package dotty.tools
package dotc
package core
import Periods._
import Names._
import Scopes._
import Flags._
import java.lang.AssertionError
import Decorators._
import Symbols._
import Contexts._
import SymDenotations._
import printing.Texts._
import printing.Printer
import Types._
import Annotations._
import util.Positions._
import DenotTransformers._
import StdNames._
import NameOps._
import ast.tpd.Tree
import ast.TreeTypeMap
import Denotations.{ Denotation, SingleDenotation, MultiDenotation }
import collection.mutable
import io.AbstractFile
import language.implicitConversions
import util.DotClass
/** Creation methods for symbols */
trait Symbols { this: Context =>
// ---- Factory methods for symbol creation ----------------------
//
// All symbol creations should be done via the next two methods.
/** Create a symbol without a denotation.
* Note this uses a cast instead of a direct type refinement because
* it's debug-friendlier not to create an anonymous class here.
*/
def newNakedSymbol[N <: Name](coord: Coord = NoCoord): Symbol { type ThisName = N } =
new Symbol(coord).asInstanceOf[Symbol { type ThisName = N }]
/** Create a class symbol without a denotation. */
def newNakedClassSymbol(coord: Coord = NoCoord, assocFile: AbstractFile = null) =
new ClassSymbol(coord, assocFile)
// ---- Symbol creation methods ----------------------------------
/** Create a symbol from a function producing its denotation */
def newSymbolDenoting[N <: Name](denotFn: Symbol => SymDenotation, coord: Coord = NoCoord): Symbol { type ThisName = N } = {
val sym = newNakedSymbol[N](coord)
sym.denot = denotFn(sym)
sym
}
/** Create a symbol from its fields (info may be lazy) */
def newSymbol[N <: Name](
owner: Symbol,
name: N,
flags: FlagSet,
info: Type,
privateWithin: Symbol = NoSymbol,
coord: Coord = NoCoord): Symbol { type ThisName = N } = {
val sym = newNakedSymbol[N](coord)
val denot = SymDenotation(sym, owner, name, flags, info, privateWithin)
sym.denot = denot
sym
}
/** Create a class symbol from a function producing its denotation */
def newClassSymbolDenoting(denotFn: ClassSymbol => SymDenotation, coord: Coord = NoCoord, assocFile: AbstractFile = null): ClassSymbol = {
val cls = newNakedClassSymbol(coord, assocFile)
cls.denot = denotFn(cls)
cls
}
/** Create a class symbol from its non-info fields and a function
* producing its info (the produced info may be lazy).
*/
def newClassSymbol(
owner: Symbol,
name: TypeName,
flags: FlagSet,
infoFn: ClassSymbol => Type,
privateWithin: Symbol = NoSymbol,
coord: Coord = NoCoord,
assocFile: AbstractFile = null): ClassSymbol
= {
val cls = newNakedClassSymbol(coord, assocFile)
val denot = SymDenotation(cls, owner, name, flags, infoFn(cls), privateWithin)
cls.denot = denot
cls
}
/** Create a class symbol from its non-info fields and the fields of its info. */
def newCompleteClassSymbol(
owner: Symbol,
name: TypeName,
flags: FlagSet,
parents: List[TypeRef],
decls: Scope = newScope,
selfInfo: Type = NoType,
privateWithin: Symbol = NoSymbol,
coord: Coord = NoCoord,
assocFile: AbstractFile = null): ClassSymbol =
newClassSymbol(
owner, name, flags,
ClassInfo(owner.thisType, _, parents, decls, selfInfo),
privateWithin, coord, assocFile)
/** Create a module symbol with associated module class
* from its non-info fields and a function producing the info
* of the module class (this info may be lazy).
*/
def newModuleSymbol(
owner: Symbol,
name: TermName,
modFlags: FlagSet,
clsFlags: FlagSet,
infoFn: (TermSymbol, ClassSymbol) => Type, // typically a ModuleClassCompleterWithDecls
privateWithin: Symbol = NoSymbol,
coord: Coord = NoCoord,
assocFile: AbstractFile = null): TermSymbol
= {
val base = owner.thisType
val module = newNakedSymbol[TermName](coord)
val modcls = newNakedClassSymbol(coord, assocFile)
val modclsFlags = clsFlags | ModuleClassCreationFlags
val modclsName = name.toTypeName.adjustIfModuleClass(modclsFlags)
val cdenot = SymDenotation(
modcls, owner, modclsName, modclsFlags,
infoFn(module, modcls), privateWithin)
val mdenot = SymDenotation(
module, owner, name, modFlags | ModuleCreationFlags,
if (cdenot.isCompleted) TypeRef.withSymAndName(owner.thisType, modcls, modclsName)
else new ModuleCompleter(modcls))
module.denot = mdenot
modcls.denot = cdenot
module
}
/** Create a module symbol with associated module class
* from its non-info fields and the fields of the module class info.
* @param flags The combined flags of the module and the module class
* These are masked with RetainedModuleValFlags/RetainedModuleClassFlags.
*/
def newCompleteModuleSymbol(
owner: Symbol,
name: TermName,
modFlags: FlagSet,
clsFlags: FlagSet,
parents: List[TypeRef],
decls: Scope,
privateWithin: Symbol = NoSymbol,
coord: Coord = NoCoord,
assocFile: AbstractFile = null): TermSymbol =
newModuleSymbol(
owner, name, modFlags, clsFlags,
(module, modcls) => ClassInfo(
owner.thisType, modcls, parents, decls, TermRef.withSymAndName(owner.thisType, module, name)),
privateWithin, coord, assocFile)
/** Create a package symbol with associated package class
* from its non-info fields and a lazy type for loading the package's members.
*/
def newPackageSymbol(
owner: Symbol,
name: TermName,
infoFn: (TermSymbol, ClassSymbol) => LazyType): TermSymbol =
newModuleSymbol(owner, name, PackageCreationFlags, PackageCreationFlags, infoFn)
/** Create a package symbol with associated package class
* from its non-info fields its member scope.
*/
def newCompletePackageSymbol(
owner: Symbol,
name: TermName,
modFlags: FlagSet = EmptyFlags,
clsFlags: FlagSet = EmptyFlags,
decls: Scope = newScope): TermSymbol =
newCompleteModuleSymbol(
owner, name,
modFlags | PackageCreationFlags, clsFlags | PackageCreationFlags,
Nil, decls)
/** Create a stub symbol that will issue a missing reference error
* when attempted to be completed.
*/
def newStubSymbol(owner: Symbol, name: Name, file: AbstractFile = null): Symbol = {
def stubCompleter = new StubInfo()
val normalizedOwner = if (owner is ModuleVal) owner.moduleClass else owner
println(s"creating stub for ${name.show}, owner = ${normalizedOwner.denot.debugString}, file = $file")
println(s"decls = ${normalizedOwner.decls.toList.map(_.debugString).mkString("\n ")}") // !!! DEBUG
//if (base.settings.debug.value) throw new Error()
val stub = name match {
case name: TermName =>
newModuleSymbol(normalizedOwner, name, EmptyFlags, EmptyFlags, stubCompleter, assocFile = file)
case name: TypeName =>
newClassSymbol(normalizedOwner, name, EmptyFlags, stubCompleter, assocFile = file)
}
stubs = stub :: stubs
stub
}
/** Create the local template dummy of given class `cls`.
* In a template
*
* trait T { val fld: Int; { val x: int = 2 }; val fld2 = { val y = 2; y }}
*
* the owner of `x` is the local dummy of the template. The owner of the local
* dummy is then the class of the template itself. By contrast, the owner of `y`
* would be `fld2`. There is a single local dummy per template.
*/
def newLocalDummy(cls: Symbol, coord: Coord = NoCoord) =
newSymbol(cls, nme.localDummyName(cls), EmptyFlags, NoType)
/** Create an import symbol pointing back to given qualifier `expr`. */
def newImportSymbol(expr: Tree, coord: Coord = NoCoord) =
newSymbol(NoSymbol, nme.IMPORT, EmptyFlags, ImportType(expr), coord = coord)
/** Create a class constructor symbol for given class `cls`. */
def newConstructor(cls: ClassSymbol, flags: FlagSet, paramNames: List[TermName], paramTypes: List[Type], privateWithin: Symbol = NoSymbol, coord: Coord = NoCoord) =
newSymbol(cls, nme.CONSTRUCTOR, flags | Method, MethodType(paramNames, paramTypes)(_ => cls.typeRef), privateWithin, coord)
/** Create an empty default constructor symbol for given class `cls`. */
def newDefaultConstructor(cls: ClassSymbol) =
newConstructor(cls, EmptyFlags, Nil, Nil)
/** Create a symbol representing a selftype declaration for class `cls`. */
def newSelfSym(cls: ClassSymbol, name: TermName = nme.WILDCARD, selfInfo: Type = NoType): TermSymbol =
ctx.newSymbol(cls, name, SelfSymFlags, selfInfo orElse cls.classInfo.selfType, coord = cls.coord)
/** Create new type parameters with given owner, names, and flags.
* @param boundsFn A function that, given type refs to the newly created
* parameters returns a list of their bounds.
*/
def newTypeParams(
owner: Symbol,
names: List[TypeName],
flags: FlagSet,
boundsFn: List[TypeRef] => List[Type]): List[TypeSymbol] = {
val tparamBuf = new mutable.ListBuffer[TypeSymbol]
val trefBuf = new mutable.ListBuffer[TypeRef]
for (name <- names) {
val tparam = newNakedSymbol[TypeName](NoCoord)
tparamBuf += tparam
trefBuf += TypeRef.withSymAndName(owner.thisType, tparam, name)
}
val tparams = tparamBuf.toList
val bounds = boundsFn(trefBuf.toList)
for ((name, tparam, bound) <- (names, tparams, bounds).zipped)
tparam.denot = SymDenotation(tparam, owner, name, flags | owner.typeParamCreationFlags, bound)
tparams
}
def newSkolem(tp: Type) = newSymbol(defn.RootClass, nme.SKOLEM, SyntheticArtifact | Permanent, tp)
def newErrorSymbol(owner: Symbol, name: Name) =
newSymbol(owner, name, SyntheticArtifact,
if (name.isTypeName) TypeAlias(ErrorType) else ErrorType)
/** Map given symbols, subjecting their attributes to the mappings
* defined in the given TreeTypeMap `ttmap`.
* Cross symbol references are brought over from originals to copies.
* Do not copy any symbols if all attributes of all symbols stay the same.
*/
def mapSymbols(originals: List[Symbol], ttmap: TreeTypeMap, mapAlways: Boolean = false): List[Symbol] =
if (originals.forall(sym =>
(ttmap.mapType(sym.info) eq sym.info) &&
!(ttmap.oldOwners contains sym.owner)) && !mapAlways)
originals
else {
val copies: List[Symbol] = for (original <- originals) yield
original match {
case original: ClassSymbol =>
newNakedClassSymbol(original.coord, original.assocFile)
case _ =>
newNakedSymbol[original.ThisName](original.coord)
}
val ttmap1 = ttmap.withSubstitution(originals, copies)
(originals, copies).zipped foreach {(original, copy) =>
copy.denot = original.denot // preliminary denotation, so that we can access symbols in subsequent transform
}
(originals, copies).zipped foreach {(original, copy) =>
val odenot = original.denot
val oinfo = original.info match {
case ClassInfo(pre, _, parents, decls, selfInfo) =>
assert(original.isClass)
ClassInfo(pre, copy.asClass, parents, decls, selfInfo)
case oinfo => oinfo
}
copy.denot = odenot.copySymDenotation(
symbol = copy,
owner = ttmap1.mapOwner(odenot.owner),
initFlags = odenot.flags &~ Frozen | Fresh,
info = ttmap1.mapType(oinfo),
privateWithin = ttmap1.mapOwner(odenot.privateWithin), // since this refers to outer symbols, need not include copies (from->to) in ownermap here.
annotations = odenot.annotations.mapConserve(ttmap1.apply))
}
copies
}
// ----- Locating predefined symbols ----------------------------------------
def requiredPackage(path: PreName): TermSymbol =
base.staticRef(path.toTermName).requiredSymbol(_ is Package).asTerm
def requiredClass(path: PreName): ClassSymbol =
base.staticRef(path.toTypeName).requiredSymbol(_.isClass).asClass
def requiredModule(path: PreName): TermSymbol =
base.staticRef(path.toTermName).requiredSymbol(_ is Module).asTerm
def requiredMethod(cls: ClassSymbol, name: PreName): TermSymbol =
cls.info.member(name.toTermName).requiredSymbol(_ is Method).asTerm
}
object Symbols {
var _nextId = 0 // !!! DEBUG, use global counter instead
def nextId = { _nextId += 1; _nextId }
/** A Symbol represents a Scala definition/declaration or a package.
*/
class Symbol private[Symbols] (val coord: Coord) extends DotClass with printing.Showable {
type ThisName <: Name
private[this] var _id: Int = nextId
//assert(_id != 30214)
/** The unique id of this symbol */
def id = _id
/** The last denotation of this symbol */
private[this] var lastDenot: SymDenotation = _
/** Set the denotation of this symbol */
private[core] def denot_=(d: SymDenotation) =
lastDenot = d
/** The current denotation of this symbol */
final def denot(implicit ctx: Context): SymDenotation = {
var denot = lastDenot
if (!(denot.validFor contains ctx.period)) {
denot = denot.current.asInstanceOf[SymDenotation]
lastDenot = denot
}
denot
}
private[core] def defRunId: RunId =
if (lastDenot == null) NoRunId else lastDenot.validFor.runId
/** Does this symbol come from a currently compiled source file? */
final def isDefinedInCurrentRun(implicit ctx: Context): Boolean = {
pos.exists && defRunId == ctx.runId
}
/** Subclass tests and casts */
final def isTerm(implicit ctx: Context): Boolean = denot.isTerm
final def isType(implicit ctx: Context): Boolean = denot.isType
final def isClass: Boolean = isInstanceOf[ClassSymbol]
final def asTerm(implicit ctx: Context): TermSymbol = { assert(isTerm, s"asTerm called on not-a-Term $this" ); asInstanceOf[TermSymbol] }
final def asType(implicit ctx: Context): TypeSymbol = { assert(isType, s"isType called on not-a-Type $this"); asInstanceOf[TypeSymbol] }
final def asClass: ClassSymbol = asInstanceOf[ClassSymbol]
final def isFresh(implicit ctx: Context) =
lastDenot != null && (lastDenot is Fresh)
/** Special cased here, because it may be used on naked symbols in substituters */
final def isStatic(implicit ctx: Context): Boolean =
lastDenot != null && denot.isStatic
/** A unique, densely packed integer tag for each class symbol, -1
* for all other symbols. To save memory, this method
* should be called only if class is a super class of some other class.
*/
def superId(implicit ctx: Context): Int = -1
/** This symbol entered into owner's scope (owner must be a class). */
final def entered(implicit ctx: Context): this.type = {
assert(this.owner.isClass, s"symbol ($this) entered the scope of non-class owner ${this.owner}") // !!! DEBUG
this.owner.asClass.enter(this)
if (this is Module) this.owner.asClass.enter(this.moduleClass)
this
}
/** Enter this symbol in its class owner after given `phase`. Create a fresh
* denotation for its owner class if the class has not yet already one
* that starts being valid after `phase`.
* @pre Symbol is a class member
*/
def enteredAfter(phase: DenotTransformer)(implicit ctx: Context): this.type =
if (ctx.phaseId != phase.next.id) enteredAfter(phase)(ctx.withPhase(phase.next))
else {
if (this.owner.is(Package)) {
denot.validFor |= InitialPeriod
if (this is Module) this.moduleClass.validFor |= InitialPeriod
}
else this.owner.asClass.ensureFreshScopeAfter(phase)
entered
}
/** This symbol, if it exists, otherwise the result of evaluating `that` */
def orElse(that: => Symbol)(implicit ctx: Context) =
if (this.exists) this else that
/** If this symbol satisfies predicate `p` this symbol, otherwise `NoSymbol` */
def filter(p: Symbol => Boolean): Symbol = if (p(this)) this else NoSymbol
/** Is this symbol a user-defined value class? */
final def isDerivedValueClass(implicit ctx: Context): Boolean =
false // will migrate to ValueClasses.isDerivedValueClass;
// unsupported value class code will continue to use this stub while it exists
/** The current name of this symbol */
final def name(implicit ctx: Context): ThisName = denot.name.asInstanceOf[ThisName]
/** The source or class file from which this class or
* the class containing this symbol was generated, null if not applicable.
* Overridden in ClassSymbol
*/
def associatedFile(implicit ctx: Context): AbstractFile =
denot.topLevelClass.symbol.associatedFile
/** The class file from which this class was generated, null if not applicable. */
final def binaryFile(implicit ctx: Context): AbstractFile =
pickFile(associatedFile, classFile = true)
/** The source file from which this class was generated, null if not applicable. */
final def sourceFile(implicit ctx: Context): AbstractFile =
pickFile(associatedFile, classFile = false)
/** Desire to re-use the field in ClassSymbol which stores the source
* file to also store the classfile, but without changing the behavior
* of sourceFile (which is expected at least in the IDE only to
* return actual source code.) So sourceFile has classfiles filtered out.
*/
private def pickFile(file: AbstractFile, classFile: Boolean): AbstractFile =
if ((file eq null) || classFile != (file.path endsWith ".class")) null else file
/** The position of this symbol, or NoPosition is symbol was not loaded
* from source.
*/
def pos: Position = if (coord.isPosition) coord.toPosition else NoPosition
// -------- GADT handling -----------------------------------------------
/** Perform given operation `op` where this symbol allows tightening of
* its type bounds.
*/
private[dotc] def withGADTFlexType[T](op: () => T)(implicit ctx: Context): () => T = { () =>
assert((denot is TypeParam) && denot.owner.isTerm)
val saved = denot
denot = denot.copySymDenotation(initFlags = denot.flags | GADTFlexType)
try op()
finally denot = saved
}
/** Disallow tightening of type bounds for this symbol from now on */
private[dotc] def resetGADTFlexType()(implicit ctx: Context): Unit = {
assert(denot is GADTFlexType)
denot = denot.copySymDenotation(initFlags = denot.flags &~ GADTFlexType)
}
/** Change info of this symbol to new, tightened type bounds */
private[core] def changeGADTInfo(bounds: TypeBounds)(implicit ctx: Context): Unit = {
assert(denot is GADTFlexType)
denot = denot.copySymDenotation(info = bounds)
}
// -------- Printing --------------------------------------------------------
/** The prefix string to be used when displaying this symbol without denotation */
protected def prefixString = "Symbol"
override def toString: String =
if (lastDenot == null) s"Naked$prefixString#$id"
else lastDenot.toString// +"#"+id // !!! DEBUG
def toText(printer: Printer): Text = printer.toText(this)
def showLocated(implicit ctx: Context): String = ctx.locatedText(this).show
def showDcl(implicit ctx: Context): String = ctx.dclText(this).show
def showKind(implicit ctx: Context): String = ctx.kindString(this)
def showName(implicit ctx: Context): String = ctx.nameString(this)
def showFullName(implicit ctx: Context): String = ctx.fullNameString(this)
}
type TermSymbol = Symbol { type ThisName = TermName }
type TypeSymbol = Symbol { type ThisName = TypeName }
class ClassSymbol private[Symbols] (coord: Coord, val assocFile: AbstractFile)
extends Symbol(coord) {
type ThisName = TypeName
/** The source or class file from which this class was generated, null if not applicable. */
override def associatedFile(implicit ctx: Context): AbstractFile =
if (assocFile != null || (this.owner is PackageClass)) assocFile
else super.associatedFile
final def classDenot(implicit ctx: Context): ClassDenotation =
denot.asInstanceOf[ClassDenotation]
private var superIdHint: Int = -1
override def superId(implicit ctx: Context): Int = {
val hint = superIdHint
if (hint >= 0 && hint <= ctx.lastSuperId && (ctx.classOfId(hint) eq this))
hint
else {
val id = ctx.superIdOfClass get this match {
case Some(id) =>
id
case None =>
val id = ctx.nextSuperId
ctx.superIdOfClass(this) = id
ctx.classOfId(id) = this
id
}
superIdHint = id
id
}
}
override protected def prefixString = "ClassSymbol"
}
class ErrorSymbol(val underlying: Symbol, msg: => String)(implicit ctx: Context) extends Symbol(NoCoord) {
type ThisName = underlying.ThisName
denot = underlying.denot
}
object NoSymbol extends Symbol(NoCoord) {
denot = NoDenotation
}
implicit class Copier[N <: Name](sym: Symbol { type ThisName = N })(implicit ctx: Context) {
/** Copy a symbol, overriding selective fields */
def copy(
owner: Symbol = sym.owner,
name: N = sym.name,
flags: FlagSet = sym.flags,
info: Type = sym.info,
privateWithin: Symbol = sym.privateWithin,
coord: Coord = sym.coord,
associatedFile: AbstractFile = sym.associatedFile): Symbol =
if (sym.isClass)
ctx.newClassSymbol(owner, name.asTypeName, flags, _ => info, privateWithin, coord, associatedFile)
else
ctx.newSymbol(owner, name, flags, info, privateWithin, coord)
}
implicit def defn(implicit ctx: Context): Definitions = ctx.definitions
/** Makes all denotation operations available on symbols */
implicit def toDenot(sym: Symbol)(implicit ctx: Context): SymDenotation = sym.denot
/** Makes all class denotations available on class symbols */
implicit def toClassDenot(cls: ClassSymbol)(implicit ctx: Context): ClassDenotation = cls.classDenot
var stubs: List[Symbol] = Nil // diagnostic
}
