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|
/* NSC -- new Scala compiler
* Copyright 2005-2006 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.typechecker
import scala.tools.nsc.util.Position
import symtab.Flags
import symtab.Flags._
/** This trait declares methods to create symbols and to enter them into scopes.
*
* @author Martin Odersky
* @version 1.0
*/
trait Namers requires Analyzer {
import global._
import definitions._
/** Convert to corresponding type parameters all skolems which satisfy one
* of the following two conditions:
* 1. The skolem is a parameter of a class or alias type
* 2. The skolem is a method parameter which appears in parameter `tparams'
*/
class DeSkolemizeMap(tparams: List[Symbol]) extends TypeMap {
def apply(tp: Type): Type = tp match {
case TypeRef(pre, sym, args) =>
val tparam = sym.deSkolemize
mapOver(
if (tparam == sym || !(tparams contains tparam)) tp
else rawTypeRef(NoPrefix, tparam, args))
case SingleType(pre, sym) if (sym.isThisSkolem) =>
ThisType(sym.deSkolemize)
case PolyType(tparams1, restpe) =>
new DeSkolemizeMap(tparams1 ::: tparams).mapOver(tp)
case ClassInfoType(parents, decls, clazz) =>
val parents1 = List.mapConserve(parents)(this)
if (parents1 eq parents) tp else ClassInfoType(parents1, decls, clazz)
case _ =>
mapOver(tp)
}
}
/** overridden by IDE to not manually enter value parameters */
protected final def doEnterValueParams = !inIDE;
protected def inIDE = false;
class Namer(val context: Context) {
val typer = newTyper(context)
def setPrivateWithin(tree: Tree, sym: Symbol, mods: Modifiers): Symbol = {
if (!mods.privateWithin.isEmpty)
sym.privateWithin = typer.qualifyingClassContext(tree, mods.privateWithin).owner
sym
}
def updatePosFlags(sym: Symbol, pos: PositionType, flags: int): Symbol = {
if (settings.debug.value) log("overwriting " + sym)
val lockedFlag = sym.flags & LOCKED
sym.reset(NoType)
sym setPos pos
sym.flags = flags | lockedFlag
if (sym.isModule && sym.moduleClass != NoSymbol)
updatePosFlags(sym.moduleClass, pos, (flags & ModuleToClassFlags) | MODULE | FINAL)
if (sym.owner.isPackageClass &&
(sym.linkedSym.rawInfo.isInstanceOf[loaders.SymbolLoader] ||
sym.linkedSym.rawInfo.isComplete && runId(sym.validTo) != currentRunId))
// pre-set linked symbol to NoType, in case it is not loaded together with this symbol.
sym.linkedSym.setInfo(NoType)
sym
}
private def isTemplateContext(context: Context): boolean = context.tree match {
case Template(_, _) => true
case Import(_, _) => isTemplateContext(context.outer)
case _ => false
}
private var innerNamerCache: Namer = null
def namerOf(sym: Symbol): Namer = {
def innerNamer: Namer = {
if (innerNamerCache eq null)
innerNamerCache =
if (!isTemplateContext(context)) this
else new Namer(context.make(context.tree, context.owner, newScope))
innerNamerCache
}
def primaryConstructorParamNamer: Namer = {
val classContext = context.enclClass
val outerContext = classContext.outer.outer
val paramContext = outerContext.makeNewScope(outerContext.tree, outerContext.owner)
classContext.owner.unsafeTypeParams foreach paramContext.scope.enter
new Namer(paramContext)
}
if (sym.isTerm &&
(sym.hasFlag(PARAM) && sym.owner.isPrimaryConstructor || sym.hasFlag(PARAMACCESSOR)))
primaryConstructorParamNamer
else
innerNamer
}
private def doubleDefError(pos: PositionType, sym: Symbol): unit =
context.error(pos,
sym.name.toString() + " is already defined as " +
(if (sym.hasFlag(CASE)) "case class " + sym.name else sym.toString()))
def enterInScope(sym: Symbol): Symbol = {
// allow for overloaded methods
if (!(sym.isSourceMethod && sym.owner.isClass && !sym.owner.isPackageClass)) {
val prev = context.scope.lookupEntry(sym.name);
if ((prev ne null) && prev.owner == context.scope &&
(!prev.sym.isSourceMethod ||
nme.isSetterName(sym.name) ||
sym.owner.isPackageClass)) {
doubleDefError(sym.pos, prev.sym)
sym setInfo ErrorType
} else context.scope enter sym
} else context.scope enter sym
sym
}
def enterPackageSymbol(pos: PositionType, name: Name): Symbol = {
val cscope = if (context.owner == EmptyPackageClass) RootClass.info.decls
else context.scope
val p: Symbol = cscope.lookup(name)
if (p.isPackage && cscope == p.owner.info.decls) {
p
} else {
val cowner = if (context.owner == EmptyPackageClass) RootClass else context.owner
val pkg = cowner.newPackage(pos, name)
pkg.moduleClass.setInfo(new PackageClassInfoType(newScope, pkg.moduleClass))
pkg.setInfo(pkg.moduleClass.tpe)
enterInScope(pkg)
}
}
def inConstructorFlag: long =
if (context.owner.isConstructor && !context.inConstructorSuffix) INCONSTRUCTOR
else 0l
private def enterClassSymbol(pos: PositionType, flags: int, name: Name): Symbol = {
var c: Symbol = context.scope.lookup(name)
if (c.isType && !currentRun.compiles(c) && context.scope == c.owner.info.decls) {
updatePosFlags(c, pos, flags)
} else {
c = enterInScope(context.owner.newClass(pos, name)).setFlag(flags | inConstructorFlag)
}
if (c.owner.isPackageClass) {
val file = context.unit.source.getFile()
val clazz = c.asInstanceOf[ClassSymbol]
if (settings.debug.value && (clazz.sourceFile ne null) && !clazz.sourceFile.equals(file)) {
Console.err.println("SOURCE MISMATCH: " + clazz.sourceFile + " vs. " + file + " SYM=" + c);
}
clazz.sourceFile = file
if (clazz.sourceFile ne null) {
assert(!currentRun.compiles(clazz) || clazz.sourceFile == currentRun.symSource(c));
currentRun.symSource(c) = clazz.sourceFile
}
}
c
}
private def enterModuleSymbol(pos: PositionType, flags: int, name: Name): Symbol = {
var m: Symbol = context.scope.lookup(name)
if (m.isModule && !m.isPackage && !currentRun.compiles(m) &&
(context.scope == m.owner.info.decls)) {
updatePosFlags(m, pos, flags)
} else {
if (m.isTerm && !m.isPackage && !currentRun.compiles(m) && (context.scope == m.owner.info.decls))
context.scope.unlink(m)
m = context.owner.newModule(pos, name)
m.setFlag(flags)
m.moduleClass.setFlag(flags | inConstructorFlag)
enterInScope(m)
}
if (m.owner.isPackageClass) {
m.moduleClass.sourceFile = context.unit.source.getFile()
currentRun.symSource(m) = m.moduleClass.sourceFile
}
m
}
private def enterCaseFactorySymbol(pos: PositionType, flags: int, name: Name): Symbol = {
var m: Symbol = context.scope.lookup(name)
if (m.isTerm && !m.isPackage && !currentRun.compiles(m) && context.scope == m.owner.info.decls) {
updatePosFlags(m, pos, flags)
} else {
m = enterInScope(context.owner.newMethod(pos, name)).setFlag(flags)
}
if (m.owner.isPackageClass)
currentRun.symSource(m) = context.unit.source.getFile()
m
}
def enterSyms(trees: List[Tree]): Namer = {
var namer : Namer = this
for (val tree <- trees) {
val txt = namer.enterSym(tree)
if (!(txt eq namer.context)) namer = new Namer(txt)
}
namer
}
def newTypeSkolems(tparams: List[Symbol]): List[Symbol] = {
val tskolems = tparams map (.newTypeSkolem)
val ltp = new LazyType {
override def complete(sym: Symbol): unit =
sym setInfo sym.deSkolemize.info.substSym(tparams, tskolems)
}
tskolems foreach (.setInfo(ltp))
tskolems
}
def skolemize(tparams: List[AbsTypeDef]): unit = {
val tskolems = newTypeSkolems(tparams map (.symbol))
for (val Pair(tparam, tskolem) <- tparams zip tskolems) tparam.symbol = tskolem
}
def applicableTypeParams(owner: Symbol): List[Symbol] =
if (owner.isTerm || owner.isPackageClass) List()
else applicableTypeParams(owner.owner) ::: owner.typeParams
def deSkolemize: TypeMap = new DeSkolemizeMap(applicableTypeParams(context.owner))
def enterSym(tree: Tree): Context = {
def finishWith(tparams: List[AbsTypeDef]): unit = {
val sym = tree.symbol
if (settings.debug.value) log("entered " + sym + " in " + context.owner + ", scope-id = " + context.scope.hashCode());
var ltype: LazyType = namerOf(sym).typeCompleter(tree)
if (!tparams.isEmpty) {
new Namer(context.makeNewScope(tree, sym)).enterSyms(tparams)
ltype = new LazyPolyType(tparams map (.symbol), ltype)
if (sym.isTerm) skolemize(tparams)
}
sym.setInfo(ltype)
}
def finish = finishWith(List())
if (tree.symbol == NoSymbol) {
val owner = context.owner
tree match {
case PackageDef(name, stats) =>
tree.symbol = enterPackageSymbol(tree.pos, name)
val namer = new Namer(
context.make(tree, tree.symbol.moduleClass, tree.symbol.info.decls))
namer.enterSyms(stats)
case ClassDef(mods, name, tparams, _, impl) =>
if ((mods.flags & (CASE | ABSTRACT)) == CASE) { // enter case factory method.
tree.symbol = enterCaseFactorySymbol(
tree.pos, mods.flags & AccessFlags | METHOD | CASE, name.toTermName)
tree.symbol.setInfo(namerOf(tree.symbol).caseFactoryCompleter(tree))
setPrivateWithin(tree, tree.symbol, mods)
}
tree.symbol = enterClassSymbol(tree.pos, mods.flags, name)
setPrivateWithin(tree, tree.symbol, mods)
finishWith(tparams)
case ModuleDef(mods, name, _) =>
tree.symbol = enterModuleSymbol(tree.pos, mods.flags | MODULE | FINAL, name)
setPrivateWithin(tree, tree.symbol, mods)
setPrivateWithin(tree, tree.symbol.moduleClass, mods)
tree.symbol.moduleClass.setInfo(namerOf(tree.symbol).moduleClassTypeCompleter(tree))
finish
case ValDef(mods, name, tp, rhs) =>
if (context.owner.isClass & (mods.flags & LOCAL) == 0) {
val accflags = ACCESSOR |
(if ((mods.flags & MUTABLE) != 0) mods.flags & ~MUTABLE else mods.flags | STABLE)
val getter = owner.newMethod(tree.pos, name).setFlag(accflags)
getter.setInfo(namerOf(getter).getterTypeCompleter(tree))
setPrivateWithin(tree, getter, mods)
enterInScope(getter)
if ((mods.flags & MUTABLE) != 0) {
val setter = owner.newMethod(tree.pos, nme.getterToSetter(name))
.setFlag(accflags & ~STABLE & ~CASEACCESSOR)
setter.setInfo(namerOf(setter).setterTypeCompleter(tree))
setPrivateWithin(tree, setter, mods)
enterInScope(setter)
}
tree.symbol =
if ((mods.flags & DEFERRED) == 0) {
val value =
enterInScope(owner.newValue(tree.pos, nme.getterToLocal(name)))
.setFlag(mods.flags & FieldFlags | PRIVATE | LOCAL)
value.setInfo(namerOf(value).typeCompleter(tree))
value
} else getter;
} else {
tree.symbol = enterInScope(owner.newValue(tree.pos, name))
.setFlag(mods.flags)
finish
}
case DefDef(mods, nme.CONSTRUCTOR, tparams, _, _, _) =>
tree.symbol = enterInScope(owner.newConstructor(tree.pos))
.setFlag(mods.flags | owner.getFlag(ConstrFlags))
setPrivateWithin(tree, tree.symbol, mods)
finishWith(tparams)
case DefDef(mods, name, tparams, _, _, _) =>
tree.symbol = enterInScope(owner.newMethod(tree.pos, name))
.setFlag(mods.flags)
setPrivateWithin(tree, tree.symbol, mods)
finishWith(tparams)
case AbsTypeDef(mods, name, _, _) =>
tree.symbol = enterInScope(owner.newAbstractType(tree.pos, name))
.setFlag(mods.flags)
setPrivateWithin(tree, tree.symbol, mods)
finish
case AliasTypeDef(mods, name, tparams, _) =>
tree.symbol = enterInScope(owner.newAliasType(tree.pos, name))
.setFlag(mods.flags)
setPrivateWithin(tree, tree.symbol, mods)
finishWith(tparams)
case DocDef(_, defn) =>
enterSym(defn)
case imp @ Import(_, _) =>
tree.symbol = NoSymbol.newImport(tree.pos)
tree.symbol.setInfo(namerOf(tree.symbol).typeCompleter(tree))
return (context.makeNewImport(imp))
case _ =>
}
}
this.context
}
// --- Lazy Type Assignment --------------------------------------------------
def typeCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
if (settings.debug.value) log("defining " + sym);
val tp = typeSig(tree)
sym.setInfo(tp)
if ((sym.isAliasType || sym.isAbstractType) && !(sym hasFlag PARAM) &&
!typer.checkNonCyclic(tree.pos, tp))
sym.setInfo(ErrorType) // this early test is there to avoid infinite baseTypes when
// adding setters and getters --> bug798
if (settings.debug.value) log("defined " + sym);
validate(sym)
}
}
def moduleClassTypeCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
tree.symbol.info // sets moduleClass info as a side effect.
}
}
def getterTypeCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
if (settings.debug.value) log("defining " + sym);
sym.setInfo(PolyType(List(), typeSig(tree)))
if (settings.debug.value) log("defined " + sym);
validate(sym)
}
}
def setterTypeCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
if (settings.debug.value) log("defining " + sym);
sym.setInfo(MethodType(List(typeSig(tree)), UnitClass.tpe))
if (settings.debug.value) log("defined " + sym);
validate(sym)
}
}
def selfTypeCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
sym.setInfo(typer.typedType(tree).tpe)
}
}
def caseFactoryCompleter(tree: Tree) = new TypeCompleter(tree) {
override def complete(sym: Symbol): unit = {
val clazz = tree.symbol
var tpe = clazz.primaryConstructor.tpe
val tparams = clazz.typeParams
if (!tparams.isEmpty) tpe = PolyType(tparams, tpe).cloneInfo(sym);
sym.setInfo(tpe)
}
}
private def deconstIfNotFinal(sym: Symbol, tpe: Type): Type =
if (sym.isVariable ||
!(sym hasFlag FINAL) ||
sym.isMethod && !(sym hasFlag ACCESSOR)) tpe.deconst
else tpe;
def enterValueParams(owner: Symbol, vparamss: List[List[ValDef]]): List[List[Symbol]] = {
def enterValueParam(param: ValDef): Symbol = if (doEnterValueParams) {
param.symbol = owner.newValueParameter(param.pos, param.name)
.setInfo(typeCompleter(param))
.setFlag(param.mods.flags & (BYNAMEPARAM | IMPLICIT))
setPrivateWithin(param, param.symbol, param.mods)
enterInScope(param.symbol)
param.symbol
} else param.symbol
vparamss.map(.map(enterValueParam))
}
/** A creator for polytypes. If tparams is empty, simply returns result type */
private def makePolyType(tparams: List[Symbol], tpe: Type): Type =
if (tparams.isEmpty) tpe
else
PolyType(tparams, tpe match {
case PolyType(List(), tpe1) => tpe1
case _ => tpe
});
private def templateSig(templ0: Template): Type = {
var templ = templ0
val clazz = context.owner
def checkParent(tpt: Tree): Type = {
val tp = tpt.tpe
if (tp.symbol == context.owner) {
context.error(tpt.pos, ""+tp.symbol+" inherits itself")
AnyRefClass.tpe
} else if (tp.isError) {
AnyRefClass.tpe
} else {
tp
}
}
val parents = typer.parentTypes(templ) map checkParent
val decls = newDecls(templ, clazz)
new Namer(context.make(templ, clazz, decls)).enterSyms(templ.body)
ClassInfoType(parents, decls, clazz)
}
private def classSig(tparams: List[AbsTypeDef], tpt: Tree, impl: Template): Type = {
val tparamSyms = typer.reenterTypeParams(tparams)
if (!tpt.isEmpty)
context.owner.typeOfThis = selfTypeCompleter(tpt)
else tpt.tpe = NoType
makePolyType(tparamSyms, templateSig(impl))
}
private def methodSig(tparams: List[AbsTypeDef], vparamss: List[List[ValDef]],
tpt: Tree, rhs: Tree): Type = {
val meth = context.owner
val tparamSyms = typer.reenterTypeParams(tparams)
val vparamSymss = enterValueParams(meth, vparamss)
if (tpt.isEmpty && meth.name == nme.CONSTRUCTOR) tpt.tpe = context.enclClass.owner.tpe
def makeMethodType(vparams: List[Symbol], restpe: Type) = {
val formals = vparams map (.tpe)
if (!vparams.isEmpty && vparams.head.hasFlag(IMPLICIT)) ImplicitMethodType(formals, restpe)
else MethodType(formals, restpe)
}
def thisMethodType(restype: Type) =
makePolyType(
tparamSyms,
if (vparamSymss.isEmpty) PolyType(List(), restype)
else (vparamSymss :\ restype)(makeMethodType))
if (meth.owner.isClass && (tpt.isEmpty || vparamss.exists(.exists(.tpt.isEmpty)))) {
// try to complete from matching definition in base type
for (val vparams <- vparamss; val vparam <- vparams)
if (vparam.tpt.isEmpty) vparam.symbol setInfo WildcardType
val schema = thisMethodType(if (tpt.isEmpty) WildcardType else typer.typedType(tpt).tpe)
val site = meth.owner.thisType
val overridden = intersectionType(meth.owner.info.parents).member(meth.name).filter(sym =>
sym != NoSymbol && (site.memberType(sym) matches schema))
if (overridden != NoSymbol && !(overridden hasFlag OVERLOADED)) {
var pt = site.memberType(overridden) match {
case PolyType(tparams, rt) => rt.substSym(tparamSyms, tparams)
case mt => mt
}
for (val vparams <- vparamss) {
var pfs = pt.paramTypes
for (val vparam <- vparams) {
if (vparam.tpt.isEmpty) {
vparam.tpt.tpe = pfs.head
vparam.symbol setInfo pfs.head
}
pfs = pfs.tail
}
pt = pt.resultType
}
if (tpt.isEmpty) {
// provisionally assign `meth' a method type with inherited result type
// that way, we can leave out the result type even if method is recursive.
meth setInfo thisMethodType(
pt match {
case PolyType(List(), rtpe) => rtpe
case MethodType(List(), rtpe) => rtpe
case _ => pt
})
}
}
}
for (val vparams <- vparamss; val vparam <- vparams; vparam.tpt.isEmpty) {
context.error(vparam.pos, "missing parameter type")
vparam.tpt.tpe = ErrorType
}
thisMethodType(
if (tpt.isEmpty) {
tpt.tpe = deconstIfNotFinal(meth, typer.computeType(rhs));
tpt.tpe
} else typer.typedType(tpt).tpe)
}
/** If `sym' is an implicit value, check that its type signature `tp' is contractive.
* This means: The type of every implicit parameter is properly contained
* in the type that is obtained by removing all implicit parameters and converting
* the rest to a function type.
* If the check succeeds return `tp' itself, otherwise `ErrorType'.
*/
private def checkContractive(sym: Symbol, tp: Type): Type = {
/* The type signature without implicit parameters converted to function type */
def provided(tp: Type): Type = tp match {
case PolyType(_, restpe) => provided(restpe)
case mt: ImplicitMethodType => mt.resultType
case MethodType(formals, restpe) => functionType(formals, provided(restpe))
case _ => tp
}
/* The types of all implicit parameters */
def required(tp: Type): List[Type] = tp match {
case PolyType(_, restpe) => required(restpe)
case mt: ImplicitMethodType => mt.paramTypes
case MethodType(formals, restpe) => required(restpe)
case _ => List()
}
var result = tp;
if (sym hasFlag IMPLICIT) {
val p = provided(tp);
for (val r <- required(tp)) {
if (!isContainedIn(r, p) || (r =:= p)) {
context.error(sym.pos, "implicit " + sym + " is not contractive," +
"\n because the implicit parameter type " + r +
"\n is not strictly contained in the signature " + p);
result = ErrorType;
}
}
}
result
}
private def aliasTypeSig(tpsym: Symbol, tparams: List[AbsTypeDef], rhs: Tree): Type =
makePolyType(typer.reenterTypeParams(tparams), typer.typedType(rhs).tpe);
def typeSig(tree: Tree): Type = {
val result =
try {
val sym: Symbol = tree.symbol
tree match {
case ClassDef(_, _, tparams, tpt, impl) =>
new Namer(makeNewScope(context, tree, sym)).classSig(tparams, tpt, impl)
case ModuleDef(_, _, impl) =>
val clazz = sym.moduleClass
clazz.setInfo(new Namer(context.make(tree, clazz)).templateSig(impl));
//clazz.typeOfThis = singleType(sym.owner.thisType, sym);
clazz.tpe;
case DefDef(_, _, tparams, vparamss, tpt, rhs) =>
val result =
new Namer(makeNewScope(context, tree, sym)).methodSig(tparams, vparamss, tpt, rhs);
checkContractive(sym, result)
case ValDef(_, _, tpt, rhs) =>
if (tpt.isEmpty) {
if (rhs.isEmpty) {
context.error(tpt.pos, "missing parameter type");
ErrorType
} else {
tpt.tpe = deconstIfNotFinal(sym, newTyper(context.make(tree, sym)).computeType(rhs));
tpt.tpe
}
} else {
val typer1 =
if (sym.hasFlag(PARAM) && sym.owner.isConstructor && !phase.erasedTypes)
newTyper(context.makeConstructorContext)
else typer;
typer1.typedType(tpt).tpe
}
case tree @ AliasTypeDef(_, _, tparams, rhs) =>
new Namer(makeNewScope(context, tree, sym)).aliasTypeSig(sym, tparams, rhs)
case AbsTypeDef(_, _, lo, hi) =>
var lt = typer.typedType(lo).tpe
if (lt.isError) lt = AllClass.tpe
var ht = typer.typedType(hi).tpe
if (ht.isError) ht = AnyClass.tpe
TypeBounds(lt, ht)
case Import(expr, selectors) =>
val expr1 = typer.typedQualifier(expr)
val base = expr1.tpe
typer.checkStable(expr1)
def checkNotRedundant(pos: PositionType, from: Name, to: Name): boolean = {
if (!tree.symbol.hasFlag(SYNTHETIC) &&
!((expr1.symbol ne null) && expr1.symbol.isInterpreterWrapper) &&
base.member(from) != NoSymbol) {
val e = context.scope.lookupEntry(to)
def warnRedundant(sym: Symbol) =
context.unit.warning(pos, "imported `"+to+
"' is permanently hidden by definition of "+sym+
sym.locationString)
if ((e ne null) && e.owner == context.scope) {
warnRedundant(e.sym); return false
} else if (context eq context.enclClass) {
val defSym = context.prefix.member(to) filter (
sym => sym.exists && context.isAccessible(sym, context.prefix, false))
if (defSym != NoSymbol) { warnRedundant(defSym); return false }
}
}
true
}
def checkSelectors(selectors: List[Pair[Name, Name]]): unit = selectors match {
case Pair(from, to) :: rest =>
if (from != nme.WILDCARD && base != ErrorType) {
if (base.member(from) == NoSymbol && base.member(from.toTypeName) == NoSymbol)
context.error(tree.pos, from.decode + " is not a member of " + expr);
if (checkNotRedundant(tree.pos, from, to))
checkNotRedundant(tree.pos, from.toTypeName, to.toTypeName)
}
if (from != nme.WILDCARD && (rest.exists (sel => sel._1 == from)))
context.error(tree.pos, from.decode + " is renamed twice");
if ((to ne null) && to != nme.WILDCARD && (rest exists (sel => sel._2 == to)))
context.error(tree.pos, to.decode + " appears twice as a target of a renaming");
checkSelectors(rest)
case Nil =>
}
checkSelectors(selectors)
ImportType(expr1)
}
} catch {
case ex: TypeError =>
//Console.println("caught " + ex + " in typeSig")//DEBUG
typer.reportTypeError(tree.pos, ex)
ErrorType
}
deSkolemize(result)
}
/** Check that symbol's definition is well-formed. This means:
* - no conflicting modifiers
* - `abstract' modifier only for classes
* - `override' modifier never for classes
* - `def' modifier never for parameters of case classes
* - declarations only in mixins or abstract classes
*/
def validate(sym: Symbol): unit = {
def checkNoConflict(flag1: int, flag2: int): unit =
if (sym.hasFlag(flag1) && sym.hasFlag(flag2))
context.error(sym.pos,
if (flag1 == DEFERRED)
"abstract member may not have " + Flags.flagsToString(flag2) + " modifier";
else
"illegal combination of modifiers: " +
Flags.flagsToString(flag1) + " and " + Flags.flagsToString(flag2));
if (sym.hasFlag(IMPLICIT) && !sym.isTerm)
context.error(sym.pos, "`implicit' modifier can be used only for values, variables and methods")
if (sym.hasFlag(IMPLICIT) && sym.owner.isPackageClass)
context.error(sym.pos, "`implicit' modifier cannot be used for top-level objects")
if (sym.hasFlag(ABSTRACT) && !sym.isClass)
context.error(sym.pos, "`abstract' modifier can be used only for classes; " +
"\nit should be omitted for abstract members")
if (sym.hasFlag(OVERRIDE | ABSOVERRIDE) && sym.isClass)
context.error(sym.pos, "`override' modifier not allowed for classes")
if (sym.hasFlag(OVERRIDE | ABSOVERRIDE) && sym.isConstructor)
context.error(sym.pos, "`override' modifier not allowed for constructors")
if (sym.hasFlag(ABSOVERRIDE) && !sym.owner.isTrait)
context.error(sym.pos, "`abstract override' modifier only allowed for members of traits")
if (sym.info.symbol == FunctionClass(0) &&
sym.isValueParameter && sym.owner.isClass && sym.owner.hasFlag(CASE))
context.error(sym.pos, "pass-by-name arguments not allowed for case class parameters");
if ((sym.flags & DEFERRED) != 0) {
if (!sym.isValueParameter && !sym.isTypeParameterOrSkolem &&
(!sym.owner.isClass || sym.owner.isModuleClass || sym.owner.isAnonymousClass)) {
context.error(sym.pos,
"only classes can have declared but undefined members" + varNotice(sym))
sym.resetFlag(DEFERRED)
}
}
checkNoConflict(DEFERRED, PRIVATE)
checkNoConflict(FINAL, SEALED)
checkNoConflict(PRIVATE, PROTECTED)
checkNoConflict(PRIVATE, OVERRIDE)
checkNoConflict(DEFERRED, FINAL)
}
}
/* Is type `tp1' properly contained in type `tp2'? */
def isContainedIn(tp1: Type, tp2: Type) = {
//Console.println("is " + tp1 + " contained in " + tp2 + "?");//DEBUG
new ContainsTraverser(tp1).traverse(tp2).result
}
/* Type `elemtp' is contained in type `tp' is one of the following holds:
* - elemtp is the same as some proper part of tp
* - tp is a function type and elemtp is not
* - tp and elemtp are function types, and arity of tp is greater than arity of elemtp
* - tp and elemtp are both parameterized types with same type constructor and prefix,
* and each type argument of elemtp is contained in the corresponding type argument of tp.
*/
private class ContainsTraverser(elemtp: Type) extends TypeTraverser {
var nested = false
var result = false
def traverse(tp: Type): ContainsTraverser = {
if (!result) {
if (elemtp =:= tp)
result = nested
else if (isFunctionType(tp) &&
(!isFunctionType(elemtp) || tp.typeArgs.length > elemtp.typeArgs.length))
result = true
else Pair(tp, elemtp) match {
case Pair(TypeRef(pre, sym, args), TypeRef(elempre, elemsym, elemargs)) =>
if ((sym == elemsym) && (pre =:= elempre) && (args.length == elemargs.length))
result = List.forall2(elemargs, args) (isContainedIn)
case _ =>
}
}
if (!result) {
tp match {
case SingleType(_, _) => nested = true
case TypeRef(_, _, _) => nested = true
case _ =>
}
mapOver(tp)
}
this
}
}
abstract class TypeCompleter(val tree: Tree) extends LazyType
/** The symbol that which this accessor represents (possibly in part).
* This is used for error messages, where we want to speak in terms
* of the actual declaration or definition, not in terms of the generated setters
* and getters */
def underlying(member: Symbol) =
if (member hasFlag ACCESSOR) {
if (member hasFlag DEFERRED) {
val getter = if (member.isSetter) member.getter(member.owner) else member
val result = getter.owner.newValue(getter.pos, getter.name)
.setInfo(getter.tpe.resultType)
.setFlag(DEFERRED)
if (getter.setter(member.owner) != NoSymbol) result.setFlag(MUTABLE)
result
} else member.accessed
} else member
/** An explanatory note to be added to error messages
* when there's a problem with abstract var defs */
def varNotice(sym: Symbol) =
if (underlying(sym).isVariable)
"\n(Note that variables need to be initialized to be defined)"
else ""
}
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