package dotty.tools.dotc
package core
import util.HashSet
import Symbols._
import TypeComparers._
import Flags._
import Names._
import Scopes._
import Constants._
import Contexts._
import Annotations._
import SymDenotations._
import Denotations._
import Periods._
import scala.util.hashing.{ MurmurHash3 => hashing }
import collection.mutable
object Types {
/** A hash value indicating that the underlying type is not
* cached in uniques.
*/
final val NotCached = 0
/** An alternative value returned from `hash` if the
* computed hashCode would be `NotCached`.
*/
private final val NotCachedAlt = Int.MinValue
/** The class of types.
* The principal subclasses and sub-objects are as follows:
*
* Type -+- ProxyType --+- NamedType ----+--- TypeRef
* | | \
* | +- SingletonType---+- TermRef
* | |
* | +- SingletonType --+- ThisType
* | +- SuperType
* | +- ConstantType
* | +- MethodParam
* | +- RefinedThis
* | +- TypeBounds
* | +- ExprType
* | +- AnnotatedType
* +- GroundType -+- PolyParam
* +- AppliedType
* +- RefinedType
* +- AndType
* +- OrType
* +- MethodType -----+- ImplicitMethodType
* | +- JavaMethodType
* +- PolyType
* +- ClassInfo
* |
* +- NoType
* +- ErrorType
* +- WildcardType
*/
abstract class Type extends DotClass {
/** The type symbol associated with the type */
final def typeSymbol(implicit ctx: Context): Symbol = this match {
case tp: TypeRef => tp.symbol
case tp: ClassInfo => tp.classd.symbol
case _ => NoSymbol
}
/** The term symbol associated with the type */
final def termSymbol(implicit ctx: Context): Symbol = this match {
case tp: TermRef => tp.symbol
case _ => NoSymbol
}
/** Does this type denote a stable reference (i.e. singleton type)? */
final def isStable(implicit ctx: Context): Boolean = this match {
case tp: TermRef => tp.prefix.isStable && tp.termSymbol.isStable
case _: SingletonType => true
case _ => false
}
/** A type T is a legal prefix in a type selection T#A if
* T is stable or T contains no uninstantiated type variables.
*/
final def isLegalPrefix(implicit ctx: Context): Boolean =
isStable || abstractTypeNames(this).isEmpty
/** The set of names that denote an abstract type member of this type
* which is also an abstract type member of `pre`
*/
final def abstractTypeNames(pre: Type)(implicit ctx: Context): Set[Name] =
memberNames(pre, abstractTypeNameFilter)
/** The set of names that denote an abstract term member of this type
* which is also an abstract term member of `pre`
*/
final def abstractTermNames(pre: Type)(implicit ctx: Context): Set[Name] =
memberNames(pre, abstractTermNameFilter)
/** The set of names that denote an abstract member of this type
* which is also an abstract member of `pre`
*/
final def abstractMemberNames(pre: Type)(implicit ctx: Context): Set[Name] =
abstractTypeNames(pre) | abstractTermNames(pre)
/** The set of names of members of this type that pass the given name filter
* when seen as members of `pre`. More precisely, these are all
* of members `name` such that `keepOnly(pre, name)` is `true`.
*/
final def memberNames(pre: Type, keepOnly: NameFilter)(implicit ctx: Context): Set[Name] = this match {
case tp: ClassInfo =>
tp.classd.memberNames(keepOnly) filter (keepOnly(pre, _))
case tp: RefinedType =>
tp.parent.memberNames(pre, keepOnly) ++ (tp.names filter (keepOnly(pre, _))).toSet
case tp: AndType =>
tp.tp1.memberNames(pre, keepOnly) | tp.tp2.memberNames(pre, keepOnly)
case tp: OrType =>
tp.tp1.memberNames(pre, keepOnly) & tp.tp2.memberNames(pre, keepOnly)
case tp: TypeProxy =>
tp.underlying.memberNames(pre, keepOnly)
case _ =>
Set()
}
/** Is this type a TypeBounds instance, with lower and upper bounds
* that are not identical?
*/
final def isRealTypeBounds: Boolean = this match {
case tp: TypeBounds => tp.lo ne tp.hi
case _ => false
}
/** This type seen as a TypeBounds */
final def bounds(implicit ctx: Context): TypeBounds = this match {
case tp: TypeBounds => tp
case _ => TypeBounds(this, this)
}
/** A type is volatile if it has an underlying type of the
* form P1 with ... with Pn { decls } (where n may be 1 or decls may
* be empty), one of the parent types Pi is an abstract type, and
* either decls or a different parent Pj, j != i, contributes
* an abstract member.
*
* A type contributes an abstract member if it has an abstract member which
* is also a member of the whole refined type. A scope `decls` contributes
* an abstract member if it has an abstract definition which is also
* a member of the whole type.
*
* Lazy values are not allowed to have volatile type, as otherwise
* unsoundness can result.
*/
final def isVolatile(implicit ctx: Context): Boolean =
ctx.isVolatile(this)
/** Is this type guaranteed not to have `null` as a value? */
final def isNotNull: Boolean = false
/** Is this type produced as a repair for an error? */
final def isError(implicit ctx: Context): Boolean =
(typeSymbol is Erroneous) || (termSymbol is Erroneous)
/** Is some part of this type produced as a repair for an error? */
final def isErroneous(implicit ctx: Context): Boolean = exists(_.isError)
/** Returns true if there is a part of this type that satisfies predicate `p`.
*/
final def exists(p: Type => Boolean): Boolean =
new ExistsAccumulator(p)(false, this)
/** Substitute all types that refer in their symbol attribute to
* one of the symbols in `from` by the corresponding types in `to`
*/
final def subst(from: List[Symbol], to: List[Type])(implicit ctx: Context): Type =
if (from.isEmpty) this
else {
val from1 = from.tail
if (from1.isEmpty) ctx.subst1(this, from.head, to.head, null)
else {
val from2 = from1.tail
if (from2.isEmpty) ctx.subst2(this, from.head, to.head, from.tail.head, to.tail.head, null)
else ctx.subst(this, from, to, null)
}
}
/** Substitute all types of the form `PolyParam(from, N)` by
* `PolyParam(to, N)`.
*/
final def subst(from: PolyType, to: PolyType)(implicit ctx: Context): Type =
ctx.subst(this, from, to, null)
/** Substitute all types of the form `MethodParam(from, N)` by
* `MethodParam(to, N)`.
*/
final def subst(from: MethodType, to: MethodType)(implicit ctx: Context): Type =
if (from.isDependent) ctx.subst(this, from, to, null)
else this
/** Substitute all occurrences of `This(clazz)` by `tp` */
final def substThis(clazz: ClassSymbol, tp: Type)(implicit ctx: Context): Type =
ctx.substThis(this, clazz, tp, null)
/** Substitute all occurrences of `RefinedThis(from)` by `tp` */
final def substThis(from: RefinedType, tp: Type)(implicit ctx: Context): Type =
ctx.substThis(this, from, tp, null)
/** For a ClassInfo type, its parents,
* For an AndType, its operands,
* For an applied type, the instantiated parents of its base type.
* Inherited by all type proxies. Empty for all other types.
* Overwritten in ClassInfo, where parents is cached.
*/
def parents(implicit ctx: Context): List[Type] = this match {
case tp: AppliedType =>
val tycon = tp.tycon
tycon.parents.mapConserve(_.subst(tycon.typeParams, tp.targs))
case tp: AndType =>
def components(tp: Type): List[Type] = tp match {
case AndType(tp1, tp2) => components(tp1) ++ components(tp2)
case _ => List(tp)
}
components(tp)
case tp: TypeProxy =>
tp.underlying.parents
case _ => List()
}
/** The normalized prefix of this type is:
* For an alias type, the normalized prefix of its alias
* For all other named type and class infos: the prefix.
* Inherited by all other type proxies.
* `NoType` for all other types.
*/
final def normalizedPrefix(implicit ctx: Context): Type = this match {
case tp: NamedType =>
if (tp.isAbstractType) tp.info.normalizedPrefix else tp.prefix
case tp: ClassInfo =>
tp.prefix
case tp: TypeProxy =>
tp.underlying.normalizedPrefix
case _ =>
NoType
}
/** The scope of all declarations of this type.
* Defined by ClassInfo, inherited by type proxies.
* Empty scope for all other types.
*/
final def decls(implicit ctx: Context): Scope = this match {
case tp: ClassInfo =>
tp.classd.decls
case tp: TypeProxy =>
tp.underlying.decls
case _ =>
EmptyScope
}
/** The declaration of this type with given name */
final def decl(name: Name)(implicit ctx: Context): Denotation =
findDecl(name, this, Flags.Empty)
/** The non-private declaration of this type with given name */
final def nonPrivateDecl(name: Name)(implicit ctx: Context): Denotation =
findDecl(name, this, Flags.Private)
/** The non-private declaration of this type with given name */
final def findDecl(name: Name, pre: Type, excluded: FlagSet)(implicit ctx: Context): Denotation = this match {
case tp: RefinedType =>
tp.findDecl(name, pre)
case tp: ClassInfo =>
tp.classd.decls
.denotsNamed(name)
.filterAccessibleFrom(pre)
.filterExcluded(excluded)
.asSeenFrom(pre, tp.classd.symbol)
.toDenot
case tp: TypeProxy =>
tp.underlying.findDecl(name, pre, excluded)
}
/** The member of this type with given name */
final def member(name: Name)(implicit ctx: Context): Denotation =
findMember(name, this, Flags.Empty)
/** The non-private member of this type with given name */
final def nonPrivateMember(name: Name)(implicit ctx: Context): Denotation =
findMember(name, this, Flags.Private)
/** Find member of this type with given name and
* produce a denotation that contains the type of the member
* as seen from given prefix `pre`. Exclude all members with one
* of the flags in `excluded` from consideration.
*/
final def findMember(name: Name, pre: Type, excluded: FlagSet)(implicit ctx: Context): Denotation = this match {
case tp: RefinedType =>
tp.parent.findMember(name, pre, excluded | Flags.Private) &
tp.findDecl(name, pre)
case tp: TypeProxy =>
tp.underlying.findMember(name, pre, excluded)
case tp: ClassInfo =>
val classd = tp.classd
val candidates = classd.membersNamed(name)
val results = candidates
.filterAccessibleFrom(pre)
.filterExcluded(excluded)
.asSeenFrom(pre, classd.symbol)
if (results.exists) results.toDenot
else new ErrorDenotation // todo: refine
case tp: AndType =>
tp.tp1.findMember(name, pre, excluded) & tp.tp2.findMember(name, pre, excluded)
case tp: OrType =>
(tp.tp1.findMember(name, pre, excluded) | tp.tp2.findMember(name, pre, excluded))(pre)
}
/** Is this type a subtype of that type? */
final def <:<(that: Type)(implicit ctx: Context): Boolean =
ctx.typeComparer.isSubType(this, that)
/** Is this type the same as that type?
* This is the case iff `this <:< that` and `that <:< this`.
*/
final def =:=(that: Type)(implicit ctx: Context): Boolean =
ctx.typeComparer.isSameType(this, that)
/** Is this type close enough to that type so that members
* with the two type would override each other?
* This means:
* - Either both types are polytypes with the same number of
* type parameters and their result types match after renaming
* corresponding type parameters
* - Or both types are (possibly nullary) method types with equivalent type parameter types
* and matching result types
* - Or both types are equivalent
* - Or phase.erasedTypes is false and both types are neither method nor
* poly types.
*/
def matches(that: Type)(implicit ctx: Context): Boolean =
ctx.typeComparer.matchesType(this, that, !ctx.phase.erasedTypes)
/** Does this type match that type
*
*/
/** The info of `sym`, seen as a member of this type. */
final def memberInfo(denot: SymDenotation)(implicit ctx: Context): Type = {
denot.info.asSeenFrom(this, denot.owner)
}
/** Widen from singleton type to its underlying non-singleton
* base type by applying one or more `underlying` dereferences,
* identity for all other types. Example:
*
* class Outer { class C ; val x: C }
* val o: Outer
* <o.x.type>.widen = o.C
*/
final def widen(implicit ctx: Context): Type = this match {
case tp: SingletonType => tp.underlying.widen
case _ => this
}
/** Widen from constant type to its underlying non-constant
* base type.
*/
final def deconst: Type = this match {
case tp: ConstantType => tp.value.tpe
case _ => this
}
//def resultType: Type = ???
/** The base classes of this type as determined by ClassDenotation.
* Inherited by all type proxies.
* `Nil` for all other types.
*/
final def baseClasses(implicit ctx: Context): List[ClassSymbol] = this match {
case tp: TypeProxy =>
tp.underlying.baseClasses
case tp: ClassInfo =>
tp.classd.baseClasses
case _ => Nil
}
final def asSeenFrom(pre: Type, clazz: Symbol)(implicit ctx: Context): Type =
if (clazz.isStaticMono ||
ctx.erasedTypes && clazz != defn.ArrayClass ||
(pre eq clazz.thisType)) this
else ctx.asSeenFrom(this, pre, clazz, null)
/** The signature of this type. This is by default NullSignature,
* but is overridden for PolyTypes, MethodTypes, and TermRefWithSignature types.
* (the reason why we deviate from the "final-method-with-pattern-match-in-base-class"
* pattern is that method signatures use caching, so encapsulation
* is improved using an OO scheme).
*/
def signature: Signature = NullSignature
final def baseType(base: Symbol)(implicit ctx: Context): Type = base.denot match {
case classd: ClassDenotation => classd.baseTypeOf(this)
case _ => NoType
}
/** The type parameters of this type are:
* For a ClassInfo type, the type parameters of its denotation.
* For an applied type, the type parameters of its constructor
* that have not been instantiated yet.
* Inherited by type proxies.
* Empty list for all other types.
*/
final def typeParams(implicit ctx: Context): List[TypeSymbol] = this match {
case tp: AppliedType =>
def loop(tparams: List[TypeSymbol], targs: List[Type]): List[TypeSymbol] = tparams match {
case tparam :: tparams1 =>
if (targs.isEmpty) tparams
else if (targs.head eq NoType) loop(tparams1, targs.tail)
else tparam :: loop(tparams1, targs.tail)
case _ =>
Nil
}
loop(tp.tycon.typeParams, tp.targs)
case tp: TypeProxy =>
tp.underlying.typeParams
case tp: ClassInfo =>
tp.classd.typeParams
case _ => Nil
}
/** The type arguments of this type are:
* For an Applied type, its type arguments.
* Inherited by type proxies.
* Empty list for all other types.
*/
final def typeArgs(implicit ctx: Context): List[Type] = this match {
case tp: AppliedType =>
tp.targs
case tp: TypeProxy =>
tp.underlying.typeArgs
case _ => Nil
}
final def isWrong: Boolean = !exists // !!! needed?
final def exists: Boolean = true
final def &(that: Type)(implicit ctx: Context): Type =
ctx.glb(this, that)
def |(that: Type)(implicit ctx: Context): Type =
ctx.lub(this, that)
def show(implicit ctx: Context): String = ctx.printer.show(this)
// ----- hashing ------------------------------------------------------
/** customized hash code of this type.
* NotCached for uncached types. Cached types
* compute hash and use it as the type's hashCode.
*/
def hash: Int
protected def hashSeed = getClass.hashCode
private def finishHash(hashCode: Int, arity: Int): Int = {
val h = hashing.finalizeHash(hashCode, arity)
if (h == NotCached) NotCachedAlt else h
}
private def finishHash(seed: Int, arity: Int, tp: Type): Int = {
val elemHash = tp.hash
if (elemHash == NotCached) return NotCached
finishHash(hashing.mix(seed, elemHash), arity + 1)
}
private def finishHash(seed: Int, arity: Int, tps: List[Type]): Int = {
var h = seed
var xs = tps
var len = arity
while (xs.nonEmpty) {
val elemHash = xs.head.hash
if (elemHash == NotCached) return NotCached
h = hashing.mix(h, elemHash)
xs = xs.tail
len += 1
}
finishHash(h, len)
}
private def finishHash(seed: Int, arity: Int, tp: Type, tps: List[Type]): Int = {
val elemHash = tp.hash
if (elemHash == NotCached) return NotCached
finishHash(hashing.mix(seed, elemHash), arity + 1, tps)
}
protected def doHash(x: Any): Int =
finishHash(hashing.mix(hashSeed, x.hashCode), 1)
protected def doHash(tp: Type): Int =
finishHash(hashSeed, 0, tp)
protected def doHash(tp1: Type, tp2: Type): Int = {
val elemHash = tp1.hash
if (elemHash == NotCached) return NotCached
finishHash(hashing.mix(hashSeed, elemHash), 1, tp2)
}
protected def doHash(x1: Any, tp2: Type): Int =
finishHash(hashing.mix(hashSeed, x1.hashCode), 1, tp2)
protected def doHash(tp1: Type, tps2: List[Type]): Int =
finishHash(hashSeed, 0, tp1, tps2)
protected def doHash(x1: Any, tp2: Type, tps3: List[Type]): Int =
finishHash(hashing.mix(hashSeed, x1.hashCode), 1, tp2, tps3)
} // end Type
/** A marker trait for cached types */
trait CachedType extends Type
def unique[T <: Type](tp: T)(implicit ctx: Context): T = {
if (tp.hash == NotCached) tp
else ctx.root.uniques.findEntryOrUpdate(tp).asInstanceOf[T]
}
/** A marker trait for type proxies.
* Each implementation is expected to redefine the `underlying` method.
*/
abstract class TypeProxy extends Type {
/** The type to which this proxy forwards operations. */
def underlying(implicit ctx: Context): Type
}
// Every type has to inherit one of the following four abstract type classes.,
// which determine whether the type is cached, and whether
// it is a proxy of some other type. The duplication in their methods
// is for efficiency.
/** Instances of this class are cached and are not proxies. */
abstract class CachedGroundType extends Type with CachedType {
final val hash = computeHash
override final def hashCode = hash
def computeHash: Int
}
/** Instances of this class are cached and are proxies. */
abstract class CachedProxyType extends TypeProxy with CachedType {
final val hash = computeHash
override final def hashCode = hash
def computeHash: Int
}
/** Instances of this class are uncached and are not proxies. */
abstract class UncachedGroundType extends Type {
final def hash = NotCached
}
/** Instances of this class are uncached and are proxies. */
abstract class UncachedProxyType extends TypeProxy {
final def hash = NotCached
}
/** A marker trait for types that are guaranteed to contain only a
* single non-null value (they might contain null in addition).
*/
trait SingletonType extends TypeProxy
// --- NamedTypes ------------------------------------------------------------------
/** A NamedType of the form Prefix # name
*/
abstract class NamedType extends CachedProxyType {
val prefix: Type
val name: Name
private[this] var lastDenotation: Denotation = null
private def checkPrefix(sym: Symbol) =
sym.isAbstractType || sym.isClass
/** The denotation currently denoted by this type */
def denot(implicit ctx: Context): Denotation = {
val validPeriods =
if (lastDenotation != null) lastDenotation.validFor else Nowhere
if (!(validPeriods contains ctx.period)) {
val thisPeriod = ctx.period
lastDenotation =
if (validPeriods.runId == thisPeriod.runId) {
lastDenotation.current
} else {
val d = loadDenot
if (d.exists || ctx.phaseId == FirstPhaseId) {
if (checkPrefix(d.symbol) && !prefix.isLegalPrefix)
throw new MalformedType(prefix, d.symbol)
d
} else {// name has changed; try load in earlier phase and make current
denot(ctx.withPhase(ctx.phaseId - 1)).current
}
}
}
lastDenotation
}
protected def loadDenot(implicit ctx: Context) = prefix.member(name)
def isType = name.isTypeName
def isTerm = name.isTermName
def symbol(implicit ctx: Context): Symbol = denot.symbol
def info(implicit ctx: Context): Type = denot.info
override def underlying(implicit ctx: Context): Type = info
def isAbstractType(implicit ctx: Context) = info.isRealTypeBounds
def derivedNamedType(prefix: Type, name: Name)(implicit ctx: Context): Type =
if (prefix eq this.prefix) this
else NamedType(prefix, name)
override def computeHash = doHash(name, prefix)
}
abstract case class TermRef(override val prefix: Type, name: TermName) extends NamedType with SingletonType
abstract case class TypeRef(override val prefix: Type, name: TypeName) extends NamedType
trait NamedNoPrefix extends NamedType {
protected val fixedSym: Symbol
override def symbol(implicit ctx: Context): Symbol = fixedSym
override def info(implicit ctx: Context): Type = fixedSym.info
override def denot(implicit ctx: Context): Denotation = fixedSym.denot
}
final class TermRefNoPrefix(val fixedSym: TermSymbol)(implicit ctx: Context)
extends TermRef(NoPrefix, fixedSym.name) with NamedNoPrefix {
}
final class TermRefWithSignature(prefix: Type, name: TermName, override val signature: Signature) extends TermRef(prefix, name) {
override def computeHash = doHash((name, signature), prefix)
override def loadDenot(implicit ctx: Context): Denotation =
super.loadDenot.atSignature(signature)
}
final class TypeRefNoPrefix(val fixedSym: TypeSymbol)(implicit ctx: Context)
extends TypeRef(NoPrefix, fixedSym.name) with NamedNoPrefix {
}
final class CachedTermRef(prefix: Type, name: TermName) extends TermRef(prefix, name)
final class CachedTypeRef(prefix: Type, name: TypeName) extends TypeRef(prefix, name)
object NamedType {
def apply(prefix: Type, name: Name)(implicit ctx: Context) =
if (name.isTermName) TermRef(prefix, name.asTermName)
else TypeRef(prefix, name.asTypeName)
}
object TermRef {
def apply(prefix: Type, name: TermName)(implicit ctx: Context) =
unique(new CachedTermRef(prefix, name))
def apply(sym: TermSymbol)(implicit ctx: Context) =
unique(new TermRefNoPrefix(sym))
def apply(prefix: Type, name: TermName, signature: Signature)(implicit ctx: Context) =
unique(new TermRefWithSignature(prefix, name, signature))
}
object TypeRef {
def apply(prefix: Type, name: TypeName)(implicit ctx: Context) =
unique(new CachedTypeRef(prefix, name))
def apply(sym: TypeSymbol)(implicit ctx: Context) =
unique(new TypeRefNoPrefix(sym))
}
// --- Other SingletonTypes: ThisType/SuperType/ConstantType ---------------------------
abstract case class ThisType(clazz: ClassSymbol) extends CachedProxyType with SingletonType {
override def underlying(implicit ctx: Context) = clazz.typeOfThis
override def computeHash = doHash(clazz)
}
final class CachedThisType(clazz: ClassSymbol) extends ThisType(clazz)
object ThisType {
def apply(clazz: ClassSymbol)(implicit ctx: Context) =
unique(new CachedThisType(clazz))
}
abstract case class SuperType(thistpe: Type, supertpe: Type) extends CachedProxyType with SingletonType {
override def underlying(implicit ctx: Context) = supertpe
def derivedSuperType(thistp: Type, supertp: Type)(implicit ctx: Context) =
if ((thistp eq thistpe) && (supertp eq supertpe)) this
else SuperType(thistp, supertp)
override def computeHash = doHash(thistpe, supertpe)
}
final class CachedSuperType(thistpe: Type, supertpe: Type) extends SuperType(thistpe, supertpe)
object SuperType {
def apply(thistpe: Type, supertpe: Type)(implicit ctx: Context) =
unique(new CachedSuperType(thistpe, supertpe))
}
abstract case class ConstantType(value: Constant) extends CachedProxyType with SingletonType {
override def underlying(implicit ctx: Context) = value.tpe
override def computeHash = doHash(value)
}
final class CachedConstantType(value: Constant) extends ConstantType(value)
object ConstantType {
def apply(value: Constant)(implicit ctx: Context) =
unique(new CachedConstantType(value))
}
// --- AppliedType -----------------------------------------------------------------
/** An applied type of the form tycon[..targs].
* ..targs must match the length to tycon.typeParams.
* Missing type arguments are represented by NoType.
*/
abstract case class AppliedType(tycon: Type, targs: List[Type]) extends CachedProxyType {
override def underlying(implicit ctx: Context) = tycon
def derivedAppliedType(tycon: Type, targs: List[Type])(implicit ctx: Context): Type =
if ((tycon eq this.tycon) && (targs eq this.targs)) this
else AppliedType(tycon, targs)
override def computeHash = doHash(tycon, targs)
}
final class CachedAppliedType(tycon: Type, targs: List[Type]) extends AppliedType(tycon, targs)
object AppliedType {
def apply(tycon: Type, targs: List[Type])(implicit ctx: Context) =
unique(new CachedAppliedType(tycon, targs))
def make(tycon: Type, targs: List[Type])(implicit ctx: Context) =
if (targs.isEmpty) tycon else apply(tycon, targs)
}
// --- Refined Type ---------------------------------------------------------
case class RefinedType(parent: Type, names: List[Name])(infosExpr: RefinedType => List[Type]) extends CachedProxyType {
override def underlying(implicit ctx: Context) = parent
lazy val infos = infosExpr(this)
def derivedRefinedType(parent1: Type, names1: List[Name], infos1: List[Type])(implicit ctx: Context): RefinedType =
if ((parent1 eq parent) && (names1 eq names) && (infos1 eq infos)) this
else
RefinedType(parent1, names1) { rt =>
val thistp = RefinedThis(rt)
infos1 map (_.substThis(this, thistp))
}
def findDecl(name: Name, pre: Type)(implicit ctx: Context): Denotation = {
var ns = names
var is = infos
var denot: Denotation = NoDenotation
while (ns.nonEmpty && (denot eq NoDenotation)) {
if (ns.head == name)
denot = new JointRefDenotation(NoSymbol, is.head.substThis(this, pre), Period.allInRun(ctx.runId))
ns = ns.tail
is = is.tail
}
denot
}
override def computeHash = doHash(names, parent, infos)
}
// --- AndType/OrType ---------------------------------------------------------------
abstract case class AndType(tp1: Type, tp2: Type) extends CachedGroundType {
type This <: AndType
def derivedAndType(t1: Type, t2: Type)(implicit ctx: Context) =
if ((t1 eq tp1) && (t2 eq tp2)) this
else AndType(t1, t2)
override def computeHash = doHash(tp1, tp2)
}
final class CachedAndType(tp1: Type, tp2: Type) extends AndType(tp1, tp2)
object AndType {
def apply(tp1: Type, tp2: Type)(implicit ctx: Context) =
unique(new CachedAndType(tp1, tp2))
}
abstract case class OrType(tp1: Type, tp2: Type) extends CachedGroundType {
def derivedOrType(t1: Type, t2: Type)(implicit ctx: Context) =
if ((t1 eq tp1) && (t2 eq tp2)) this
else OrType(t1, t2)
override def computeHash = doHash(tp1, tp2)
}
final class CachedOrType(tp1: Type, tp2: Type) extends OrType(tp1, tp2)
object OrType {
def apply(tp1: Type, tp2: Type)(implicit ctx: Context) =
unique(new CachedOrType(tp1, tp2))
}
// ----- Method types: MethodType/ExprType/PolyType/MethodParam/PolyParam ---------------
// Note: method types are cached whereas poly types are not.
// The reason is that most poly types are cyclic via poly params,
// and therefore two different poly types would never be equal.
abstract case class MethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type) extends CachedGroundType {
lazy val resultType = resultTypeExp(this)
def isJava = false
def isImplicit = false
lazy val isDependent = resultType exists {
case MethodParam(mt, _) => mt eq this
case _ => false
}
override lazy val signature: List[TypeName] = {
def paramSig(tp: Type): TypeName = ???
val followSig = resultType match {
case rtp: MethodType => rtp.signature
case _ => Nil
}
(paramTypes map paramSig) ++ followSig
}
def derivedMethodType(paramNames: List[TermName], paramTypes: List[Type], restpe: Type)(implicit ctx: Context) =
if ((paramNames eq this.paramNames) && (paramTypes eq this.paramTypes) && (restpe eq this.resultType)) this
else {
val restpeExpr = (x: MethodType) => restpe.subst(this, x)
if (isJava) JavaMethodType(paramNames, paramTypes)(restpeExpr)
else if (isImplicit) ImplicitMethodType(paramNames, paramTypes)(restpeExpr)
else MethodType(paramNames, paramTypes)(restpeExpr)
}
def instantiate(argTypes: List[Type])(implicit ctx: Context): Type =
if (isDependent) new InstMethodMap(this, argTypes) apply resultType
else resultType
override def computeHash = doHash(paramNames, resultType, paramTypes)
}
final class CachedMethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)
extends MethodType(paramNames, paramTypes)(resultTypeExp)
final class JavaMethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)
extends MethodType(paramNames, paramTypes)(resultTypeExp) {
override def isJava = true
}
final class ImplicitMethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)
extends MethodType(paramNames, paramTypes)(resultTypeExp) {
override def isImplicit = true
}
object MethodType {
def apply(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)(implicit ctx: Context) =
unique(new CachedMethodType(paramNames, paramTypes)(resultTypeExp))
}
def JavaMethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)(implicit ctx: Context) =
unique(new JavaMethodType(paramNames, paramTypes)(resultTypeExp))
def ImplicitMethodType(paramNames: List[TermName], paramTypes: List[Type])(resultTypeExp: MethodType => Type)(implicit ctx: Context) =
unique(new ImplicitMethodType(paramNames, paramTypes)(resultTypeExp))
abstract case class ExprType(resultType: Type) extends CachedProxyType {
override def underlying(implicit ctx: Context): Type = resultType
override def signature: Signature = Nil
def derivedExprType(rt: Type)(implicit ctx: Context) =
if (rt eq resultType) this else ExprType(rt)
override def computeHash = doHash(resultType)
}
final class CachedExprType(resultType: Type) extends ExprType(resultType)
object ExprType {
def apply(resultType: Type)(implicit ctx: Context) =
unique(new CachedExprType(resultType))
}
case class PolyType(paramNames: List[TypeName])(paramBoundsExp: PolyType => List[TypeBounds], resultTypeExp: PolyType => Type) extends UncachedGroundType {
lazy val paramBounds = paramBoundsExp(this)
lazy val resultType = resultTypeExp(this)
override def signature = resultType.signature
def instantiate(argTypes: List[Type])(implicit ctx: Context): Type =
new InstPolyMap(this, argTypes) apply resultType
def derivedPolyType(paramNames: List[TypeName], paramBounds: List[TypeBounds], restpe: Type)(implicit ctx: Context) =
if ((paramNames eq this.paramNames) && (paramBounds eq this.paramBounds) && (restpe eq this.resultType)) this
else
PolyType(paramNames)(
x => paramBounds mapConserve (_.substBounds(this, x)),
x => restpe.subst(this, x))
// need to override hashCode and equals to be object identity
// because paramNames by itself is not discriminatory enough
override def hashCode = System.identityHashCode(this)
override def equals(other: Any) = other match {
case that: PolyType => this eq that
case _ => false
}
}
case class MethodParam(mt: MethodType, paramNum: Int) extends UncachedProxyType with SingletonType {
override def underlying(implicit ctx: Context) = mt.paramTypes(paramNum)
override def hashCode = doHash(System.identityHashCode(mt) + paramNum)
}
case class RefinedThis(rt: RefinedType) extends UncachedProxyType with SingletonType {
override def underlying(implicit ctx: Context) = rt.parent
override def hashCode = doHash(System.identityHashCode(rt))
}
case class PolyParam(pt: PolyType, paramNum: Int) extends UncachedProxyType {
override def underlying(implicit ctx: Context) = pt.paramBounds(paramNum).hi
// no hashCode needed because cycle is broken in PolyType
}
// ------ ClassInfo, Type Bounds ------------------------------------------------------------
abstract case class ClassInfo(prefix: Type, classd: ClassDenotation) extends CachedGroundType {
def typeTemplate(implicit ctx: Context): Type =
classd.typeTemplate asSeenFrom (prefix, classd.symbol)
def typeConstructor(implicit ctx: Context): Type =
NamedType(prefix, classd.symbol.name)
// cached because baseType needs parents
private var parentsCache: List[Type] = null
override def parents(implicit ctx: Context): List[Type] = {
if (parentsCache == null)
parentsCache = classd.parents.mapConserve(_.substThis(classd.symbol, prefix))
parentsCache
}
override def computeHash = doHash(classd.symbol, prefix)
}
final class CachedClassInfo(prefix: Type, classd: ClassDenotation) extends ClassInfo(prefix, classd)
object ClassInfo {
def apply(prefix: Type, classd: ClassDenotation)(implicit ctx: Context) =
unique(new CachedClassInfo(prefix, classd))
}
abstract case class TypeBounds(lo: Type, hi: Type) extends CachedProxyType {
override def underlying(implicit ctx: Context): Type = hi
def derivedTypeBounds(lo1: Type, hi1: Type)(implicit ctx: Context) =
if ((lo1 eq lo) && (hi1 eq hi)) this
else TypeBounds(lo, hi)
def &(that: TypeBounds)(implicit ctx: Context): TypeBounds =
TypeBounds(this.lo | that.lo, this.hi & that.hi)
def |(that: TypeBounds)(implicit ctx: Context): TypeBounds =
TypeBounds(this.lo & that.lo, this.hi | that.hi)
def substBounds(from: PolyType, to: PolyType)(implicit ctx: Context) =
subst(from, to).asInstanceOf[TypeBounds]
def map(f: Type => Type)(implicit ctx: Context): TypeBounds =
TypeBounds(f(lo), f(hi))
override def computeHash = doHash(lo, hi)
}
final class CachedTypeBounds(lo: Type, hi: Type) extends TypeBounds(lo, hi)
object TypeBounds {
def apply(lo: Type, hi: Type)(implicit ctx: Context) =
unique(new CachedTypeBounds(lo, hi))
}
// ----- AnnotatedTypes -----------------------------------------------------------
case class AnnotatedType(annots: List[Annotation], tpe: Type) extends UncachedProxyType {
override def underlying(implicit ctx: Context): Type = tpe
def derivedAnnotatedType(annots1: List[Annotation], tpe1: Type) =
if ((annots1 eq annots) && (tpe1 eq tpe)) this
else AnnotatedType.make(annots1, tpe1)
}
object AnnotatedType {
def make(annots: List[Annotation], underlying: Type) =
if (annots.isEmpty) underlying
else AnnotatedType(annots, underlying)
}
// Special type objects ------------------------------------------------------------
case object NoType extends UncachedGroundType {
def symbol = NoSymbol
def info = NoType
}
/** Cached for efficiency because hashing is faster */
case object NoPrefix extends CachedGroundType {
override def computeHash = hashSeed
}
abstract class ErrorType extends UncachedGroundType
object ErrorType extends ErrorType
case object WildcardType extends UncachedGroundType
// ----- TypeMaps --------------------------------------------------------------------
abstract class TypeMap(implicit ctx: Context) extends (Type => Type) {
def apply(tp: Type): Type
def applyToBounds(tp: TypeBounds): TypeBounds =
apply(tp: Type).asInstanceOf[TypeBounds]
/** Map this function over given type */
def mapOver(tp: Type): Type = tp match {
case tp: NamedType =>
tp.derivedNamedType(this(tp.prefix), tp.name)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _) => tp
case tp @ AppliedType(tycon, targs) =>
tp.derivedAppliedType(this(tycon), targs mapConserve this)
case tp @ PolyType(pnames) =>
tp.derivedPolyType(
pnames, tp.paramBounds mapConserve applyToBounds, this(tp.resultType))
case tp @ MethodType(pnames, ptypes) =>
tp.derivedMethodType(pnames, ptypes mapConserve this, this(tp.resultType))
case tp @ ExprType(restpe) =>
tp.derivedExprType(this(restpe))
case tp @ SuperType(thistp, supertp) =>
tp.derivedSuperType(this(thistp), this(supertp))
case tp @ TypeBounds(lo, hi) =>
if (lo eq hi) {
val lo1 = this(lo)
tp.derivedTypeBounds(lo1, lo1)
} else {
tp.derivedTypeBounds(this(lo), this(hi))
}
case tp @ RefinedType(parent, names) =>
tp.derivedRefinedType(this(parent), names, tp.infos mapConserve this)
case tp @ AnnotatedType(annots, underlying) =>
tp.derivedAnnotatedType(mapOverAnnotations(annots), this(underlying))
case _ =>
tp
}
def mapOverAnnotations(annots: List[Annotation]): List[Annotation] = ???
}
class InstMethodMap(mt: MethodType, argtypes: List[Type])(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp match {
case MethodParam(`mt`, n) => argtypes(n)
case _ => mapOver(tp)
}
}
class InstPolyMap(pt: PolyType, argtypes: List[Type])(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp match {
case PolyParam(`pt`, n) => argtypes(n)
case _ => mapOver(tp)
}
}
class InstRefinedMap(rt: RefinedType)(implicit ctx: Context) extends TypeMap {
def apply(tp: Type) = tp match {
case RefinedThis(`rt`) => rt.parent
case _ => mapOver(tp)
}
}
// ----- TypeAccumulators ----------------------------------------------------
abstract class TypeAccumulator[T] extends ((T, Type) => T) {
def apply(x: T, tp: Type): T
def apply(x: T, annot: Annotation): T = ???
def foldOver(x: T, tp: Type): T = tp match {
case tp: NamedType =>
this(x, tp.prefix)
case ThisType(_)
| MethodParam(_, _)
| PolyParam(_, _)
| ConstantType(_)
| NoPrefix => x
case AppliedType(tycon, targs) =>
(this(x, tycon) /: targs)(this)
case tp @ PolyType(pnames) =>
this((x /: tp.paramBounds)(this), tp.resultType)
case tp @ MethodType(pnames, ptypes) =>
this((x /: ptypes)(this), tp.resultType)
case ExprType(restpe) =>
this(x, restpe)
case SuperType(thistp, supertp) =>
this(this(x, thistp), supertp)
case TypeBounds(lo, hi) =>
this(this(x, lo), hi)
case tp @ RefinedType(parent, names) =>
(this(x, parent) /: tp.infos)(apply)
case AnnotatedType(annots, underlying) =>
this((x /: annots)(apply), underlying)
case _ => x
}
}
class ExistsAccumulator(p: Type => Boolean) extends TypeAccumulator[Boolean] {
def apply(x: Boolean, tp: Type) = x || p(tp) || foldOver(x, tp)
}
// ----- Name Filters --------------------------------------------------
/** A name filter selects or discards a member name of a type `pre`.
* To enable efficient caching, name filters have to satisfy the
* following invariant: If `keep` is a name filter, and `pre` has
* class `C` as a base class, then
*
* keep(pre, name) => keep(C.this, name)
*/
abstract class NameFilter {
def apply(pre: Type, name: Name)(implicit ctx: Context): Boolean
}
/** A filter for names of abstract types of a given type */
object abstractTypeNameFilter extends NameFilter {
def apply(pre: Type, name: Name)(implicit ctx: Context): Boolean =
name.isTypeName && (pre member name).info.isRealTypeBounds
}
/** A filter for names of deferred term definitions of a given type */
object abstractTermNameFilter extends NameFilter {
def apply(pre: Type, name: Name)(implicit ctx: Context): Boolean =
name.isTermName && (pre member name).symbol.isDeferred
}
// ----- Exceptions -------------------------------------------------------------
class TypeError(msg: String) extends Exception(msg)
class FatalTypeError(msg: String) extends TypeError(msg)
class MalformedType(pre: Type, sym: Symbol) extends FatalTypeError(s"malformed type: $pre.$sym")
class CyclicReference(sym: Symbol) extends FatalTypeError("cyclic reference involving $sym")
// ----- Misc utilities ---------------------------------------------------------
/** like map2, but returns list `xs` itself - instead of a copy - if function
* `f` maps all elements to themselves.
*/
def map2Conserve[A <: AnyRef, B](xs: List[A], ys: List[B])(f: (A, B) => A): List[A] =
if (xs.isEmpty) xs
else {
val x1 = f(xs.head, ys.head)
val xs1 = map2Conserve(xs.tail, ys.tail)(f)
if ((x1 eq xs.head) && (xs1 eq xs.tail)) xs
else x1 :: xs1
}
/** True if two lists have the same length. Since calling length on linear sequences
* is O(n), it is an inadvisable way to test length equality.
*/
final def sameLength[T](xs: List[T], ys: List[T]): Boolean = xs match {
case _ :: xs1 =>
ys match {
case _ :: ys1 => sameLength(xs1, ys1)
case _ => false
}
case _ => ys.isEmpty
}
}
