Fix more errors in DDC SDK.

Fix more errors in DDC SDK.

R=jacobr@google.com, vsm@google.com

Committed: https://github.com/dart-lang/sdk/commit/979a75c4b3b850fff5c63beef25fcf26ed3e1f56

[Bob Nystrom, 2017-05-10 22:53:06]

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

[Bob Nystrom, 2017-05-10 22:53:59]

https://codereview.chromium.org/2871363002/diff/1/pkg/dev_compiler/tool/input...
File pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart (right):

https://codereview.chromium.org/2871363002/diff/1/pkg/dev_compiler/tool/input...
pkg/dev_compiler/tool/input_sdk/lib/js/dart2js/js_dart2js.dart:370: void
operator []=(Object index, value) {
Removing "E" here means that the argument is no longer checked to see if it
conforms to the type argument. Is that OK? Should this be a covariant override
instead?

[Bob Nystrom, 2017-05-10 22:56:13]

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

[Bob Nystrom, 2017-05-10 22:56:14]

Jacob, can you take a look at my change to JsArray?

[vsm, 2017-05-10 23:05:38]

lgtm

[Jacob, 2017-05-11 04:00:00]

lgtm for JsArray change.

[Jacob, 2017-05-11 04:05:25]

https://codereview.chromium.org/2871363002/diff/10001/pkg/dev_compiler/tool/i...
File pkg/dev_compiler/tool/input_sdk/lib/js_util/dart2js/js_util_dart2js.dart
(right):

https://codereview.chromium.org/2871363002/diff/10001/pkg/dev_compiler/tool/i...
pkg/dev_compiler/tool/input_sdk/lib/js_util/dart2js/js_util_dart2js.dart:112:
var args = <dynamic>[null]..addAll(arguments);
Were we inferring that [null] has type List<Null> or is there something more
complex leading to the error from the errors.txt file?
That seems like a bug if that is what is happening.
We wouldn't infer that
var x = null;
means that x has type null. So I'm missing why we should do the equivalent of
that in this case.

[Bob Nystrom, 2017-05-11 16:56:53]

On 2017/05/11 04:05:25, Jacob wrote:
>
https://codereview.chromium.org/2871363002/diff/10001/pkg/dev_compiler/tool/i...
> File pkg/dev_compiler/tool/input_sdk/lib/js_util/dart2js/js_util_dart2js.dart
> (right):
> 
>
https://codereview.chromium.org/2871363002/diff/10001/pkg/dev_compiler/tool/i...
> pkg/dev_compiler/tool/input_sdk/lib/js_util/dart2js/js_util_dart2js.dart:112:
> var args = <dynamic>[null]..addAll(arguments);
> Were we inferring that [null] has type List<Null>

It was a combination of that and the fact that arguments is a List but addAll()
takes an Iterable.

So it was trying to pass a List<dynamic> to something that expected an
Iterable<Null>.

That requires both upcasting the outer type from List to Iterable and then
contravariantly casting the type argument from dynamic to Null. The type system
doesn't allow that.

In this case, though, Null is clearly the wrong type argument for args. It
should be a List<dynamic> since we're adding other non-Null stuff to it later.

> That seems like a bug if that is what is happening.
> We wouldn't infer that
> var x = null;
> means that x has type null.

I believe we do infer that, actually. However, since Null is the bottom type,
that still lets you assign a value of any other type to x, so the weird
inference isn't as visible.

– bob

[Bob Nystrom, 2017-05-11 18:22:11]

Description was changed from

==========
Fix more errors in DDC SDK.
==========

to

==========
Fix more errors in DDC SDK.

R=jacobr@google.com, vsm@google.com

Committed:
https://github.com/dart-lang/sdk/commit/979a75c4b3b850fff5c63beef25fcf26ed3e1f56
==========

[Bob Nystrom, 2017-05-11 18:22:12]

Committed patchset #3 (id:20001) manually as
979a75c4b3b850fff5c63beef25fcf26ed3e1f56 (presubmit successful).