fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

We've had this flag off in testing for quite a while. This should not affect user code because it's removing a throw.

R=leafp@google.com

Committed: https://github.com/dart-lang/sdk/commit/65e609548d9cfacb29cc369bfa8646bbe19788b3

[Jennifer Messerly, 2017-08-05 01:17:28]

Description was changed from

==========
fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc
==========

to

==========
fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

We've had this flag off in testing for quite a while. This should not affect
user code because it's removing a throw.
==========

[Jennifer Messerly, 2017-08-05 01:17:28]

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

[Jennifer Messerly, 2017-08-05 01:22:20]

FYI, I also checked internal code and did not find any use of this flag. I
believe it is safe, as we already have `is` check divergences possible even with
this flag (e.g. inference)

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
File pkg/dev_compiler/test/browser/language_tests.js (right):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
pkg/dev_compiler/test/browser/language_tests.js:84: 'call_test': fail,
this is just triage for another language test migration failure

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
File pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/operations.dart
(right):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/operations.dart:511: bool
instanceOfOrNull(obj, type) {
fyi, I checked that this does not cause any new casts in the runtime code

[Leaf, 2017-08-05 02:24:27]

lgtm!  WOOHOO!

Can you add a CHANGELOG entry?

Up to you whether to keep the flag disabled or just wipe it.

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
File pkg/dev_compiler/test/browser/runtime_tests.js (right):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
pkg/dev_compiler/test/browser/runtime_tests.js:251: function checkType(x, type,
expectedTrue, strongOnly) {
Is strongOnly dead now?

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
File pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart (left):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart:40: JS('',
'dart.__failForWeakModeIsChecks = #', flag);
Is it worth keeping this flag, just turned off?  I'm not super keen on keeping
essentially dead code around, but it might be useful to triage DDC bug reports. 
WDYT?

[Jennifer Messerly, 2017-08-07 23:30:53]

Done & added changelog entry

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
File pkg/dev_compiler/test/browser/runtime_tests.js (right):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/test/brows...
pkg/dev_compiler/test/browser/runtime_tests.js:251: function checkType(x, type,
expectedTrue, strongOnly) {
On 2017/08/05 02:24:27, Leaf wrote:
> Is strongOnly dead now?

Done.

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
File pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart (left):

https://codereview.chromium.org/2996573002/diff/1/pkg/dev_compiler/tool/input...
pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart:40: JS('',
'dart.__failForWeakModeIsChecks = #', flag);
On 2017/08/05 02:24:27, Leaf wrote:
> Is it worth keeping this flag, just turned off?  I'm not super keen on keeping
> essentially dead code around, but it might be useful to triage DDC bug
reports. 
> WDYT?

yeah ... IMO, less code to keep around as we do all the various migrations &
other Dart 2 impls won't have it, plus if we ever refactor subtype stuff, we
won't need to keep the weak mode impl of subtype around. Also we were trying to
remove "StrongModeError" from DDC's runtime code (there's an issue for that).

but I haven't personally ever used it for triage, so I may be biased. I don't
think it would be too hard to hand edit `dart.is` in the SDK JS to try and solve
a really tricky case (basically `if (result == null) debugger;`). Or we can
revert most of this patch to add back the feature, worst case :)

[Leaf, 2017-08-07 23:39:17]

still lgtm!

[Jennifer Messerly, 2017-08-07 23:41:28]

Description was changed from

==========
fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

We've had this flag off in testing for quite a while. This should not affect
user code because it's removing a throw.
==========

to

==========
fix #28988, remove throw on Dart1 incompatible is-checks for dartdevc

We've had this flag off in testing for quite a while. This should not affect
user code because it's removing a throw.

R=leafp@google.com

Committed:
https://github.com/dart-lang/sdk/commit/65e609548d9cfacb29cc369bfa8646bbe19788b3
==========

[Jennifer Messerly, 2017-08-07 23:41:29]

Committed patchset #2 (id:10001) manually as
65e609548d9cfacb29cc369bfa8646bbe19788b3 (presubmit successful).