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package scala.reflect
package internal
abstract class TreeGen {
val global: SymbolTable
import global._
import definitions._
def rootId(name: Name) = Select(Ident(nme.ROOTPKG), name)
def rootScalaDot(name: Name) = Select(rootId(nme.scala_) setSymbol ScalaPackage, name)
def scalaDot(name: Name) = Select(Ident(nme.scala_) setSymbol ScalaPackage, name)
def scalaAnyRefConstr = scalaDot(tpnme.AnyRef)
def scalaUnitConstr = scalaDot(tpnme.Unit)
def scalaScalaObjectConstr = scalaDot(tpnme.ScalaObject)
def productConstr = scalaDot(tpnme.Product)
def serializableConstr = scalaDot(tpnme.Serializable)
def scalaFunctionConstr(argtpes: List[Tree], restpe: Tree, abstractFun: Boolean = false): Tree = {
val cls = if (abstractFun)
AppliedTypeTree(cls, argtpes :+ restpe)
/** A creator for method calls, e.g. fn[T1, T2, ...](v1, v2, ...)
* There are a number of variations.
* @param receiver symbol of the method receiver
* @param methodName name of the method to call
* @param targs type arguments (if Nil, no TypeApply node will be generated)
* @param args value arguments
* @return the newly created trees.
def mkMethodCall(receiver: Symbol, methodName: Name, targs: List[Type], args: List[Tree]): Tree =
mkMethodCall(Select(mkAttributedRef(receiver), methodName), targs, args)
def mkMethodCall(method: Symbol, targs: List[Type], args: List[Tree]): Tree =
mkMethodCall(mkAttributedRef(method), targs, args)
def mkMethodCall(method: Symbol, args: List[Tree]): Tree =
mkMethodCall(method, Nil, args)
def mkMethodCall(target: Tree, args: List[Tree]): Tree =
mkMethodCall(target, Nil, args)
def mkMethodCall(receiver: Symbol, methodName: Name, args: List[Tree]): Tree =
mkMethodCall(receiver, methodName, Nil, args)
def mkMethodCall(receiver: Tree, method: Symbol, targs: List[Type], args: List[Tree]): Tree =
mkMethodCall(Select(receiver, method), targs, args)
def mkMethodCall(target: Tree, targs: List[Type], args: List[Tree]): Tree = {
val typeApplied = if (targs.isEmpty) target else TypeApply(target, targs map TypeTree)
Apply(typeApplied, args)
/** Builds a reference to value whose type is given stable prefix.
* The type must be suitable for this. For example, it
* must not be a TypeRef pointing to an abstract type variable.
def mkAttributedQualifier(tpe: Type): Tree =
mkAttributedQualifier(tpe, NoSymbol)
/** Builds a reference to value whose type is given stable prefix.
* If the type is unsuitable, e.g. it is a TypeRef for an
* abstract type variable, then an Ident will be made using
* termSym as the Ident's symbol. In that case, termSym must
* not be NoSymbol.
def mkAttributedQualifier(tpe: Type, termSym: Symbol): Tree = tpe match {
case NoPrefix =>
case ThisType(clazz) =>
if (clazz.isEffectiveRoot) EmptyTree
else mkAttributedThis(clazz)
case SingleType(pre, sym) =>
applyIfNoArgs(mkAttributedStableRef(pre, sym))
case TypeRef(pre, sym, args) =>
if (sym.isRoot) {
} else if (sym.isModuleClass) {
applyIfNoArgs(mkAttributedRef(pre, sym.sourceModule))
} else if (sym.isModule || sym.isClass) {
assert(phase.erasedTypes, tpe)
} else if (sym.isType) {
assert(termSym != NoSymbol, tpe)
mkAttributedIdent(termSym) setType tpe
} else {
mkAttributedRef(pre, sym)
case ConstantType(value) =>
Literal(value) setType tpe
case AnnotatedType(_, atp, _) =>
case RefinedType(parents, _) =>
// I am unclear whether this is reachable, but
// the following implementation looks logical -Lex
val firstStable = parents.find(_.isStable)
assert(!firstStable.isEmpty, tpe)
case _ =>
abort("bad qualifier: " + tpe)
/** If this is a reference to a method with an empty
* parameter list, wrap it in an apply.
private def applyIfNoArgs(qual: Tree) = qual.tpe match {
case MethodType(Nil, restpe) => Apply(qual, Nil) setType restpe
case _ => qual
/** Builds a reference to given symbol with given stable prefix. */
def mkAttributedRef(pre: Type, sym: Symbol): Tree = {
val qual = mkAttributedQualifier(pre)
qual match {
case EmptyTree => mkAttributedIdent(sym)
case This(clazz) if qual.symbol.isEffectiveRoot => mkAttributedIdent(sym)
case _ => mkAttributedSelect(qual, sym)
/** Builds a reference to given symbol. */
def mkAttributedRef(sym: Symbol): Tree =
if (sym.owner.isClass) mkAttributedRef(sym.owner.thisType, sym)
else mkAttributedIdent(sym)
/** Builds an untyped reference to given symbol. */
def mkUnattributedRef(sym: Symbol): Tree =
if (sym.owner.isClass) Select(This(sym.owner), sym)
else Ident(sym)
/** Replaces tree type with a stable type if possible */
def stabilize(tree: Tree): Tree = {
for(tp <- stableTypeFor(tree)) tree.tpe = tp
/** Computes stable type for a tree if possible */
def stableTypeFor(tree: Tree): Option[Type] = tree match {
case Ident(_) if tree.symbol.isStable =>
Some(singleType(tree.symbol.owner.thisType, tree.symbol))
case Select(qual, _) if ((tree.symbol ne null) && (qual.tpe ne null)) && // turned assert into guard for #4064
tree.symbol.isStable && qual.tpe.isStable =>
Some(singleType(qual.tpe, tree.symbol))
case _ =>
/** Cast `tree` to type `pt` */
def mkCast(tree: Tree, pt: Type): Tree = {
if (settings.debug.value) log("casting " + tree + ":" + tree.tpe + " to " + pt)
assert(!tree.tpe.isInstanceOf[MethodType], tree)
assert(pt eq pt.normalize, tree +" : "+ debugString(pt) +" ~>"+ debugString(pt.normalize)) //@MAT only called during erasure, which already takes care of that
atPos(tree.pos)(mkAsInstanceOf(tree, pt, false))
/** Builds a reference with stable type to given symbol */
def mkAttributedStableRef(pre: Type, sym: Symbol): Tree =
stabilize(mkAttributedRef(pre, sym))
def mkAttributedStableRef(sym: Symbol): Tree =
def mkAttributedThis(sym: Symbol): Tree =
This( setSymbol sym setType sym.thisType
def mkAttributedIdent(sym: Symbol): Tree =
Ident( setSymbol sym setType sym.tpe
def mkAttributedSelect(qual: Tree, sym: Symbol): Tree = {
// Tests involving the repl fail without the .isEmptyPackage condition.
if (qual.symbol != null && (qual.symbol.isEffectiveRoot || qual.symbol.isEmptyPackage))
else {
val pkgQualifier =
if (sym != null && sym.owner.isPackageObjectClass && sym.owner.owner == qual.tpe.typeSymbol) {
val obj = sym.owner.sourceModule
Select(qual, nme.PACKAGEkw) setSymbol obj setType singleType(qual.tpe, obj)
else qual
val tree = Select(pkgQualifier, sym)
if (pkgQualifier.tpe == null) tree
else tree setType (qual.tpe memberType sym)
private def mkTypeApply(value: Tree, tpe: Type, what: Symbol) =
mkAttributedSelect(value, what),
/** Builds an instance test with given value and type. */
def mkIsInstanceOf(value: Tree, tpe: Type, any: Boolean = true): Tree =
mkTypeApply(value, tpe, (if (any) Any_isInstanceOf else Object_isInstanceOf))
/** Builds a cast with given value and type. */
def mkAsInstanceOf(value: Tree, tpe: Type, any: Boolean = true): Tree =
mkTypeApply(value, tpe, (if (any) Any_asInstanceOf else Object_asInstanceOf))
/** Cast `tree` to `pt`, unless tpe is a subtype of pt, or pt is Unit. */
def maybeMkAsInstanceOf(tree: Tree, pt: Type, tpe: Type, beforeRefChecks: Boolean = false): Tree =
if ((pt == UnitClass.tpe) || (tpe <:< pt)) {
log("no need to cast from " + tpe + " to " + pt)
} else
atPos(tree.pos) {
if (beforeRefChecks)
TypeApply(mkAttributedSelect(tree, Any_asInstanceOf), List(TypeTree(pt)))
mkAsInstanceOf(tree, pt)
/** Apparently we smuggle a Type around as a Literal(Constant(tp))
* and the implementation of Constant#tpe is such that x.tpe becomes
* ClassType(value.asInstanceOf[Type]), i.e. java.lang.Class[Type].
* Can't find any docs on how/why it's done this way. See ticket
* SI-490 for some interesting comments from lauri alanko suggesting
* that the type given by classOf[T] is too strong and should be
* weakened so as not to suggest that classOf[List[String]] is any
* different from classOf[List[Int]].
* !!! See deconstMap in Erasure for one bug this encoding has induced:
* I would be very surprised if there aren't more.
def mkClassOf(tp: Type): Tree =
Literal(Constant(tp)) setType ConstantType(Constant(tp))
/** Builds a list with given head and tail. */
def mkNewCons(head: Tree, tail: Tree): Tree =
New(Apply(mkAttributedRef(ConsClass), List(head, tail)))
/** Builds a list with given head and tail. */
def mkNil: Tree = mkAttributedRef(NilModule)
/** Builds a tree representing an undefined local, as in
* var x: T = _
* which is appropriate to the given Type.
def mkZero(tp: Type): Tree = {
val tree = tp.typeSymbol match {
case UnitClass => Literal(())
case BooleanClass => Literal(false)
case FloatClass => Literal(0.0f)
case DoubleClass => Literal(0.0d)
case ByteClass => Literal(0.toByte)
case ShortClass => Literal(0.toShort)
case IntClass => Literal(0)
case LongClass => Literal(0L)
case CharClass => Literal(0.toChar)
case _ =>
if (NullClass.tpe <:< tp) Literal(null: Any)
else abort("Cannot determine zero for " + tp)
tree setType tp
/** Builds a tuple */
def mkTuple(elems: List[Tree]): Tree =
if (elems.isEmpty) Literal(())
else Apply(
Select(mkAttributedRef(TupleClass(elems.length).caseModule), nme.apply),
// tree1 AND tree2
def mkAnd(tree1: Tree, tree2: Tree): Tree =
Apply(Select(tree1, Boolean_and), List(tree2))
// tree1 OR tree2
def mkOr(tree1: Tree, tree2: Tree): Tree =
Apply(Select(tree1, Boolean_or), List(tree2))