revert add enumLabel to Mirror

compiler/src/dotty/tools/dotc/transform/SyntheticMembers.scala

@@ -513,34 +513,6 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
  Match(param, cases)
  }
 
- /** For an enum T:
- *
- * def enumLabel(x: MirroredMonoType) = x.enumLabel
- *
- * For sealed trait with children of normalized types C_1, ..., C_n:
- *
- * def enumLabel(x: MirroredMonoType) = x match {
- * case _: C_1 => "C_1"
- * ...
- * case _: C_n => "C_n"
- * }
- *
- * Here, the normalized type of a class C is C[?, ...., ?] with
- * a wildcard for each type parameter. The normalized type of an object
- * O is O.type.
- */
- def enumLabelBody(cls: Symbol, param: Tree)(using Context): Tree =
- if (cls.is(Enum)) param.select(nme.enumLabel).ensureApplied
- else {
- val cases =
- for ((child, idx) <- cls.children.zipWithIndex) yield {
- val patType = if (child.isTerm) child.termRef else child.rawTypeRef
- val pat = Typed(untpd.Ident(nme.WILDCARD).withType(patType), TypeTree(patType))
- CaseDef(pat, EmptyTree, Literal(Constant(child.name.toString)))
- }
- Match(param, cases)
- }
-
  /** - If `impl` is the companion of a generic sum, add `deriving.Mirror.Sum` parent
  * and `MirroredMonoType` and `ordinal` members.
  * - If `impl` is the companion of a generic product, add `deriving.Mirror.Product` parent
@@ -592,8 +564,6 @@ class SyntheticMembers(thisPhase: DenotTransformer) {
  addParent(defn.Mirror_SumClass.typeRef)
  addMethod(nme.ordinal, MethodType(monoType.typeRef :: Nil, defn.IntType), cls,
  ordinalBody(_, _))
- addMethod(nme.enumLabel, MethodType(monoType.typeRef :: Nil, defn.StringType), cls,
- enumLabelBody(_, _))
  }
 
  if (clazz.is(Module)) {