Frog: 'this' is rejected as interpolation identifier

[rakudrama]

bug1b.dart:3:20: fatal: expected identifier, but found keyword 'this'(this)
    print('Thing: $this');
                   ^^^^
bug1b.dart:3:20: warning: can not resolve "this" on "Thing"
    print('Thing: $this');
                   ^^^^
bug1b.dart:3:20: warning: this is not defined anywhere in the world.
    print('Thing: $this');
                   ^^^^
compilation failed with 1 errors

The VM does it right. Priority-Low because one can use ${this}.

bug1b.dart:
class Thing {
  Thing() {
    print('Thing: $this');
    print('Thing: ${this}');
  }
}

main() {
  new Thing();
}

[jmesserly]

Set owner to @jmesserly.
Added Fixed label.