remove override flags from ordinal, enumLabel

Author: bishabosha

compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala

@@ -125,9 +125,9 @@ object DesugarEnums {
   /** A creation method for a value of enum type `E`, which is defined as follows:
    *
    *   private def $new(_$ordinal: Int, $name: String) = new E with scala.runtime.EnumValue {
-   *     override def ordinal = _$ordinal   // if `E` does not derive from `java.lang.Enum`
-   *     override def enumLabel = $name     // if `E` does not derive from `java.lang.Enum`
-   *     override def enumLabel = this.name // if `E` derives from `java.lang.Enum`
+   *     def ordinal = _$ordinal   // if `E` does not derive from `java.lang.Enum`
+   *     def enumLabel = $name     // if `E` does not derive from `java.lang.Enum`
+   *     def enumLabel = this.name // if `E` derives from `java.lang.Enum`
    *     $values.register(this)
    *   }
    */
@@ -274,10 +274,10 @@ object DesugarEnums {
   private def isJavaEnum(using Context): Boolean = ctx.owner.linkedClass.derivesFrom(defn.JavaEnumClass)
 
   def ordinalMeth(body: Tree)(using Context): DefDef =
-    DefDef(nme.ordinal, Nil, Nil, TypeTree(defn.IntType), body).withFlags(Override)
+    DefDef(nme.ordinal, Nil, Nil, TypeTree(defn.IntType), body)
 
   def enumLabelMeth(body: Tree)(using Context): DefDef =
-    DefDef(nme.enumLabel, Nil, Nil, TypeTree(defn.StringType), body).withFlags(Override)
+    DefDef(nme.enumLabel, Nil, Nil, TypeTree(defn.StringType), body)
 
   def ordinalMethLit(ord: Int)(using Context): DefDef =
     ordinalMeth(Literal(Constant(ord)))

docs/docs/reference/enums/desugarEnums.md

@@ -174,8 +174,8 @@ If `E` contains at least one simple case, its companion object will define in ad
      follows.
      ```scala
      private def $new(_$ordinal: Int, $name: String) = new E with runtime.EnumValue {
-       override def ordinal = _$ordinal
-       override def enumLabel = $name
+       def ordinal = _$ordinal
+       def enumLabel = $name
        override def productPrefix = enumLabel // if not overridden in `E`
        override def toString = enumLabel      // if not overridden in `E`
        $values.register(this) // register enum value so that `valueOf` and `values` can return it.

docs/docs/reference/enums/enums.md

@@ -132,8 +132,8 @@ For instance, the `Venus` value above would be defined like this:
 ```scala
 val Venus: Planet =
   new Planet(4.869E24, 6051800.0) {
-    override def ordinal: Int = 1
-    override def enumLabel: String = "Venus"
+    def ordinal: Int = 1
+    def enumLabel: String = "Venus"
     override def productPrefix: String = enumLabel
     override def toString: String = enumLabel
     // internal code to register value

tests/neg/enumsLabelDef.scala

@@ -1,7 +1,19 @@
 enum Labelled {
 
-  case A // error: cannot override final member method enumLabel in class Labelled
-  case B(arg: Int) // error: cannot override final member method enumLabel in class Labelled
+  case A // error overriding method enumLabel in class Labelled of type => String;
+  case B(arg: Int) // error overriding method enumLabel in class Labelled of type => String;
 
-  final def enumLabel: String = "nolabel"
+  def enumLabel: String = "nolabel"
+}
+
+trait Mixin { def enumLabel: String = "mixin" }
+
+enum Mixed extends Mixin {
+  case C // error overriding method enumLabel in trait Mixin of type => String;
+}
+
+trait HasEnumLabel { def enumLabel: String }
+
+enum MyEnum extends HasEnumLabel {
+  case D // ok
 }

tests/run/enum-custom-toString.scala

@@ -7,7 +7,6 @@ enum EJ extends java.lang.Enum[EJ]:
   override def toString: String = "overridden"
 
 trait Mixin extends Enum:
-  override def enumLabel: String = "nolabel"
   override def productPrefix: String = "noprefix"
   override def toString: String = "overridden"
 
@@ -56,7 +55,7 @@ object Tag:
   assert(EJ.valueOf("B") == EJ.B,             s"EJ.valueOf(B) = ${EJ.valueOf("B")}")
   assert(EM.C.toString == "overridden",       s"EM.C.toString = ${EM.C.toString}")
   assert(EM.C.productPrefix == "noprefix",    s"EM.C.productPrefix = ${EM.C.productPrefix}")
-  assert(EM.C.enumLabel == "C",               s"EM.C.enumLabel = ${EM.C.enumLabel}") // enumLabel override is useless
+  assert(EM.C.enumLabel == "C",               s"EM.C.enumLabel = ${EM.C.enumLabel}")
   assert(EM.valueOf("C") == EM.C,             s"EM.valueOf(C) = ${EM.valueOf("C")}")
   assert(ET.D.toString == "overridden",       s"ET.D.toString = ${ET.D.toString}")
   assert(ET.D.productPrefix == "D",           s"ET.D.productPrefix = ${ET.D.productPrefix}")
@@ -80,11 +79,11 @@ object Tag:
   assert(EO.I(0).enumLabel == "I",            s"EO.I(0).enumLabel = ${EO.I(0).enumLabel}")
   assert(EQ.J.toString == "overridden",       s"EQ.J.toString = ${EQ.J.toString}")
   assert(EQ.J.productPrefix == "noprefix",    s"EQ.J.productPrefix = ${EQ.J.productPrefix}")
-  assert(EQ.J.enumLabel == "J",               s"EQ.J.enumLabel = ${EQ.J.enumLabel}") // enumLabel override is useless
+  assert(EQ.J.enumLabel == "J",               s"EQ.J.enumLabel = ${EQ.J.enumLabel}")
   assert(EQ.valueOf("J") == EQ.J,             s"EQ.valueOf(J) = ${EQ.valueOf("J")}")
   assert(EQ.K(0).toString == "overridden",    s"EQ.K(0).toString = ${EQ.K(0).toString}")
   assert(EQ.K(0).productPrefix == "noprefix", s"EQ.K(0).productPrefix = ${EQ.K(0).productPrefix}")
-  assert(EQ.K(0).enumLabel == "K",            s"EQ.K(0).enumLabel = ${EQ.K(0).enumLabel}") // enumLabel override is useless
+  assert(EQ.K(0).enumLabel == "K",            s"EQ.K(0).enumLabel = ${EQ.K(0).enumLabel}")
   assert(Tag.IntTag.productPrefix == "",      s"Tag.IntTag.productPrefix = ${Tag.IntTag.productPrefix}")
   assert(Tag.IntTag.enumLabel == "IntTag",    s"Tag.IntTag.enumLabel = ${Tag.IntTag.enumLabel}")
   assert(