Infer types of catpured variables and use the types in the SSA builder.

tests/compiler/dart2js/types_of_captured_variables_test.dart

Index: tests/compiler/dart2js/types_of_captured_variables_test.dart
===================================================================
--- tests/compiler/dart2js/types_of_captured_variables_test.dart	(revision 0)
+++ tests/compiler/dart2js/types_of_captured_variables_test.dart	(revision 0)
@@ -0,0 +1,48 @@
+// 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.
+
+import 'compiler_helper.dart';
+
+const String TEST1 = r"""
+main() {
+  var a = 52;
+  var f = () => a + 3;
+  f();
+}
+""";
+
+const String TEST2 = r"""
+main() {
+  var a = 52;
+  var g = () { a = 48; };
+  var f = () => a + 3;
+  f();
+  g();
+}
+""";
+
+const String TEST3 = r"""
+main() {
+  var a = 52;
+  var g = () { a = 'foo'; };
+  var f = () => a + 3;
+  f();
+  g();
+}
+""";
+
+main() {
+  // Test that we know the type of captured, non-mutated variables.
+  String generated = compileAll(TEST1);
+  Expect.isTrue(generated.contains('+ 3'));
+
+  // Test that we know the type of captured, mutated variables.
+  generated = compileAll(TEST2);
+  Expect.isTrue(generated.contains('+ 3'));
+
+  // Test that we know when types of a captured, mutated variable
+  // conflict.
+  generated = compileAll(TEST3);
+  Expect.isFalse(generated.contains('+ 3'));
+}