fix #27410, subtype should not use DartType.==

fix #27410, subtype should not use DartType.==

This should improve performance of subtype tests & simplify things, as we are not recursing structurally over the types multiple times.

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/d614c8dcd40fc1b11200928cad0f3b65f9983bd8

[Jennifer Messerly, 2016-09-29 01:40:23]

Description was changed from

==========
fix #27410, subtype should not use DartType.==
==========

to

==========
fix #27410, subtype should not use DartType.==

This should improve performance of subtype tests & simplify things, as we are
not recursing structurally over the types multiple times.
==========

[Jennifer Messerly, 2016-09-29 01:40:23]

jmesserly@google.com changed reviewers:
+ leafp@google.com

[Leaf, 2016-09-29 05:19:19]

lgtm

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/type_system.dart (left):

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/type_system.dart:909: if (t1 == t2) {
consider keeping an identity check?  At some point, I think we should experiment
with hash-consing types during resolution so that even if they aren't truly
canonical, they are at least in practice usually shared.

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/type_system.dart (right):

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/type_system.dart:856: if (i1 == i2) {
maybe here too?

[Jennifer Messerly, 2016-09-29 07:11:12]

thanks, addressed those.

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/type_system.dart (left):

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/type_system.dart:909: if (t1 == t2) {
On 2016/09/29 05:19:19, Leaf wrote:
> consider keeping an identity check?  At some point, I think we should
experiment
> with hash-consing types during resolution so that even if they aren't truly
> canonical, they are at least in practice usually shared. 

great idea! done.

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/type_system.dart (right):

https://codereview.chromium.org/2381773002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/type_system.dart:856: if (i1 == i2) {
On 2016/09/29 05:19:19, Leaf wrote:
> maybe here too?

good catch!

[Jennifer Messerly, 2016-09-29 07:11:39]

Description was changed from

==========
fix #27410, subtype should not use DartType.==

This should improve performance of subtype tests & simplify things, as we are
not recursing structurally over the types multiple times.
==========

to

==========
fix #27410, subtype should not use DartType.==

This should improve performance of subtype tests & simplify things, as we are
not recursing structurally over the types multiple times.

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/d614c8dcd40fc1b11200928cad0f3b65f9983bd8
==========

[Jennifer Messerly, 2016-09-29 07:11:40]

Committed patchset #2 (id:20001) manually as
d614c8dcd40fc1b11200928cad0f3b65f9983bd8 (presubmit successful).

[Bob Nystrom, 2016-09-29 17:10:27]

rnystrom@google.com changed reviewers:
+ rnystrom@google.com

[Bob Nystrom, 2016-09-29 17:10:28]

lgtm

[Jennifer Messerly, 2016-09-29 17:31:40]

On 2016/09/29 17:10:28, Bob Nystrom wrote:
> lgtm

fyi there was some breakage caused by this, only happens with circular types:
https://github.com/dart-lang/sdk/issues/27454

I'm looking into it.