[CP] DDC support for record subtype checks with web numeric semantics

[Markzipan]

Commit(s) to merge

44b5ca7
8dfd25a

Target

stable

Prepared changelist for beta/stable

https://dart-review.googlesource.com/c/sdk/+/306307

Issue Description

The subtype check implementation for records in DDC did not respect web semantics for numerics (int being a subtype of double)

What is the fix

Update DDC's subtype check implementation to dispatch on the subtype checks for each of its fields.

Why cherry-pick

This pattern can be triggered extremely easily in DDC. E.g.:

void main() {
  var recordList = <(double, String)>[];
  recordList.add((1.0, 'hello')); // crashes but should be allowed
}

The issue has a high impact potential due records being widely advertised in the Dart 3.0 release.

Risk

low

Issue link(s)

#52480

Extra Info

This contains cherry-picks for the CLs in this chain. The latter just adds a regression test. Additionally, this change diverges very slightly from main in RecordType's as check. For a clean merge, RecordImpl (in main) is renamed to _RecordImpl.

[Markzipan]

@nshahan @sigmundch for context

[itsjustkevin]

Hey @Markzipan, I noticed that your request points to the CL that landed on main. To continue triaging this cherry-pick request, we would need that field to point to the cherry-pick to the stable channel.

For further instructions, please refer to: https://github.com/dart-lang/sdk/wiki/Cherry-picks-to-a-release-channel.

Thank you.

[itsjustkevin]

@sigmundch and @nshahan could you take a look at this cherry-pick request?

[Markzipan]

Thanks Kevin - updated the link

[sigmundch]

I'm very supportive of this cherry-pick. It's low risk but highly visible problem.