Show up "Expected token ARROW but got Token(RBRACKET,],3116,])" when using EitherT.leftT[IO,()]

[ChunChiehHuang18]

Failed at .getOrElse(EitherT.leftT[IO, ()](SomeError("failed to call method")))

Failed case:

foo match {
      case Right(value) => {
        bar
          .someMethod(value)
          .headOption
          .getOrElse(EitherT.leftT[IO, ()](SomeError("failed to call method")))
      }
      ...
    }

I found out it can pass when workaround with changing () to Unit
.getOrElse(EitherT.leftT[IO, Unit](SomeError("failed to call method")))

Pass case:

foo match {
      case Right(value) => {
        bar
          .someMethod(value)
          .headOption
          .getOrElse(EitherT.leftT[IO, Unit](SomeError("failed to call method")))
      }
      ...
    }