add parser parseAsync flag

add parser parseAsync flag
add new ASYNC_NOT_SUPPORTED error code
update ParseTask to support enableAsync
add AnalysisOptions.enableAsync flag

partially addresses https://github.com/dart-lang/sdk/issues/25373

R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/b852ddc41ac83152f49be92114254f2ec3548633

[danrubel, 2016-01-08 17:42:17]

danrubel@google.com changed reviewers:
+ brianwilkerson@google.com

[Brian Wilkerson, 2016-01-08 18:43:47]

LGTM

This doesn't produce errors for uses of "async for", "await" or "yield". Are you
planning on handling those later (for example, by not marking the function
bodies as being async)? Or are we not going to produce errors in those cases
because one error on the "sync" or "async" keyword should cover the rest of the
cases?

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/engine.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/engine.dart:1050: * Return `true` to if analysis
is to include async support.
"if analysis is to include" --> "enable"

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/parser.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/parser.dart:9382: * Some environments such as
fletch do not support async.
"fletch" or "Fletch"?

"environments such as fletch do" --> "environments, such as fletch, do"

And is that true, that none of the platforms that Fletch supports will include
async support?

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/parser.dart:9386: "Async and sync are not
supported in this environment.");
"in this environment" or "on this platform"? What terminology makes the most
sense to users?

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/task/o...
File pkg/analyzer/lib/src/task/options.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/task/o...
pkg/analyzer/lib/src/task/options.dart:433: new
AnalysisOptionsImpl.from(context.analysisOptions);
Seems kind of wasteful to create a new options object for every flag. It might
not matter much in terms of performance, though.

[danrubel, 2016-01-08 20:45:51]

On 2016/01/08 18:43:47, Brian Wilkerson wrote:
> This doesn't produce errors for uses of "async for", "await" or "yield". 

Correct.

> Are you
> planning on handling those later (for example, by not marking the function
> bodies as being async)? Or are we not going to produce errors in those cases
> because one error on the "sync" or "async" keyword should cover the rest of
the
> cases?

One error is enough, because as soon as they fix it, the other errors will show
up.

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/engine.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/engine.dart:1050: * Return `true` to if analysis
is to include async support.
On 2016/01/08 18:43:47, Brian Wilkerson wrote:
> "if analysis is to include" --> "enable"

Done.

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
File pkg/analyzer/lib/src/generated/parser.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/parser.dart:9382: * Some environments such as
fletch do not support async.
On 2016/01/08 18:43:47, Brian Wilkerson wrote:
> "fletch" or "Fletch"?
> 
> "environments such as fletch do" --> "environments, such as fletch, do"
> 
> And is that true, that none of the platforms that Fletch supports will include
> async support?

Done.

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/genera...
pkg/analyzer/lib/src/generated/parser.dart:9386: "Async and sync are not
supported in this environment.");
On 2016/01/08 18:43:47, Brian Wilkerson wrote:
> "in this environment" or "on this platform"? What terminology makes the most
> sense to users?

Really good question... I struggled with this as well.
I'm happy to change it in a subsequent CL if we find better wording.

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/task/o...
File pkg/analyzer/lib/src/task/options.dart (right):

https://codereview.chromium.org/1570183002/diff/1/pkg/analyzer/lib/src/task/o...
pkg/analyzer/lib/src/task/options.dart:433: new
AnalysisOptionsImpl.from(context.analysisOptions);
On 2016/01/08 18:43:47, Brian Wilkerson wrote:
> Seems kind of wasteful to create a new options object for every flag. It might
> not matter much in terms of performance, though.

I don't think this is a performance bottleneck, so I did not spend the time to
optimize the performance.

[danrubel, 2016-01-08 20:50:42]

Description was changed from

==========
add parser parseAsync flag
add new ASYNC_NOT_SUPPORTED error code
update ParseTask to support enableAsync
add AnalysisOptions.enableAsync flag

partially addresses https://github.com/dart-lang/sdk/issues/25373
==========

to

==========
add parser parseAsync flag
add new ASYNC_NOT_SUPPORTED error code
update ParseTask to support enableAsync
add AnalysisOptions.enableAsync flag

partially addresses https://github.com/dart-lang/sdk/issues/25373

R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/b852ddc41ac83152f49be92114254f2ec3548633
==========

[danrubel, 2016-01-08 20:50:43]

Committed patchset #3 (id:40001) manually as
b852ddc41ac83152f49be92114254f2ec3548633 (presubmit successful).