package dotty.tools
package dotc
package typer
import core._
import ast._
import Trees._, Constants._, StdNames._, Scopes._, Denotations._
import Contexts._, Symbols._, Types._, SymDenotations._, Names._, NameOps._, Flags._, Decorators._
import ast.desugar, ast.desugar._
import ProtoTypes._
import util.Positions._
import util.{Property, SourcePosition, DotClass}
import collection.mutable
import annotation.tailrec
import ErrorReporting._
import tpd.ListOfTreeDecorator
import config.Config
import config.Printers.{typr, completions, noPrinter}
import Annotations._
import Inferencing._
import transform.ValueClasses._
import TypeApplications._
import language.implicitConversions
trait NamerContextOps { this: Context =>
/** Enter symbol into current class, if current class is owner of current context,
* or into current scope, if not. Should always be called instead of scope.enter
* in order to make sure that updates to class members are reflected in
* finger prints.
*/
def enter(sym: Symbol): Symbol = {
ctx.owner match {
case cls: ClassSymbol => cls.enter(sym)
case _ => this.scope.openForMutations.enter(sym)
}
sym
}
/** The denotation with the given name in current context */
def denotNamed(name: Name): Denotation =
if (owner.isClass)
if (outer.owner == owner) { // inner class scope; check whether we are referring to self
if (scope.size == 1) {
val elem = scope.lastEntry
if (elem.name == name) return elem.sym.denot // return self
}
assert(scope.size <= 1, scope)
owner.thisType.member(name)
}
else // we are in the outermost context belonging to a class; self is invisible here. See inClassContext.
owner.findMember(name, owner.thisType, EmptyFlags)
else
scope.denotsNamed(name).toDenot(NoPrefix)
/** Either the current scope, or, if the current context owner is a class,
* the declarations of the current class.
*/
def effectiveScope: Scope =
if (owner != null && owner.isClass) owner.asClass.unforcedDecls
else scope
/** The symbol (stored in some typer's symTree) of an enclosing context definition */
def symOfContextTree(tree: untpd.Tree) = {
def go(ctx: Context): Symbol = {
ctx.typeAssigner match {
case typer: Typer =>
tree.getAttachment(typer.SymOfTree) match {
case Some(sym) => sym
case None =>
var cx = ctx.outer
while (cx.typeAssigner eq typer) cx = cx.outer
go(cx)
}
case _ => NoSymbol
}
}
go(this)
}
/** Context where `sym` is defined, assuming we are in a nested context. */
def defContext(sym: Symbol) =
outersIterator
.dropWhile(_.owner != sym)
.dropWhile(_.owner == sym)
.next
/** The given type, unless `sym` is a constructor, in which case the
* type of the constructed instance is returned
*/
def effectiveResultType(sym: Symbol, typeParams: List[Symbol], given: Type) =
if (sym.name == nme.CONSTRUCTOR) sym.owner.typeRef.appliedTo(typeParams map (_.typeRef))
else given
/** if isConstructor, make sure it has one non-implicit parameter list */
def normalizeIfConstructor(paramSymss: List[List[Symbol]], isConstructor: Boolean) =
if (isConstructor &&
(paramSymss.isEmpty || paramSymss.head.nonEmpty && (paramSymss.head.head is Implicit)))
Nil :: paramSymss
else
paramSymss
/** The method type corresponding to given parameters and result type */
def methodType(typeParams: List[Symbol], valueParamss: List[List[Symbol]], resultType: Type, isJava: Boolean = false)(implicit ctx: Context): Type = {
val monotpe =
(valueParamss :\ resultType) { (params, resultType) =>
val make =
if (params.nonEmpty && (params.head is Implicit)) ImplicitMethodType
else if (isJava) JavaMethodType
else MethodType
if (isJava)
for (param <- params)
if (param.info.isDirectRef(defn.ObjectClass)) param.info = defn.AnyType
make.fromSymbols(params, resultType)
}
if (typeParams.nonEmpty) PolyType.fromSymbols(typeParams, monotpe)
else if (valueParamss.isEmpty) ExprType(monotpe)
else monotpe
}
/** Find moduleClass/sourceModule in effective scope */
private def findModuleBuddy(name: Name)(implicit ctx: Context) = {
val scope = effectiveScope
val it = scope.lookupAll(name).filter(_ is Module)
assert(it.hasNext, s"no companion $name in $scope")
it.next
}
/** Add moduleClass or sourceModule functionality to completer
* for a module or module class
*/
def adjustModuleCompleter(completer: LazyType, name: Name) =
if (name.isTermName)
completer withModuleClass (_ => findModuleBuddy(name.moduleClassName))
else
completer withSourceModule (_ => findModuleBuddy(name.sourceModuleName))
}
/** This class creates symbols from definitions and imports and gives them
* lazy types.
*
* Timeline:
*
* During enter, trees are expanded as necessary, populating the expandedTree map.
* Symbols are created, and the symOfTree map is set up.
*
* Symbol completion causes some trees to be already typechecked and typedTree
* entries are created to associate the typed trees with the untyped expanded originals.
*
* During typer, original trees are first expanded using expandedTree. For each
* expanded member definition or import we extract and remove the corresponding symbol
* from the symOfTree map and complete it. We then consult the typedTree map to see
* whether a typed tree exists already. If yes, the typed tree is returned as result.
* Otherwise, we proceed with regular type checking.
*
* The scheme is designed to allow sharing of nodes, as long as each duplicate appears
* in a different method.
*/
class Namer { typer: Typer =>
import untpd._
val TypedAhead = new Property.Key[tpd.Tree]
val ExpandedTree = new Property.Key[Tree]
val SymOfTree = new Property.Key[Symbol]
/** A partial map from unexpanded member and pattern defs and to their expansions.
* Populated during enterSyms, emptied during typer.
*/
//lazy val expandedTree = new mutable.AnyRefMap[DefTree, Tree]
/*{
override def default(tree: DefTree) = tree // can't have defaults on AnyRefMaps :-(
}*/
/** A map from expanded MemberDef, PatDef or Import trees to their symbols.
* Populated during enterSyms, emptied at the point a typed tree
* with the same symbol is created (this can be when the symbol is completed
* or at the latest when the tree is typechecked.
*/
//lazy val symOfTree = new mutable.AnyRefMap[Tree, Symbol]
/** A map from expanded trees to their typed versions.
* Populated when trees are typechecked during completion (using method typedAhead).
*/
// lazy val typedTree = new mutable.AnyRefMap[Tree, tpd.Tree]
/** A map from method symbols to nested typers.
* Populated when methods are completed. Emptied when they are typechecked.
* The nested typer contains new versions of the four maps above including this
* one, so that trees that are shared between different DefDefs can be independently
* used as indices. It also contains a scope that contains nested parameters.
*/
lazy val nestedTyper = new mutable.AnyRefMap[Symbol, Typer]
/** The scope of the typer.
* For nested typers this is a place parameters are entered during completion
* and where they survive until typechecking. A context with this typer also
* has this scope.
*/
val scope = newScope
/** The symbol of the given expanded tree. */
def symbolOfTree(tree: Tree)(implicit ctx: Context): Symbol = {
val xtree = expanded(tree)
xtree.getAttachment(TypedAhead) match {
case Some(ttree) => ttree.symbol
case none => xtree.attachment(SymOfTree)
}
}
/** The enclosing class with given name; error if none exists */
def enclosingClassNamed(name: TypeName, pos: Position)(implicit ctx: Context): Symbol = {
if (name.isEmpty) NoSymbol
else {
val cls = ctx.owner.enclosingClassNamed(name)
if (!cls.exists) ctx.error(s"no enclosing class or object is named $name", pos)
cls
}
}
/** Record `sym` as the symbol defined by `tree` */
def recordSym(sym: Symbol, tree: Tree)(implicit ctx: Context): Symbol = {
val refs = tree.attachmentOrElse(References, Nil)
if (refs.nonEmpty) {
tree.removeAttachment(References)
refs foreach (_.pushAttachment(OriginalSymbol, sym))
}
tree.pushAttachment(SymOfTree, sym)
sym
}
/** If this tree is a member def or an import, create a symbol of it
* and store in symOfTree map.
*/
def createSymbol(tree: Tree)(implicit ctx: Context): Symbol = {
def privateWithinClass(mods: Modifiers) =
enclosingClassNamed(mods.privateWithin, mods.pos)
def checkFlags(flags: FlagSet) =
if (flags.isEmpty) flags
else {
val (ok, adapted, kind) = tree match {
case tree: TypeDef => (flags.isTypeFlags, flags.toTypeFlags, "type")
case _ => (flags.isTermFlags, flags.toTermFlags, "value")
}
if (!ok)
ctx.error(i"modifier(s) `$flags' incompatible with $kind definition", tree.pos)
adapted
}
/** Add moduleClass/sourceModule to completer if it is for a module val or class */
def adjustIfModule(completer: LazyType, tree: MemberDef) =
if (tree.mods is Module) ctx.adjustModuleCompleter(completer, tree.name.encode)
else completer
typr.println(i"creating symbol for $tree in ${ctx.mode}")
def checkNoConflict(name: Name): Name = {
def errorName(msg: => String) = {
ctx.error(msg, tree.pos)
name.freshened
}
def preExisting = ctx.effectiveScope.lookup(name)
if (ctx.owner is PackageClass)
if (preExisting.isDefinedInCurrentRun)
errorName(s"${preExisting.showLocated} is compiled twice")
else name
else
if ((!ctx.owner.isClass || name.isTypeName) && preExisting.exists)
errorName(i"$name is already defined as $preExisting")
else name
}
val inSuperCall = if (ctx.mode is Mode.InSuperCall) InSuperCall else EmptyFlags
tree match {
case tree: TypeDef if tree.isClassDef =>
val name = checkNoConflict(tree.name.encode).asTypeName
val flags = checkFlags(tree.mods.flags &~ Implicit)
val cls = recordSym(ctx.newClassSymbol(
ctx.owner, name, flags | inSuperCall,
cls => adjustIfModule(new ClassCompleter(cls, tree)(ctx), tree),
privateWithinClass(tree.mods), tree.namePos, ctx.source.file), tree)
cls.completer.asInstanceOf[ClassCompleter].init()
cls
case tree: MemberDef =>
val name = checkNoConflict(tree.name.encode)
val flags = checkFlags(tree.mods.flags)
val isDeferred = lacksDefinition(tree)
val deferred = if (isDeferred) Deferred else EmptyFlags
val method = if (tree.isInstanceOf[DefDef]) Method else EmptyFlags
val inSuperCall1 = if (tree.mods is ParamOrAccessor) EmptyFlags else inSuperCall
// suppress inSuperCall for constructor parameters
val higherKinded = tree match {
case tree: TypeDef if tree.tparams.nonEmpty && isDeferred => HigherKinded
case _ => EmptyFlags
}
// to complete a constructor, move one context further out -- this
// is the context enclosing the class. Note that the context in which a
// constructor is recorded and the context in which it is completed are
// different: The former must have the class as owner (because the
// constructor is owned by the class), the latter must not (because
// constructor parameters are interpreted as if they are outside the class).
// Don't do this for Java constructors because they need to see the import
// of the companion object, and it is not necessary for them because they
// have no implementation.
val cctx = if (tree.name == nme.CONSTRUCTOR && !(tree.mods is JavaDefined)) ctx.outer else ctx
val completer = tree match {
case tree: TypeDef => new TypeDefCompleter(tree)(cctx)
case _ => new Completer(tree)(cctx)
}
recordSym(ctx.newSymbol(
ctx.owner, name, flags | deferred | method | higherKinded | inSuperCall1,
adjustIfModule(completer, tree),
privateWithinClass(tree.mods), tree.namePos), tree)
case tree: Import =>
recordSym(ctx.newSymbol(
ctx.owner, nme.IMPORT, Synthetic, new Completer(tree), NoSymbol, tree.pos), tree)
case _ =>
NoSymbol
}
}
/** If `sym` exists, enter it in effective scope. Check that
* package members are not entered twice in the same run.
*/
def enterSymbol(sym: Symbol)(implicit ctx: Context) = {
if (sym.exists) {
typr.println(s"entered: $sym in ${ctx.owner} and ${ctx.effectiveScope}")
ctx.enter(sym)
}
sym
}
/** Create package if it does not yet exist. */
private def createPackageSymbol(pid: RefTree)(implicit ctx: Context): Symbol = {
val pkgOwner = pid match {
case Ident(_) => if (ctx.owner eq defn.EmptyPackageClass) defn.RootClass else ctx.owner
case Select(qual: RefTree, _) => createPackageSymbol(qual).moduleClass
}
val existing = pkgOwner.info.decls.lookup(pid.name)
if ((existing is Package) && (pkgOwner eq existing.owner)) existing
else ctx.newCompletePackageSymbol(pkgOwner, pid.name.asTermName).entered
}
/** Expand tree and store in `expandedTree` */
def expand(tree: Tree)(implicit ctx: Context): Unit = tree match {
case mdef: DefTree =>
val expanded = desugar.defTree(mdef)
typr.println(i"Expansion: $mdef expands to $expanded")
if (expanded ne mdef) mdef.pushAttachment(ExpandedTree, expanded)
case _ =>
}
/** The expanded version of this tree, or tree itself if not expanded */
def expanded(tree: Tree)(implicit ctx: Context): Tree = tree match {
case ddef: DefTree => ddef.attachmentOrElse(ExpandedTree, ddef)
case _ => tree
}
/** A new context that summarizes an import statement */
def importContext(sym: Symbol, selectors: List[Tree])(implicit ctx: Context) =
ctx.fresh.setImportInfo(new ImportInfo(sym, selectors))
/** A new context for the interior of a class */
def inClassContext(selfInfo: DotClass /* Should be Type | Symbol*/)(implicit ctx: Context): Context = {
val localCtx: Context = ctx.fresh.setNewScope
selfInfo match {
case sym: Symbol if sym.exists && sym.name != nme.WILDCARD =>
localCtx.scope.openForMutations.enter(sym)
case _ =>
}
localCtx
}
/** For all class definitions `stat` in `xstats`: If the companion class if not also defined
* in `xstats`, invalidate it by setting its info to NoType.
*/
def invalidateCompanions(pkg: Symbol, xstats: List[untpd.Tree])(implicit ctx: Context): Unit = {
val definedNames = xstats collect { case stat: NameTree => stat.name }
def invalidate(name: TypeName) =
if (!(definedNames contains name)) {
val member = pkg.info.decl(name).asSymDenotation
if (member.isClass && !(member is Package)) member.info = NoType
}
xstats foreach {
case stat: TypeDef if stat.isClassDef =>
invalidate(stat.name.moduleClassName)
case _ =>
}
}
/** Expand tree and create top-level symbols for statement and enter them into symbol table */
def index(stat: Tree)(implicit ctx: Context): Context = {
expand(stat)
indexExpanded(stat)
}
/** Create top-level symbols for all statements in the expansion of this statement and
* enter them into symbol table
*/
def indexExpanded(origStat: Tree)(implicit ctx: Context): Context = {
def recur(stat: Tree): Context = stat match {
case pcl: PackageDef =>
val pkg = createPackageSymbol(pcl.pid)
index(pcl.stats)(ctx.fresh.setOwner(pkg.moduleClass))
invalidateCompanions(pkg, Trees.flatten(pcl.stats map expanded))
setDocstring(pkg, stat)
ctx
case imp: Import =>
importContext(createSymbol(imp), imp.selectors)
case mdef: DefTree =>
val sym = enterSymbol(createSymbol(mdef))
setDocstring(sym, origStat)
addEnumConstants(mdef, sym)
ctx
case stats: Thicket =>
stats.toList.foreach(recur)
ctx
case _ =>
ctx
}
recur(expanded(origStat))
}
/** Determines whether this field holds an enum constant.
* To qualify, the following conditions must be met:
* - The field's class has the ENUM flag set
* - The field's class extends java.lang.Enum
* - The field has the ENUM flag set
* - The field is static
* - The field is stable
*/
def isEnumConstant(vd: ValDef)(implicit ctx: Context) = {
// val ownerHasEnumFlag =
// Necessary to check because scalac puts Java's static members into the companion object
// while Scala's enum constants live directly in the class.
// We don't check for clazz.superClass == JavaEnumClass, because this causes a illegal
// cyclic reference error. See the commit message for details.
// if (ctx.compilationUnit.isJava) ctx.owner.companionClass.is(Enum) else ctx.owner.is(Enum)
vd.mods.is(allOf(Enum, Stable, JavaStatic, JavaDefined)) // && ownerHasEnumFlag
}
/** Add java enum constants */
def addEnumConstants(mdef: DefTree, sym: Symbol)(implicit ctx: Context): Unit = mdef match {
case vdef: ValDef if (isEnumConstant(vdef)) =>
val enumClass = sym.owner.linkedClass
if (!(enumClass is Flags.Sealed)) enumClass.setFlag(Flags.AbstractSealed)
enumClass.addAnnotation(Annotation.makeChild(sym))
case _ =>
}
def setDocstring(sym: Symbol, tree: Tree)(implicit ctx: Context) = tree match {
case t: MemberDef => ctx.docbase.addDocstring(sym, t.rawComment)
case _ => ()
}
/** Create top-level symbols for statements and enter them into symbol table */
def index(stats: List[Tree])(implicit ctx: Context): Context = {
val classDef = mutable.Map[TypeName, TypeDef]()
val moduleDef = mutable.Map[TypeName, TypeDef]()
/** Merge the definitions of a synthetic companion generated by a case class
* and the real companion, if both exist.
*/
def mergeCompanionDefs() = {
for (cdef @ TypeDef(name, _) <- stats)
if (cdef.isClassDef) {
classDef(name) = cdef
cdef.attachmentOrElse(ExpandedTree, cdef) match {
case Thicket(cls :: mval :: (mcls @ TypeDef(_, _: Template)) :: crest) =>
moduleDef(name) = mcls
case _ =>
}
}
for (mdef @ ModuleDef(name, _) <- stats if !mdef.mods.is(Flags.Package)) {
val typName = name.toTypeName
val Thicket(vdef :: (mcls @ TypeDef(_, impl: Template)) :: Nil) = mdef.attachment(ExpandedTree)
moduleDef(typName) = mcls
classDef get name.toTypeName match {
case Some(cdef) =>
cdef.attachmentOrElse(ExpandedTree, cdef) match {
case Thicket(cls :: mval :: TypeDef(_, compimpl: Template) :: crest) =>
val mcls1 = cpy.TypeDef(mcls)(
rhs = cpy.Template(impl)(body = compimpl.body ++ impl.body))
mdef.putAttachment(ExpandedTree, Thicket(vdef :: mcls1 :: Nil))
moduleDef(typName) = mcls1
cdef.putAttachment(ExpandedTree, Thicket(cls :: crest))
case _ =>
}
case none =>
}
}
}
def createLinks(classTree: TypeDef, moduleTree: TypeDef)(implicit ctx: Context) = {
val claz = ctx.denotNamed(classTree.name.encode).symbol
val modl = ctx.denotNamed(moduleTree.name.encode).symbol
ctx.synthesizeCompanionMethod(nme.COMPANION_CLASS_METHOD, claz, modl).entered
ctx.synthesizeCompanionMethod(nme.COMPANION_MODULE_METHOD, modl, claz).entered
}
def createCompanionLinks(implicit ctx: Context): Unit = {
for (cdef @ TypeDef(name, _) <- classDef.values) {
moduleDef.getOrElse(name, EmptyTree) match {
case t: TypeDef =>
createLinks(cdef, t)
case EmptyTree =>
}
}
}
stats foreach expand
mergeCompanionDefs()
val ctxWithStats = (ctx /: stats) ((ctx, stat) => indexExpanded(stat)(ctx))
createCompanionLinks(ctxWithStats)
ctxWithStats
}
/** The completer of a symbol defined by a member def or import (except ClassSymbols) */
class Completer(val original: Tree)(implicit ctx: Context) extends LazyType {
protected def localContext(owner: Symbol) = ctx.fresh.setOwner(owner).setTree(original)
protected def typeSig(sym: Symbol): Type = original match {
case original: ValDef =>
if (sym is Module) moduleValSig(sym)
else valOrDefDefSig(original, sym, Nil, Nil, identity)(localContext(sym).setNewScope)
case original: DefDef =>
val typer1 = ctx.typer.newLikeThis
nestedTyper(sym) = typer1
typer1.defDefSig(original, sym)(localContext(sym).setTyper(typer1))
case imp: Import =>
try {
val expr1 = typedAheadExpr(imp.expr, AnySelectionProto)
ImportType(expr1)
} catch {
case ex: CyclicReference =>
typr.println(s"error while completing ${imp.expr}")
throw ex
}
}
final override def complete(denot: SymDenotation)(implicit ctx: Context) = {
if (completions != noPrinter && ctx.typerState != this.ctx.typerState) {
completions.println(completions.getClass.toString)
def levels(c: Context): Int =
if (c.typerState eq this.ctx.typerState) 0
else if (c.typerState == null) -1
else if (c.outer.typerState == c.typerState) levels(c.outer)
else levels(c.outer) + 1
completions.println(s"!!!completing ${denot.symbol.showLocated} in buried typerState, gap = ${levels(ctx)}")
}
completeInCreationContext(denot)
}
protected def addAnnotations(denot: SymDenotation): Unit = original match {
case original: untpd.MemberDef =>
for (annotTree <- untpd.modsDeco(original).mods.annotations) {
val cls = typedAheadAnnotation(annotTree)
val ann = Annotation.deferred(cls, implicit ctx => typedAnnotation(annotTree))
denot.addAnnotation(ann)
if (cls == defn.InlineAnnot) addInlineInfo(denot, original)
}
case _ =>
}
private def addInlineInfo(denot: SymDenotation, original: untpd.Tree) = original match {
case original: untpd.DefDef =>
Inliner.registerInlineInfo(
denot,
implicit ctx => typedAheadExpr(original).asInstanceOf[tpd.DefDef].rhs
)(localContext(denot.symbol))
case _ =>
}
/** Intentionally left without `implicit ctx` parameter. We need
* to pick up the context at the point where the completer was created.
*/
def completeInCreationContext(denot: SymDenotation): Unit = {
addAnnotations(denot)
denot.info = typeSig(denot.symbol)
Checking.checkWellFormed(denot.symbol)
}
}
class TypeDefCompleter(original: TypeDef)(ictx: Context) extends Completer(original)(ictx) with TypeParamsCompleter {
private var myTypeParams: List[TypeSymbol] = null
private var nestedCtx: Context = null
assert(!original.isClassDef)
def completerTypeParams(sym: Symbol)(implicit ctx: Context): List[TypeSymbol] = {
if (myTypeParams == null) {
//println(i"completing type params of $sym in ${sym.owner}")
nestedCtx = localContext(sym).setNewScope
myTypeParams = {
implicit val ctx: Context = nestedCtx
completeParams(original.tparams)
original.tparams.map(symbolOfTree(_).asType)
}
}
myTypeParams
}
override protected def typeSig(sym: Symbol): Type =
typeDefSig(original, sym, completerTypeParams(sym)(ictx))(nestedCtx)
}
class ClassCompleter(cls: ClassSymbol, original: TypeDef)(ictx: Context) extends Completer(original)(ictx) {
withDecls(newScope)
protected implicit val ctx: Context = localContext(cls).setMode(ictx.mode &~ Mode.InSuperCall)
val TypeDef(name, impl @ Template(constr, parents, self, _)) = original
val (params, rest) = impl.body span {
case td: TypeDef => td.mods is Param
case vd: ValDef => vd.mods is ParamAccessor
case _ => false
}
def init() = index(params)
/** The type signature of a ClassDef with given symbol */
override def completeInCreationContext(denot: SymDenotation): Unit = {
/* The type of a parent constructor. Types constructor arguments
* only if parent type contains uninstantiated type parameters.
*/
def parentType(parent: untpd.Tree)(implicit ctx: Context): Type =
if (parent.isType) {
typedAheadType(parent, AnyTypeConstructorProto).tpe
} else {
val (core, targs) = stripApply(parent) match {
case TypeApply(core, targs) => (core, targs)
case core => (core, Nil)
}
val Select(New(tpt), nme.CONSTRUCTOR) = core
val targs1 = targs map (typedAheadType(_))
val ptype = typedAheadType(tpt).tpe appliedTo targs1.tpes
if (ptype.typeParams.isEmpty) ptype
else typedAheadExpr(parent).tpe
}
/* Check parent type tree `parent` for the following well-formedness conditions:
* (1) It must be a class type with a stable prefix (@see checkClassTypeWithStablePrefix)
* (2) If may not derive from itself
* (3) Overriding type parameters must be correctly forwarded. (@see checkTypeParamOverride)
*/
def checkedParentType(parent: untpd.Tree, paramAccessors: List[Symbol]): Type = {
val ptype = parentType(parent)(ctx.superCallContext)
if (cls.isRefinementClass) ptype
else {
val pt = checkClassType(ptype, parent.pos,
traitReq = parent ne parents.head, stablePrefixReq = true)
if (pt.derivesFrom(cls)) {
val addendum = parent match {
case Select(qual: Super, _) if ctx.scala2Mode =>
"\n(Note that inheriting a class of the same name is no longer allowed)"
case _ => ""
}
ctx.error(i"cyclic inheritance: $cls extends itself$addendum", parent.pos)
defn.ObjectType
}
else if (!paramAccessors.forall(checkTypeParamOverride(pt, _)))
defn.ObjectType
else pt
}
}
/* Check that every parameter with the same name as a visible named parameter in the parent
* class satisfies the following two conditions:
* (1) The overriding parameter is also named (i.e. not local/name mangled).
* (2) The overriding parameter is passed on directly to the parent parameter, or the
* parent parameter is not fully defined.
* @return true if conditions are satisfied, false otherwise.
*/
def checkTypeParamOverride(parent: Type, paramAccessor: Symbol): Boolean = {
var ok = true
val pname = paramAccessor.name
def illegal(how: String): Unit = {
ctx.error(em"Illegal override of public type parameter $pname in $parent$how", paramAccessor.pos)
ok = false
}
def checkAlias(tp: Type): Unit = tp match {
case tp: RefinedType =>
if (tp.refinedName == pname)
tp.refinedInfo match {
case TypeAlias(alias) =>
alias match {
case TypeRef(pre, name1) if name1 == pname && (pre =:= cls.thisType) =>
// OK, parameter is passed on directly
case _ =>
illegal(em".\nParameter is both redeclared and instantiated with $alias.")
}
case _ => // OK, argument is not fully defined
}
else checkAlias(tp.parent)
case _ =>
}
if (parent.nonPrivateMember(paramAccessor.name).symbol.is(Param))
if (paramAccessor is Private)
illegal("\nwith private parameter. Parameter definition needs to be prefixed with `type'.")
else
checkAlias(parent)
ok
}
addAnnotations(denot)
val selfInfo =
if (self.isEmpty) NoType
else if (cls.is(Module)) {
val moduleType = cls.owner.thisType select sourceModule
if (self.name == nme.WILDCARD) moduleType
else recordSym(
ctx.newSymbol(cls, self.name, self.mods.flags, moduleType, coord = self.pos),
self)
}
else createSymbol(self)
// pre-set info, so that parent types can refer to type params
val tempInfo = new TempClassInfo(cls.owner.thisType, cls, decls, selfInfo)
denot.info = tempInfo
// Ensure constructor is completed so that any parameter accessors
// which have type trees deriving from its parameters can be
// completed in turn. Note that parent types access such parameter
// accessors, that's why the constructor needs to be completed before
// the parent types are elaborated.
index(constr)
symbolOfTree(constr).ensureCompleted()
index(rest)(inClassContext(selfInfo))
val tparamAccessors = decls.filter(_ is TypeParamAccessor).toList
val parentTypes = ensureFirstIsClass(parents.map(checkedParentType(_, tparamAccessors)))
val parentRefs = ctx.normalizeToClassRefs(parentTypes, cls, decls)
typr.println(s"completing $denot, parents = $parents, parentTypes = $parentTypes, parentRefs = $parentRefs")
tempInfo.finalize(denot, parentRefs)
Checking.checkWellFormed(cls)
if (isDerivedValueClass(cls)) cls.setFlag(Final)
cls.setApplicableFlags(
(NoInitsInterface /: impl.body)((fs, stat) => fs & defKind(stat)))
}
}
/** Typecheck tree during completion, and remember result in typedtree map */
private def typedAheadImpl(tree: Tree, pt: Type)(implicit ctx: Context): tpd.Tree = {
val xtree = expanded(tree)
xtree.getAttachment(TypedAhead) match {
case Some(ttree) => ttree
case none =>
val ttree = typer.typed(tree, pt)
xtree.pushAttachment(TypedAhead, ttree)
ttree
}
}
def typedAheadType(tree: Tree, pt: Type = WildcardType)(implicit ctx: Context): tpd.Tree =
typedAheadImpl(tree, pt)(ctx retractMode Mode.PatternOrType addMode Mode.Type)
def typedAheadExpr(tree: Tree, pt: Type = WildcardType)(implicit ctx: Context): tpd.Tree =
typedAheadImpl(tree, pt)(ctx retractMode Mode.PatternOrType)
def typedAheadAnnotation(tree: Tree)(implicit ctx: Context): Symbol = tree match {
case Apply(fn, _) => typedAheadAnnotation(fn)
case TypeApply(fn, _) => typedAheadAnnotation(fn)
case Select(qual, nme.CONSTRUCTOR) => typedAheadAnnotation(qual)
case New(tpt) => typedAheadType(tpt).tpe.classSymbol
}
/** Enter and typecheck parameter list */
def completeParams(params: List[MemberDef])(implicit ctx: Context) = {
index(params)
for (param <- params) typedAheadExpr(param)
}
/** The signature of a module valdef.
* This will compute the corresponding module class TypeRef immediately
* without going through the defined type of the ValDef. This is necessary
* to avoid cyclic references involving imports and module val defs.
*/
def moduleValSig(sym: Symbol)(implicit ctx: Context): Type = {
val clsName = sym.name.moduleClassName
val cls = ctx.denotNamed(clsName) suchThat (_ is ModuleClass)
ctx.owner.thisType select (clsName, cls)
}
/** The type signature of a ValDef or DefDef
* @param mdef The definition
* @param sym Its symbol
* @param paramFn A wrapping function that produces the type of the
* defined symbol, given its final return type
*/
def valOrDefDefSig(mdef: ValOrDefDef, sym: Symbol, typeParams: List[Symbol], paramss: List[List[Symbol]], paramFn: Type => Type)(implicit ctx: Context): Type = {
def inferredType = {
/** A type for this definition that might be inherited from elsewhere:
* If this is a setter parameter, the corresponding getter type.
* If this is a class member, the conjunction of all result types
* of overridden methods.
* NoType if neither case holds.
*/
val inherited =
if (sym.owner.isTerm) NoType
else {
// TODO: Look only at member of supertype instead?
lazy val schema = paramFn(WildcardType)
val site = sym.owner.thisType
((NoType: Type) /: sym.owner.info.baseClasses.tail) { (tp, cls) =>
def instantiatedResType(info: Type, tparams: List[Symbol], paramss: List[List[Symbol]]): Type = info match {
case info: PolyType =>
if (info.paramNames.length == typeParams.length)
instantiatedResType(info.instantiate(tparams.map(_.typeRef)), Nil, paramss)
else NoType
case info: MethodType =>
paramss match {
case params :: paramss1 if info.paramNames.length == params.length =>
instantiatedResType(info.instantiate(params.map(_.termRef)), tparams, paramss1)
case _ =>
NoType
}
case _ =>
if (tparams.isEmpty && paramss.isEmpty) info.widenExpr
else NoType
}
val iRawInfo =
cls.info.nonPrivateDecl(sym.name).matchingDenotation(site, schema).info
val iResType = instantiatedResType(iRawInfo, typeParams, paramss).asSeenFrom(site, cls)
if (iResType.exists)
typr.println(i"using inherited type for ${mdef.name}; raw: $iRawInfo, inherited: $iResType")
tp & iResType
}
}
/** The proto-type to be used when inferring the result type from
* the right hand side. This is `WildcardType` except if the definition
* is a default getter. In that case, the proto-type is the type of
* the corresponding parameter where bound parameters are replaced by
* Wildcards.
*/
def rhsProto = {
val name = sym.asTerm.name
val idx = name.defaultGetterIndex
if (idx < 0) WildcardType
else {
val original = name.defaultGetterToMethod
val meth: Denotation =
if (original.isConstructorName && (sym.owner is ModuleClass))
sym.owner.companionClass.info.decl(nme.CONSTRUCTOR)
else
ctx.defContext(sym).denotNamed(original)
def paramProto(paramss: List[List[Type]], idx: Int): Type = paramss match {
case params :: paramss1 =>
if (idx < params.length) wildApprox(params(idx))
else paramProto(paramss1, idx - params.length)
case nil =>
WildcardType
}
val defaultAlts = meth.altsWith(_.hasDefaultParams)
if (defaultAlts.length == 1)
paramProto(defaultAlts.head.info.widen.paramTypess, idx)
else
WildcardType
}
}
// println(s"final inherited for $sym: ${inherited.toString}") !!!
// println(s"owner = ${sym.owner}, decls = ${sym.owner.info.decls.show}")
def isInline = sym.is(Final, butNot = Method | Mutable)
// Widen rhs type and approximate `|' but keep ConstantTypes if
// definition is inline (i.e. final in Scala2).
def widenRhs(tp: Type): Type = tp.widenTermRefExpr match {
case tp: ConstantType if isInline => tp
case _ => tp.widen.approximateUnion
}
// Replace aliases to Unit by Unit itself. If we leave the alias in
// it would be erased to BoxedUnit.
def dealiasIfUnit(tp: Type) = if (tp.isRef(defn.UnitClass)) defn.UnitType else tp
val rhsCtx = ctx.addMode(Mode.InferringReturnType)
def rhsType = typedAheadExpr(mdef.rhs, inherited orElse rhsProto)(rhsCtx).tpe
def cookedRhsType = ctx.deskolemize(dealiasIfUnit(widenRhs(rhsType)))
lazy val lhsType = fullyDefinedType(cookedRhsType, "right-hand side", mdef.pos)
//if (sym.name.toString == "y") println(i"rhs = $rhsType, cooked = $cookedRhsType")
if (inherited.exists)
if (sym.is(Final, butNot = Method) && lhsType.isInstanceOf[ConstantType])
lhsType // keep constant types that fill in for a non-constant (to be revised when inline has landed).
else inherited
else {
if (sym is Implicit) {
val resStr = if (mdef.isInstanceOf[DefDef]) "result " else ""
ctx.error(s"${resStr}type of implicit definition needs to be given explicitly", mdef.pos)
sym.resetFlag(Implicit)
}
lhsType orElse WildcardType
}
}
val tptProto = mdef.tpt match {
case _: untpd.DerivedTypeTree =>
WildcardType
case TypeTree(untpd.EmptyTree) =>
inferredType
case TypedSplice(tpt: TypeTree) if !isFullyDefined(tpt.tpe, ForceDegree.none) =>
val rhsType = typedAheadExpr(mdef.rhs, tpt.tpe).tpe
mdef match {
case mdef: DefDef if mdef.name == nme.ANON_FUN =>
val hygienicType = avoid(rhsType, paramss.flatten)
if (!(hygienicType <:< tpt.tpe))
ctx.error(i"return type ${tpt.tpe} of lambda cannot be made hygienic;\n" +
i"it is not a supertype of the hygienic type $hygienicType", mdef.pos)
//println(i"lifting $rhsType over $paramss -> $hygienicType = ${tpt.tpe}")
//println(TypeComparer.explained { implicit ctx => hygienicType <:< tpt.tpe })
case _ =>
}
WildcardType
case _ =>
WildcardType
}
paramFn(typedAheadType(mdef.tpt, tptProto).tpe)
}
/** The type signature of a DefDef with given symbol */
def defDefSig(ddef: DefDef, sym: Symbol)(implicit ctx: Context) = {
val DefDef(name, tparams, vparamss, _, _) = ddef
val isConstructor = name == nme.CONSTRUCTOR
// The following 3 lines replace what was previously just completeParams(tparams).
// But that can cause bad bounds being computed, as witnessed by
// tests/pos/paramcycle.scala. The problematic sequence is this:
// 0. Class constructor gets completed.
// 1. Type parameter CP of constructor gets completed
// 2. As a first step CP's bounds are set to Nothing..Any.
// 3. CP's real type bound demands the completion of corresponding type parameter DP
// of enclosing class.
// 4. Type parameter DP has a rhs a DerivedFromParam tree, as installed by
// desugar.classDef
// 5. The completion of DP then copies the current bounds of CP, which are still Nothing..Any.
// 6. The completion of CP finishes installing the real type bounds.
// Consequence: CP ends up with the wrong bounds!
// To avoid this we always complete type parameters of a class before the type parameters
// of the class constructor, but after having indexed the constructor parameters (because
// indexing is needed to provide a symbol to copy for DP's completion.
// With the patch, we get instead the following sequence:
// 0. Class constructor gets completed.
// 1. Class constructor parameter CP is indexed.
// 2. Class parameter DP starts completion.
// 3. Info of CP is computed (to be copied to DP).
// 4. CP is completed.
// 5. Info of CP is copied to DP and DP is completed.
index(tparams)
if (isConstructor) sym.owner.typeParams.foreach(_.ensureCompleted())
for (tparam <- tparams) typedAheadExpr(tparam)
vparamss foreach completeParams
def typeParams = tparams map symbolOfTree
val paramSymss = ctx.normalizeIfConstructor(vparamss.nestedMap(symbolOfTree), isConstructor)
def wrapMethType(restpe: Type): Type = {
val restpe1 = // try to make anonymous functions non-dependent, so that they can be used in closures
if (name == nme.ANON_FUN) avoid(restpe, paramSymss.flatten)
else restpe
ctx.methodType(tparams map symbolOfTree, paramSymss, restpe1, isJava = ddef.mods is JavaDefined)
}
if (isConstructor) {
// set result type tree to unit, but take the current class as result type of the symbol
typedAheadType(ddef.tpt, defn.UnitType)
wrapMethType(ctx.effectiveResultType(sym, typeParams, NoType))
}
else valOrDefDefSig(ddef, sym, typeParams, paramSymss, wrapMethType)
}
def typeDefSig(tdef: TypeDef, sym: Symbol, tparamSyms: List[TypeSymbol])(implicit ctx: Context): Type = {
def abstracted(tp: Type): Type =
if (tparamSyms.nonEmpty) tp.LambdaAbstract(tparamSyms) else tp
val dummyInfo = abstracted(TypeBounds.empty)
sym.info = dummyInfo
// Temporarily set info of defined type T to ` >: Nothing <: Any.
// This is done to avoid cyclic reference errors for F-bounds.
// This is subtle: `sym` has now an empty TypeBounds, but is not automatically
// made an abstract type. If it had been made an abstract type, it would count as an
// abstract type of its enclosing class, which might make that class an invalid
// prefix. I verified this would lead to an error when compiling io.ClassPath.
// A distilled version is in pos/prefix.scala.
//
// The scheme critically relies on an implementation detail of isRef, which
// inspects a TypeRef's info, instead of simply dealiasing alias types.
val isDerived = tdef.rhs.isInstanceOf[untpd.DerivedTypeTree]
val rhsBodyType = typedAheadType(tdef.rhs).tpe
val rhsType = if (isDerived) rhsBodyType else abstracted(rhsBodyType)
val unsafeInfo = rhsType match {
case bounds: TypeBounds => bounds
case alias => TypeAlias(alias, if (sym is Local) sym.variance else 0)
}
if (isDerived) sym.info = unsafeInfo
else {
sym.info = NoCompleter
sym.info = checkNonCyclic(sym, unsafeInfo, reportErrors = true)
}
// Here we pay the price for the cavalier setting info to TypeBounds.empty above.
// We need to compensate by invalidating caches in references that might
// still contain the TypeBounds.empty. If we do not do this, stdlib factories
// fail with a bounds error in PostTyper.
def ensureUpToDate(tp: Type, outdated: Type) = tp match {
case tref: TypeRef if tref.info == outdated && sym.info != outdated =>
tref.uncheckedSetSym(null)
case _ =>
}
ensureUpToDate(sym.typeRef, dummyInfo)
ensureUpToDate(sym.typeRef.appliedTo(tparamSyms.map(_.typeRef)), TypeBounds.empty)
sym.info
}
}