Implement non-function type alias support in web debuggers

[leafpetersen]

This issue tracks support of the non-function type alias feature. See the enclosing meta-issue for details.

cc @franklinyow @sigmundch @mit-mit

[sigmundch]

I don't believe there is any specific work required for this, other than validating that the feature works as expected.

@jacob314 @grouma - do you agree?

[grouma]

Yeah I think we just need to validate that it works and if it doesn't, likely make edits to the logic here.

[leafpetersen]

@grouma do we have a plan for validating this?

[grouma]

I think making use of the feature in a package:dwds smoke test, along with some specific VM Service protocols, should give us enough confidence.

[sigmundch]

Maybe it is worth also adding a couple tests to cover #44925 as well?

[grouma]

Wouldn't hurt. We'll need to know the SDK version that contains these features.

[leafpetersen]

@grouma this will be released in 2.13 are you waiting on a dev build or can you go ahead and validate? This CL can be patched in to build a version with the feature on by default.

[grouma]

Ping me when a dev build is available. It's much easier to validate that way.

[franklinyow]

It seems we won't have a dev build this week due to Easter holiday in Europe , can we validate with the CL?

[leafpetersen]

@grouma this has landed, can you please test on master (I don't expect we will have a dev build before the branch cut window opens).

[grouma]

I downloaded the latest SDK:
Dart SDK version: 2.13.0-203.0.dev (dev) (Mon Apr 5 09:39:33 2021 -0700) on "macos_x64"

I updated the minimum SDK for my example project and included this:

typedef JsonMap = Map<String, dynamic>;

There are no errors with analysis, however I'm having issues building:

[SEVERE] build_web_compilers:entrypoint on web/main.dart: This builder requires Dart inputs without syntax errors.
However, asset:webdev_example_app/web/main.dart (or an existing part) contains the following errors.
main.dart:11:17: Invalid generic function type.

Try fixing the errors and re-running the build.


[INFO] Running build completed, took 3.7s
[INFO] Caching finalized dependency graph completed, took 180ms
[SEVERE] Failed after 3.9s
[INFO] ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

cc @jakemac53

Without being able to build it's impossible for me to validate.

[leafpetersen]

@grouma This is not in any dev build and I don't think it will be until AAR is back from vacation which will be too late. I think you need to test this out on master.

[grouma]

I'll build from master locally but I'm confused as to why this isn't in the latest raw SDK. I thought raw corresponded to master. The given timestamp says it was built this morning. Correct my understanding.

[leafpetersen]

@grouma is this a pkg:analyzer issue then? You may need a version of pkg:analyzer with this enabled - cc @scheglov .

[grouma]

I don't think this is an analyzer issue. There are no analysis errors. (There were some until I upgraded the SDK and updated the pubspec). I think this may be a package:build issue. cc @natebosch

[scheglov]

FYI, I'm waiting for the flag switch to be rolled into google3, and will publish package:analyzer then.

[natebosch]

@grouma webdev serve works for me.

I had to ensure that the language version is 2.13, and use a dependency_override on analyzer from my local SDK checkout since it isn't published yet. It also took a few other overrides to get a valid solve. Here is the pubspec I used in a project where this worked:

name: dart_repro

environment:
  sdk: ">=2.13.0-0 <3.0.0"

dev_dependencies:
  build_runner: any
  build_web_compilers: any

dependency_overrides:
  analyzer:
    path: ../dart-sdk/sdk/pkg/analyzer
  front_end:
    path: ../dart-sdk/sdk/pkg/front_end
  _fe_analyzer_shared:
    path: ../dart-sdk/sdk/pkg/_fe_analyzer_shared
  package_config: 2.0.0

[grouma]

Thanks @natebosch, I was able to get it working.

Debugging doesn't blow up so that's good. I'm not sure what the intended behavior is here though. The displayed types are desugared. Look at the variables and console in the screenshot below. I suppose that's the desired behavior?

[leafpetersen]

Expanding the types seems like fine behavior to me.