Infer AsExpression types.

Infer AsExpression types.

R=paulberry@google.com
BUG=

Committed: https://github.com/dart-lang/sdk/commit/f7c8c7e3efab489a8b09c1e4200170f9f49cc845

[Paul Berry, 2017-05-04 17:05:19]

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart (right):

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart:33: return typeNeeded
? type : null;
You need to recurse into the subexpression in case it contains anything that
needs to be inferred or promoted.  So this method body should be:

inferrer.inferAsExpression(typeContext, typeNeeded, operand, type);

And TypeInferrerImpl.inferAsExpression should look something like this:

DartType inferAsExpression(...) {
  inferExpression(operand, null, false);
  return typeNeeded ? type : null;
}

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
File pkg/front_end/testcases/inference/type_cast.dart (right):

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
pkg/front_end/testcases/inference/type_cast.dart:15: var /*@topType=B<int>*/ b =
(a as B<int>);
I believe once the fix above is applied, this will need to change to:

var /*@topType=B<int>*/ b = (/*@promotedType=none*/ a as B<int>);

[scheglov, 2017-05-04 17:27:32]

PTAL

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart (right):

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.dart:33: return typeNeeded
? type : null;
On 2017/05/04 17:05:18, Paul Berry wrote:
> You need to recurse into the subexpression in case it contains anything that
> needs to be inferred or promoted.  So this method body should be:
> 
> inferrer.inferAsExpression(typeContext, typeNeeded, operand, type);
> 
> And TypeInferrerImpl.inferAsExpression should look something like this:
> 
> DartType inferAsExpression(...) {
>   inferExpression(operand, null, false);
>   return typeNeeded ? type : null;
> }

Ah, yes.
Of course.

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
File pkg/front_end/testcases/inference/type_cast.dart (right):

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
pkg/front_end/testcases/inference/type_cast.dart:15: var /*@topType=B<int>*/ b =
(a as B<int>);
On 2017/05/04 17:05:18, Paul Berry wrote:
> I believe once the fix above is applied, this will need to change to:
> 
> var /*@topType=B<int>*/ b = (/*@promotedType=none*/ a as B<int>);

AFAIK promotion happens only for local variables.
I made a copy for the local case.

[Paul Berry, 2017-05-04 20:01:00]

lgtm

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
File pkg/front_end/testcases/inference/type_cast.dart (right):

https://codereview.chromium.org/2862043002/diff/1/pkg/front_end/testcases/inf...
pkg/front_end/testcases/inference/type_cast.dart:15: var /*@topType=B<int>*/ b =
(a as B<int>);
On 2017/05/04 17:27:32, scheglov wrote:
> On 2017/05/04 17:05:18, Paul Berry wrote:
> > I believe once the fix above is applied, this will need to change to:
> > 
> > var /*@topType=B<int>*/ b = (/*@promotedType=none*/ a as B<int>);
> 
> AFAIK promotion happens only for local variables.
> I made a copy for the local case.

Oops, you're right.

[scheglov, 2017-05-04 20:27:50]

Description was changed from

==========
Infer AsExpression types.

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

to

==========
Infer AsExpression types.

R=paulberry@google.com
BUG=

Committed:
https://github.com/dart-lang/sdk/commit/f7c8c7e3efab489a8b09c1e4200170f9f49cc845
==========

[scheglov, 2017-05-04 20:27:52]

Committed patchset #2 (id:20001) manually as
f7c8c7e3efab489a8b09c1e4200170f9f49cc845 (presubmit successful).