/
Namers.scala
1787 lines (1607 loc) · 75 KB
/
Namers.scala
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/* NSC -- new Scala compiler
* Copyright 2005-2013 LAMP/EPFL
* @author Martin Odersky
*/
package scala.tools.nsc
package typechecker
import scala.collection.mutable
import symtab.Flags._
import scala.language.postfixOps
import scala.reflect.internal.util.ListOfNil
/** This trait declares methods to create symbols and to enter them into scopes.
*
* @author Martin Odersky
* @version 1.0
*/
trait Namers extends MethodSynthesis {
self: Analyzer =>
import global._
import definitions._
var _lockedCount = 0
def lockedCount = this._lockedCount
/** Replaces any Idents for which cond is true with fresh TypeTrees().
* Does the same for any trees containing EmptyTrees.
*/
private class TypeTreeSubstituter(cond: Name => Boolean) extends Transformer {
override def transform(tree: Tree): Tree = tree match {
case Ident(name) if cond(name) => TypeTree()
case _ => super.transform(tree)
}
def apply(tree: Tree) = {
val r = transform(tree)
if (r exists { case tt: TypeTree => tt.isEmpty case _ => false })
TypeTree()
else r
}
}
private def isTemplateContext(ctx: Context): Boolean = ctx.tree match {
case Template(_, _, _) => true
case Import(_, _) => isTemplateContext(ctx.outer)
case _ => false
}
private class NormalNamer(context: Context) extends Namer(context)
def newNamer(context: Context): Namer = new NormalNamer(context)
abstract class Namer(val context: Context) extends MethodSynth with NamerContextErrors { thisNamer =>
// overridden by the presentation compiler
def saveDefaultGetter(meth: Symbol, default: Symbol) { }
import NamerErrorGen._
val typer = newTyper(context)
private lazy val innerNamer =
if (isTemplateContext(context)) createInnerNamer() else this
def createNamer(tree: Tree): Namer = {
val sym = tree match {
case ModuleDef(_, _, _) => tree.symbol.moduleClass
case _ => tree.symbol
}
def isConstrParam(vd: ValDef) = {
(sym hasFlag PARAM | PRESUPER) &&
!vd.mods.isJavaDefined &&
sym.owner.isConstructor
}
val ownerCtx = tree match {
case vd: ValDef if isConstrParam(vd) =>
context.makeConstructorContext
case _ =>
context
}
newNamer(ownerCtx.makeNewScope(tree, sym))
}
def createInnerNamer() = {
newNamer(context.make(context.tree, owner, newScope))
}
def createPrimaryConstructorParameterNamer: Namer = { //todo: can we merge this with SCCmode?
val classContext = context.enclClass
val outerContext = classContext.outer.outer
val paramContext = outerContext.makeNewScope(outerContext.tree, outerContext.owner)
owner.unsafeTypeParams foreach (paramContext.scope enter _)
newNamer(paramContext)
}
def enclosingNamerWithScope(scope: Scope) = {
var cx = context
while (cx != NoContext && cx.scope != scope) cx = cx.outer
if (cx == NoContext || cx == context) thisNamer
else newNamer(cx)
}
def enterValueParams(vparamss: List[List[ValDef]]): List[List[Symbol]] = {
mmap(vparamss) { param =>
val sym = assignSymbol(param, param.name, mask = ValueParameterFlags)
setPrivateWithin(param, sym)
enterInScope(sym)
sym setInfo monoTypeCompleter(param)
}
}
protected def owner = context.owner
def contextFile = context.unit.source.file
def typeErrorHandler[T](tree: Tree, alt: T): PartialFunction[Throwable, T] = {
case ex: TypeError =>
// H@ need to ensure that we handle only cyclic references
TypeSigError(tree, ex)
alt
}
// All lazy vals need accessors, including those owned by terms (e.g., in method) or private[this] in a class
def deriveAccessors(vd: ValDef) = vd.mods.isLazy || (owner.isClass && deriveAccessorsInClass(vd))
private def deriveAccessorsInClass(vd: ValDef) =
!vd.mods.isPrivateLocal && // note, private[this] lazy vals do get accessors -- see outer disjunction of deriveAccessors
!(vd.name startsWith nme.OUTER) && // outer accessors are added later, in explicitouter
!isEnumConstant(vd) // enums can only occur in classes, so only check here
/** 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) = {
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 (context.unit.isJava) owner.companionClass.hasJavaEnumFlag else owner.hasJavaEnumFlag
vd.mods.hasAllFlags(JAVA_ENUM | STABLE | STATIC) && ownerHasEnumFlag
}
def setPrivateWithin[T <: Symbol](tree: Tree, sym: T, mods: Modifiers): T =
if (sym.isPrivateLocal || !mods.hasAccessBoundary) sym
else sym setPrivateWithin typer.qualifyingClass(tree, mods.privateWithin, packageOK = true)
def setPrivateWithin(tree: MemberDef, sym: Symbol): Symbol =
setPrivateWithin(tree, sym, tree.mods)
def inConstructorFlag: Long = {
val termOwnedContexts: List[Context] =
context.enclosingContextChain.takeWhile(c => c.owner.isTerm && !c.owner.isAnonymousFunction)
val constructorNonSuffix = termOwnedContexts exists (c => c.owner.isConstructor && !c.inConstructorSuffix)
val earlyInit = termOwnedContexts exists (_.owner.isEarlyInitialized)
if (constructorNonSuffix || earlyInit) INCONSTRUCTOR else 0L
}
def moduleClassFlags(moduleFlags: Long) =
(moduleFlags & ModuleToClassFlags) | inConstructorFlag
def updatePosFlags(sym: Symbol, pos: Position, flags: Long): Symbol = {
debuglog("[overwrite] " + sym)
val newFlags = (sym.flags & LOCKED) | flags
// !!! needed for: pos/t5954d; the uniques type cache will happily serve up the same TypeRef
// over this mutated symbol, and we witness a stale cache for `parents`.
invalidateCaches(sym.rawInfo, sym :: sym.moduleClass :: Nil)
sym reset NoType setFlag newFlags setPos pos
sym.moduleClass andAlso (updatePosFlags(_, pos, moduleClassFlags(flags)))
if (sym.isTopLevel) {
companionSymbolOf(sym, context) andAlso { companion =>
val assignNoType = companion.rawInfo match {
case _: SymLoader => true
case tp => tp.isComplete && (runId(sym.validTo) != currentRunId)
}
// pre-set linked symbol to NoType, in case it is not loaded together with this symbol.
if (assignNoType)
companion setInfo NoType
}
}
sym
}
def namerOf(sym: Symbol): Namer = {
val usePrimary = sym.isTerm && (
(sym.isParamAccessor)
|| (sym.isParameter && sym.owner.isPrimaryConstructor)
)
if (usePrimary) createPrimaryConstructorParameterNamer
else innerNamer
}
// FIXME - this logic needs to be thoroughly explained
// and justified. I know it's wrong with respect to package
// objects, but I think it's also wrong in other ways.
protected def conflict(newS: Symbol, oldS: Symbol) = (
( !oldS.isSourceMethod
|| nme.isSetterName(newS.name)
|| newS.isTopLevel
) &&
!( // @M: allow repeated use of `_` for higher-order type params
(newS.owner.isTypeParameter || newS.owner.isAbstractType)
// FIXME: name comparisons not successful, are these underscores
// sometimes nme.WILDCARD and sometimes tpnme.WILDCARD?
&& (newS.name string_== nme.WILDCARD)
)
)
private def allowsOverload(sym: Symbol) = (
sym.isSourceMethod && sym.owner.isClass && !sym.isTopLevel
)
private def inCurrentScope(m: Symbol): Boolean = {
if (owner.isClass) owner == m.owner
else m.owner.isClass && context.scope == m.owner.info.decls
}
/** Enter symbol into context's scope and return symbol itself */
def enterInScope(sym: Symbol): Symbol = enterInScope(sym, context.scope)
/** Enter symbol into given scope and return symbol itself */
def enterInScope(sym: Symbol, scope: Scope): Symbol = {
// FIXME - this is broken in a number of ways.
//
// 1) If "sym" allows overloading, that is not itself sufficient to skip
// the check, because "prev.sym" also must allow overloading.
//
// 2) There is nothing which reconciles a package's scope with
// the package object's scope. This is the source of many bugs
// with e.g. defining a case class in a package object. When
// compiling against classes, the class symbol is created in the
// package and in the package object, and the conflict is undetected.
// There is also a non-deterministic outcome for situations like
// an object with the same name as a method in the package object.
// allow for overloaded methods
if (!allowsOverload(sym)) {
val prev = scope.lookupEntry(sym.name)
if ((prev ne null) && prev.owner == scope && conflict(sym, prev.sym)) {
if (sym.isSynthetic || prev.sym.isSynthetic) {
handleSyntheticNameConflict(sym, prev.sym)
handleSyntheticNameConflict(prev.sym, sym)
}
DoubleDefError(sym, prev.sym)
sym setInfo ErrorType
scope unlink prev.sym // let them co-exist...
// FIXME: The comment "let them co-exist" is confusing given that the
// line it comments unlinks one of them. What does it intend?
}
}
scope enter sym
}
/** Logic to handle name conflicts of synthetically generated symbols
* We handle right now: t6227
*/
def handleSyntheticNameConflict(sym1: Symbol, sym2: Symbol) = {
if (sym1.isImplicit && sym1.isMethod && sym2.isModule && sym2.companionClass.isCaseClass)
validate(sym2.companionClass)
}
def enterSym(tree: Tree): Context = pluginsEnterSym(this, tree)
/** Default implementation of `enterSym`.
* Can be overridden by analyzer plugins (see AnalyzerPlugins.pluginsEnterSym for more details)
*/
def standardEnterSym(tree: Tree): Context = {
def dispatch() = {
var returnContext = this.context
tree match {
case tree @ PackageDef(_, _) => enterPackage(tree)
case tree @ ClassDef(_, _, _, _) => enterClassDef(tree)
case tree @ ModuleDef(_, _, _) => enterModuleDef(tree)
case tree @ ValDef(_, _, _, _) => enterValDef(tree)
case tree @ DefDef(_, _, _, _, _, _) => enterDefDef(tree)
case tree @ TypeDef(_, _, _, _) => enterTypeDef(tree)
case DocDef(_, defn) => enterSym(defn)
case tree @ Import(_, _) =>
assignSymbol(tree)
returnContext = context.make(tree)
case _ =>
}
returnContext
}
tree.symbol match {
case NoSymbol => try dispatch() catch typeErrorHandler(tree, this.context)
case sym => enterExistingSym(sym, tree)
}
}
/** Creates a new symbol and assigns it to the tree, returning the symbol
*/
def assignSymbol(tree: Tree): Symbol =
logAssignSymbol(tree, tree match {
case PackageDef(pid, _) => createPackageSymbol(tree.pos, pid)
case Import(_, _) => createImportSymbol(tree)
case mdef: MemberDef => createMemberSymbol(mdef, mdef.name, -1L)
case _ => abort("Unexpected tree: " + tree)
})
def assignSymbol(tree: MemberDef, name: Name, mask: Long): Symbol =
logAssignSymbol(tree, createMemberSymbol(tree, name, mask))
def assignAndEnterSymbol(tree: MemberDef): Symbol = {
val sym = assignSymbol(tree, tree.name, -1L)
setPrivateWithin(tree, sym)
enterInScope(sym)
}
def assignAndEnterFinishedSymbol(tree: MemberDef): Symbol = {
val sym = assignAndEnterSymbol(tree)
sym setInfo completerOf(tree)
// log("[+info] " + sym.fullLocationString)
sym
}
private def logAssignSymbol(tree: Tree, sym: Symbol): Symbol = {
if (isPastTyper) sym.name.toTermName match {
case nme.IMPORT | nme.OUTER | nme.ANON_CLASS_NAME | nme.ANON_FUN_NAME | nme.CONSTRUCTOR => ()
case _ =>
tree match {
case md: DefDef => log("[+symbol] " + sym.debugLocationString)
case _ =>
}
}
tree.symbol = sym
sym
}
/** Create a new symbol at the context owner based on the given tree.
* A different name can be given. If the modifier flags should not be
* be transferred to the symbol as they are, supply a mask containing
* the flags to keep.
*/
def createMemberSymbol(tree: MemberDef, name: Name, mask: Long): Symbol = {
val pos = tree.pos
val isParameter = tree.mods.isParameter
val flags = tree.mods.flags & mask
tree match {
case TypeDef(_, _, _, _) if isParameter => owner.newTypeParameter(name.toTypeName, pos, flags)
case TypeDef(_, _, _, _) => owner.newTypeSymbol(name.toTypeName, pos, flags)
case DefDef(_, nme.CONSTRUCTOR, _, _, _, _) => owner.newConstructor(pos, flags)
case DefDef(_, _, _, _, _, _) => owner.newMethod(name.toTermName, pos, flags)
case ClassDef(_, _, _, _) => owner.newClassSymbol(name.toTypeName, pos, flags)
case ModuleDef(_, _, _) => owner.newModule(name.toTermName, pos, flags)
case PackageDef(pid, _) => createPackageSymbol(pos, pid)
case ValDef(_, _, _, _) =>
if (isParameter) owner.newValueParameter(name.toTermName, pos, flags)
else owner.newValue(name.toTermName, pos, flags)
}
}
def createFieldSymbol(tree: ValDef): TermSymbol =
owner.newValue(tree.localName, tree.pos, tree.mods.flags & FieldFlags | PrivateLocal)
def createImportSymbol(tree: Tree) =
NoSymbol.newImport(tree.pos) setInfo completerOf(tree)
/** All PackageClassInfoTypes come from here. */
def createPackageSymbol(pos: Position, pid: RefTree): Symbol = {
val pkgOwner = pid match {
case Ident(_) => if (owner.isEmptyPackageClass) rootMirror.RootClass else owner
case Select(qual: RefTree, _) => createPackageSymbol(pos, qual).moduleClass
}
val existing = pkgOwner.info.decls.lookup(pid.name)
if (existing.hasPackageFlag && pkgOwner == existing.owner)
existing
else {
val pkg = pkgOwner.newPackage(pid.name.toTermName, pos)
val pkgClass = pkg.moduleClass
val pkgClassInfo = new PackageClassInfoType(newPackageScope(pkgClass), pkgClass)
pkgClass setInfo pkgClassInfo
pkg setInfo pkgClass.tpe
enterInScope(pkg, pkgOwner.info.decls)
}
}
private def enterClassSymbol(tree: ClassDef, clazz: ClassSymbol): Symbol = {
if (clazz.sourceFile != null && clazz.sourceFile != contextFile)
devWarning(s"Source file mismatch in $clazz: ${clazz.sourceFile} vs. $contextFile")
clazz.associatedFile = contextFile
if (clazz.sourceFile != null) {
assert(currentRun.canRedefine(clazz) || clazz.sourceFile == currentRun.symSource(clazz), clazz.sourceFile)
currentRun.symSource(clazz) = clazz.sourceFile
}
registerTopLevelSym(clazz)
assert(clazz.name.toString.indexOf('(') < 0, clazz.name) // )
clazz
}
def enterClassSymbol(tree: ClassDef): Symbol = {
val existing = context.scope.lookup(tree.name)
val isRedefinition = (
existing.isType
&& existing.isTopLevel
&& context.scope == existing.owner.info.decls
&& currentRun.canRedefine(existing)
)
val clazz: Symbol = {
if (isRedefinition) {
updatePosFlags(existing, tree.pos, tree.mods.flags)
setPrivateWithin(tree, existing)
clearRenamedCaseAccessors(existing)
existing
}
else assignAndEnterSymbol(tree) setFlag inConstructorFlag
}
clazz match {
case csym: ClassSymbol if csym.isTopLevel => enterClassSymbol(tree, csym)
case _ => clazz
}
}
/** Given a ClassDef or ModuleDef, verifies there isn't a companion which
* has been defined in a separate file.
*/
def validateCompanionDefs(tree: ImplDef) {
val sym = tree.symbol orElse { return }
val ctx = if (context.owner.isPackageObjectClass) context.outer else context
val module = if (sym.isModule) sym else ctx.scope lookupModule tree.name
val clazz = if (sym.isClass) sym else ctx.scope lookupClass tree.name
val fails = (
module.isModule
&& clazz.isClass
&& !module.isSynthetic
&& !clazz.isSynthetic
&& (clazz.sourceFile ne null)
&& (module.sourceFile ne null)
&& !(module isCoDefinedWith clazz)
&& module.exists
&& clazz.exists
&& (currentRun.compiles(clazz) == currentRun.compiles(module))
)
if (fails) {
reporter.error(tree.pos, (
s"Companions '$clazz' and '$module' must be defined in same file:\n"
+ s" Found in ${clazz.sourceFile.canonicalPath} and ${module.sourceFile.canonicalPath}")
)
}
}
def enterModuleDef(tree: ModuleDef) = {
val sym = enterModuleSymbol(tree)
sym.moduleClass setInfo namerOf(sym).moduleClassTypeCompleter(tree)
sym setInfo completerOf(tree)
validateCompanionDefs(tree)
sym
}
/** Enter a module symbol.
*/
def enterModuleSymbol(tree : ModuleDef): Symbol = {
var m: Symbol = context.scope lookupModule tree.name
val moduleFlags = tree.mods.flags | MODULE
if (m.isModule && !m.hasPackageFlag && inCurrentScope(m) && (currentRun.canRedefine(m) || m.isSynthetic)) {
// This code accounts for the way the package objects found in the classpath are opened up
// early by the completer of the package itself. If the `packageobjects` phase then finds
// the same package object in sources, we have to clean the slate and remove package object
// members from the package class.
//
// TODO SI-4695 Pursue the approach in https://github.com/scala/scala/pull/2789 that avoids
// opening up the package object on the classpath at all if one exists in source.
if (m.isPackageObject) {
val packageScope = m.enclosingPackageClass.rawInfo.decls
packageScope.foreach(mem => if (mem.owner != m.enclosingPackageClass) packageScope unlink mem)
}
updatePosFlags(m, tree.pos, moduleFlags)
setPrivateWithin(tree, m)
m.moduleClass andAlso (setPrivateWithin(tree, _))
context.unit.synthetics -= m
tree.symbol = m
}
else {
m = assignAndEnterSymbol(tree)
m.moduleClass setFlag moduleClassFlags(moduleFlags)
setPrivateWithin(tree, m.moduleClass)
}
if (m.isTopLevel && !m.hasPackageFlag) {
m.moduleClass.associatedFile = contextFile
currentRun.symSource(m) = m.moduleClass.sourceFile
registerTopLevelSym(m)
}
m
}
def enterSyms(trees: List[Tree]): Namer = {
trees.foldLeft(this: Namer) { (namer, t) =>
val ctx = namer enterSym t
// for Import trees, enterSym returns a changed context, so we need a new namer
if (ctx eq namer.context) namer
else newNamer(ctx)
}
}
def applicableTypeParams(owner: Symbol): List[Symbol] =
if (owner.isTerm || owner.isPackageClass) Nil
else applicableTypeParams(owner.owner) ::: owner.typeParams
/** If no companion object for clazz exists yet, create one by applying `creator` to
* class definition tree.
* @return the companion object symbol.
*/
def ensureCompanionObject(cdef: ClassDef, creator: ClassDef => Tree = companionModuleDef(_)): Symbol =
pluginsEnsureCompanionObject(this, cdef, creator)
/** Default implementation of `ensureCompanionObject`.
* Can be overridden by analyzer plugins (see AnalyzerPlugins.pluginsEnsureCompanionObject for more details)
*/
def standardEnsureCompanionObject(cdef: ClassDef, creator: ClassDef => Tree = companionModuleDef(_)): Symbol = {
val m = companionSymbolOf(cdef.symbol, context)
// @luc: not sure why "currentRun.compiles(m)" is needed, things breaks
// otherwise. documentation welcome.
//
// @PP: I tried to reverse engineer said documentation. The only tests
// which fail are buildmanager tests, as follows. Given A.scala:
// case class Foo()
// If you recompile A.scala, the Changes Map is
// Map(class Foo -> Nil, object Foo -> Nil)
// But if you remove the 'currentRun.compiles(m)' condition, it is
// Map(class Foo -> Nil)
// What exactly this implies and whether this is a sensible way to
// enforce it, I don't know.
//
// @martin: currentRun.compiles is needed because we might have a stale
// companion object from another run in scope. In that case we should still
// overwrite the object. I.e.
// Compile run #1: object Foo { ... }
// Compile run #2: case class Foo ...
// The object Foo is still in scope, but because it is not compiled in current run
// it should be ditched and a new one created.
if (m != NoSymbol && currentRun.compiles(m)) m
else enterSyntheticSym(atPos(cdef.pos.focus)(creator(cdef)))
}
private def checkSelectors(tree: Import): Unit = {
import DuplicatesErrorKinds._
val Import(expr, selectors) = tree
val base = expr.tpe
def checkNotRedundant(pos: Position, from: Name, to0: Name) {
def check(to: Name) = {
val e = context.scope.lookupEntry(to)
if (e != null && e.owner == context.scope && e.sym.exists)
typer.permanentlyHiddenWarning(pos, to0, e.sym)
else if (context ne context.enclClass) {
val defSym = context.prefix.member(to) filter (
sym => sym.exists && context.isAccessible(sym, context.prefix, superAccess = false))
defSym andAlso (typer.permanentlyHiddenWarning(pos, to0, _))
}
}
if (!tree.symbol.isSynthetic && expr.symbol != null && !expr.symbol.isInterpreterWrapper) {
if (base.member(from) != NoSymbol)
check(to0)
if (base.member(from.toTypeName) != NoSymbol)
check(to0.toTypeName)
}
}
def checkSelector(s: ImportSelector) = {
val ImportSelector(from, fromPos, to, _) = s
def isValid(original: Name) =
original.bothNames forall (x => (base nonLocalMember x) == NoSymbol)
if (from != nme.WILDCARD && base != ErrorType) {
if (isValid(from)) {
// for Java code importing Scala objects
if (!nme.isModuleName(from) || isValid(from.dropModule)) {
typer.TyperErrorGen.NotAMemberError(tree, expr, from)
}
}
// Setting the position at the import means that if there is
// more than one hidden name, the second will not be warned.
// So it is the position of the actual hidden name.
//
// Note: java imports have precedence over definitions in the same package
// so don't warn for them. There is a corresponding special treatment
// in the shadowing rules in typedIdent to (SI-7232). In any case,
// we shouldn't be emitting warnings for .java source files.
if (!context.unit.isJava)
checkNotRedundant(tree.pos withPoint fromPos, from, to)
}
}
def noDuplicates(names: List[Name], check: DuplicatesErrorKinds.Value) {
def loop(xs: List[Name]): Unit = xs match {
case Nil => ()
case hd :: tl =>
if (hd == nme.WILDCARD || !(tl contains hd)) loop(tl)
else DuplicatesError(tree, hd, check)
}
loop(names filterNot (x => x == null || x == nme.WILDCARD))
}
selectors foreach checkSelector
// checks on the whole set
noDuplicates(selectors map (_.name), RenamedTwice)
noDuplicates(selectors map (_.rename), AppearsTwice)
}
def enterCopyMethod(copyDef: DefDef): Symbol = {
val sym = copyDef.symbol
val lazyType = completerOf(copyDef)
/* Assign the types of the class parameters to the parameters of the
* copy method. See comment in `Unapplies.caseClassCopyMeth` */
def assignParamTypes() {
val clazz = sym.owner
val constructorType = clazz.primaryConstructor.tpe
val subst = new SubstSymMap(clazz.typeParams, copyDef.tparams map (_.symbol))
val classParamss = constructorType.paramss
map2(copyDef.vparamss, classParamss)((copyParams, classParams) =>
map2(copyParams, classParams)((copyP, classP) =>
copyP.tpt setType subst(classP.tpe)
)
)
}
sym setInfo {
mkTypeCompleter(copyDef) { sym =>
assignParamTypes()
lazyType complete sym
}
}
}
def completerOf(tree: Tree): TypeCompleter = {
val mono = namerOf(tree.symbol) monoTypeCompleter tree
val tparams = treeInfo.typeParameters(tree)
if (tparams.isEmpty) mono
else {
/* @M! TypeDef's type params are handled differently, e.g., in `type T[A[x <: B], B]`, A and B are entered
* first as both are in scope in the definition of x. x is only in scope in `A[x <: B]`.
* No symbols are created for the abstract type's params at this point, i.e. the following assertion holds:
* !tree.symbol.isAbstractType || { tparams.forall(_.symbol == NoSymbol)
* (tested with the above example, `trait C { type T[A[X <: B], B] }`). See also comment in PolyTypeCompleter.
*/
if (!tree.symbol.isAbstractType) //@M TODO: change to isTypeMember ?
createNamer(tree) enterSyms tparams
new PolyTypeCompleter(tparams, mono, context) //@M
}
}
def enterValDef(tree: ValDef): Unit = {
val isScala = !context.unit.isJava
if (isScala) {
if (nme.isSetterName(tree.name)) ValOrVarWithSetterSuffixError(tree)
if (tree.mods.isPrivateLocal && tree.mods.isCaseAccessor) PrivateThisCaseClassParameterError(tree)
}
if (isScala && deriveAccessors(tree)) enterGetterSetter(tree)
else assignAndEnterFinishedSymbol(tree)
if (isEnumConstant(tree)) {
tree.symbol setInfo ConstantType(Constant(tree.symbol))
tree.symbol.owner.linkedClassOfClass addChild tree.symbol
}
}
def enterLazyVal(tree: ValDef, lazyAccessor: Symbol): TermSymbol = {
// If the owner is not a class, this is a lazy val from a method,
// with no associated field. It has an accessor with $lzy appended to its name and
// its flags are set differently. The implicit flag is reset because otherwise
// a local implicit "lazy val x" will create an ambiguity with itself
// via "x$lzy" as can be seen in test #3927.
val sym = (
if (owner.isClass) createFieldSymbol(tree)
else owner.newValue(tree.name append nme.LAZY_LOCAL, tree.pos, (tree.mods.flags | ARTIFACT) & ~IMPLICIT)
)
enterValSymbol(tree, sym setFlag MUTABLE setLazyAccessor lazyAccessor)
}
def enterStrictVal(tree: ValDef): TermSymbol = {
enterValSymbol(tree, createFieldSymbol(tree))
}
def enterValSymbol(tree: ValDef, sym: TermSymbol): TermSymbol = {
enterInScope(sym)
sym setInfo namerOf(sym).monoTypeCompleter(tree)
}
def enterPackage(tree: PackageDef) {
val sym = assignSymbol(tree)
newNamer(context.make(tree, sym.moduleClass, sym.info.decls)) enterSyms tree.stats
}
def enterTypeDef(tree: TypeDef) = assignAndEnterFinishedSymbol(tree)
def enterDefDef(tree: DefDef): Unit = tree match {
case DefDef(_, nme.CONSTRUCTOR, _, _, _, _) =>
assignAndEnterFinishedSymbol(tree)
case DefDef(mods, name, tparams, _, _, _) =>
val bridgeFlag = if (mods hasAnnotationNamed tpnme.bridgeAnnot) BRIDGE | ARTIFACT else 0
val sym = assignAndEnterSymbol(tree) setFlag bridgeFlag
if (name == nme.copy && sym.isSynthetic)
enterCopyMethod(tree)
else
sym setInfo completerOf(tree)
}
def enterClassDef(tree: ClassDef) {
val ClassDef(mods, _, _, impl) = tree
val primaryConstructorArity = treeInfo.firstConstructorArgs(impl.body).size
tree.symbol = enterClassSymbol(tree)
tree.symbol setInfo completerOf(tree)
if (mods.isCase) {
val m = ensureCompanionObject(tree, caseModuleDef)
m.moduleClass.updateAttachment(new ClassForCaseCompanionAttachment(tree))
}
val hasDefault = impl.body exists treeInfo.isConstructorWithDefault
if (hasDefault) {
val m = ensureCompanionObject(tree)
m.updateAttachment(new ConstructorDefaultsAttachment(tree, null))
}
val owner = tree.symbol.owner
if (settings.warnPackageObjectClasses && owner.isPackageObjectClass && !mods.isImplicit) {
reporter.warning(tree.pos,
"it is not recommended to define classes/objects inside of package objects.\n" +
"If possible, define " + tree.symbol + " in " + owner.skipPackageObject + " instead."
)
}
// Suggested location only.
if (mods.isImplicit) {
if (primaryConstructorArity == 1) {
log("enter implicit wrapper "+tree+", owner = "+owner)
enterImplicitWrapper(tree)
}
else reporter.error(tree.pos, "implicit classes must accept exactly one primary constructor parameter")
}
validateCompanionDefs(tree)
}
// Hooks which are overridden in the presentation compiler
def enterExistingSym(sym: Symbol, tree: Tree): Context = {
this.context
}
def enterIfNotThere(sym: Symbol) { }
def enterSyntheticSym(tree: Tree): Symbol = {
enterSym(tree)
context.unit.synthetics(tree.symbol) = tree
tree.symbol
}
// --- Lazy Type Assignment --------------------------------------------------
def findCyclicalLowerBound(tp: Type): Symbol = {
tp match {
case TypeBounds(lo, _) =>
// check that lower bound is not an F-bound
// but carefully: class Foo[T <: Bar[_ >: T]] should be allowed
for (tp1 @ TypeRef(_, sym, _) <- lo) {
if (settings.breakCycles) {
if (!sym.maybeInitialize) {
log(s"Cycle inspecting $lo for possible f-bounds: ${sym.fullLocationString}")
return sym
}
}
else sym.initialize
}
case _ =>
}
NoSymbol
}
def monoTypeCompleter(tree: Tree) = mkTypeCompleter(tree) { sym =>
// this early test is there to avoid infinite baseTypes when
// adding setters and getters --> bug798
// It is a def in an attempt to provide some insulation against
// uninitialized symbols misleading us. It is not a certainty
// this accomplishes anything, but performance is a non-consideration
// on these flag checks so it can't hurt.
def needsCycleCheck = sym.isNonClassType && !sym.isParameter && !sym.isExistential
logAndValidate(sym) {
val tp = typeSig(tree)
findCyclicalLowerBound(tp) andAlso { sym =>
if (needsCycleCheck) {
// neg/t1224: trait C[T] ; trait A { type T >: C[T] <: C[C[T]] }
// To avoid an infinite loop on the above, we cannot break all cycles
log(s"Reinitializing info of $sym to catch any genuine cycles")
sym reset sym.info
sym.initialize
}
}
sym setInfo {
if (sym.isJavaDefined) RestrictJavaArraysMap(tp)
else tp
}
if (needsCycleCheck) {
log(s"Needs cycle check: ${sym.debugLocationString}")
if (!typer.checkNonCyclic(tree.pos, tp))
sym setInfo ErrorType
}
}
}
def moduleClassTypeCompleter(tree: ModuleDef) = {
mkTypeCompleter(tree) { sym =>
val moduleSymbol = tree.symbol
assert(moduleSymbol.moduleClass == sym, moduleSymbol.moduleClass)
moduleSymbol.info // sets moduleClass info as a side effect.
}
}
/* Explicit isSetter required for bean setters (beanSetterSym.isSetter is false) */
def accessorTypeCompleter(tree: ValDef, isSetter: Boolean) = mkTypeCompleter(tree) { sym =>
logAndValidate(sym) {
sym setInfo {
val tp = if (isSetter) MethodType(List(sym.newSyntheticValueParam(typeSig(tree))), UnitTpe)
else NullaryMethodType(typeSig(tree))
pluginsTypeSigAccessor(tp, typer, tree, sym)
}
}
}
def selfTypeCompleter(tree: Tree) = mkTypeCompleter(tree) { sym =>
val selftpe = typer.typedType(tree).tpe
sym setInfo {
if (selftpe.typeSymbol isNonBottomSubClass sym.owner) selftpe
else intersectionType(List(sym.owner.tpe, selftpe))
}
}
/** This method has a big impact on the eventual compiled code.
* At this point many values have the most specific possible
* type (e.g. in val x = 42, x's type is Int(42), not Int) but
* most need to be widened to avoid undesirable propagation of
* those singleton types.
*
* However, the compilation of pattern matches into switch
* statements depends on constant folding, which will only take
* place for those values which aren't widened. The "final"
* modifier is the present means of signaling that a constant
* value should not be widened, so it has a use even in situations
* whether it is otherwise redundant (such as in a singleton.)
*/
private def widenIfNecessary(sym: Symbol, tpe: Type, pt: Type): Type = {
val getter =
if (sym.isValue && sym.owner.isClass && sym.isPrivate)
sym.getterIn(sym.owner)
else sym
def isHidden(tp: Type): Boolean = tp match {
case SingleType(pre, sym) =>
(sym isLessAccessibleThan getter) || isHidden(pre)
case ThisType(sym) =>
sym isLessAccessibleThan getter
case p: SimpleTypeProxy =>
isHidden(p.underlying)
case _ =>
false
}
val shouldWiden = (
!tpe.typeSymbolDirect.isModuleClass // Infer Foo.type instead of "object Foo"
&& (tpe.widen <:< pt) // Don't widen our way out of conforming to pt
&& ( sym.isVariable
|| sym.isMethod && !sym.hasAccessorFlag
|| isHidden(tpe)
)
)
dropIllegalStarTypes(
if (shouldWiden) tpe.widen
else if (sym.isFinal) tpe // "final val" allowed to retain constant type
else tpe.deconst
)
}
/** Computes the type of the body in a ValDef or DefDef, and
* assigns the type to the tpt's node. Returns the type.
*/
private def assignTypeToTree(tree: ValOrDefDef, defnTyper: Typer, pt: Type): Type = {
val rhsTpe = tree match {
case ddef: DefDef if tree.symbol.isTermMacro => defnTyper.computeMacroDefType(ddef, pt)
case _ => defnTyper.computeType(tree.rhs, pt)
}
val defnTpe = widenIfNecessary(tree.symbol, rhsTpe, pt)
tree.tpt defineType defnTpe setPos tree.pos.focus
tree.tpt.tpe
}
// owner is the class with the self type
def enterSelf(self: ValDef) {
val ValDef(_, name, tpt, _) = self
if (self eq noSelfType)
return
val hasName = name != nme.WILDCARD
val hasType = !tpt.isEmpty
if (!hasType)
tpt defineType NoType
val sym = (
if (hasType || hasName) {
owner.typeOfThis = if (hasType) selfTypeCompleter(tpt) else owner.tpe_*
val selfSym = owner.thisSym setPos self.pos
if (hasName) selfSym setName name else selfSym
}
else {
val symName = if (name != nme.WILDCARD) name else nme.this_
owner.newThisSym(symName, owner.pos) setInfo owner.tpe
}
)
self.symbol = context.scope enter sym
}
private def templateSig(templ: Template): Type = {
val clazz = context.owner
def checkParent(tpt: Tree): Type = {
if (tpt.tpe.isError) AnyRefTpe
else tpt.tpe
}
val parents = typer.typedParentTypes(templ) map checkParent
enterSelf(templ.self)
val decls = newScope
val templateNamer = newNamer(context.make(templ, clazz, decls))
templateNamer enterSyms templ.body
// add apply and unapply methods to companion objects of case classes,
// unless they exist already; here, "clazz" is the module class
if (clazz.isModuleClass) {
clazz.attachments.get[ClassForCaseCompanionAttachment] foreach { cma =>
val cdef = cma.caseClass
assert(cdef.mods.isCase, "expected case class: "+ cdef)
addApplyUnapply(cdef, templateNamer)
}
}
// add the copy method to case classes; this needs to be done here, not in SyntheticMethods, because
// the namer phase must traverse this copy method to create default getters for its parameters.
// here, clazz is the ClassSymbol of the case class (not the module). (!clazz.hasModuleFlag) excludes
// the moduleClass symbol of the companion object when the companion is a "case object".
if (clazz.isCaseClass && !clazz.hasModuleFlag) {
val modClass = companionSymbolOf(clazz, context).moduleClass
modClass.attachments.get[ClassForCaseCompanionAttachment] foreach { cma =>
val cdef = cma.caseClass
def hasCopy = (decls containsName nme.copy) || parents.exists(_ member nme.copy exists)
// SI-5956 needs (cdef.symbol == clazz): there can be multiple class symbols with the same name
if (cdef.symbol == clazz && !hasCopy)
addCopyMethod(cdef, templateNamer)
}
}
// if default getters (for constructor defaults) need to be added to that module, here's the namer
// to use. clazz is the ModuleClass. sourceModule works also for classes defined in methods.
val module = clazz.sourceModule
for (cda <- module.attachments.get[ConstructorDefaultsAttachment]) {
debuglog(s"Storing the template namer in the ConstructorDefaultsAttachment of ${module.debugLocationString}.")
cda.companionModuleClassNamer = templateNamer
}
val classTp = ClassInfoType(parents, decls, clazz)
pluginsTypeSig(classTp, templateNamer.typer, templ, WildcardType)
}
private def classSig(cdef: ClassDef): Type = {
val clazz = cdef.symbol
val ClassDef(_, _, tparams, impl) = cdef
val tparams0 = typer.reenterTypeParams(tparams)
val resultType = templateSig(impl)
val res = GenPolyType(tparams0, resultType)
val pluginsTp = pluginsTypeSig(res, typer, cdef, WildcardType)
// Already assign the type to the class symbol (monoTypeCompleter will do it again).
// Allows isDerivedValueClass to look at the info.
clazz setInfo pluginsTp
if (clazz.isDerivedValueClass) {
log("Ensuring companion for derived value class " + cdef.name + " at " + cdef.pos.show)
clazz setFlag FINAL
// Don't force the owner's info lest we create cycles as in SI-6357.
enclosingNamerWithScope(clazz.owner.rawInfo.decls).ensureCompanionObject(cdef)
}
pluginsTp
}
private def moduleSig(mdef: ModuleDef): Type = {
val moduleSym = mdef.symbol
// The info of both the module and the moduleClass symbols need to be assigned. monoTypeCompleter assigns
// the result of typeSig to the module symbol. The module class info is assigned here as a side-effect.
val result = templateSig(mdef.impl)
val pluginsTp = pluginsTypeSig(result, typer, mdef, WildcardType)
// Assign the moduleClass info (templateSig returns a ClassInfoType)
val clazz = moduleSym.moduleClass
clazz setInfo pluginsTp
// clazz.tpe_* returns a `ModuleTypeRef(clazz)`, a typeRef that links to the module class `clazz`
// (clazz.info would the ClassInfoType, which is not what should be assigned to the module symbol)
clazz.tpe_*
}
/**
* The method type for `ddef`.
*
* If a PolyType(tparams, restp) is returned, `tparams` are the external symbols (not type skolems),
* i.e. instances of AbstractTypeSymbol. All references in `restp` to the type parameters are TypeRefs
* to these non-skolems.