Add 'Introduce new local with cast type' quick assist.

Add 'Introduce new local with cast type' quick assist.

Unfortunately we still often need it in Dart, as we always need it in Java.

Type promotion does not work for "if (name is Type)" if "name" is a field,
an expression or "name" is modified _anywhere_ in the function.

R=paulberry@google.com, brianwilkerson@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=40824

[Paul Berry, 2014-09-30 20:34:46]

lgtm

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/services/correction/assist.dart (right):

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/services/correction/assist.dart:76: "Introduce new
local with cast type");
I think this terminology may be confusing to Dart users, since in Dart
terminology, a "cast" only refers to expressions like "x as T".  Expressions
like "X is T" are called "type tests" by the spec.

How about changing the text to "Introduce new local with tested type"?

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/services/correction/assist_internal.dart
(right):

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/services/correction/assist_internal.dart:564: if
(node is! IsExpression) {
We should also bail out if node is IsExpression and node.notOperator != null. 
We don't want to offer this quick assist for "is!" tests.

[scheglov, 2014-09-30 20:44:07]

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/services/correction/assist.dart (right):

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/services/correction/assist.dart:76: "Introduce new
local with cast type");
On 2014/09/30 20:34:46, Paul Berry wrote:
> I think this terminology may be confusing to Dart users, since in Dart
> terminology, a "cast" only refers to expressions like "x as T".  Expressions
> like "X is T" are called "type tests" by the spec.
> 
> How about changing the text to "Introduce new local with tested type"?

Done.

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
File pkg/analysis_server/lib/src/services/correction/assist_internal.dart
(right):

https://codereview.chromium.org/618833003/diff/1/pkg/analysis_server/lib/src/...
pkg/analysis_server/lib/src/services/correction/assist_internal.dart:564: if
(node is! IsExpression) {
On 2014/09/30 20:34:46, Paul Berry wrote:
> We should also bail out if node is IsExpression and node.notOperator != null. 
> We don't want to offer this quick assist for "is!" tests.

Yes, I was going to extend the assist to support:
if (foo is! Bar) {
  return;
}

=>

if (foo is! Bar) {
  return;
}
Bar bar = foo;

For now I will commit it as is.

[scheglov, 2014-09-30 20:45:14]

Committed patchset #1 (id:1) manually as 40824 (presubmit successful).

[Brian Wilkerson, 2014-09-30 21:36:09]

LGTM