message: Better error handling for undefined service identifier
diff: @@ -6,8 +6,10 @@ export const PROVIDER_OPTIONS = 'provider-options';
  export function getServiceIdentifierName<T>(serviceIdentifier: ServiceIdentifier<T>) {
  if (typeof serviceIdentifier === 'function' && isType<T>(serviceIdentifier)) {
  return serviceIdentifier.name;
  - } else {
  + } else if (typeof serviceIdentifier !== 'undefined') {
  return serviceIdentifier.toString();
  + } else {
  + return 'undefined';
  }
  }
  