Fix async/await type checking in analyzer.

pkg/analyzer/test/generated/static_type_warning_code_test.dart

Index: pkg/analyzer/test/generated/static_type_warning_code_test.dart
diff --git a/pkg/analyzer/test/generated/static_type_warning_code_test.dart b/pkg/analyzer/test/generated/static_type_warning_code_test.dart
index 0ceb9d4bf141f905d3a90e4a8c23e844fd24f702..12c028cf1bf17c7363412a5902887f13074c1a89 100644
--- a/pkg/analyzer/test/generated/static_type_warning_code_test.dart
+++ b/pkg/analyzer/test/generated/static_type_warning_code_test.dart
@@ -567,6 +567,41 @@ f(A a, B b) {
     verify([source]);
   }
 
+  void test_returnOfInvalidType_async_future_int_mismatches_future_null() {
+    Source source = addSource('''
+import 'dart:async';
+Future<Null> f() async {
+  return 5;
+}
+''');
+    resolve(source);
+    assertErrors(source, [StaticTypeWarningCode.RETURN_OF_INVALID_TYPE]);
+    verify([source]);
+  }
+
+  void test_returnOfInvalidType_async_future_int_mismatches_future_string() {
+    Source source = addSource('''
+import 'dart:async';
+Future<String> f() async {
+  return 5;
+}
+''');
+    resolve(source);
+    assertErrors(source, [StaticTypeWarningCode.RETURN_OF_INVALID_TYPE]);
+    verify([source]);
+  }
+
+  void test_returnOfInvalidType_async_future_int_mismatches_int() {
+    Source source = addSource('''
+int f() async {
+  return 5;
+}
+''');
+    resolve(source);
+    assertErrors(source, [StaticTypeWarningCode.RETURN_OF_INVALID_TYPE]);
+    verify([source]);
+  }
+
   void test_returnOfInvalidType_expressionFunctionBody_function() {
     Source source = addSource("int f() => '0';");
     resolve(source);