Meta issue to track progress of --preview-dart-2 being turned on by default in flutter

[a-siva]

This meta issue has been created to track blocker issues that prevent running flutter
apps in strong mode.

[a-siva]

Blocker issues that have been fixed

• Fasta strong mode inference confused same class extending Base<C> and mixing class extending Base<B> #31656 which seems to be dependent on Kernel's VM specific mixin transformation generates classes with incompatible overrides #30674, kernel: Do not abstract and share mixin applications #31118 (these issues are causing compile time errors)
• roll of 2.0 dart sdk into flutter/flutter which is happening with the pull request Roll Dart SDK to 2.0.0-dev.16.0, along with associated package updates flutter/flutter#13857 (breaking change email which is a pre-requisite for this PR landing is here https://groups.google.com/forum/#!topic/flutter-dev/E22RdKAYjs8)
• code in flutter/flutter code base needs to be cleaned up to use 'void' instead of 'Null' as a generic parameter #31869 flutter/flutter code needs to be cleaned up to use 'void' generic type instead of 'Null'
• Fasta: Generalized void #30470 Fasta: Generalized void
• Analyzer: Support generalized void #30177 Analyzer: Generalized void @MichaelRFairhurst
• Fix various strong mode issues. flutter/flutter#14284 Fix various strong mode issues in Flutter code
• need super-mixins flag in Fasta to alter warnings/errors around super calls #31994 Need super mixins flag to avoid errors/warnings around super calls
• flutter gallery app seems to have a number of errors when compiling the code in strong mode, these errors need to be investigated and the code fixed up #31975 Strong mode compilation errors in flutter gallery
• Frontend complains about non-matching type from mixin and base class #31984 Front end complains about non matching type from mixin and base class
• StandardMessageCodec produces Map<dynamic, dynamic> but users expect Map<String, dynamic> flutter/flutter#14556 - StandardMessageCodec produces Map<dynamic, dynamic> but users expect Map<String, dynamic>
• when const factory redirects to a generic const constructor type argument is not reified  #32068 - when const factory redirects to a generic const constructor type argument is not reified
• incremental compiler should be able to initialize it's state from a previously generated dill file #31691 - IKG should be able to initialize it's state from a dill file
• engine should pick up strong mode flag from snapshot and not as an activity flag flutter/flutter#14594 - engine should pick up strong mode flag from snapshot
• need to support deferred libraries in VM / incremental compiler at least as noops #32245 (deferred libraries need to be supported equivalent to --load-deferred-eagerly)
• Geting Unexpected input. Please report this at dartbug.com from StreamingDartTypeTranslator::BuildTypeParameterType #32267 (getting unexpected input from StreamingDartTypeTranslator::BuildFunctionType
• Kernel Instantiation node is not supported in VMs constant evaluator #32268 (error: Not a constant expression)
• coverage reports with forceCompile are broken in Dart 2 mode #32282 (coverage reports with forceCompile are broken in Dart 2 mode)
• [ Close enough for beta2] Minimize performance hit from strong mode checks on microbenchmarks and flutter benchmarks #31798 (this is a meta bug to track all runtime performance related issues, currently we don't have a base number yet as the apps are not running in strong mode).

[a-siva]

/cc @kmillikin @mraleph @sigmundch @vsmenon

[mit-mit]

@a-siva Leaf completed the roll, so flutter/flutter is now on Dart 2.0.0-dev.16.0, so I marked that complete in your blocker list.

[mit-mit]

Hi @a-siva what is blocking this now?

[mraleph]

@mit-mit I would say mixins are blocking this now, we are not blocked from resolving individual issues but mixins is a big-big-big problem. I think it even is blocking SDK roll.

[a-siva]

I moving the milestone of this to 2.0-alpha-2 and changed the description to make this the meta issue to track turning the --preview-dart-2 flag on by default in flutter.