frog is incorrectly saying that String is not Object

[DartBot]

This issue was originally filed by mattsh@google.com

---

Small example here:

main() {
  String s = "hello";
  if (s is Object) {
    print("yes, String is Object");
  } else {
    print("no, String is not Object");
  }
  print("done");
}

frog is printing out:
no, String is not Object
done

whereas the dart vm is printing out:
yes, String is Object
done

(I'm assuming this is a frog bug, not a vm bug, so triaging to Area-Frog.)

[DartBot]

This comment was originally written by mattsh@google.com

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btw, just some background, I actually hit this bug because I did

catch(Object e) {
  ...
}

assuming I would catch all exception. This failed to catch string exceptions.
So, in frog catch(Object e) currently does not correctly catch all exceptions but it should.

(Also, I just noticed numbers also don't correctly report themselves as being Object in frog, so this bug is actually more general than String.)

[jmesserly]

Yeah, it's turning "is Object" into "instanceof Object" which in JS is false for bools, numbers, strings, null and undefined. When really in Dart it should just be true always.

[jmesserly]

Added Fixed label.