Support type promotion in dart2js.

tests/language/type_promotion_closure_test.dart

Index: tests/language/type_promotion_closure_test.dart
diff --git a/tests/language/type_promotion_closure_test.dart b/tests/language/type_promotion_closure_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5c32a77a546ff01e363ae4c4b93b1635fc3eddde
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+++ b/tests/language/type_promotion_closure_test.dart
@@ -0,0 +1,161 @@
+// Copyright (c) 2013, 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.
+
+// Test type promotion of locals potentially mutated in closures.
+
+class A {
+  var a = "a";
+  A operator +(int i) => this;
+}
+class B extends A {
+  var b = "b";
+}
+class C extends B {
+  var c = "c";
+}
+class D extends A {
+  var d = "d";
+}
+class E implements C, D {
+  var a = "";
+  var b = "";
+  var c = "";
+  var d = "";
+}
+
+func(x) => true;
+
+void main() {
+  test1();
+  test2();
+  test3();
+  test4();
+  test5();
+  test6();
+  test7();
+  test8();
+  test9();
+  test10();
+  test11();
+  test12();
+}
+
+void test1() {
+  A a = new E();
+  if (a is B) {
+    print(a.a);
+    print(a.b); /// 01: static type warning
+  }
+  void foo() {
+    a = new D();
+  }
+}
+
+void test2() {
+  A a = new E();
+  void foo() {
+    a = new D();
+  }
+  if (a is B) {
+    print(a.a);
+    print(a.b); /// 02: static type warning
+  }
+}
+
+void test3() {
+  A a = new E();
+  void foo() {
+    a = new D();
+  }
+  if (a is B) {
+    print(a.a);
+    print(a.b); /// 03: static type warning
+    void foo() {
+      a = new D();
+    }
+    print(a.a);
+    print(a.b); /// 04: static type warning
+  }
+}
+
+void test4() {
+  A a = new E();
+  if (a is B) {
+    func(() => a.b); /// 05: ok
+    print(a.a);
+    print(a.b);
+  }
+}
+
+void test5() {
+  A a = new E();
+  if (a is B) {
+    func(() => a.b); /// 06: static type warning
+    print(a.a);
+  }
+  a = null;
+}
+
+void test6() {
+  A a = new E();
+  if (a is B) {
+    func(() => a);
+    print(a.a);
+    print(a.b); /// 07: static type warning
+  }
+  a = null;
+}
+
+void test7() {
+  A a = new E();
+  if (a is B && func(() => a)) {
+    print(a.a);
+    print(a.b); /// 08: ok
+  }
+  a = null;
+}
+
+void test8() {
+  A a = new E();
+  if (a is B
+      && func(() => a.b) /// 09: static type warning
+                        ) {
+    print(a.a);
+  }
+  a = null;
+}
+
+void test9() {
+  A a = new E();
+  var b = a is B ? func(() => a.b) : false; /// 10: static type warning
+  a = null;
+}
+
+void test10() {
+  List<A> a = <E>[new E()];
+  if (a is List<B>) {
+    func(() => a[0]);
+    print(a[0].b); /// 11: static type warning
+  }
+  a = null;
+}
+
+void test11() {
+  List<A> a = <E>[new E()];
+  if (a is List<B>) {
+    func(() => a[0] = null);
+    print(a[0].b); /// 12: static type warning
+  }
+  a = null;
+}
+
+void test12() {
+  A a = new E();
+  if (a is B) {
+    func(() => a++);
+    print(a.a);
+    print(a.b); /// 13: static type warning
+  }
+  a = null;
+}