Implement type inference of getters/setters based on inheritance.

Implement type inference of getters/setters based on inheritance.

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/7939ea00efd7179acc1ccd86625139abe5e05050

[Paul Berry, 2017-06-18 22:53:40]

paulberry@google.com changed reviewers:
+ ahe@google.com, scheglov@google.com, sigmund@google.com

[Paul Berry, 2017-06-18 22:53:41]

I only need a review from one of you.

[scheglov, 2017-06-18 23:03:43]

LGTM

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
File pkg/analyzer/test/src/task/strong/front_end_inference_test.dart (right):

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/front_end_inference_test.dart:464: if
(parameter.element.hasImplicitType) {
Would "parameter.type == null" work?
It would be consistent with the returnType check.

[Paul Berry, 2017-06-18 23:34:32]

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
File pkg/analyzer/test/src/task/strong/front_end_inference_test.dart (right):

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/front_end_inference_test.dart:464: if
(parameter.element.hasImplicitType) {
On 2017/06/18 23:03:43, scheglov wrote:
> Would "parameter.type == null" work?
> It would be consistent with the returnType check.

I considered that too, but it wouldn't work because FormalParameter doesn't have
a getter `type`.  The reason is because of function-typed formal parameters,
which have `returnType` and `parameters` getters rather than a `type` getter.

I suppose I could have done:

  var parameterElement = parameter.element;
  if (parameterElement is SimpleFormalParameter && parameterElement.type ==
null)

But it seemed simpler to just use `hasImplicitType`.

I've added a comment explaining this.

[Paul Berry, 2017-06-18 23:35:08]

Description was changed from

==========
Implement type inference of getters/setters based on inheritance.
==========

to

==========
Implement type inference of getters/setters based on inheritance.

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/7939ea00efd7179acc1ccd86625139abe5e05050
==========

[Paul Berry, 2017-06-18 23:35:10]

Committed patchset #1 (id:1) manually as
7939ea00efd7179acc1ccd86625139abe5e05050 (presubmit successful).

[Paul Berry, 2017-06-19 18:18:27]

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
File pkg/analyzer/test/src/task/strong/front_end_inference_test.dart (right):

https://codereview.chromium.org/2943273002/diff/1/pkg/analyzer/test/src/task/...
pkg/analyzer/test/src/task/strong/front_end_inference_test.dart:464: if
(parameter.element.hasImplicitType) {
On 2017/06/18 23:34:31, Paul Berry wrote:
> On 2017/06/18 23:03:43, scheglov wrote:
> > Would "parameter.type == null" work?
> > It would be consistent with the returnType check.
> 
> I considered that too, but it wouldn't work because FormalParameter doesn't
have
> a getter `type`.  The reason is because of function-typed formal parameters,
> which have `returnType` and `parameters` getters rather than a `type` getter.
> 
> I suppose I could have done:
> 
>   var parameterElement = parameter.element;
>   if (parameterElement is SimpleFormalParameter && parameterElement.type ==
> null)
> 
> But it seemed simpler to just use `hasImplicitType`.
> 
> I've added a comment explaining this.

After further experimentation it turns out that ParameterElement.hasImplicitType
has a bug where it returns `true` for a function-typed parameter without an
explicit return type.  So this code is no good either until we fix the bug.

I'll send out a bug fix and add some more test cases.