diff --git a/goldens/public-api/core/core.d.ts b/goldens/public-api/core/core.d.ts
index 3048dddf4d..6334c6632a 100644
--- a/goldens/public-api/core/core.d.ts
+++ b/goldens/public-api/core/core.d.ts
@@ -53,7 +53,7 @@ export declare function asNativeElements(debugEls: DebugElement[]): any;
 export declare function assertPlatform(requiredToken: any): PlatformRef;
 
 export declare interface Attribute {
-    attributeName?: string;
+    attributeName: string;
 }
 
 export declare const Attribute: AttributeDecorator;
diff --git a/packages/compiler/src/core.ts b/packages/compiler/src/core.ts
index cf3175985d..f6612c93de 100644
--- a/packages/compiler/src/core.ts
+++ b/packages/compiler/src/core.ts
@@ -22,10 +22,10 @@ export const createInjectionToken = makeMetadataFactory<object>(
     'InjectionToken', (desc: string) => ({_desc: desc, ɵprov: undefined}));
 
 export interface Attribute {
-  attributeName?: string;
+  attributeName: string;
 }
 export const createAttribute =
-    makeMetadataFactory<Attribute>('Attribute', (attributeName?: string) => ({attributeName}));
+    makeMetadataFactory<Attribute>('Attribute', (attributeName: string) => ({attributeName}));
 
 export interface Query {
   descendants: boolean;
diff --git a/packages/core/src/di/metadata.ts b/packages/core/src/di/metadata.ts
index 2790c0152f..521d6faf7b 100644
--- a/packages/core/src/di/metadata.ts
+++ b/packages/core/src/di/metadata.ts
@@ -271,7 +271,7 @@ export interface Attribute {
   /**
    * The name of the attribute whose value can be injected.
    */
-  attributeName?: string;
+  attributeName: string;
 }
 
 /**