chore: remove old support for getClass in scala.AnyVal

Author: hamzaremmal

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

@@ -775,17 +775,7 @@ object desugar {
         case PatDef(_, ids: List[Ident] @ unchecked, _, _) => ids
       }
 
-      val stats0 = impl.body.map(expandConstructor)
-      val stats =
-        if (ctx.owner eq defn.ScalaPackageClass) && defn.hasProblematicGetClass(className) then
-          stats0.filterConserve {
-            case ddef: DefDef =>
-              ddef.name ne nme.getClass_
-            case _ =>
-              true
-          }
-        else
-          stats0
+      val stats = impl.body.map(expandConstructor)
 
       if (isEnum) {
         val (enumCases, enumStats) = stats.partition(DesugarEnums.isEnumCase)

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -1940,27 +1940,6 @@ class Definitions {
     if (isBoxedUnitClass(cls)) parents.filter(_.typeSymbol != JavaSerializableClass)
     else parents
 
-  private val HasProblematicGetClass: Set[Name] = Set(
-    tpnme.AnyVal, tpnme.Byte, tpnme.Short, tpnme.Char, tpnme.Int, tpnme.Long, tpnme.Float, tpnme.Double,
-    tpnme.Unit, tpnme.Boolean)
-
-  /** When typing a primitive value class or AnyVal, we ignore the `getClass`
-   *  member: it's supposed to be an override of the `getClass` defined on `Any`,
-   *  but in dotty `Any#getClass` is polymorphic so it ends up being an overload.
-   *  This is especially problematic because it means that when writing:
-   *
-   *    1.asInstanceOf[Int & AnyRef].getClass
-   *
-   *  the `getClass` that returns `Class[Int]` defined in Int can be selected,
-   *  but this call is specified to return `classOf[Integer]`, see
-   *  tests/run/t5568.scala.
-   *
-   *  FIXME: remove all the `getClass` methods defined in the standard library
-   *  so we don't have to hot-patch it like this.
-   */
-  def hasProblematicGetClass(className: Name): Boolean =
-    HasProblematicGetClass.contains(className)
-
   @tu lazy val assumedTransparentNames: Map[Name, Set[Symbol]] =
     // we should do a more through sweep through it then.
     val strs = Map(

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -444,11 +444,9 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
 
     var flags = unpickleScalaFlags(readLongNat(), name.isTypeName)
 
-    if (name eq nme.getClass_) && defn.hasProblematicGetClass(owner.name)
-       // Scala 2 sometimes pickle the same type parameter symbol multiple times
-       // (see i11173 for an example), but we should only unpickle it once.
-       || tag == TYPEsym && flags.is(TypeParam) && symScope(owner).lookup(name.asTypeName).exists
-    then
+    // Scala 2 sometimes pickle the same type parameter symbol multiple times
+    // (see i11173 for an example), but we should only unpickle it once.
+    if tag == TYPEsym && flags.is(TypeParam) && symScope(owner).lookup(name.asTypeName).exists then
       // skip this member
       return NoSymbol
 

compiler/src/dotty/tools/dotc/typer/RefChecks.scala

@@ -1034,15 +1034,7 @@ object RefChecks {
         nonMatching match {
           case Nil =>
             report.error(OverridesNothing(member), member.srcPos)
-          case ms =>
-            // getClass in primitive value classes is defined in the standard library as:
-            //     override def getClass(): Class[Int] = ???
-            // However, it's not actually an override in Dotty because our Any#getClass
-            // is polymorphic (see `Definitions#Any_getClass`), so since we can't change
-            // the standard library, we need to drop the override flag without reporting
-            // an error.
-            if (!(member.name == nme.getClass_ && clazz.isPrimitiveValueClass))
-              report.error(OverridesNothingButNameExists(member, ms), member.srcPos)
+          case _ =>
         }
         member.resetFlag(Override)
         member.resetFlag(AbsOverride)

library/src/scala/AnyVal.scala

@@ -55,6 +55,4 @@ import scala.language.`2.13`
  * still must allocate a value class instance at runtime. These limitations and circumstances are
  * explained in greater detail in the [[https://docs.scala-lang.org/overviews/core/value-classes.html Value Classes and Universal Traits]].
  */
-transparent abstract class AnyVal extends Any, Matchable {
-  def getClass(): Class[? <: AnyVal] = null.asInstanceOf[Class[? <: AnyVal]]
-}
+transparent abstract class AnyVal extends Any, Matchable

library/src/scala/Boolean.scala

@@ -108,8 +108,6 @@ final abstract class Boolean private extends AnyVal {
     */
   def ^(x: Boolean): Boolean
 
-  // Provide a more specific return type for Scaladoc
-  override def getClass(): Class[Boolean] = ???
 }
 
 object Boolean extends AnyValCompanion {

library/src/scala/Byte.scala

@@ -444,8 +444,6 @@ final abstract class Byte private extends AnyVal {
   /** Returns the remainder of the division of this value by `x`. */
   def %(x: Double): Double
 
-  // Provide a more specific return type for Scaladoc
-  override def getClass(): Class[Byte] = ???
 }
 
 object Byte extends AnyValCompanion {

library/src/scala/Char.scala

@@ -444,8 +444,6 @@ final abstract class Char private extends AnyVal {
   /** Returns the remainder of the division of this value by `x`. */
   def %(x: Double): Double
 
-  // Provide a more specific return type for Scaladoc
-  override def getClass(): Class[Char] = ???
 }
 
 object Char extends AnyValCompanion {

library/src/scala/Double.scala

@@ -207,8 +207,6 @@ final abstract class Double private extends AnyVal {
   /** Returns the remainder of the division of this value by `x`. */
   def %(x: Double): Double
 
-  // Provide a more specific return type for Scaladoc
-  override def getClass(): Class[Double] = ???
 }
 
 object Double extends AnyValCompanion {

library/src/scala/Float.scala

@@ -207,8 +207,6 @@ final abstract class Float private extends AnyVal {
   /** Returns the remainder of the division of this value by `x`. */
   def %(x: Double): Double
 
-  // Provide a more specific return type for Scaladoc
-  override def getClass(): Class[Float] = ???
 }
 
 object Float extends AnyValCompanion {