EitherT.pure does not call F.pure on the 'Right' value

[aherrmann13]

EitherT.pure (and EitherT.rightT) does not have the same behavior as EitherT.leftT

EitherT.rightTcalls EitherT.pure, which calls right(F.pure(b)), which results in EitherT(F.map(F.pure(b))(Right(_)))

EitherT.leftT calls EitherT(F.pure(Left(a)))

when using IO the execution of converting F[B] => F[Either[A, B]] is delayed until IO is run on EitherT.pure and EitherT.rightT and it is not delayed on EitherT.leftT

Is there a reason for having pure as an alias for rightT, and evaluating F.pure(a) and then converting it to a Right value with map instead of using EitherT(F.pure(Right(b)))?

[joroKr21]

I think we should use the more performant version 👍