Revert "special-case ListMixin.setRange from same list"

Revert "special-case ListMixin.setRange from same list"

This reverts commit 001ce2aad76bf0a4af12bfa5159812c56b8cce49.

TBR=lrn@google.com

BUG=

Committed: https://github.com/dart-lang/sdk/commit/e97610ec38d8499362308c5f06a7b54ac044ef21

[sra1, 2017-06-26 23:44:54]

Description was changed from

==========
Revert "special-case ListMixin.setRange from same list"

This reverts commit 001ce2aad76bf0a4af12bfa5159812c56b8cce49.

TBR=lrn@google.com

BUG=
==========

to

==========
Revert "special-case ListMixin.setRange from same list"

This reverts commit 001ce2aad76bf0a4af12bfa5159812c56b8cce49.

TBR=lrn@google.com

BUG=

Committed:
https://github.com/dart-lang/sdk/commit/e97610ec38d8499362308c5f06a7b54ac044ef21
==========

[sra1, 2017-06-26 23:44:55]

Committed patchset #1 (id:1) manually as
e97610ec38d8499362308c5f06a7b54ac044ef21 (presubmit successful).

[sra1, 2017-06-27 00:14:26]

On 2017/06/26 23:44:55, sra1 wrote:
> Committed patchset #1 (id:1) manually as
> e97610ec38d8499362308c5f06a7b54ac044ef21 (presubmit successful).

There were two problems, which show up with NodeList:

 1. Caching of length is wrong for Nodelist where the length can change when an
element is moved within the list by assignment.
 2. setRange on some classes throws an exception and this is necessary for
correct behaviour, i.e. to prevent modification of fixed-length and immutable
lists.

It is hard to see how to get around #2, since there is no public API on List to
test for fixed length or immutability.

The benefits of this change were:

 (a) reduced checking since [start, end) bounds were correct by construction
 (b) better dart2js tree-shaking since setRange was not called from mixin code,
preventing pulling in of all List setRange methods.

I think we have to abandon this approach and its benefits until there are List
APIs for testing fixed-length and immutability.

[sra1, 2017-06-27 02:21:25]

On 2017/06/27 00:14:26, sra1 wrote:
> On 2017/06/26 23:44:55, sra1 wrote:
> > Committed patchset #1 (id:1) manually as
> > e97610ec38d8499362308c5f06a7b54ac044ef21 (presubmit successful).
> 
> There were two problems, which show up with NodeList:
> 
>  1. Caching of length is wrong for Nodelist where the length can change when
an
> element is moved within the list by assignment.
>  2. setRange on some classes throws an exception and this is necessary for
> correct behaviour, i.e. to prevent modification of fixed-length and immutable
> lists.
> 
> It is hard to see how to get around #2, since there is no public API on List
to
> test for fixed length or immutability.
> 
> The benefits of this change were:
> 
>  (a) reduced checking since [start, end) bounds were correct by construction
>  (b) better dart2js tree-shaking since setRange was not called from mixin
code,
> preventing pulling in of all List setRange methods.
> 
> I think we have to abandon this approach and its benefits until there are List
> APIs for testing fixed-length and immutability.

On further investigation, this is a bug on _ChildNodeListLazy - it is missing
removeRange.
I will fix this and retry.