Refine append return type (#16140)

dwijnand · web-flow · commit d99d9bfc6429 · 2023-01-16T16:26:54.000Z
diff --git a/library/src/scala/Tuple.scala b/library/src/scala/Tuple.scala
@@ -83,7 +83,7 @@ sealed trait Tuple extends Product {
 object Tuple {
 
   /** Type of a tuple with an element appended */
-  type Append[X <: Tuple, Y] <: Tuple = X match {
+  type Append[X <: Tuple, Y] <: NonEmptyTuple = X match {
     case EmptyTuple => Y *: EmptyTuple
     case x *: xs => x *: Append[xs, Y]
   }

Original file line number	Diff line number	Diff line change
`@@ -83,7 +83,7 @@ sealed trait Tuple extends Product {`
`83`	`83`	`object Tuple {`
`84`	`84`
`85`	`85`	`/** Type of a tuple with an element appended */`
`86`		`- type Append[X <: Tuple, Y] <: Tuple = X match {`
	`86`	`+ type Append[X <: Tuple, Y] <: NonEmptyTuple = X match {`
`87`	`87`	`case EmptyTuple => Y *: EmptyTuple`
`88`	`88`	`case x : xs => x : Append[xs, Y]`
`89`	`89`	`}`