Merge pull request #10266 from dotty-staging/topic/enum-delete-scala-enum

remove scala.Enum type alias

Author: bishabosha

docs/docs/reference/enums/enums.md

@@ -89,10 +89,11 @@ object Planet {
 ```
 
 ### Compatibility with Java Enums
-If you want to use the Scala-defined enums as Java enums, you can do so by extending `java.lang.Enum` class as follows:
+If you want to use the Scala-defined enums as Java enums, you can do so by extending
+the class `java.lang.Enum`, which is imported by default, as follows:
 
 ```scala
-enum Color extends java.lang.Enum[Color] { case Red, Green, Blue }
+enum Color extends Enum[Color] { case Red, Green, Blue }
 ```
 
 The type parameter comes from the Java enum [definition](https://docs.oracle.com/javase/8/docs/api/index.html?java/lang/Enum.html) and should be the same as the type of the enum.

library/src/scala/Enum.scala

@@ -3,6 +3,8 @@ package annotations
 
 import scala.annotation.StaticAnnotation
 
+import java.lang.{Enum => _}
+import scala.reflect.Enum
 
 class SomeObject(val s: String)
 
@@ -25,4 +27,4 @@ class AnnotatedMethods
 {
   @MyAnnotation @AnnotationWithMultiArg(2, "cda", 'a', 'b', 'c') def a: String
   = ???
-}
+}

scala3doc-testcases/src/tests/annotations.scala

@@ -1,7 +1,7 @@
 object Planet:
   final val G = 6.67300E-11
 
-enum Planet(mass: Double, radius: Double) extends java.lang.Enum[Planet]:
+enum Planet(mass: Double, radius: Double) extends Enum[Planet]:
   def surfaceGravity = Planet.G * mass / (radius * radius)
   def surfaceWeight(otherMass: Double) =  otherMass * surfaceGravity
 

tests/pos/enum-companion-first.scala

@@ -1,6 +1,6 @@
 object Test {
   def test: Unit = {
-    val e: java.lang.Enum[_] = java.util.concurrent.TimeUnit.SECONDS
+    val e: Enum[_] = java.util.concurrent.TimeUnit.SECONDS
     e match { case x => println(x) }
 
 

tests/pos/t7716.scala

@@ -6,7 +6,7 @@ enum EJ extends java.lang.Enum[EJ]:
   case B
   override def toString: String = "overridden"
 
-trait Mixin extends Enum:
+trait Mixin extends reflect.Enum:
   override def productPrefix: String = "noprefix"
   override def toString: String = "overridden"
 
@@ -36,7 +36,7 @@ enum EQ:
   case J           extends EQ with Mixin
   case K(arg: Int) extends EQ with Mixin
 
-abstract class Tag[T] extends Enum
+abstract class Tag[T] extends reflect.Enum
 object Tag:
   private final class IntTagImpl extends Tag[Int] with runtime.EnumValue:
     def ordinal = 0

tests/run/enum-custom-toString.scala

@@ -8,7 +8,7 @@ import Shapes._
  *    case Blue
  *  }
  */
-sealed trait Color extends Enum
+sealed trait Color extends EnumLike
 
 object Color {
 

tests/run/generic/Color.scala

@@ -1,11 +1,11 @@
 package generic
 
-trait Enum {
+trait EnumLike {
   def ordinal: Int
 }
 
 object runtime {
-  class EnumValues[E <: Enum] {
+  class EnumValues[E <: EnumLike] {
     private[this] var myMap: Map[Int, E] = Map()
     private[this] var fromNameCache: Map[String, E] = null
 

tests/run/generic/Enum.scala

@@ -7,7 +7,7 @@ import Shapes._
  *    case Nil()
  *  }
  */
-sealed trait List0[T] extends Enum
+sealed trait List0[T] extends EnumLike
 object List0 {
   abstract case class Cons[T](hd: T, tl: List0[T]) extends List0[T] {
     def ordinal = 0
@@ -51,7 +51,7 @@ object List0 {
  *    case Nil extends List[Nothing]
  *  }
  */
-sealed trait List[+T] extends Enum
+sealed trait List[+T] extends EnumLike
 object List {
   abstract case class Cons[T](hd: T, tl: List[T]) extends List[T] {
     def ordinal = 0

tests/run/generic/List.scala

@@ -9,7 +9,7 @@ import Shapes._
  *    case Ambiguous(alt1: SearchResult, alt2: SearchResult)
  *  }
  */
-sealed trait SearchResult extends Enum
+sealed trait SearchResult extends EnumLike
 
 object SearchResult {