Don't type promote local functions.

pkg/front_end/testcases/inference/type_promotion_ignores_local_functions.dart

Index: pkg/front_end/testcases/inference/type_promotion_ignores_local_functions.dart
diff --git a/pkg/front_end/testcases/inference/type_promotion_ignores_local_functions.dart b/pkg/front_end/testcases/inference/type_promotion_ignores_local_functions.dart
new file mode 100644
index 0000000000000000000000000000000000000000..b0d9f63d6d1241ae2b19a26dbfe6b73358430382
--- /dev/null
+++ b/pkg/front_end/testcases/inference/type_promotion_ignores_local_functions.dart
@@ -0,0 +1,15 @@
+// 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.md file.
+
+/*@testedFeatures=inference*/
+library test;
+
+typedef int FunctionReturningInt();
+
+main() {
+  num f() => 0;
+  if (f is FunctionReturningInt) {
+    f;
+  }
+}