Support type promotion in dart2js.

tests/language/type_promotion_local_test.dart

Index: tests/language/type_promotion_local_test.dart
diff --git a/tests/language/type_promotion_local_test.dart b/tests/language/type_promotion_local_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d16e93f9aac56376dd984a23c079ef701d21950c
--- /dev/null
+++ b/tests/language/type_promotion_local_test.dart
@@ -0,0 +1,159 @@
+// 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.
+
+class A {
+  var a = "a";
+}
+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 = "";
+}
+
+void main() {
+  A a = new E();
+  print(a.a);
+  print(a.b); /// 01: static type warning
+  print(a.c); /// 02: static type warning
+  print(a.d); /// 03: static type warning
+
+  if (a is B) {
+    print(a.a);
+    print(a.b);
+    print(a.c); /// 04: static type warning
+    print(a.d); /// 05: static type warning
+
+    if (a is C) {
+      print(a.a);
+      print(a.b);
+      print(a.c);
+      print(a.d); /// 06: static type warning
+    }
+
+    print(a.a);
+    print(a.b);
+    print(a.c); /// 07: static type warning
+    print(a.d); /// 08: static type warning
+  }
+  if (a is C) {
+    print(a.a);
+    print(a.b);
+    print(a.c);
+    print(a.d); /// 09: static type warning
+
+    if (a is B) {
+      print(a.a);
+      print(a.b);
+      print(a.c);
+      print(a.d); /// 10: static type warning
+    }
+    if (a is D) {
+      print(a.a);
+      print(a.b);
+      print(a.c);
+      print(a.d); /// 11: static type warning
+    }
+
+    print(a.a);
+    print(a.b);
+    print(a.c);
+    print(a.d); /// 12: static type warning
+  }
+
+  print(a.a);
+  print(a.b); /// 13: static type warning
+  print(a.c); /// 14: static type warning
+  print(a.d); /// 15: static type warning
+
+  if (a is D) {
+    print(a.a);
+    print(a.b); /// 16: static type warning
+    print(a.c); /// 17: static type warning
+    print(a.d);
+  }
+
+  print(a.a);
+  print(a.b); /// 18: static type warning
+  print(a.c); /// 19: static type warning
+  print(a.d); /// 20: static type warning
+
+  var o1 = a is B  ?
+      '${a.a}'
+      '${a.b}'
+      '${a.c}' /// 21: static type warning
+      '${a.d}' /// 22: static type warning
+      :
+      '${a.a}'
+      '${a.b}' /// 23: static type warning
+      '${a.c}' /// 24: static type warning
+      '${a.d}' /// 25: static type warning
+      ;
+
+  var o2 = a is C  ?
+      '${a.a}'
+      '${a.b}'
+      '${a.c}'
+      '${a.d}' /// 26: static type warning
+      :
+      '${a.a}'
+      '${a.b}' /// 27: static type warning
+      '${a.c}' /// 28: static type warning
+      '${a.d}' /// 29: static type warning
+      ;
+
+  var o3 = a is D  ?
+      '${a.a}'
+      '${a.b}' /// 30: static type warning
+      '${a.c}' /// 31: static type warning
+      '${a.d}'
+      :
+      '${a.a}'
+      '${a.b}' /// 32: static type warning
+      '${a.c}' /// 33: static type warning
+      '${a.d}' /// 34: static type warning
+      ;
+
+  if (a is B && a is B) {
+    print(a.a);
+    print(a.b);
+    print(a.c); /// 35: static type warning
+    print(a.d); /// 36: static type warning
+  }
+  if (a is B && a is C) {
+    print(a.a);
+    print(a.b);
+    print(a.c);
+    print(a.d); /// 37: static type warning
+  }
+  if (a is C && a is B) {
+    print(a.a);
+    print(a.b);
+    print(a.c);
+    print(a.d); /// 38: static type warning
+  }
+  if (a is C && a is D) {
+    print(a.a);
+    print(a.b);
+    print(a.c);
+    print(a.d); /// 39: static type warning
+  }
+  if (a is D && a is C) {
+    print(a.a);
+    print(a.b); /// 40: static type warning
+    print(a.c); /// 41: static type warning
+    print(a.d);
+  }
+}