diff --git a/CHANGELOG.md b/CHANGELOG.md
index 80bd92ed..15302e0d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## 0.7.1
 
+### `Generator{ForAnnotation}`
+
+* Return type of `generate{ForAnnotatedElement}` is now `FutureOr<String>`.
+
 ### `LibraryReader`
 
 * Added `annotatedElements` to return all elements annotated with something.
diff --git a/lib/src/generator.dart b/lib/src/generator.dart
index 84636e62..923da228 100644
--- a/lib/src/generator.dart
+++ b/lib/src/generator.dart
@@ -20,7 +20,7 @@ abstract class Generator {
   /// output is Dart code returned through the Future. If there is nothing to
   /// generate for this library may return null, or a Future that resolves to
   /// null or the empty string.
-  Future<String> generate(LibraryReader library, BuildStep buildStep) => null;
+  FutureOr<String> generate(LibraryReader library, BuildStep buildStep) => null;
 
   @override
   String toString() => this.runtimeType.toString();
diff --git a/lib/src/generator_for_annotation.dart b/lib/src/generator_for_annotation.dart
index 46b76071..c4dc0ace 100644
--- a/lib/src/generator_for_annotation.dart
+++ b/lib/src/generator_for_annotation.dart
@@ -36,7 +36,7 @@ abstract class GeneratorForAnnotation<T> extends Generator {
   @override
   Future<String> generate(LibraryReader library, BuildStep buildStep) async {
     var elements = library.annotatedWith(typeChecker);
-    var allOutput = await Future.wait(elements.map((e) =>
+    var allOutput = await Future.wait(elements.map((e) async =>
         generateForAnnotatedElement(e.element, e.annotation, buildStep)));
     // TODO interleave comments indicating which element produced the output?
     return allOutput.join('\n');
@@ -46,6 +46,6 @@ abstract class GeneratorForAnnotation<T> extends Generator {
   ///
   /// This method is invoked based on finding elements annotated with an
   /// instance of [T]. The [annotation] is provided as a [ConstantReader].
-  Future<String> generateForAnnotatedElement(
+  FutureOr<String> generateForAnnotatedElement(
       Element element, ConstantReader annotation, BuildStep buildStep);
 }
diff --git a/pubspec.yaml b/pubspec.yaml
index 3359f685..6e93eec9 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: source_gen
-version: 0.7.0
+version: 0.7.1-dev
 author: Dart Team <misc@dartlang.org>
 description: Automated source code generation for Dart.
 homepage: https://github.com/dart-lang/source_gen