path: root/src/library/scala/reflect/base/Base.scala

package scala.reflect
package base

import java.io.PrintWriter
import scala.annotation.switch
import scala.ref.WeakReference
import scala.collection.mutable

class Base extends Universe { self =>

  private var nextId = 0

  abstract class Symbol(val name: Name, val flags: FlagSet) extends SymbolBase {
    val id = { nextId += 1; nextId }
    def owner: Symbol
    def fullName: String =
      if (isEffectiveRoot || owner.isEffectiveRoot) name.toString else owner.fullName + "." + name
    private def isEffectiveRoot =
      this == NoSymbol || this == rootMirror.RootClass || this == rootMirror.EmptyPackageClass

    def newTermSymbol(name: TermName, pos: Position = NoPosition, flags: FlagSet = NoFlags): TermSymbol =
      new TermSymbol(this, name, flags)

    def newModuleAndClassSymbol(name: Name, pos: Position = NoPosition, flags: FlagSet = NoFlags): (ModuleSymbol, ClassSymbol) = {
      val c = new ModuleClassSymbol(this, name.toTypeName, flags)
      val m = new ModuleSymbol(this, name.toTermName, flags, c)
      (m, c)
    }

    def newMethodSymbol(name: TermName, pos: Position = NoPosition, flags: FlagSet = NoFlags): MethodSymbol
      = new MethodSymbol(this, name, flags)

    def newTypeSymbol(name: TypeName, pos: Position = NoPosition, flags: FlagSet = NoFlags): TypeSymbol =
      new TypeSymbol(this, name, flags)

    def newClassSymbol(name: TypeName, pos: Position = NoPosition, flags: FlagSet = NoFlags): ClassSymbol =
      new ClassSymbol(this, name, flags)

    def newFreeTermSymbol(name: TermName, value: => Any, flags: FlagSet = NoFlags, origin: String = null) =
      new FreeTermSymbol(this, name, flags)

    def newFreeTypeSymbol(name: TypeName, flags: FlagSet = NoFlags, origin: String = null) =
      new FreeTypeSymbol(this, name, flags)

    private def kindString: String =
      if (isModule) "module"
      else if (isClass) "class"
      else if (isFreeType) "free type"
      else if (isType) "type"
      else if (isMethod) "method"
      else if (isFreeTerm) "free term"
      else if (isTerm) "value"
      else "symbol"
    override def toString() = s"$kindString $name"
  }
  implicit val SymbolTag = ClassTag[Symbol](classOf[Symbol])

  class TermSymbol(val owner: Symbol, override val name: TermName, flags: FlagSet)
      extends Symbol(name, flags) with TermSymbolBase
  implicit val TermSymbolTag = ClassTag[TermSymbol](classOf[TermSymbol])

  class TypeSymbol(val owner: Symbol, override val name: TypeName, flags: FlagSet)
      extends Symbol(name, flags) with TypeSymbolBase {
    override def toTypeConstructor = TypeRef(ThisType(owner), this, Nil)
    override def toType = TypeRef(ThisType(owner), this, Nil)
    override def toTypeIn(site: Type) = TypeRef(ThisType(owner), this, Nil)
  }
  implicit val TypeSymbolTag = ClassTag[TypeSymbol](classOf[TypeSymbol])

  class MethodSymbol(owner: Symbol, name: TermName, flags: FlagSet)
      extends TermSymbol(owner, name, flags) with MethodSymbolBase
  implicit val MethodSymbolTag = ClassTag[MethodSymbol](classOf[MethodSymbol])

  class ModuleSymbol(owner: Symbol, name: TermName, flags: FlagSet, override val moduleClass: Symbol)
      extends TermSymbol(owner, name, flags) with ModuleSymbolBase
  implicit val ModuleSymbolTag = ClassTag[ModuleSymbol](classOf[ModuleSymbol])

  class ClassSymbol(owner: Symbol, name: TypeName, flags: FlagSet)
      extends TypeSymbol(owner, name, flags) with ClassSymbolBase
  class ModuleClassSymbol(owner: Symbol, name: TypeName, flags: FlagSet)
      extends ClassSymbol(owner, name, flags) { override def isModuleClass = true }
  implicit val ClassSymbolTag = ClassTag[ClassSymbol](classOf[ClassSymbol])

  class FreeTermSymbol(owner: Symbol, name: TermName, flags: FlagSet)
      extends TermSymbol(owner, name, flags) with FreeTermSymbolBase
  implicit val FreeTermSymbolTag = ClassTag[FreeTermSymbol](classOf[FreeTermSymbol])

  class FreeTypeSymbol(owner: Symbol, name: TypeName, flags: FlagSet)
      extends TypeSymbol(owner, name, flags) with FreeTypeSymbolBase
  implicit val FreeTypeSymbolTag = ClassTag[FreeTypeSymbol](classOf[FreeTypeSymbol])


  object NoSymbol extends Symbol(nme.NO_NAME, NoFlags) {
    override def owner = throw new UnsupportedOperationException("NoSymbol.owner")
  }

  // todo. write a decent toString that doesn't crash on recursive types
  class Type extends TypeBase {
    def termSymbol: Symbol = NoSymbol
    def typeSymbol: Symbol = NoSymbol
  }
  implicit val TypeTagg = ClassTag[Type](classOf[Type])

  val NoType = new Type { override def toString = "NoType" }
  val NoPrefix = new Type { override def toString = "NoPrefix" }

  class SingletonType extends Type
  implicit val SingletonTypeTag = ClassTag[SingletonType](classOf[SingletonType])

  case class ThisType(sym: Symbol) extends SingletonType { override val typeSymbol = sym }
  object ThisType extends ThisTypeExtractor
  implicit val ThisTypeTag = ClassTag[ThisType](classOf[ThisType])

  case class SingleType(pre: Type, sym: Symbol) extends SingletonType { override val termSymbol = sym }
  object SingleType extends SingleTypeExtractor
  implicit val SingleTypeTag = ClassTag[SingleType](classOf[SingleType])

  case class SuperType(thistpe: Type, supertpe: Type) extends SingletonType
  object SuperType extends SuperTypeExtractor
  implicit val SuperTypeTag = ClassTag[SuperType](classOf[SuperType])

  case class ConstantType(value: Constant) extends SingletonType
  object ConstantType extends ConstantTypeExtractor
  implicit val ConstantTypeTag = ClassTag[ConstantType](classOf[ConstantType])

  case class TypeRef(pre: Type, sym: Symbol, args: List[Type]) extends Type { override val typeSymbol = sym }
  object TypeRef extends TypeRefExtractor
  implicit val TypeRefTag = ClassTag[TypeRef](classOf[TypeRef])

  abstract class CompoundType extends Type
  implicit val CompoundTypeTag = ClassTag[CompoundType](classOf[CompoundType])

  case class RefinedType(parents: List[Type], decls: Scope) extends CompoundType
  object RefinedType extends RefinedTypeExtractor {
    def apply(parents: List[Type], decls: Scope, clazz: Symbol): RefinedType =
      RefinedType(parents, decls)
  }
  implicit val RefinedTypeTag = ClassTag[RefinedType](classOf[RefinedType])

  case class ClassInfoType(parents: List[Type], decls: Scope, override val typeSymbol: Symbol) extends CompoundType
  object ClassInfoType extends ClassInfoTypeExtractor
  implicit val ClassInfoTypeTag = ClassTag[ClassInfoType](classOf[ClassInfoType])

  case class MethodType(params: List[Symbol], resultType: Type) extends Type
  object MethodType extends MethodTypeExtractor
  implicit val MethodTypeTag = ClassTag[MethodType](classOf[MethodType])

  case class NullaryMethodType(resultType: Type) extends Type
  object NullaryMethodType extends NullaryMethodTypeExtractor
  implicit val NullaryMethodTypeTag = ClassTag[NullaryMethodType](classOf[NullaryMethodType])

  case class PolyType(typeParams: List[Symbol], resultType: Type) extends Type
  object PolyType extends PolyTypeExtractor
  implicit val PolyTypeTag = ClassTag[PolyType](classOf[PolyType])

  case class ExistentialType(quantified: List[Symbol], underlying: Type) extends Type { override def typeSymbol = underlying.typeSymbol }
  object ExistentialType extends ExistentialTypeExtractor
  implicit val ExistentialTypeTag = ClassTag[ExistentialType](classOf[ExistentialType])

  case class AnnotatedType(annotations: List[AnnotationInfo], underlying: Type, selfsym: Symbol) extends Type { override def typeSymbol = underlying.typeSymbol }
  object AnnotatedType extends AnnotatedTypeExtractor
  implicit val AnnotatedTypeTag = ClassTag[AnnotatedType](classOf[AnnotatedType])

  case class TypeBounds(lo: Type, hi: Type) extends Type
  object TypeBounds extends TypeBoundsExtractor
  implicit val TypeBoundsTag = ClassTag[TypeBounds](classOf[TypeBounds])

  val WildcardType = new Type

  case class BoundedWildcardType(bounds: TypeBounds) extends Type
  object BoundedWildcardType extends BoundedWildcardTypeExtractor
  implicit val BoundedWildcardTypeTag = ClassTag[BoundedWildcardType](classOf[BoundedWildcardType])

  class Scope(elems: Iterable[Symbol]) extends ScopeBase with MemberScopeBase {
    def iterator = elems.iterator
    def sorted = elems.toList
  }
  type MemberScope = Scope
  implicit val ScopeTag = ClassTag[Scope](classOf[Scope])
  implicit val MemberScopeTag = ClassTag[MemberScope](classOf[MemberScope])

  def newScope: Scope = newScopeWith()
  def newNestedScope(outer: Scope): Scope = newScope
  def newScopeWith(elems: Symbol*): Scope = new Scope(elems)

  abstract class Name(str: String) extends NameBase {
    override def toString = str
  }
  implicit val NameTag = ClassTag[Name](classOf[Name])

  class TermName(str: String) extends Name(str) {
    def isTermName = true
    def isTypeName = false
    def toTermName = this
    def toTypeName = new TypeName(str)
  }
  implicit val TermNameTag = ClassTag[TermName](classOf[TermName])

  class TypeName(str: String) extends Name(str) {
    def isTermName = false
    def isTypeName = true
    def toTermName = new TermName(str)
    def toTypeName = this
  }
  implicit val TypeNameTag = ClassTag[TypeName](classOf[TypeName])

  def newTermName(str: String) = new TermName(str)
  def newTypeName(str: String) = new TypeName(str)

  object nme extends TermNamesBase {
    type NameType = TermName
    val WILDCARD             = newTermName("_")
    val CONSTRUCTOR          = newTermName("<init>")
    val ROOTPKG              = newTermName("_root_")
    val EMPTY                = newTermName("")
    val EMPTY_PACKAGE_NAME   = newTermName("<empty>")
    val ROOT                 = newTermName("<root>")
    val NO_NAME            = newTermName("<none>")
  }

  object tpnme extends TypeNamesBase {
    type NameType = TypeName
    val WILDCARD             = nme.WILDCARD.toTypeName
    val EMPTY                = nme.EMPTY.toTypeName
    val WILDCARD_STAR        = newTypeName("_*")
    val EMPTY_PACKAGE_NAME   = nme.EMPTY_PACKAGE_NAME.toTypeName
    val ROOT                 = nme.ROOT.toTypeName
  }

  type FlagSet = Long
  val NoFlags = 0L
  implicit val FlagSetTag = ClassTag[FlagSet](classOf[FlagSet])

  class Modifiers(override val flags: FlagSet,
                  override val privateWithin: Name,
                  override val annotations: List[Tree]) extends ModifiersBase {
    def hasFlag(flags: FlagSet) = (this.flags & flags) != 0
  }

  implicit val ModifiersTag = ClassTag[Modifiers](classOf[Modifiers])

  object Modifiers extends ModifiersCreator {
    def apply(flags: Long,
              privateWithin: Name,
              annotations: List[Tree]) = new Modifiers(flags, privateWithin, annotations)
  }

  case class Constant(value: Any)
  object Constant extends ConstantExtractor
  implicit val ConstantTag = ClassTag[Constant](classOf[Constant])

  case class AnnotationInfo(atp: Type, args: List[Tree], assocs: List[(Name, ClassfileAnnotArg)])
  object AnnotationInfo extends AnnotationInfoExtractor
  implicit val AnnotationInfoTag = ClassTag[AnnotationInfo](classOf[AnnotationInfo])

  abstract class ClassfileAnnotArg
  implicit val ClassfileAnnotArgTag = ClassTag[ClassfileAnnotArg](classOf[ClassfileAnnotArg])

  case class LiteralAnnotArg(const: Constant) extends ClassfileAnnotArg
  object LiteralAnnotArg extends LiteralAnnotArgExtractor
  implicit val LiteralAnnotArgTag = ClassTag[LiteralAnnotArg](classOf[LiteralAnnotArg])

  case class ArrayAnnotArg(args: Array[ClassfileAnnotArg]) extends ClassfileAnnotArg
  object ArrayAnnotArg extends ArrayAnnotArgExtractor
  implicit val ArrayAnnotArgTag = ClassTag[ArrayAnnotArg](classOf[ArrayAnnotArg])

  case class NestedAnnotArg(annInfo: AnnotationInfo) extends ClassfileAnnotArg
  object NestedAnnotArg extends NestedAnnotArgExtractor
  implicit val NestedAnnotArgTag = ClassTag[NestedAnnotArg](classOf[NestedAnnotArg])

  class Position extends Attachments {
    override type Pos = Position
    def pos = this
    def withPos(newPos: Position) = newPos
    def isRange = false
    def focus = this
  }
  implicit val PositionTag = ClassTag[Position](classOf[Position])

  val NoPosition = new Position

  private val generated = new mutable.HashMap[String, WeakReference[Symbol]]

  private def cached(name: String)(symExpr: => Symbol): Symbol =
    generated get name match {
      case Some(WeakReference(sym)) =>
        sym
      case _ =>
        val sym = symExpr
        generated(name) = WeakReference(sym)
        sym
    }

  object build extends BuildBase {
    def selectType(owner: Symbol, name: String): TypeSymbol = {
      val clazz = new ClassSymbol(owner, newTypeName(name), NoFlags)
      cached(clazz.fullName)(clazz).asType
    }

    def selectTerm(owner: Symbol, name: String): TermSymbol = {
      val valu = new MethodSymbol(owner, newTermName(name), NoFlags)
      cached(valu.fullName)(valu).asTerm
    }

    def selectOverloadedMethod(owner: Symbol, name: String, index: Int): MethodSymbol =
      selectTerm(owner, name).asMethod

    def newNestedSymbol(owner: Symbol, name: Name, pos: Position, flags: Long, isClass: Boolean): Symbol =
      if (name.isTypeName)
        if (isClass) new ClassSymbol(owner, name.toTypeName, flags)
        else new TypeSymbol(owner, name.toTypeName, flags)
      else new TermSymbol(owner, name.toTermName, flags)

    def newFreeTerm(name: String, value: => Any, flags: Long = 0L, origin: String = null): FreeTermSymbol =
      new FreeTermSymbol(rootMirror.RootClass, newTermName(name), flags)

    def newFreeType(name: String, flags: Long = 0L, origin: String = null): FreeTypeSymbol =
      new FreeTypeSymbol(rootMirror.RootClass, newTypeName(name), flags)

    def setTypeSignature[S <: Symbol](sym: S, tpe: Type): S = sym

    def setAnnotations[S <: Symbol](sym: S, annots: List[AnnotationInfo]): S = sym

    def flagsFromBits(bits: Long): FlagSet = bits

    object emptyValDef extends ValDef(NoMods, nme.WILDCARD, TypeTree(NoType), EmptyTree) {
      override def isEmpty = true
    }

    def This(sym: Symbol): Tree = self.This(sym.name.toTypeName)

    def Select(qualifier: Tree, sym: Symbol): Select = self.Select(qualifier, sym.name)

    def Ident(sym: Symbol): Ident = self.Ident(sym.name)

    def TypeTree(tp: Type): TypeTree = self.TypeTree()

    def thisPrefix(sym: Symbol): Type = SingleType(NoPrefix, sym)

    def setType[T <: Tree](tree: T, tpe: Type): T = tree

    def setSymbol[T <: Tree](tree: T, sym: Symbol): T = tree
  }

  import build._

  class Mirror extends MirrorOf[self.type] {
    val universe: self.type = self

    lazy val RootClass    = new ClassSymbol(NoSymbol, tpnme.ROOT, NoFlags) { override def isModuleClass = true }
    lazy val RootPackage  = new ModuleSymbol(NoSymbol, nme.ROOT, NoFlags, RootClass)
    lazy val EmptyPackageClass = new ClassSymbol(RootClass, tpnme.EMPTY_PACKAGE_NAME, NoFlags) { override def isModuleClass = true }
    lazy val EmptyPackage = new ModuleSymbol(RootClass, nme.EMPTY_PACKAGE_NAME, NoFlags, EmptyPackageClass)

    def staticClass(fullName: String): ClassSymbol =
      mkStatic[ClassSymbol](fullName)

    def staticModule(fullName: String): ModuleSymbol =
      mkStatic[ModuleSymbol](fullName)

    def staticPackage(fullName: String): ModuleSymbol =
      staticModule(fullName) // this toy universe doesn't care about the distinction between packages and modules

    private def mkStatic[S <: Symbol : ClassTag](fullName: String): S =
      cached(fullName) {
        val point = fullName lastIndexOf '.'
        val owner =
          if (point > 0) staticModule(fullName take point).moduleClass
          else rootMirror.RootClass
        val name = fullName drop point + 1
        val symtag = implicitly[ClassTag[S]]
        if (symtag == ClassSymbolTag) new ClassSymbol(owner, newTypeName(name), NoFlags)
        else owner.newModuleAndClassSymbol(newTermName(name))._1
      }.asInstanceOf[S]
  }

  lazy val rootMirror = new Mirror

  import rootMirror._

  object definitions extends DefinitionsBase {
    lazy val ScalaPackage = staticModule("scala")
    lazy val ScalaPackageClass = ScalaPackage.moduleClass.asClass

    lazy val AnyClass     = staticClass("scala.Any")
    lazy val AnyValClass  = staticClass("scala.Any")
    lazy val ObjectClass  = staticClass("java.lang.Object")
    lazy val AnyRefClass  = ObjectClass

    lazy val NullClass    = staticClass("scala.Null")
    lazy val NothingClass = staticClass("scala.Nothing")

    lazy val UnitClass    = staticClass("scala.Unit")
    lazy val ByteClass    = staticClass("scala.Byte")
    lazy val ShortClass   = staticClass("scala.Short")
    lazy val CharClass    = staticClass("scala.Char")
    lazy val IntClass     = staticClass("scala.Int")
    lazy val LongClass    = staticClass("scala.Long")
    lazy val FloatClass   = staticClass("scala.Float")
    lazy val DoubleClass  = staticClass("scala.Double")
    lazy val BooleanClass = staticClass("scala.Boolean")

    lazy val StringClass  = staticClass("java.lang.String")
    lazy val ClassClass   = staticClass("java.lang.Class")
    lazy val ArrayClass   = staticClass("scala.Array")
    lazy val ListClass    = staticClass("scala.List")

    lazy val PredefModule = staticModule("scala.Predef")

    lazy val ByteTpe    = TypeRef(ScalaPrefix, ByteClass, Nil)
    lazy val ShortTpe   = TypeRef(ScalaPrefix, ShortClass, Nil)
    lazy val CharTpe    = TypeRef(ScalaPrefix, CharClass, Nil)
    lazy val IntTpe     = TypeRef(ScalaPrefix, IntClass, Nil)
    lazy val LongTpe    = TypeRef(ScalaPrefix, LongClass, Nil)
    lazy val FloatTpe   = TypeRef(ScalaPrefix, FloatClass, Nil)
    lazy val DoubleTpe  = TypeRef(ScalaPrefix, DoubleClass, Nil)
    lazy val BooleanTpe = TypeRef(ScalaPrefix, BooleanClass, Nil)
    lazy val UnitTpe    = TypeRef(ScalaPrefix, UnitClass, Nil)
    lazy val AnyTpe     = TypeRef(ScalaPrefix, AnyClass, Nil)
    lazy val AnyValTpe  = TypeRef(ScalaPrefix, AnyValClass, Nil)
    lazy val NothingTpe = TypeRef(ScalaPrefix, NothingClass, Nil)
    lazy val NullTpe    = TypeRef(ScalaPrefix, NullClass, Nil)
    lazy val ObjectTpe  = TypeRef(JavaLangPrefix, ObjectClass, Nil)
    lazy val AnyRefTpe  = ObjectTpe
  }

  import definitions._

  private def thisModuleType(fullName: String): Type = ThisType(staticModule(fullName).moduleClass)
  private lazy val ScalaPrefix = thisModuleType("scala")
  private lazy val JavaLangPrefix = thisModuleType("java.lang")

  private var nodeCount = 0 // not synchronized

  abstract class Tree extends TreeBase with Product {
    def isDef: Boolean = false
    def isEmpty: Boolean = false

    /** The canonical way to test if a Tree represents a term.
     */
    def isTerm: Boolean = this match {
      case _: TermTree       => true
      case Bind(name, _)     => name.isTermName
      case Select(_, name)   => name.isTermName
      case Ident(name)       => name.isTermName
      case Annotated(_, arg) => arg.isTerm
      case _                 => false
    }

    /** The canonical way to test if a Tree represents a type.
     */
    def isType: Boolean = this match {
      case _: TypTree        => true
      case Bind(name, _)     => name.isTypeName
      case Select(_, name)   => name.isTypeName
      case Ident(name)       => name.isTypeName
      case Annotated(_, arg) => arg.isType
      case _                 => false
    }
  }

  def treeToString(tree: Tree) = s"<tree ${tree.getClass}>"

  def treeType(tree: Tree) = NoType

  trait TermTree extends Tree

  trait TypTree extends Tree

  trait SymTree extends Tree

  trait NameTree extends Tree {
    def name: Name
  }

  trait RefTree extends SymTree with NameTree {
    def qualifier: Tree    // empty for Idents
    def name: Name
  }

  abstract class DefTree extends SymTree with NameTree {
    def name: Name
    override def isDef = true
  }

  case object EmptyTree extends TermTree {
    val asList = List(this)
    override def isEmpty = true
  }

  abstract class MemberDef extends DefTree {
    def mods: Modifiers
  }

  case class PackageDef(pid: RefTree, stats: List[Tree])
       extends MemberDef {
    def name = pid.name
    def mods = NoMods
  }
  object PackageDef extends PackageDefExtractor

  abstract class ImplDef extends MemberDef {
    def impl: Template
  }

  case class ClassDef(mods: Modifiers, name: TypeName, tparams: List[TypeDef], impl: Template)
       extends ImplDef
  object ClassDef extends ClassDefExtractor

  case class ModuleDef(mods: Modifiers, name: TermName, impl: Template)
        extends ImplDef
  object ModuleDef extends ModuleDefExtractor

  abstract class ValOrDefDef extends MemberDef {
    val name: Name
    val tpt: Tree
    val rhs: Tree
  }

  case class ValDef(mods: Modifiers, name: TermName, tpt: Tree, rhs: Tree) extends ValOrDefDef
  object ValDef extends ValDefExtractor

  case class DefDef(mods: Modifiers, name: Name, tparams: List[TypeDef],
                    vparamss: List[List[ValDef]], tpt: Tree, rhs: Tree) extends ValOrDefDef
  object DefDef extends DefDefExtractor

  case class TypeDef(mods: Modifiers, name: TypeName, tparams: List[TypeDef], rhs: Tree)
       extends MemberDef
  object TypeDef extends TypeDefExtractor

  case class LabelDef(name: TermName, params: List[Ident], rhs: Tree)
       extends DefTree with TermTree
  object LabelDef extends LabelDefExtractor

  case class ImportSelector(name: Name, namePos: Int, rename: Name, renamePos: Int)
  object ImportSelector extends ImportSelectorExtractor

  case class Import(expr: Tree, selectors: List[ImportSelector])
       extends SymTree
  object Import extends ImportExtractor

  case class Template(parents: List[Tree], self: ValDef, body: List[Tree])
       extends SymTree
  object Template extends TemplateExtractor

  case class Block(stats: List[Tree], expr: Tree)
       extends TermTree
  object Block extends BlockExtractor

  case class CaseDef(pat: Tree, guard: Tree, body: Tree)
       extends Tree
  object CaseDef extends CaseDefExtractor

  case class Alternative(trees: List[Tree])
       extends TermTree
  object Alternative extends AlternativeExtractor

  case class Star(elem: Tree)
       extends TermTree
  object Star extends StarExtractor

  case class Bind(name: Name, body: Tree)
       extends DefTree
  object Bind extends BindExtractor

  case class UnApply(fun: Tree, args: List[Tree])
       extends TermTree
  object UnApply extends UnApplyExtractor

  case class ArrayValue(elemtpt: Tree, elems: List[Tree])
       extends TermTree
  object ArrayValue extends ArrayValueExtractor

  case class Function(vparams: List[ValDef], body: Tree)
       extends TermTree with SymTree
  object Function extends FunctionExtractor

  case class Assign(lhs: Tree, rhs: Tree)
       extends TermTree
  object Assign extends AssignExtractor

  case class AssignOrNamedArg(lhs: Tree, rhs: Tree)
       extends TermTree
  object AssignOrNamedArg extends AssignOrNamedArgExtractor

  case class If(cond: Tree, thenp: Tree, elsep: Tree)
       extends TermTree
  object If extends IfExtractor

  case class Match(selector: Tree, cases: List[CaseDef])
       extends TermTree
  object Match extends MatchExtractor

  case class Return(expr: Tree)
       extends TermTree with SymTree
  object Return extends ReturnExtractor

  case class Try(block: Tree, catches: List[CaseDef], finalizer: Tree)
       extends TermTree
  object Try extends TryExtractor

  case class Throw(expr: Tree)
       extends TermTree
  object Throw extends ThrowExtractor

  case class New(tpt: Tree) extends TermTree
  object New extends NewExtractor

  case class Typed(expr: Tree, tpt: Tree)
       extends TermTree
  object Typed extends TypedExtractor

  abstract class GenericApply extends TermTree {
    val fun: Tree
    val args: List[Tree]
  }

  case class TypeApply(fun: Tree, args: List[Tree])
       extends GenericApply
  object TypeApply extends TypeApplyExtractor

  case class Apply(fun: Tree, args: List[Tree])
       extends GenericApply
  object Apply extends ApplyExtractor

  case class Super(qual: Tree, mix: TypeName) extends TermTree
  object Super extends SuperExtractor

  case class This(qual: TypeName)
        extends TermTree with SymTree
  object This extends ThisExtractor

  case class Select(qualifier: Tree, name: Name)
       extends RefTree
  object Select extends SelectExtractor

  case class Ident(name: Name) extends RefTree {
    def qualifier: Tree = EmptyTree
  }
  object Ident extends IdentExtractor

  case class ReferenceToBoxed(ident: Ident) extends TermTree
  object ReferenceToBoxed extends ReferenceToBoxedExtractor

  case class Literal(value: Constant)
        extends TermTree {
    assert(value ne null)
  }
  object Literal extends LiteralExtractor

  case class Annotated(annot: Tree, arg: Tree) extends Tree
  object Annotated extends AnnotatedExtractor

  case class SingletonTypeTree(ref: Tree)
        extends TypTree
  object SingletonTypeTree extends SingletonTypeTreeExtractor

  case class SelectFromTypeTree(qualifier: Tree, name: TypeName)
       extends TypTree with RefTree
  object SelectFromTypeTree extends SelectFromTypeTreeExtractor

  case class CompoundTypeTree(templ: Template)
       extends TypTree
  object CompoundTypeTree extends CompoundTypeTreeExtractor

  case class AppliedTypeTree(tpt: Tree, args: List[Tree])
       extends TypTree
  object AppliedTypeTree extends AppliedTypeTreeExtractor

  case class TypeBoundsTree(lo: Tree, hi: Tree)
       extends TypTree
  object TypeBoundsTree extends TypeBoundsTreeExtractor

  case class ExistentialTypeTree(tpt: Tree, whereClauses: List[Tree])
       extends TypTree
  object ExistentialTypeTree extends ExistentialTypeTreeExtractor

  case class TypeTree() extends TypTree {
    val original: Tree = null
    override def isEmpty = true
  }
  object TypeTree extends TypeTreeExtractor

  implicit val TreeTag = ClassTag[Tree](classOf[Tree])
  implicit val TermTreeTag = ClassTag[TermTree](classOf[TermTree])
  implicit val TypTreeTag = ClassTag[TypTree](classOf[TypTree])
  implicit val SymTreeTag = ClassTag[SymTree](classOf[SymTree])
  implicit val NameTreeTag = ClassTag[NameTree](classOf[NameTree])
  implicit val RefTreeTag = ClassTag[RefTree](classOf[RefTree])
  implicit val DefTreeTag = ClassTag[DefTree](classOf[DefTree])
  implicit val MemberDefTag = ClassTag[MemberDef](classOf[MemberDef])
  implicit val PackageDefTag = ClassTag[PackageDef](classOf[PackageDef])
  implicit val ImplDefTag = ClassTag[ImplDef](classOf[ImplDef])
  implicit val ClassDefTag = ClassTag[ClassDef](classOf[ClassDef])
  implicit val ModuleDefTag = ClassTag[ModuleDef](classOf[ModuleDef])
  implicit val ValOrDefDefTag = ClassTag[ValOrDefDef](classOf[ValOrDefDef])
  implicit val ValDefTag = ClassTag[ValDef](classOf[ValDef])
  implicit val DefDefTag = ClassTag[DefDef](classOf[DefDef])
  implicit val TypeDefTag = ClassTag[TypeDef](classOf[TypeDef])
  implicit val LabelDefTag = ClassTag[LabelDef](classOf[LabelDef])
  implicit val ImportSelectorTag = ClassTag[ImportSelector](classOf[ImportSelector])
  implicit val ImportTag = ClassTag[Import](classOf[Import])
  implicit val TemplateTag = ClassTag[Template](classOf[Template])
  implicit val BlockTag = ClassTag[Block](classOf[Block])
  implicit val CaseDefTag = ClassTag[CaseDef](classOf[CaseDef])
  implicit val AlternativeTag = ClassTag[Alternative](classOf[Alternative])
  implicit val StarTag = ClassTag[Star](classOf[Star])
  implicit val BindTag = ClassTag[Bind](classOf[Bind])
  implicit val UnApplyTag = ClassTag[UnApply](classOf[UnApply])
  implicit val ArrayValueTag = ClassTag[ArrayValue](classOf[ArrayValue])
  implicit val FunctionTag = ClassTag[Function](classOf[Function])
  implicit val AssignTag = ClassTag[Assign](classOf[Assign])
  implicit val AssignOrNamedArgTag = ClassTag[AssignOrNamedArg](classOf[AssignOrNamedArg])
  implicit val IfTag = ClassTag[If](classOf[If])
  implicit val MatchTag = ClassTag[Match](classOf[Match])
  implicit val ReturnTag = ClassTag[Return](classOf[Return])
  implicit val TryTag = ClassTag[Try](classOf[Try])
  implicit val ThrowTag = ClassTag[Throw](classOf[Throw])
  implicit val NewTag = ClassTag[New](classOf[New])
  implicit val TypedTag = ClassTag[Typed](classOf[Typed])
  implicit val GenericApplyTag = ClassTag[GenericApply](classOf[GenericApply])
  implicit val TypeApplyTag = ClassTag[TypeApply](classOf[TypeApply])
  implicit val ApplyTag = ClassTag[Apply](classOf[Apply])
  implicit val SuperTag = ClassTag[Super](classOf[Super])
  implicit val ThisTag = ClassTag[This](classOf[This])
  implicit val SelectTag = ClassTag[Select](classOf[Select])
  implicit val IdentTag = ClassTag[Ident](classOf[Ident])
  implicit val ReferenceToBoxedTag = ClassTag[ReferenceToBoxed](classOf[ReferenceToBoxed])
  implicit val LiteralTag = ClassTag[Literal](classOf[Literal])
  implicit val AnnotatedTag = ClassTag[Annotated](classOf[Annotated])
  implicit val SingletonTypeTreeTag = ClassTag[SingletonTypeTree](classOf[SingletonTypeTree])
  implicit val SelectFromTypeTreeTag = ClassTag[SelectFromTypeTree](classOf[SelectFromTypeTree])
  implicit val CompoundTypeTreeTag = ClassTag[CompoundTypeTree](classOf[CompoundTypeTree])
  implicit val AppliedTypeTreeTag = ClassTag[AppliedTypeTree](classOf[AppliedTypeTree])
  implicit val TypeBoundsTreeTag = ClassTag[TypeBoundsTree](classOf[TypeBoundsTree])
  implicit val ExistentialTypeTreeTag = ClassTag[ExistentialTypeTree](classOf[ExistentialTypeTree])
  implicit val TypeTreeTag = ClassTag[TypeTree](classOf[TypeTree])

  def ClassDef(sym: Symbol, impl: Template): ClassDef = ???
  def ModuleDef(sym: Symbol, impl: Template): ModuleDef = ???
  def ValDef(sym: Symbol, rhs: Tree): ValDef = ???
  def ValDef(sym: Symbol): ValDef = ???
  def DefDef(sym: Symbol, mods: Modifiers, vparamss: List[List[ValDef]], rhs: Tree): DefDef = ???
  def DefDef(sym: Symbol, vparamss: List[List[ValDef]], rhs: Tree): DefDef = ???
  def DefDef(sym: Symbol, mods: Modifiers, rhs: Tree): DefDef = ???
  def DefDef(sym: Symbol, rhs: Tree): DefDef = ???
  def DefDef(sym: Symbol, rhs: List[List[Symbol]] => Tree): DefDef = ???
  def TypeDef(sym: Symbol, rhs: Tree): TypeDef = ???
  def TypeDef(sym: Symbol): TypeDef = ???
  def LabelDef(sym: Symbol, params: List[Symbol], rhs: Tree): LabelDef = ???
  def CaseDef(pat: Tree, body: Tree): CaseDef = ???
  def Bind(sym: Symbol, body: Tree): Bind = ???
  def Try(body: Tree, cases: (Tree, Tree)*): Try = ???
  def Throw(tpe: Type, args: Tree*): Throw = ???
  def Apply(sym: Symbol, args: Tree*): Tree = ???
  def New(tpt: Tree, argss: List[List[Tree]]): Tree = ???
  def New(tpe: Type, args: Tree*): Tree = ???
  def New(sym: Symbol, args: Tree*): Tree = ???
  def ApplyConstructor(tpt: Tree, args: List[Tree]): Tree = ???
  def Super(sym: Symbol, mix: TypeName): Tree = ???
  def This(sym: Symbol): Tree = ???
  def Select(qualifier: Tree, name: String): Select = ???
  def Select(qualifier: Tree, sym: Symbol): Select = ???
  def Ident(name: String): Ident = ???
  def Ident(sym: Symbol): Ident = ???
  def Block(stats: Tree*): Block = ???
  def TypeTree(tp: Type): TypeTree = ???
}