Optimize boolean asserts

Optimize boolean asserts
This change adds a notion of non-nullability to the type system. We use this to track nullable vs non-nullable bools, removing a lot of the checks in "if" "for" etc.
Also fixes ?: precedence, uncovered by sra's PEG tests

Committed: https://code.google.com/p/dart/source/detail?r=1481

[Jennifer Messerly, 2011-11-11 23:32:12]

tbr

[jimhug, 2011-11-12 00:26:36]

lgtm

http://codereview.chromium.org/8463027/diff/2001/frog/frogsh
File frog/frogsh (right):

http://codereview.chromium.org/8463027/diff/2001/frog/frogsh#newcode268
frog/frogsh:268: i < this._arguments.length; i++) {
I love the improvements to this file.

http://codereview.chromium.org/8463027/diff/2001/frog/type.dart
File frog/type.dart (right):

http://codereview.chromium.org/8463027/diff/2001/frog/type.dart#newcode65
frog/type.dart:65: // as an optimization for booleans to generate better code in
checked mode.
Nice!

http://codereview.chromium.org/8463027/diff/2001/frog/type.dart#newcode366
frog/type.dart:366: class NonNullableType extends Type {
This seems like a decent choice - but it shares the ugliness of ConcreteType in
terms of having to forward way too much.  I'm not sure but I suspect there's a
better design here that we'll get to over time.

http://codereview.chromium.org/8463027/diff/2001/frog/value.dart
File frog/value.dart (right):

http://codereview.chromium.org/8463027/diff/2001/frog/value.dart#newcode72
frog/value.dart:72: // So it should be pretty easy to make this go away.
+1

[Jennifer Messerly, 2011-11-12 00:33:00]

http://codereview.chromium.org/8463027/diff/2001/frog/type.dart
File frog/type.dart (right):

http://codereview.chromium.org/8463027/diff/2001/frog/type.dart#newcode366
frog/type.dart:366: class NonNullableType extends Type {
On 2011/11/12 00:26:36, jimhug wrote:
> This seems like a decent choice - but it shares the ugliness of ConcreteType
in
> terms of having to forward way too much.  I'm not sure but I suspect there's a
> better design here that we'll get to over time.

Funny huh? Nothing obviously better sprung to mind, as much as I wanted to
design it better.

I think I lose my privileges to complain about ConcreteType now :)