Implement inferTypeFromConstraints in front_end.

Implement inferTypeFromConstraints in front_end.

This is an intermediate algorithm used in type inference.  It
corresponds to the method _GenericInferrer.infer() in analyzer.

R=jmesserly@google.com, scheglov@google.com

Note: error reporting will be added in a follow-up CL.
Committed: https://github.com/dart-lang/sdk/commit/28f277a7e2304d2afd7e11186b22d4e93a58c048

[Paul Berry, 2017-05-04 23:03:08]

paulberry@google.com changed reviewers:
+ jmesserly@google.com, leafp@google.com, scheglov@google.com

[Jennifer Messerly, 2017-05-04 23:14:26]

lgtm!

https://codereview.chromium.org/2863823002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/type_inference/type_schema_environment.dart
(right):

https://codereview.chromium.org/2863823002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/type_inference/type_schema_environment.dart:19:
DartType lower = const UnknownType();
did you mean to remove the initializer?

https://codereview.chromium.org/2863823002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/type_inference/type_schema_environment.dart:170: ///
inferred during this stage will be stored in [typesFromDownwardsInference]
lovely! I really wanted to do this in Analyzer and it was hard to find a clean
way to track it as temporary state between different parts of Resolver. This is
way better.

[Paul Berry, 2017-05-04 23:27:51]

https://codereview.chromium.org/2863823002/diff/1/pkg/front_end/lib/src/fasta...
File pkg/front_end/lib/src/fasta/type_inference/type_schema_environment.dart
(right):

https://codereview.chromium.org/2863823002/diff/1/pkg/front_end/lib/src/fasta...
pkg/front_end/lib/src/fasta/type_inference/type_schema_environment.dart:19:
DartType lower = const UnknownType();
On 2017/05/04 23:14:26, Jennifer Messerly wrote:
> did you mean to remove the initializer?

Oops, thank you.  Done.

[scheglov, 2017-05-04 23:28:22]

LGTM

[Paul Berry, 2017-05-04 23:32:36]

Description was changed from

==========
Implement inferTypeFromConstraints in front_end.

This is an intermediate algorithm used in type inference.  It
corresponds to the method _GenericInferrer.infer() in analyzer.

Note: error reporting will be added in a follow-up CL.
==========

to

==========
Implement inferTypeFromConstraints in front_end.

This is an intermediate algorithm used in type inference.  It
corresponds to the method _GenericInferrer.infer() in analyzer.

R=jmesserly@google.com, scheglov@google.com

Note: error reporting will be added in a follow-up CL.
Committed:
https://github.com/dart-lang/sdk/commit/28f277a7e2304d2afd7e11186b22d4e93a58c048
==========

[Paul Berry, 2017-05-04 23:32:37]

Committed patchset #1 (id:1) manually as
28f277a7e2304d2afd7e11186b22d4e93a58c048 (presubmit successful).