Generated front_end/testcases/inference test files from Analyzer tests.

pkg/front_end/testcases/inference/future_union_downwards.dart

+// 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';
+
+class MyFuture<T> implements Future<T> {
+  MyFuture() {}
+  MyFuture.value([x]) {}
+  dynamic noSuchMethod(invocation);
+  MyFuture<S> then<S>(FutureOr<S> f(T x), {Function onError}) => null;
+}
+
+MyFuture f;
+// Instantiates Future<int>
+Future<int> t1 = f.then(/*@returnType=Future<int>*/ (/*@type=dynamic*/ _) =>
+    /*@typeArgs=int*/ new Future.value('hi'));
+
+// Instantiates List<int>
+Future<List<int>> t2 = f.then(
+    /*@returnType=List<int>*/ (/*@type=dynamic*/ _) => /*@typeArgs=int*/ [3]);
+Future<List<int>> g2() async {
+  return /*@typeArgs=int*/ [3];
+}
+
+Future<List<int>> g3() async {
+  return /*@typeArgs=List<int>*/ new Future.value(
+      /*@typeArgs=int*/ [3]);
+}