Use declared return type for inference of return and yield statements.

pkg/front_end/testcases/inference/local_return_and_yield.dart

Index: pkg/front_end/testcases/inference/local_return_and_yield.dart
diff --git a/pkg/front_end/testcases/inference/local_return_and_yield.dart b/pkg/front_end/testcases/inference/local_return_and_yield.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5feced12f33fe8d3a87e206d1e5fbab7ef57bf8c
--- /dev/null
+++ b/pkg/front_end/testcases/inference/local_return_and_yield.dart
@@ -0,0 +1,42 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/*@testedFeatures=inference*/
+library test;
+
+import 'dart:async';
+
+typedef int IntToInt(int i);
+
+main() {
+  IntToInt a() {
+    return /*@returnType=int*/ (/*@type=int*/ x) => x;
+  }
+
+  Future<IntToInt> b() async {
+    // TODO(paulberry): this is broken due to bug 29689.
+    return /*@returnType=dynamic*/ (/*@type=dynamic*/ x) => x;
+  }
+
+  Iterable<IntToInt> c() sync* {
+    yield /*@returnType=int*/ (/*@type=int*/ x) => x;
+  }
+
+  Iterable<IntToInt> d() sync* {
+    yield* /*@typeArgs=(int) -> int*/ [
+      /*@returnType=int*/ (/*@type=int*/ x) => x
+    ];
+  }
+
+  Stream<IntToInt> e() async* {
+    yield /*@returnType=int*/ (/*@type=int*/ x) => x;
+  }
+
+  Stream<IntToInt> f() async* {
+    yield* new /*@typeArgs=(int) -> int*/ Stream.fromIterable(
+        /*@typeArgs=(int) -> int*/ [
+          /*@returnType=int*/ (/*@type=int*/ x) => x
+        ]);
+  }
+}