package dotty.tools
package dotc
package typer
import core._
import ast._
import Scopes._, Contexts._, Constants._, Types._, Symbols._, Names._, Flags._, Decorators._
import ErrorReporting._, Annotations._, Denotations._, SymDenotations._, StdNames._
import util.Positions._
import config.Printers._
trait TypeAssigner {
import tpd._
/** The enclosing class, except if we are in a super call, in which case
* it is the next outer one.
*/
def effectiveEnclosingClass(implicit ctx: Context) = {
val enclClass = ctx.owner.enclosingClass
if ((ctx.mode is Mode.InSuperCall) && enclClass.exists) enclClass.owner.enclosingClass
else enclClass
}
/** The qualifying class of a this or super with prefix `qual` (which might be empty).
* @param packageOk The qualifier may refer to a package.
*/
def qualifyingClass(tree: untpd.Tree, qual: Name, packageOK: Boolean)(implicit ctx: Context): Symbol = {
effectiveEnclosingClass.ownersIterator.find(o => qual.isEmpty || o.isClass && o.name == qual) match {
case Some(c) if packageOK || !(c is Package) =>
c
case _ =>
ctx.error(
if (qual.isEmpty) tree.show + " can be used only in a class, object, or template"
else qual.show + " is not an enclosing class", tree.pos)
NoSymbol
}
}
def avoid(tp: Type, syms: => List[Symbol])(implicit ctx: Context): Type = {
val widenMap = new TypeMap {
lazy val forbidden = syms.toSet
def toAvoid(tp: Type): Boolean = tp match {
case tp: TermRef =>
val sym = tp.symbol
sym.exists && (
sym.owner.isTerm && (forbidden contains sym)
|| !(sym.owner is Package) && toAvoid(tp.prefix)
)
case _ =>
false
}
def apply(tp: Type) = tp match {
case tp: TermRef if toAvoid(tp) && variance > 0 =>
apply(tp.info)
case tp: TypeRef if toAvoid(tp.prefix) =>
tp.info match {
case TypeAlias(ref) => apply(ref)
case _ => mapOver(tp)
}
case tp: RefinedType =>
val tp1 @ RefinedType(parent1, _) = mapOver(tp)
if (tp1.refinedInfo existsPart toAvoid) {
typr.println(s"dropping refinement from $tp1")
parent1
}
else tp1
case _ =>
mapOver(tp)
}
}
widenMap(tp)
}
def localSyms(stats: List[tpd.Tree])(implicit ctx: Context): List[Symbol] =
for (stat <- stats if stat.isDef) yield stat.symbol
def seqToRepeated(tree: Tree)(implicit ctx: Context): Tree =
Typed(tree, TypeTree(tree.tpe.widen.translateParameterized(defn.SeqClass, defn.RepeatedParamClass)))
/** A denotation exists really if it exists and does not point to a stale symbol. */
final def reallyExists(denot: Denotation)(implicit ctx: Context): Boolean = try
denot match {
case denot: SymDenotation =>
denot.exists && {
denot.ensureCompleted
!denot.isAbsent
}
case denot: SingleDenotation =>
val sym = denot.symbol
(sym eq NoSymbol) || reallyExists(sym.denot)
case _ =>
true
}
catch {
case ex: StaleSymbol => false
}
/** If `tpe` is a named type, check that its denotation is accessible in the
* current context. Return the type with those alternatives as denotations
* which are accessible.
*/
def ensureAccessible(tpe: Type, superAccess: Boolean, pos: Position)(implicit ctx: Context): Type = {
def test(tpe: Type, firstTry: Boolean): Type = tpe match {
case tpe: NamedType =>
val pre = tpe.prefix
val name = tpe.name
val d = tpe.denot.accessibleFrom(pre, superAccess)
if (!d.exists) {
// it could be that we found an inaccessbile private member, but there is
// an inherited non-private member with the same name and signature.
val d2 = pre.nonPrivateMember(name)
if (reallyExists(d2) && firstTry) test(pre.select(name, d2), false)
else {
val alts = tpe.denot.alternatives.map(_.symbol).filter(_.exists)
val what = alts match {
case Nil =>
name.toString
case sym :: Nil =>
if (sym.owner == pre.typeSymbol) sym.show else sym.showLocated
case _ =>
i"none of the overloaded alternatives named $name"
}
val where = if (ctx.owner.exists) s" from ${ctx.owner.enclosingClass}" else ""
val whyNot = new StringBuffer
alts foreach (_.isAccessibleFrom(pre, superAccess, whyNot))
if (!tpe.isError)
ctx.error(i"$what cannot be accessed as a member of $pre$where.$whyNot", pos)
ErrorType
}
} else if (d.symbol is TypeParamAccessor) // always dereference type param accessors
ensureAccessible(d.info.bounds.hi, superAccess, pos)
else
tpe withDenot d
case _ =>
tpe
}
test(tpe, true)
}
/** The type of a selection with `name` of a tree with type `site`.
*/
def selectionType(site: Type, name: Name, pos: Position)(implicit ctx: Context): Type = {
val mbr = site.member(name)
if (reallyExists(mbr)) site.select(name, mbr)
else {
if (!site.isErroneous) {
ctx.error(
if (name == nme.CONSTRUCTOR) i"$site does not have a constructor"
else i"$name is not a member of $site", pos)
}
ErrorType
}
}
/** The selection type, which is additionally checked for accessibility.
*/
def accessibleSelectionType(tree: untpd.RefTree, qual1: Tree)(implicit ctx: Context): Type = {
val ownType = selectionType(qual1.tpe.widenIfUnstable, tree.name, tree.pos)
ensureAccessible(ownType, qual1.isInstanceOf[Super], tree.pos)
}
/** Type assignment method. Each method takes as parameters
* - an untpd.Tree to which it assigns a type,
* - typed child trees it needs to access to cpmpute that type,
* - any further information it needs to access to compute that type.
*/
def assignType(tree: untpd.Ident, rawType: Type)(implicit ctx: Context) = {
tree.withType(if (tree.isType) rawType else rawType.underlyingIfRepeated)
}
def assignType(tree: untpd.Select, qual: Tree)(implicit ctx: Context) = {
tree.withType(accessibleSelectionType(tree, qual))
}
def assignType(tree: untpd.SelectFromTypeTree, qual: Tree)(implicit ctx: Context) = {
tree.withType(accessibleSelectionType(tree, qual))
}
def assignType(tree: untpd.New, tpt: Tree)(implicit ctx: Context) =
tree.withType(tpt.tpe)
def assignType(tree: untpd.Literal)(implicit ctx: Context) =
tree.withType {
tree.const.tag match {
case UnitTag => defn.UnitType
case NullTag => defn.NullType
case _ => ConstantType(tree.const)
}
}
def assignType(tree: untpd.This)(implicit ctx: Context) = {
val cls = qualifyingClass(tree, tree.qual, packageOK = false)
tree.withType(cls.thisType)
}
def assignType(tree: untpd.Super, qual: Tree, inConstrCall: Boolean)(implicit ctx: Context) = {
val mix = tree.mix
val cls = qual.tpe.widen.typeSymbol
def findMixinSuper(site: Type): Type = site.parents filter (_.name == mix) match {
case p :: Nil =>
p
case Nil =>
errorType(i"$mix does not name a parent class of $cls", tree.pos)
case p :: q :: _ =>
errorType(s"ambiguous parent class qualifier", tree.pos)
}
val owntype =
if (!mix.isEmpty) findMixinSuper(cls.info)
else if (inConstrCall) cls.info.firstParent
else cls.info.parents.reduceLeft((x: Type, y: Type) => AndType(x, y))
tree.withType(SuperType(cls.thisType, owntype))
}
def assignType(tree: untpd.Apply, fn: Tree, args: List[Tree])(implicit ctx: Context) = {
val ownType = fn.tpe.widen match {
case fntpe @ MethodType(_, ptypes) =>
if (sameLength(ptypes, args)) fntpe.instantiate(args.tpes)
else errorType(s"wrong number of type parameters for ${fn.tpe}; expected: ${ptypes.length}", tree.pos)
case t =>
errorType(s"${err.exprStr(fn)} does not take type parameters", tree.pos)
}
tree.withType(ownType)
}
def assignType(tree: untpd.TypeApply, fn: Tree, args: List[Tree])(implicit ctx: Context) = {
val ownType = fn.tpe.widen match {
case pt: PolyType =>
val argTypes = args.tpes
if (sameLength(argTypes, pt.paramNames)) pt.instantiate(args.tpes)
else errorType(i"wrong number of type parameters for ${fn.tpe}; expected: ${pt.paramNames.length}", tree.pos)
case _ =>
errorType(s"${err.exprStr(fn)} does not take type parameters", tree.pos)
}
tree.withType(ownType)
}
def assignType(tree: untpd.Pair, left: Tree, right: Tree)(implicit ctx: Context) =
tree.withType(defn.PairType.appliedTo(left.tpe :: right.tpe :: Nil))
def assignType(tree: untpd.Typed, tpt: Tree)(implicit ctx: Context) =
tree.withType(tpt.tpe)
def assignType(tree: untpd.NamedArg, arg: Tree)(implicit ctx: Context) =
tree.withType(arg.tpe)
def assignType(tree: untpd.Assign)(implicit ctx: Context) =
tree.withType(defn.UnitType)
def assignType(tree: untpd.Block, stats: List[Tree], expr: Tree)(implicit ctx: Context) =
tree.withType(avoid(expr.tpe, localSyms(stats)))
def assignType(tree: untpd.If, thenp: Tree, elsep: Tree)(implicit ctx: Context) =
tree.withType(thenp.tpe | elsep.tpe)
def assignType(tree: untpd.Closure, meth: Tree, target: Tree)(implicit ctx: Context) =
tree.withType(if (target.isEmpty) meth.tpe.widen.toFunctionType else target.tpe)
def assignType(tree: untpd.CaseDef, body: Tree)(implicit ctx: Context) =
tree.withType(body.tpe)
def assignType(tree: untpd.Match, cases: List[CaseDef])(implicit ctx: Context) =
tree.withType(ctx.typeComparer.lub(cases.tpes))
def assignType(tree: untpd.Return)(implicit ctx: Context) =
tree.withType(defn.NothingType)
def assignType(tree: untpd.Try, expr: Tree, handler: Tree)(implicit ctx: Context) = {
val handlerTypeArgs = handler.tpe.baseArgTypesHi(defn.FunctionClass(1))
tree.withType(if (handlerTypeArgs.nonEmpty) expr.tpe | handlerTypeArgs(1) else expr.tpe)
}
def assignType(tree: untpd.Throw)(implicit ctx: Context) =
tree.withType(defn.NothingType)
def assignType(tree: untpd.SeqLiteral, elems: List[Tree])(implicit ctx: Context) =
tree.withType(defn.SeqType.appliedTo(ctx.typeComparer.lub(elems.tpes)))
def assignType(tree: untpd.SingletonTypeTree, ref: Tree)(implicit ctx: Context) =
tree.withType(ref.tpe)
def assignType(tree: untpd.AndTypeTree, left: Tree, right: Tree)(implicit ctx: Context) =
tree.withType(left.tpe & right.tpe)
def assignType(tree: untpd.OrTypeTree, left: Tree, right: Tree)(implicit ctx: Context) =
tree.withType(left.tpe | right.tpe)
// RefinedTypeTree is missing, handled specially in Typer and Unpickler.
def assignType(tree: untpd.AppliedTypeTree, tycon: Tree, args: List[Tree])(implicit ctx: Context) = {
val tparams = tycon.tpe.typeParams
val ownType =
if (sameLength(tparams, args)) tycon.tpe.appliedTo(args.tpes)
else errorType(i"wrong number of type arguments for ${tycon.tpe}, should be ${tparams.length}", tree.pos)
tree.withType(ownType)
}
def assignType(tree: untpd.ByNameTypeTree, result: Tree)(implicit ctx: Context) =
tree.withType(ExprType(result.tpe))
def assignType(tree: untpd.TypeBoundsTree, lo: Tree, hi: Tree)(implicit ctx: Context) =
tree.withType(TypeBounds(lo.tpe, hi.tpe))
def assignType(tree: untpd.Bind, sym: TermSymbol)(implicit ctx: Context) =
tree.withType(TermRef(NoPrefix, sym))
def assignType(tree: untpd.Alternative, trees: List[Tree])(implicit ctx: Context) =
tree.withType(ctx.typeComparer.lub(trees.tpes))
def assignType(tree: untpd.UnApply, proto: Type)(implicit ctx: Context) =
tree.withType(proto)
def assignType(tree: untpd.ValDef, sym: Symbol)(implicit ctx: Context) =
tree.withType(if (sym.exists) sym.valRef else NoType)
def assignType(tree: untpd.DefDef, sym: Symbol)(implicit ctx: Context) =
tree.withType(sym.termRefWithSig)
def assignType(tree: untpd.TypeDef, sym: Symbol)(implicit ctx: Context) =
tree.withType(sym.typeRef)
def assignType(tree: untpd.Import, sym: Symbol)(implicit ctx: Context) =
tree.withType(sym.termRef)
def assignType(tree: untpd.Annotated, annot: Tree, arg: Tree)(implicit ctx: Context) =
tree.withType(AnnotatedType(Annotation(annot), arg.tpe))
def assignType(tree: untpd.PackageDef, pid: Tree)(implicit ctx: Context) =
tree.withType(pid.symbol.valRef)
}
object TypeAssigner extends TypeAssigner