Added Triaged label.

This comment was originally written by Ruper...@gmail.com

The regression was introduced into dart2js between versions 8942 and 9258.
(I'd planned to report since I've been developing DartBox2D and updating Dart weekly but couldn't determine sufficiently minimal test-case. The commit I'm hoping to push for DartBox2D includes a minimal DartBox2D testcase but this still drags-in lots of code!)
HTH, R.

Set owner to @floitschG.
Added Started label.

Tracked it down to commit 9019.
Investigating what exactly went wrong now.

CL uploaded: https://chromiumcodereview.appspot.com/10704229/

Fixed in r9695.

The bug was triggered by a loop that didn't have any back-edge: http://code.google.com/p/dartbox2d/source/browse/lib/dynamics/contacts/ContactSolver.dart#­374

This should be correctly handled now, but if the loop is not needed it should maybe be removed. Dart2js does not yet detect that the loop is not needed.

Added Fixed label.

This comment was originally written by domi...@google.com

Thank you so much for chasing this down.

You're right that the loop is not necessary, however it is a valid code construct to avoid complex nested if-statements. As it happens, I'd prefer the nested conditionals but dart2js should still be able to handle the code.

Is there already an open issue for this?

It does handle it correctly now. Just not as optimized as without the loop.
For example it will assume that the code inside the loop is executed more than once and will therefore try to optimize more optimistically for the body.

This comment was originally written by Ruper...@gmail.com

Confirmed this fixes the bug in dartbox2d. Thanks!