Fix bad type-inferrence for logical expressions.

tests/language/logical_expression2_test.dart

+// Copyright (c) 2014, 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.

[ngeoffray, 2014/02/27 10:33:12]

New line.

[floitsch, 2014/02/27 16:07:08]

Done.

+// Dart test program for testing if statement.

[ngeoffray, 2014/02/27 10:33:12]

Rephrase comment.

[floitsch, 2014/02/27 16:07:08]

Removed. The description is below.

+
+import "package:expect/expect.dart";
+
+// For logical-or conditions with an and-expression in the rhs dart2js
+// unconditionally propagated is-checks of the logical and.

[sra1, 2014/02/27 03:12:55]

This past-tense sentence will be confusing in the future.

Rephrase to what must be done ("... would be incorrect to propagate ...")
and say this was a bug with dart2js, and reference the bug.

Since it is a bug in dart2js, maybe this test should live in dart2js_extra?

[floitsch, 2014/02/27 16:07:08]

Test should work with the VM too. I don't see any need to keep it dart2js
private.
Moved bug description to `if`, but referenced issue number here.

+
+int globalCounter = 0;
+
+void nonInlinedUse(Object object) {
+  if (new DateTime.now().millisecondsSinceEpoch == 42) nonInlinedUse(object);
+  if (object is! String) globalCounter++;
+}
+
+main() {
+  var o = [ "foo", 499 ][1];

[sra1, 2014/02/27 03:12:55]

With array tracing, dart2js can probably constant-fold this whole program (or
should be close to being able to.)

[floitsch, 2014/02/27 16:07:08]

Done.

+
+  if ((o is num) ||
+      (o is String && true)) {
+    nonInlinedUse(o);
+  }
+  Expect.equals(1, globalCounter);
+}