False positive in unreachable_from_main

[natebosch]

jsonEncode checks for the presence of a toJson method and uses it when it exists. It's a common pattern to have a toJson without any static references to it. I think we should consider it a false positive to flag a toJson member.

import 'dart:convert';

void main() async {
  print(jsonEncode([C()]));
}

class C {
  List toJson() => ['c'];
  //   ^ unreachable_from_main
}

[pq]

/fyi @srawlins

[srawlins]

I'm happy to take this as a false positive, but I am extremely curious: how does dart:convert#jsonEncode do this? Mirrors? native magic?

[natebosch]

I am extremely curious: how does dart:convert#jsonEncode do this?

Cast the object to dynamic for dynamic dispatch, use try {} catch {} for the NoSuchMethodError when it doesn't exist.

[srawlins]

Fixed by 954ed42