Make extension method names semantic

Author: odersky

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

@@ -132,6 +132,13 @@ object NameKinds {
  case DerivedTermName(underlying, info: this.NumberedInfo) => Some((underlying, info.num))
  case _ => None
  }
+ protected def skipSeparatorAndNum(name: SimpleTermName, separator: String): Int = {
+ var i = name.length
+ while (i > 0 && name(i - 1).isDigit) i -= 1
+ if (i > separator.length && i < name.length &&
+ name.slice(i - separator.length, i).toString == separator) i
+ else -1
+ }
  }
 
  case class UniqueNameKind(val separator: String)
@@ -205,6 +212,18 @@ object NameKinds {
  val SkolemName = new UniqueNameKind("?")
  val LiftedTreeName = new UniqueNameKind("liftedTree")
 
+ val UniqueExtMethName = new UniqueNameKind("$extension") {
+ override def unmangle(name: SimpleTermName): TermName = {
+ val i = skipSeparatorAndNum(name, separator)
+ if (i > 0) {
+ val index = name.drop(i).toString.toInt
+ var original = name.take(i - separator.length).asTermName
+ apply(original, index)
+ }
+ else name
+ }
+ }
+
  val PatMatStdBinderName = new UniqueNameKind("x")
  val PatMatPiName = new UniqueNameKind("pi") // FIXME: explain what this is
  val PatMatPName = new UniqueNameKind("p") // FIXME: explain what this is
@@ -218,15 +237,12 @@ object NameKinds {
  val prefix = if (underlying.isConstructorName) nme.DEFAULT_GETTER_INIT else underlying
  prefix.toString + str.DEFAULT_GETTER + (info.num + 1)
  }
-
- private val dgLen = str.DEFAULT_GETTER.length
-
+ // TODO: Reduce code duplication with UniqueExtMethName
  override def unmangle(name: SimpleTermName): TermName = {
- var i = name.length
- while (i > 0 && name(i - 1).isDigit) i -= 1
- if (i > dgLen && i < name.length && name.slice(i - dgLen, i) == nme.DEFAULT_GETTER) {
+ val i = skipSeparatorAndNum(name, str.DEFAULT_GETTER)
+ if (i > 0) {
  val index = name.drop(i).toString.toInt - 1
- var original = name.take(i - dgLen).asTermName
+ var original = name.take(i - str.DEFAULT_GETTER.length).asTermName
  if (original == nme.DEFAULT_GETTER_INIT) original = Names.CONSTRUCTOR
  apply(original, index)
  }
@@ -260,6 +276,7 @@ object NameKinds {
  val AvoidClashName = new SuffixNameKind(AVOIDCLASH, "$_avoid_name_clash_$")
  val DirectName = new SuffixNameKind(DIRECT, "$direct")
  val FieldName = new SuffixNameKind(FIELD, "$$local")
+ val ExtMethName = new SuffixNameKind(EXTMETH, "$extension")
  val ModuleVarName = new SuffixNameKind(OBJECTVAR, "$module")
  val ModuleClassName = new SuffixNameKind(OBJECTCLASS, "$", optInfoString = "ModuleClass")
 
@@ -283,7 +300,7 @@ object NameKinds {
  }
 
  val Scala2MethodNameKinds: List[NameKind] =
- List(DefaultGetterName, ProtectedAccessorName, ProtectedSetterName)
+ List(DefaultGetterName, ExtMethName, UniqueExtMethName, ProtectedAccessorName, ProtectedSetterName)
 
  def simpleNameKindOfTag : collection.Map[Int, ClassifiedNameKind] = simpleNameKinds
  def qualifiedNameKindOfTag : collection.Map[Int, QualifiedNameKind] = qualifiedNameKinds

compiler/src/dotty/tools/dotc/core/tasty/TastyFormat.scala

@@ -239,6 +239,7 @@ object TastyFormat {
  final val DIRECT = 31
  final val FIELD = 32
  final val SETTER = 33
+ final val EXTMETH = 34
  final val OBJECTVAR = 39
  final val OBJECTCLASS = 40
 

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

@@ -16,6 +16,7 @@ import Types._, Contexts._, Constants._, Names._, NameOps._, Flags._, DenotTrans
 import SymDenotations._, Symbols._, StdNames._, Annotations._, Trees._, Scopes._, Denotations._
 import TypeErasure.{ valueErasure, ErasedValueType }
 import TypeUtils._
+import NameKinds.{ExtMethName, UniqueExtMethName}
 import util.Positions._
 import Decorators._
 import SymUtils._
@@ -206,11 +207,11 @@ object ExtensionMethods {
  val alts = decl.alternatives
  val index = alts indexOf imeth.denot
  assert(index >= 0, alts + " does not contain " + imeth)
- def altName(index: Int) = (imeth.name + "$extension" + index).toTermName
+ def altName(index: Int) = UniqueExtMethName(imeth.name.asTermName, index)
  altName(index) #:: ((0 until alts.length).toStream filter (index != _) map altName)
  case decl =>
  assert(decl.exists, imeth.name + " not found in " + imeth.owner + "'s decls: " + imeth.owner.info.decls)
- Stream((imeth.name + "$extension").toTermName)
+ Stream(ExtMethName(imeth.name.asTermName))
  }
  }