pkg/front_end/testcases/inference/logical_or_promotion.dart:16:11: Context: Possible promotion of o@338
    if (o is A || o is B) {
          ^^
pkg/front_end/testcases/inference/logical_or_promotion.dart:16:21: Context: Possible promotion of o@338
    if (o is A || o is B) {
                    ^^
pkg/front_end/testcases/inference/logical_or_promotion.dart:17:13: Context: Possible promotion of o@338
      if (o is A) {
            ^^