package dotty.tools.dotc package core import util.HashSet import Symbols._ import SubTypers._ import Flags._ import Names._ import Scopes._ import Constants._ import Contexts._ import Annotations._ import Denotations._ import Referenceds._ 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): Referenced = findDecl(name, this, Flags.Empty) /** The non-private declaration of this type with given name */ final def nonPrivateDecl(name: Name)(implicit ctx: Context): Referenced = 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): Referenced = this match { case tp: RefinedType => tp.findDecl(name, pre) case tp: ClassInfo => tp.classd.decls .refsNamed(name) .filterAccessibleFrom(pre) .filterExcluded(excluded) .asSeenFrom(pre, tp.classd.symbol) .toRef 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): Referenced = findMember(name, this, Flags.Empty) /** The non-private member of this type with given name */ final def nonPrivateMember(name: Name)(implicit ctx: Context): Referenced = findMember(name, this, Flags.Private) /** Find member of this type with given name and * produce a referenced 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): Referenced = 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.memberRefsNamed(name) val resultSyms = candidates .filterAccessibleFrom(pre) .filterExcluded(excluded) .asSeenFrom(pre, classd.symbol) if (resultSyms.exists) resultSyms.toRef else new ErrorRefd // 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.subTyper.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.subTyper.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.subTyper.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(sym: Symbol)(implicit ctx: Context): Type = { sym.info.asSeenFrom(this, sym.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 * .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.deref 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 => tp.tycon.typeParams drop tp.targs.length 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) // 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 lastReferenced: Referenced = null private def checkPrefix(sym: Symbol) = sym.isAbstractType || sym.isClass /** The referenced currently denoted by this type */ def deref(implicit ctx: Context): Referenced = { val validPeriods = if (lastReferenced != null) lastReferenced.validFor else Nowhere if (!(validPeriods contains ctx.period)) { val thisPeriod = ctx.period lastReferenced = if (validPeriods.runId == thisPeriod.runId) lastReferenced.current else if (thisPeriod.phaseId > name.lastIntroPhaseId) ctx.atPhase(name.lastIntroPhaseId)(prefix.member(name)(_)).current else prefix.member(name) if (checkPrefix(lastReferenced.symbol) && !prefix.isLegalPrefix) throw new MalformedType(prefix, lastReferenced.symbol) } lastReferenced } def isType = name.isTypeName def isTerm = name.isTermName def symbol(implicit ctx: Context): Symbol = deref.symbol def info(implicit ctx: Context): Type = deref.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 deref(implicit ctx: Context): Referenced = fixedSym.deref } 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 deref(implicit ctx: Context): Referenced = super.deref.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 ----------------------------------------------------------------- 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): Referenced = { var ns = names var is = infos var ref: Referenced = NoRefd while (ns.nonEmpty && (ref eq NoRefd)) { if (ns.head == name) ref = new JointSymRefd(NoSymbol, is.head.substThis(this, pre), Period.allInRun(ctx.runId)) ns = ns.tail is = is.tail } ref } 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[AnnotationInfo], tpe: Type) extends UncachedProxyType { override def underlying(implicit ctx: Context): Type = tpe def derivedAnnotatedType(annots1: List[AnnotationInfo], tpe1: Type) = if ((annots1 eq annots) && (tpe1 eq tpe)) this else AnnotatedType.make(annots1, tpe1) } object AnnotatedType { def make(annots: List[AnnotationInfo], 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[AnnotationInfo]): List[AnnotationInfo] = ??? } 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: AnnotationInfo): 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 } }