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Symbols.scala
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Symbols.scala
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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
*/
package scala
package reflect
package internal
import scala.collection.immutable
import scala.collection.mutable.ListBuffer
import util.{ ReusableInstance, Statistics, shortClassOfInstance }
import Flags._
import scala.annotation.tailrec
import scala.reflect.io.{AbstractFile, NoAbstractFile}
import Variance._
trait Symbols extends api.Symbols { self: SymbolTable =>
import definitions._
import statistics._
protected var ids = 0
def getCurrentSymbolIdCount: Int = ids
protected def nextId() = { ids += 1; ids }
/** Used to keep track of the recursion depth on locked symbols */
private[this] var _recursionTable = immutable.Map.empty[Symbol, Int]
def recursionTable = _recursionTable
def recursionTable_=(value: immutable.Map[Symbol, Int]) = _recursionTable = value
private[this] var _lockedCount = 0
def lockedCount = this._lockedCount
def lockedCount_=(i: Int) = _lockedCount = i
@deprecated("Global existential IDs no longer used", "2.12.1")
private[this] var existentialIds = 0
@deprecated("Global existential IDs no longer used", "2.12.1")
protected def nextExistentialId() = { existentialIds += 1; existentialIds }
@deprecated("Use overload that accepts an id", "2.12.1")
protected def freshExistentialName(suffix: String): TypeName = freshExistentialName(suffix, nextExistentialId())
protected def freshExistentialName(suffix: String, id: Int): TypeName = newTypeName("_" + id + suffix)
// Set the fields which point companions at one another. Returns the module.
def connectModuleToClass(m: ModuleSymbol, moduleClass: ClassSymbol): ModuleSymbol = {
moduleClass.sourceModule = m
m setModuleClass moduleClass
m
}
/** Create a new free term. Its owner is NoSymbol.
*/
def newFreeTermSymbol(name: TermName, value: => Any, flags: Long = 0L, origin: String): FreeTermSymbol =
new FreeTermSymbol(name, value, origin) initFlags flags
/** Create a new free type. Its owner is NoSymbol.
*/
def newFreeTypeSymbol(name: TypeName, flags: Long = 0L, origin: String): FreeTypeSymbol =
new FreeTypeSymbol(name, origin) initFlags flags
/**
* This map stores the original owner the first time the owner of a symbol is re-assigned.
* The original owner of a symbol is needed in some places in the backend. Ideally, owners should
* be versioned like the type history.
*/
private[this] val originalOwnerMap = perRunCaches.newAnyRefMap[Symbol, Symbol]()
// TODO - don't allow the owner to be changed without checking invariants, at least
// when under some flag. Define per-phase invariants for owner/owned relationships,
// e.g. after flatten all classes are owned by package classes, there are lots and
// lots of these to be declared (or more realistically, discovered.)
// could be private since 2.11.6, but left protected to avoid potential breakages (eg ensime)
protected def saveOriginalOwner(sym: Symbol): Unit = {
// some synthetic symbols have NoSymbol as owner initially
if (sym.owner != NoSymbol) {
if (originalOwnerMap contains sym) ()
else defineOriginalOwner(sym, sym.rawowner)
}
}
def defineOriginalOwner(sym: Symbol, owner: Symbol): Unit = {
originalOwnerMap(sym) = owner
}
def symbolOf[T: WeakTypeTag]: TypeSymbol = weakTypeOf[T].typeSymbolDirect.asType
abstract class SymbolContextApiImpl extends SymbolApi {
this: Symbol =>
def isFreeTerm: Boolean = false
def asFreeTerm: FreeTermSymbol = throw new ScalaReflectionException(s"$this is not a free term")
def isFreeType: Boolean = false
def asFreeType: FreeTypeSymbol = throw new ScalaReflectionException(s"$this is not a free type")
def isExistential: Boolean = this.isExistentiallyBound
def isParamWithDefault: Boolean = this.hasDefault
// `isByNameParam` is only true for a call-by-name parameter of a *method*,
// an argument of the primary constructor seen in the class body is excluded by `isValueParameter`
def isByNameParam: Boolean = this.isValueParameter && (this hasFlag BYNAMEPARAM)
def isImplementationArtifact: Boolean = this hasFlag (BRIDGE | VBRIDGE | ARTIFACT)
def isJava: Boolean = isJavaDefined
def isField: Boolean = isTerm && !isModule && (!isMethod || owner.isTrait && isAccessor)
def isMutableVal = if (owner.isTrait) !hasFlag(STABLE) else isMutable
def isVal: Boolean = isField && !isMutableVal
def isVar: Boolean = isField && !isLazy && isMutableVal
def isAbstract: Boolean = isAbstractClass || isDeferred || isAbstractType
def isPrivateThis = this hasAllFlags (PRIVATE | LOCAL)
def isProtectedThis = this hasAllFlags (PROTECTED | LOCAL)
def isJavaEnum: Boolean = hasJavaEnumFlag
def isJavaAnnotation: Boolean = hasJavaAnnotationFlag
def isStaticAnnotation: Boolean =
initialize.hasJavaAnnotationFlag || isNonBottomSubClass(StaticAnnotationClass) && this != NowarnClass
def newNestedSymbol(name: Name, pos: Position, newFlags: Long, isClass: Boolean): Symbol = name match {
case n: TermName => newTermSymbol(n, pos, newFlags)
case n: TypeName => if (isClass) newClassSymbol(n, pos, newFlags) else newNonClassSymbol(n, pos, newFlags)
}
def knownDirectSubclasses = {
// See `getFlag` to learn more about the `isThreadsafe` call in the body of this method.
if (!isCompilerUniverse && !isThreadsafe(purpose = AllOps)) initialize
enclosingPackage.info.decls.foreach { sym =>
if(sourceFile == sym.sourceFile) {
sym.rawInfo.forceDirectSuperclasses()
}
}
if(!isPastTyper)
updateAttachment(KnownDirectSubclassesCalled)
children
}
def selfType = {
// See `getFlag` to learn more about the `isThreadsafe` call in the body of this method.
if (!isCompilerUniverse && !isThreadsafe(purpose = AllOps)) initialize
typeOfThis
}
def baseClasses = info.baseClasses
def module = sourceModule
def thisPrefix: Type = thisType
def superPrefix(supertpe: Type): Type = SuperType(thisType, supertpe)
// These two methods used to call fullyInitializeSymbol on `this`.
//
// The only positive effect of that is, to the best of my knowledge, convenient printing
// (if you print a signature of the symbol that's not fully initialized,
// you might end up with weird <?>'s in value/type params)
//
// Another effect is obviously full initialization of that symbol,
// but that one shouldn't be necessary from the public API standpoint,
// because everything that matters auto-initializes at runtime,
// and auto-initialization at compile-time is anyway dubious
// (I've had spurious cyclic refs caused by calling typeSignature
// that initialized parent, which was in the middle of initialization).
//
// Given that and also given the pressure of being uniform with info and infoIn,
// I've removed calls to fullyInitializeSymbol from typeSignature and typeSignatureIn,
// injected fullyInitializeSymbol in showDecl, and injected fullyInitializeType in runtime Type.toString
// (the latter will make things a bit harder to debug in runtime universe, because
// toString might now very rarely cause cyclic references, but we also have showRaw that doesn't do initialization).
//
// Auto-initialization in runtime Type.toString is one of the examples of why a cake-based design
// isn't a very good idea for reflection API. Sometimes we want to same pretty name for both a compiler-facing
// and a user-facing API that should have different behaviors (other examples here include isPackage, isCaseClass, etc).
// Within a cake it's fundamentally impossible to achieve that.
def typeSignature: Type = info
def typeSignatureIn(site: Type): Type = site memberInfo this
def toType: Type = tpe
def toTypeIn(site: Type): Type = site.memberType(this)
def toTypeConstructor: Type = typeConstructor
def setAnnotations(annots: AnnotationInfo*): this.type = { setAnnotations(annots.toList); this }
def getter: Symbol = getterIn(owner)
def setter: Symbol = setterIn(owner)
def companion: Symbol = {
if (isModule && !hasPackageFlag) companionSymbol
else if (isModuleClass && !isPackageClass) sourceModule.companionSymbol
else if (isClass && !isModuleClass && !isPackageClass) companionSymbol
else NoSymbol
}
def infoIn(site: Type): Type = typeSignatureIn(site)
def overrides: List[Symbol] = allOverriddenSymbols
def paramLists: List[List[Symbol]] = paramss
}
private[reflect] final case class SymbolKind(accurate: String, sanitized: String, abbreviation: String) {
def skolemize: SymbolKind = copy(accurate = s"$accurate skolem", abbreviation = s"$abbreviation#SKO")
}
protected def newStubSymbol(owner: Symbol,
name: Name,
missingMessage: String): Symbol = {
name match {
case n: TypeName => new StubClassSymbol(owner, n, missingMessage)
case _ => new StubTermSymbol(owner, name.toTermName, missingMessage)
}
}
/** The class for all symbols */
abstract class Symbol protected[Symbols] (initOwner: Symbol, initPos: Position, initName: Name)
extends SymbolContextApiImpl
with HasFlags
with Annotatable[Symbol]
with Attachable {
protected[this] final var _rawname = initName
// makes sure that all symbols that runtime reflection deals with are synchronized
private def isSynchronized = this.isInstanceOf[scala.reflect.runtime.SynchronizedSymbols#SynchronizedSymbol]
private def isAprioriThreadsafe = isThreadsafe(AllOps)
if (!(isCompilerUniverse || isSynchronized || isAprioriThreadsafe))
throw new AssertionError(s"unsafe symbol $initName (child of $initOwner) in runtime reflection universe") // Not an assert to avoid retention of `initOwner` as a field!
type AccessBoundaryType = Symbol
type AnnotationType = AnnotationInfo
// TODO - don't allow names to be renamed in this unstructured fashion.
// Rename as little as possible. Enforce invariants on all renames.
type TypeOfClonedSymbol >: Null <: Symbol { type NameType = Symbol.this.NameType }
final def rawname: NameType = _rawname.asInstanceOf[NameType]
final def name: NameType = if (needsFlatClasses) flattenedName else _rawname.asInstanceOf[NameType]
def name_=(n: Name): Unit = {
if (shouldLogAtThisPhase) {
def msg = s"In $owner, renaming $name -> $n"
if (isSpecialized) debuglog(msg) else log(msg)
}
}
protected[this] def flattenedName: NameType = rawname
def asNameType(n: Name): NameType
// Syncnote: need not be protected, as only assignment happens in owner_=, which is not exposed to api
// The null check is for NoSymbol, which can't pass a reference to itself to the constructor and also
// can't call owner_= due to an assertion it contains.
private[this] var _rawowner = if (initOwner eq null) this else initOwner
private[this] var _rawflags: Long = _
final def rawowner = _rawowner
final def rawflags = _rawflags
rawatt = initPos
final val id = nextId() // identity displayed when -uniqid
//assert(id != 3390, initName)
private[this] var _validTo: Period = NoPeriod
if (traceSymbolActivity)
traceSymbols.recordNewSymbol(this)
def validTo = _validTo
def validTo_=(x: Period): Unit = { _validTo = x}
def setName(name: Name): this.type = { this.name = asNameType(name) ; this }
// Update the surrounding scopes
protected[this] def changeNameInOwners(name: Name): Unit = {
if (owner.isClass) {
var ifs = owner.infos
while (ifs != null) {
ifs.info.decls.rehash(this, name)
ifs = ifs.prev
}
}
}
def rawFlagString(mask: Long): String = calculateFlagString(rawflags & mask)
def rawFlagString: String = rawFlagString(flagMask)
def debugFlagString: String = flagString(AllFlags)
/** String representation of symbol's variance */
def varianceString: String = variance.symbolicString
override def flagMask =
if (settings.isDebug && !isAbstractType) AllFlags
else if (owner.isRefinementClass) ExplicitFlags & ~OVERRIDE
else ExplicitFlags
// make the error message more googlable
def flagsExplanationString =
if (isGADTSkolem) " (this is a GADT skolem)"
else ""
def shortSymbolClass = shortClassOfInstance(this)
def symbolCreationString: String = (
"%s%25s | %-40s | %s".format(
if (settings.uniqid) "%06d | ".format(id) else "",
shortSymbolClass,
name.decode + " in " + owner,
rawFlagString
)
)
// ------ creators -------------------------------------------------------------------
final def newValue(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): TermSymbol =
newTermSymbol(name, pos, newFlags)
final def newVariable(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): TermSymbol =
newTermSymbol(name, pos, MUTABLE | newFlags)
final def newValueParameter(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): TermSymbol =
newTermSymbol(name, pos, PARAM | newFlags)
/** Create local dummy for template (owner of local blocks) */
final def newLocalDummy(pos: Position): TermSymbol =
newTermSymbol(nme.localDummyName(this), pos) setInfo NoType
final def newMethod(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): MethodSymbol =
createMethodSymbol(name, pos, METHOD | newFlags)
final def newMethodSymbol(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): MethodSymbol =
createMethodSymbol(name, pos, METHOD | newFlags)
final def newLabel(name: TermName, pos: Position = NoPosition): MethodSymbol =
newMethod(name, pos, LABEL)
/** Propagates ConstrFlags (JAVA, specifically) from owner to constructor. */
final def newConstructor(pos: Position, newFlags: Long = 0L): MethodSymbol =
newMethod(nme.CONSTRUCTOR, pos, getFlag(ConstrFlags) | newFlags)
/** Static constructor with info set. */
def newStaticConstructor(pos: Position): MethodSymbol =
newConstructor(pos, STATIC) setInfo UnitTpe
/** Instance constructor with info set. */
def newClassConstructor(pos: Position): MethodSymbol =
newConstructor(pos) setInfo MethodType(Nil, this.tpe)
def newLinkedModule(moduleClass: Symbol, newFlags: Long = 0L): ModuleSymbol = {
val m = newModuleSymbol(moduleClass.name.toTermName, moduleClass.pos, MODULE | newFlags)
connectModuleToClass(m, moduleClass.asInstanceOf[ClassSymbol])
}
final def newModule(name: TermName, pos: Position = NoPosition, newFlags0: Long = 0L): ModuleSymbol = {
val newFlags = newFlags0 | MODULE
val m = newModuleSymbol(name, pos, newFlags)
val clazz = newModuleClass(name.toTypeName, pos, newFlags & ModuleToClassFlags)
connectModuleToClass(m, clazz)
}
final def newPackage(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): ModuleSymbol = {
assert(name == nme.ROOT || isPackageClass, this)
newModule(name, pos, PackageFlags | newFlags)
}
final def newThisSym(name: TermName = nme.this_, pos: Position = NoPosition): TermSymbol =
newTermSymbol(name, pos, SYNTHETIC)
final def newImport(pos: Position): TermSymbol =
newTermSymbol(nme.IMPORT, pos)
final def newModuleSymbol(name: TermName, pos: Position = NoPosition, newFlags: Long = 0L): ModuleSymbol =
newTermSymbol(name, pos, newFlags).asInstanceOf[ModuleSymbol]
final def newModuleAndClassSymbol(name: Name, pos: Position, flags0: FlagSet): (ModuleSymbol, ClassSymbol) = {
val flags = flags0 | MODULE
val m = newModuleSymbol(name.toTermName, pos, flags)
val c = newModuleClass(name.toTypeName, pos, flags & ModuleToClassFlags)
connectModuleToClass(m, c)
(m, c)
}
final def newModuleClassSymbol(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): ModuleClassSymbol =
newClassSymbol(name, pos, newFlags).asInstanceOf[ModuleClassSymbol]
final def newTypeSkolemSymbol(name: TypeName, origin: AnyRef, pos: Position = NoPosition, newFlags: Long = 0L): TypeSkolem =
createTypeSkolemSymbol(name, origin, pos, newFlags)
/** @param pre type relative to which alternatives are seen.
* for instance:
* class C[T] {
* def m(x: T): T
* def m'(): T
* }
* val v: C[Int]
*
* Then v.m has symbol TermSymbol(flags = {OVERLOADED},
* tpe = OverloadedType(C[Int], List(m, m')))
* You recover the type of m doing a
*
* m.tpe.asSeenFrom(pre, C) (generally, owner of m, which is C here).
*
* or:
*
* pre.memberType(m)
*/
final def newOverloaded(pre: Type, alternatives: List[Symbol]): TermSymbol = {
val triedCookingFlag = if (alternatives.forall(_.hasFlag(TRIEDCOOKING))) TRIEDCOOKING else 0L
newTermSymbol(alternatives.head.name.toTermName, alternatives.head.pos, OVERLOADED | triedCookingFlag) setInfo OverloadedType(pre, alternatives)
}
final def newErrorValue(name: TermName): TermSymbol =
newTermSymbol(name, pos, SYNTHETIC | IS_ERROR) setInfo ErrorType
/** Symbol of a type definition type T = ...
*/
final def newAliasType(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): AliasTypeSymbol =
createAliasTypeSymbol(name, pos, newFlags)
/** Symbol of an abstract type type T >: ... <: ...
*/
final def newAbstractType(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): AbstractTypeSymbol =
createAbstractTypeSymbol(name, pos, DEFERRED | newFlags)
/** Symbol of a type parameter
*/
final def newTypeParameter(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): TypeSymbol =
newAbstractType(name, pos, PARAM | newFlags)
// is defined in SymbolCreations
// final def newTypeSymbol(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): TypeSymbol =
// (if ((newFlags & DEFERRED) != 0) new AbstractTypeSymbol(this, pos, name)
// else new AbstractTypeSymbol(this, pos, name)) setFlag newFlags
/** Symbol of an existential type T forSome { ... }
*/
final def newExistential(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): TypeSymbol =
newAbstractType(name, pos, EXISTENTIAL | newFlags)
private def freshNamer: () => TermName = {
var cnt = 0
() => { cnt += 1; nme.syntheticParamName(cnt) }
}
/** Synthetic value parameters when parameter symbols are not available.
* Calling this method multiple times will re-use the same parameter names.
*/
final def newSyntheticValueParams(argtypes: List[Type]): List[TermSymbol] =
newSyntheticValueParams(argtypes, freshNamer)
final def newSyntheticValueParams(argtypes: List[Type], freshName: () => TermName): List[TermSymbol] =
argtypes map (tp => newSyntheticValueParam(tp, freshName()))
/** Synthetic value parameter when parameter symbol is not available.
* Calling this method multiple times will re-use the same parameter name.
*/
final def newSyntheticValueParam(argtype: Type, name: TermName = nme.syntheticParamName(1)): TermSymbol =
newValueParameter(name, owner.pos.focus, SYNTHETIC) setInfo argtype
def newSyntheticTypeParam(name: String, newFlags: Long): TypeSymbol = newTypeParameter(newTypeName(name), NoPosition, newFlags) setInfo TypeBounds.empty
def newSyntheticTypeParams(num: Int): List[TypeSymbol] = (0 until num).toList map (n => newSyntheticTypeParam("T" + n, 0L))
/** Create a new existential type skolem with this symbol its owner,
* based on the given symbol and origin.
*/
def newExistentialSkolem(basis: Symbol, origin: AnyRef): TypeSkolem =
newExistentialSkolem(basis.name.toTypeName, basis.info, basis.flags, basis.pos, origin)
/** Create a new existential type skolem with this symbol its owner, and the given other properties.
*/
def newExistentialSkolem(name: TypeName, info: Type, flags: Long, pos: Position, origin: AnyRef): TypeSkolem = {
val skolem = newTypeSkolemSymbol(name.toTypeName, origin, pos, (flags | EXISTENTIAL) & ~PARAM)
skolem setInfo (info cloneInfo skolem)
}
// don't test directly -- use isGADTSkolem
// used to single out a gadt skolem symbol in deskolemizeGADT
// gadtskolems are created in adaptConstrPattern and removed at the end of typedCase
final protected[Symbols] def GADT_SKOLEM_FLAGS = CASEACCESSOR | SYNTHETIC
// flags set up to maintain TypeSkolem's invariant: origin.isInstanceOf[Symbol] == !hasFlag(EXISTENTIAL)
// GADT_SKOLEM_FLAGS (== CASEACCESSOR | SYNTHETIC) used to single this symbol out in deskolemizeGADT
// TODO: it would be better to allocate a new bit in the flag long for GADTSkolem rather than OR'ing together CASEACCESSOR | SYNTHETIC
def newGADTSkolem(name: TypeName, origin: Symbol, info: Type): TypeSkolem =
newTypeSkolemSymbol(name, origin, origin.pos, origin.flags & ~(EXISTENTIAL | PARAM) | GADT_SKOLEM_FLAGS) setInfo info
@deprecated("Use overload that accepts an id", "2.12.1")
final def freshExistential(suffix: String): TypeSymbol =
newExistential(freshExistentialName(suffix), pos)
final def freshExistential(suffix: String, id: Int): TypeSymbol =
newExistential(freshExistentialName(suffix, id), pos)
/** Type skolems are type parameters ''seen from the inside''
* Assuming a polymorphic method m[T], its type is a PolyType which has a TypeParameter
* with name `T` in its typeParams list. While type checking the parameters, result type and
* body of the method, there's a local copy of `T` which is a TypeSkolem.
*/
final def newTypeSkolem: TypeSkolem =
owner.newTypeSkolemSymbol(name.toTypeName, this, pos, flags)
final def newClass(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): ClassSymbol =
newClassSymbol(name, pos, newFlags)
/** A new class with its info set to a ClassInfoType with given scope and parents. */
def newClassWithInfo(name: TypeName, parents: List[Type], scope: Scope, pos: Position = NoPosition, newFlags: Long = 0L): ClassSymbol = {
val clazz = newClass(name, pos, newFlags)
clazz setInfo ClassInfoType(parents, scope, clazz)
}
final def newErrorClass(name: TypeName): ClassSymbol =
newClassWithInfo(name, Nil, new ErrorScope(this), pos, SYNTHETIC | IS_ERROR)
final def newModuleClass(name: TypeName, pos: Position = NoPosition, newFlags: Long = 0L): ModuleClassSymbol =
newModuleClassSymbol(name, pos, newFlags | MODULE)
final def newAnonymousFunctionClass(pos: Position = NoPosition, newFlags: Long = 0L): ClassSymbol =
newClassSymbol(tpnme.ANON_FUN_NAME, pos, FINAL | SYNTHETIC | newFlags)
final def newAnonymousFunctionValue(pos: Position, newFlags: Long = 0L): TermSymbol =
newTermSymbol(nme.ANON_FUN_NAME, pos, SYNTHETIC | newFlags) setInfo NoType
/** Refinement types P { val x: String; type T <: Number }
* also have symbols, they are refinementClasses
*/
final def newRefinementClass(pos: Position): RefinementClassSymbol =
createRefinementClassSymbol(pos, 0L)
final def newErrorSymbol(name: Name): Symbol = name match {
case x: TypeName => newErrorClass(x)
case x: TermName => newErrorValue(x)
}
/** Creates a placeholder symbol for when a name is encountered during
* unpickling for which there is no corresponding classfile. This defers
* failure to the point when that name is used for something, which is
* often to the point of never.
*/
def newStubSymbol(name: Name, missingMessage: String): Symbol = {
// Invoke the overridden `newStubSymbol` in Global that gives us access to typer
Symbols.this.newStubSymbol(this, name, missingMessage)
}
/** Given a field, construct a term symbol that represents the source construct that gave rise the field */
def sugaredSymbolOrSelf = {
val getter = getterIn(owner)
if (getter == NoSymbol) {
this
} else {
val result = owner.newValue(getter.name.toTermName, newFlags = getter.flags & ~Flags.METHOD).setPrivateWithin(getter.privateWithin).setInfo(getter.info.resultType)
val setter = setterIn(owner)
if (setter != NoSymbol) result.setFlag(Flags.MUTABLE)
result
}
}
// ----- locking and unlocking ------------------------------------------------------
// True if the symbol is unlocked.
// True if the symbol is locked but still below the allowed recursion depth.
// False otherwise
private[scala] def lockOK: Boolean = {
((_rawflags & LOCKED) == 0L) ||
((settings.Yrecursion.value != 0) &&
(recursionTable get this match {
case Some(n) => (n <= settings.Yrecursion.value)
case None => true }))
}
// Lock a symbol, using the handler if the recursion depth becomes too great.
private[scala] def lock(handler: => Unit): Boolean = {
if ((_rawflags & LOCKED) != 0L) {
if (settings.Yrecursion.value != 0) {
recursionTable get this match {
case Some(n) =>
if (n > settings.Yrecursion.value) {
handler
false
} else {
recursionTable += (this -> (n + 1))
true
}
case None =>
recursionTable += (this -> 1)
true
}
} else { handler; false }
} else {
_rawflags |= LOCKED
true
}
}
// Unlock a symbol
private[scala] def unlock() = {
if ((_rawflags & LOCKED) != 0L) {
_rawflags &= ~LOCKED
if (settings.Yrecursion.value != 0)
recursionTable -= this
}
}
// ----- tests ----------------------------------------------------------------------
def isAliasType = false
def isAbstractType = false
def isSkolem = false
/** A Type, but not a Class. */
def isNonClassType = false
/** The bottom classes are Nothing and Null, found in Definitions. */
def isBottomClass = false
/** These are all tests for varieties of ClassSymbol, which has these subclasses:
* - ModuleClassSymbol
* - RefinementClassSymbol
* - PackageClassSymbol (extends ModuleClassSymbol)
*/
def isAbstractClass = false
def isAnonOrRefinementClass = false
def isAnonymousClass = false
def isCaseClass = false
def isConcreteClass = false
@deprecated("trait implementation classes have been removed in Scala 2.12", "2.12.0")
def isImplClass = false
def isJavaInterface = false
def isNumericValueClass = false
def isPrimitiveValueClass = false
def isRefinementClass = false
override def isTrait = false
/** Qualities of Types, always false for TermSymbols.
*/
def isContravariant = false
def isCovariant = false
def isExistentialSkolem = false
def isExistentiallyBound = false
def isGADTSkolem = false
def isTypeParameter = false
def isTypeParameterOrSkolem = false
def isTypeSkolem = false
def isInvariant = !isCovariant && !isContravariant
/** Qualities of Terms, always false for TypeSymbols.
*/
def isAccessor = false
def isBridge = false
def isCapturedVariable = false
def isClassConstructor = false
def isConstructor = false
def isEarlyInitialized = false
def isGetter = false
def isDefaultGetter = false
def isLocalDummy = false
def isMixinConstructor = false
def isOverloaded = false
def isSetter = false
def isSetterParameter = false
def isValue = false
def isValueParameter = false
def isVariable = false
def isTermMacro = false
/** Qualities of MethodSymbols, always false for TypeSymbols
* and other TermSymbols.
*/
def isCaseAccessorMethod = false
def isLiftedMethod = false
def isSourceMethod = false
def isVarargsMethod = false
override def isLabel = false
/** Package/package object tests */
def isPackageClass = false
def isPackageObject = false
def isPackageObjectClass = false
def isPackageObjectOrClass = isPackageObject || isPackageObjectClass
def isModuleOrModuleClass = isModule || isModuleClass
/** Overridden in custom objects in Definitions */
def isRoot = false
def isRootPackage = false
def isRootSymbol = false // RootPackage and RootClass. TODO: also NoSymbol.
def isEmptyPackage = false
def isEmptyPackageClass = false
/** Is this symbol an effective root for fullname string?
*/
def isEffectiveRoot = false
/** Can this symbol only be subclassed by bottom classes? This is assessed
* to be the case if it is final, and any type parameters are invariant.
*/
def hasOnlyBottomSubclasses = {
@tailrec
def loop(tparams: List[Symbol]): Boolean = tparams match {
case Nil => true
case x :: xs => x.variance.isInvariant && loop(xs)
}
isClass && isFinal && loop(typeParams)
}
final def isOverridableMember = !(isClass || isEffectivelyFinal || isTypeParameter) && safeOwner.isClass
/** Does this symbol denote a wrapper created by the repl? */
final def isInterpreterWrapper = isTopLevel && nme.isReplWrapperName(name)
/** In our current architecture, symbols for top-level classes and modules
* are created as dummies. Package symbols just call newClass(name) or newModule(name) and
* consider their job done.
*
* In order for such a dummy to provide meaningful info (e.g. a list of its members),
* it needs to go through unpickling. Unpickling is a process of reading Scala metadata
* from ScalaSignature annotations and assigning it to symbols and types.
*
* A single unpickling session takes a top-level class or module, parses the ScalaSignature annotation
* and then reads metadata for the unpicklee, its companion (if any) and all their members recursively
* (i.e. the pickle not only contains info about directly nested classes/modules, but also about
* classes/modules nested into those and so on).
*
* Unpickling is triggered automatically whenever info (info in compiler parlance) is called.
* This happens because package symbols assign completer thunks to the dummies they create.
* Therefore metadata loading happens lazily and transparently.
*
* Almost transparently. Unfortunately metadata isn't limited to just signatures (i.e. lists of members).
* It also includes flags (which determine e.g. whether a class is sealed or not), annotations and privateWithin.
* This gives rise to unpleasant effects like in scala/bug#6277, when a flag test called on an uninitialize symbol
* produces incorrect results.
*
* One might think that the solution is simple: automatically call the completer
* whenever one needs flags, annotations and privateWithin - just like it's done for info.
* Unfortunately, this leads to weird crashes in scalac, and currently we can't attempt
* to fix the core of the compiler risk stability a few weeks before the final release.
* upd. Haha, "a few weeks before the final release". This surely sounds familiar :)
*
* However we do need to fix this for runtime reflection, since this idiosyncrasy is not something
* we'd like to expose to reflection users. Therefore a proposed solution is to check whether we're in a
* runtime reflection universe, and if yes and if we've not yet loaded the requested info, then to commence initialization.
*/
def getFlag(mask: Long): Long = {
mask & (if ((mask & PhaseIndependentFlags) == mask) rawflags else flags)
}
/** Does symbol have ANY flag in `mask` set? */
final def hasFlag(mask: Long): Boolean = getFlag(mask) != 0
/** Does symbol have ALL the flags in `mask` set? */
final def hasAllFlags(mask: Long): Boolean = getFlag(mask) == mask
def setFlag(mask: Long): this.type = { _rawflags |= mask ; this }
def resetFlag(mask: Long): this.type = { _rawflags &= ~mask ; this }
def resetFlags(): Unit = { rawflags = 0 }
/** Default implementation calls the generic string function, which
* will print overloaded flags as <flag1/flag2/flag3>. Subclasses
* of Symbol refine.
*/
override def resolveOverloadedFlag(flag: Long): String = Flags.flagToString(flag)
/** Set the symbol's flags to the given value, asserting
* that the previous value was 0.
*/
def initFlags(mask: Long): this.type = {
assert(rawflags == 0L, symbolCreationString)
_rawflags = mask
this
}
final def flags: Long = {
flags(phase.flagMask)
}
private[reflect] final def flags(phaseFlagMask: Long): Long = {
val fs = _rawflags & phaseFlagMask
(fs | ((fs & LateFlags) >>> LateShift)) & ~((fs & AntiFlags) >>> AntiShift)
}
def flags_=(fs: Long) = _rawflags = fs
def rawflags_=(x: Long): Unit = { _rawflags = x }
final def hasGetter = isTerm && nme.isLocalName(name)
/**
* Nested modules with a non-static owner receive the METHOD flag during UnCurry's info transform.
* (They are replaced by a ClassDef and DefDef for the module accessor during the fields phase.)
*
* Note: the METHOD flag is added lazily in the info transformer of the UnCurry phase.
* This means that forcing the `sym.info` may change the value of `sym.isMethod`. Forcing the
* info is in the responsibility of the caller. Doing it eagerly here was tried (0ccdb151f) but
* has proven to lead to bugs (scala/bug#8907).
*
* Here's an example where one can see all four of FF FT TF TT for (isStatic, isMethod) at
* various phases.
*
* trait A1 { case class Quux() }
* object A2 extends A1 { object Flax }
* // -- namer object Quux in trait A1
* // -M flatten object Quux in trait A1
* // S- flatten object Flax in object A2
* // -M posterasure object Quux in trait A1
* // -M jvm object Quux in trait A1
* // SM jvm object Quux in object A2
*
* So "isModuleNotMethod" exists not for its achievement in brevity, but to encapsulate the
* relevant condition.
*/
def isModuleNotMethod = isModule && !isMethod
// After RefChecks, the `isStatic` check is mostly redundant: all non-static modules should
// be methods (and vice versa). There's a corner case on the vice-versa with mixed-in module
// symbols:
// trait T { object A }
// object O extends T
// The module symbol A is cloned into T$impl (addInterfaces), and then cloned into O (mixin).
// Since the original A is not static, it's turned into a method. The clone in O however is
// static (owned by a module), but it's also a method.
def isStaticModule = isModuleNotMethod && isStatic
final def isInitializedToDefault = !isType && hasAllFlags(DEFAULTINIT | ACCESSOR)
final def isThisSym = isTerm && owner.thisSym == this
final def isError = hasFlag(IS_ERROR)
final def isErroneous = isError || isInitialized && tpe_*.isErroneous
def isHigherOrderTypeParameter = owner.isTypeParameterOrSkolem
// class C extends D( { class E { ... } ... } ). Here, E is a class local to a constructor
def isClassLocalToConstructor = false
final def isDerivedValueClass =
isClass && !hasFlag(PACKAGE | TRAIT) &&
!phase.erasedTypes && info.firstParent.typeSymbol == AnyValClass && !isPrimitiveValueClass
final def isMethodWithExtension =
isMethod && owner.isDerivedValueClass && !isParamAccessor && !isConstructor && !hasFlag(SUPERACCESSOR) && !isMacro && !isSpecialized
final def isAnonymousFunction = isSynthetic && (name containsName tpnme.ANON_FUN_NAME)
final def isDelambdafyFunction = isSynthetic && (name containsName tpnme.DELAMBDAFY_LAMBDA_CLASS_NAME)
final def isDelambdafyTarget = isArtifact && isMethod && hasAttachment[DelambdafyTarget.type]
final def isDefinedInPackage = effectiveOwner.isPackageClass
final def needsFlatClasses = phase.flatClasses && (rawowner ne NoSymbol) && !rawowner.isPackageClass && !isMethod
// TODO introduce a flag for these?
final def isPatternTypeVariable: Boolean =
isAbstractType && !isExistential && !isTypeParameterOrSkolem && isLocalToBlock
/** change name by appending $$<fully-qualified-name-of-class `base`>
* Do the same for any accessed symbols to preserve serialization compatibility.
* Implementation in TermSymbol.
*/
def expandName(base: Symbol): Unit = ()
// In java.lang, Predef, or scala package/package object
def isInDefaultNamespace = UnqualifiedOwners(effectiveOwner)
/** The owner, skipping package objects.
*/
def effectiveOwner = owner.skipPackageObject
/** If this is a package object or its implementing class, its owner: otherwise this.
*/
def skipPackageObject: Symbol = this
/** The package object symbol corresponding to this package or package class symbol, or NoSymbol otherwise */
@tailrec
final def packageObject: Symbol =
if (isPackageClass) tpe.packageObject
else if (hasPackageFlag) moduleClass.packageObject
else NoSymbol
/** If this is a constructor, its owner: otherwise this.
*/
final def skipConstructor: Symbol = if (isConstructor) owner else this
/** Conditions where we omit the prefix when printing a symbol, to avoid
* unpleasantries like Predef.String, $read.$iw.Foo and <empty>.Bippy.
*/
final def isOmittablePrefix = /*!settings.debug.value &&*/ {
// scala/bug#5941 runtime reflection can have distinct symbols representing `package scala` (from different mirrors)
// We check equality by FQN here to make sure we omit prefixes uniformly for all of them.
def matches(sym1: Symbol, sym2: Symbol) = (sym1 eq sym2) || (sym1.hasPackageFlag && sym2.hasPackageFlag && sym1.name == sym2.name && sym1.fullNameString == sym2.fullNameString)
val skipped = skipPackageObject
UnqualifiedOwners.exists((sym: Symbol) => matches(sym, skipped)) || isEmptyPrefix
}
def isEmptyPrefix = (
isEffectiveRoot // has no prefix for real, <empty> or <root>
|| isAnonOrRefinementClass // has uninteresting <anon> or <refinement> prefix
|| nme.isReplWrapperName(name) // $read.$iw.Foo or $read.INSTANCE.$iw.Foo
)
def isFBounded = info match {
case TypeBounds(_, _) => info.baseTypeSeq exists (_ contains this)
case _ => false
}
/** Is symbol a monomorphic type?
* assumption: if a type starts out as monomorphic, it will not acquire
* type parameters in later phases.
*/
final def isMonomorphicType =
isType && {
val info = originalInfo
( (info eq null)
|| (info.isComplete && !info.isHigherKinded)
)
}
@tailrec
final def isStrictFP: Boolean = this != NoSymbol && !isDeferred && (hasAnnotation(ScalaStrictFPAttr) || originalOwner.isStrictFP)
def isSerializable = info.baseClasses.exists(_ == SerializableClass)
def isDeprecated = hasAnnotation(DeprecatedAttr) || (isJava && hasAnnotation(JavaDeprecatedAttr))
def deprecationMessage = getAnnotation(DeprecatedAttr) flatMap (_ stringArg 0)
def deprecationVersion = getAnnotation(DeprecatedAttr) flatMap (_ stringArg 1)
def deprecatedParamName = getAnnotation(DeprecatedNameAttr) flatMap (ann => ann.symbolArg(0).orElse(ann.stringArg(0).map(newTermName)).orElse(Some(nme.NO_NAME)))
def deprecatedParamVersion = getAnnotation(DeprecatedNameAttr) flatMap (_ stringArg 1)
def hasDeprecatedInheritanceAnnotation
= hasAnnotation(DeprecatedInheritanceAttr)
def deprecatedInheritanceMessage
= getAnnotation(DeprecatedInheritanceAttr) flatMap (_ stringArg 0)
def deprecatedInheritanceVersion
= getAnnotation(DeprecatedInheritanceAttr) flatMap (_ stringArg 1)
def hasDeprecatedOverridingAnnotation
= hasAnnotation(DeprecatedOverridingAttr)
def deprecatedOverridingMessage
= getAnnotation(DeprecatedOverridingAttr) flatMap (_ stringArg 0)
def deprecatedOverridingVersion
= getAnnotation(DeprecatedOverridingAttr) flatMap (_ stringArg 1)
// !!! when annotation arguments are not literal strings, but any sort of
// assembly of strings, there is a fair chance they will turn up here not as
// Literal(const) but some arbitrary AST. However nothing in the compiler
// prevents someone from writing a @migration annotation with a calculated
// string. So this needs attention. For now the fact that migration is
// private[scala] ought to provide enough protection.
def hasMigrationAnnotation = hasAnnotation(MigrationAnnotationClass)
def migrationMessage = getAnnotation(MigrationAnnotationClass) flatMap { _.stringArg(0) }
def migrationVersion = getAnnotation(MigrationAnnotationClass) flatMap { _.stringArg(1) }
def elisionLevel = getAnnotation(ElidableMethodClass) flatMap { _.intArg(0) }
def implicitNotFoundMsg = getAnnotation(ImplicitNotFoundClass).flatMap(_.stringArg(0))
def implicitAmbiguousMsg = getAnnotation(ImplicitAmbiguousClass) flatMap { _.stringArg(0) }
def isCompileTimeOnly = hasAnnotation(CompileTimeOnlyAttr)
def compileTimeOnlyMessage = getAnnotation(CompileTimeOnlyAttr) flatMap (_ stringArg 0)
def isExperimental = hasAnnotation(ExperimentalAnnotationClass)
/** Is this symbol an accessor method for outer? */
final def isOuterAccessor = hasFlag(STABLE | ARTIFACT) && (unexpandedName == nme.OUTER)
/** Is this symbol an accessor method for outer? */
final def isOuterField = isArtifact && (unexpandedName == nme.OUTER_LOCAL)
/** Is this symbol an outer parameter in a constructor */
final def isOuterParam = isParameter && owner.isConstructor && (name == nme.OUTER_ARG || name == nme.OUTER)
/** Does this symbol denote a stable value, ignoring volatility?
*
* Stability and volatility are checked separately to allow volatile paths in patterns that amount to equality checks. scala/bug#6815
*/
final def isStable = isTerm && !isMutable && !(hasFlag(BYNAMEPARAM)) && (!isMethod || hasStableFlag)
final def hasVolatileType = tpe.isVolatile && !hasAnnotation(uncheckedStableClass)
/** Does this symbol denote the primary constructor of its enclosing class? */
final def isPrimaryConstructor =
isConstructor && owner.primaryConstructor == this
/** Does this symbol denote an auxiliary constructor of its enclosing class? */
final def isAuxiliaryConstructor =
isConstructor && !isPrimaryConstructor
/** Is this symbol a synthetic apply or unapply method in a companion object of a case class? */
// xeno-by: why this obscure use of the CASE flag? why not simply compare name with nme.apply and nme.unapply?
// dnw: "fixed in Dotty"? In Scala 3 unapply methods don't use the CASE flag.
final def isCaseApplyOrUnapply =
isMethod && isCase && isSynthetic
/** Is this symbol a synthetic copy method in a case class? */
final def isCaseCopy =
isMethod && owner.isCase && isSynthetic && name == nme.copy
final def isModuleVar = hasFlag(MODULEVAR)
final def isScala3Defined = hasFlag(SCALA3X)
/**
* Is this symbol static (i.e. with no outer instance)?
* Q: When exactly is a sym marked as STATIC?
* A: If it's a member of a toplevel object, or of an object contained in a toplevel object, or
* any number of levels deep.
* https://groups.google.com/group/scala-internals/browse_thread/thread/d385bcd60b08faf6
*
* TODO: should this only be invoked on class / module symbols? because there's also `isStaticMember`.
*
* Note: the result of `isStatic` changes over time.
* - Lambdalift local definitions to the class level, the `owner` field is modified.
* object T { def foo { object O } }
* After lambdalift, the OModule.isStatic is true.
*
* - After flatten, nested classes are moved to the package level. Invoking `owner` on a
* class returns a package class, for which `isStaticOwner` is true. For example,
* class C { object O }
* OModuleClass.isStatic is true after flatten. Using phase travel to get before flatten,
* method `owner` returns the class C.
*
* Why not make a stable version of `isStatic`? Maybe some parts of the compiler depend on the
* current implementation.
*/
def isStatic = (this hasFlag STATIC) || owner.isStaticOwner