diff --git a/library/src/scala/Tuple.scala b/library/src/scala/Tuple.scala index c4e04359a3e1..e14588ba43a5 100644 --- a/library/src/scala/Tuple.scala +++ b/library/src/scala/Tuple.scala @@ -175,14 +175,13 @@ object Tuple { } /** Given two tuples, `A1 *: ... *: An * At` and `B1 *: ... *: Bn *: Bt` - * where at least one of `At` or `Bt` is `EmptyTuple` or `Tuple`, * returns the tuple type `(A1, B1) *: ... *: (An, Bn) *: Ct` - * where `Ct` is `EmptyTuple` if `At` or `Bt` is `EmptyTuple`, otherwise `Ct` is `Tuple`. + * where `Ct` is `EmptyTuple` if `At` and `Bt` are `EmptyTuple`, + * otherwise `Ct` is stuck as `Zip[At, Bt]`. */ type Zip[T1 <: Tuple, T2 <: Tuple] <: Tuple = (T1, T2) match { case (h1 *: t1, h2 *: t2) => (h1, h2) *: Zip[t1, t2] - case (EmptyTuple, _) => EmptyTuple - case (_, EmptyTuple) => EmptyTuple + case (EmptyTuple, EmptyTuple) => EmptyTuple } /** Converts a tuple `(F[T1], ..., F[Tn])` to `(T1, ... Tn)` */