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 {
 

tests/run/generic/SearchResult.scala

@@ -69,4 +69,4 @@ object Test {
     sds(data4)
     assert(sCount == 1, sCount)
   }
-}
+}

tests/run/generic/Test.scala

@@ -12,7 +12,7 @@ import Shapes._
  *    case If(cond: Boolean, thenp: Tree[T], elsep: Tree[T])
  *  }
  */
-sealed trait Tree[TR] extends Enum
+sealed trait Tree[TR] extends EnumLike
 
 object Tree {
 

tests/run/generic/Tree.scala

@@ -54,7 +54,7 @@ object Enums/*<-_empty_::Enums.*/:
 
   val some1/*<-_empty_::Enums.some1.*/ = /*->_empty_::Enums.unwrap().*/Some/*->scala::Some.*//*->scala::Some.apply().*/(Some/*->scala::Some.*//*->scala::Some.apply().*/(1))/*->_empty_::Enums.`<:<`.given_T().*/.unwrap
 
-  enum Planet/*<-_empty_::Enums.Planet#*/(mass/*<-_empty_::Enums.Planet#mass.*/: Double/*->scala::Double#*/, radius/*<-_empty_::Enums.Planet#radius.*/: Double/*->scala::Double#*/) extends java.lang.Enum/*->java::lang::Enum#*/[Planet/*->_empty_::Enums.Planet#*/]/*->java::lang::Enum#`<init>`().*/:
+  enum Planet/*<-_empty_::Enums.Planet#*/(mass/*<-_empty_::Enums.Planet#mass.*/: Double/*->scala::Double#*/, radius/*<-_empty_::Enums.Planet#radius.*/: Double/*->scala::Double#*/) extends Enum/*->java::lang::Enum#*/[Planet/*->_empty_::Enums.Planet#*/]/*->java::lang::Enum#`<init>`().*/:
     private final val G/*<-_empty_::Enums.Planet#G.*/ = 6.67300E-11
     def surfaceGravity/*<-_empty_::Enums.Planet#surfaceGravity().*/ = G/*->_empty_::Enums.Planet#G.*/ */*->scala::Double#`*`(+6).*/ mass/*->_empty_::Enums.Planet#mass.*/ //*->scala::Double#`::`(+6).*/ (radius/*->_empty_::Enums.Planet#radius.*/ */*->scala::Double#`*`(+6).*/ radius/*->_empty_::Enums.Planet#radius.*/)
     def surfaceWeight/*<-_empty_::Enums.Planet#surfaceWeight().*/(otherMass/*<-_empty_::Enums.Planet#surfaceWeight().(otherMass)*/: Double/*->scala::Double#*/) = otherMass/*->_empty_::Enums.Planet#surfaceWeight().(otherMass)*/ */*->scala::Double#`*`(+6).*/ surfaceGravity/*->_empty_::Enums.Planet#surfaceGravity().*/

tests/semanticdb/expect/Enums.expect.scala

@@ -54,7 +54,7 @@ object Enums:
 
   val some1 = Some(Some(1)).unwrap
 
-  enum Planet(mass: Double, radius: Double) extends java.lang.Enum[Planet]:
+  enum Planet(mass: Double, radius: Double) extends Enum[Planet]:
     private final val G = 6.67300E-11
     def surfaceGravity = G * mass / (radius * radius)
     def surfaceWeight(otherMass: Double) = otherMass * surfaceGravity

tests/semanticdb/expect/Enums.scala

@@ -642,7 +642,7 @@ Uri => Enums.scala
 Text => empty
 Language => Scala
 Symbols => 181 entries
-Occurrences => 203 entries
+Occurrences => 201 entries
 
 Symbols:
 _empty_/Enums. => final object Enums
@@ -979,11 +979,9 @@ Occurrences:
 [56:20..56:26): Double -> scala/Double#
 [56:28..56:34): radius <- _empty_/Enums.Planet#radius.
 [56:36..56:42): Double -> scala/Double#
-[56:52..56:56): java -> java/
-[56:57..56:61): lang -> java/lang/
-[56:62..56:66): Enum -> java/lang/Enum#
-[56:67..56:73): Planet -> _empty_/Enums.Planet#
-[56:74..56:74): -> java/lang/Enum#`<init>`().
+[56:52..56:56): Enum -> java/lang/Enum#
+[56:57..56:63): Planet -> _empty_/Enums.Planet#
+[56:64..56:64): -> java/lang/Enum#`<init>`().
 [57:22..57:23): G <- _empty_/Enums.Planet#G.
 [58:8..58:22): surfaceGravity <- _empty_/Enums.Planet#surfaceGravity().
 [58:25..58:26): G -> _empty_/Enums.Planet#G.