiagnostics implements ExtHostDiagnosticsShape {
 		return result;
 	}
 
-	getDiagnostics(resource?: vscode.Uri): vscode.Diagnostic[] {
+	getDiagnostics(resource: vscode.Uri): vscode.Diagnostic[];
+	getDiagnostics(): [vscode.Uri, vscode.Diagnostic[]][];
+	getDiagnostics(resource?: vscode.Uri): vscode.Diagnostic[] | [vscode.Uri, vscode.Diagnostic[]][] {
+		if (resource) {
+			return this._getDiagnostics(resource);
+		} else {
+			let index = new Map<string, number>();
+			let res: [vscode.Uri, vscode.Diagnostic[]][] = [];
+			for (const collection of this._collections) {
+				collection.forEach((uri, diagnostics) => {
+					let idx = index.get(uri.toString());
+					if (typeof idx === 'undefined') {
+						idx = res.length;
+						index.set(uri.toString(), idx);
+						res.push([uri, []]);
+					}
+					res[idx][1] = res[idx][1].concat(...diagnostics);
+				});
+			}
+			return res;
+		}
+	}
+
+	private _getDiagnostics(resource: vscode.Uri): vscode.Diagnostic[] {
 		let res: vscode.Diagnostic[] = [];
 		for (const collection of this._collections) {
-			if (resource) {
-				// filtered
-				if (collection.has(resource)) {
-					res = res.concat(collection.get(resource));
-				}
-			} else {
-				// all
-				collection.forEach((uri, diag) => res = res.concat(diag));
+			if (collection.has(resource)) {
+				res = res.concat(collection.get(resource));
 			}
 		}
 		return res;