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Namers.scala
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Namers.scala
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/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala.tools.nsc
package typechecker
import scala.annotation.{nowarn, tailrec}
import scala.collection.mutable
import symtab.Flags._
import scala.reflect.internal.util.ListOfNil
import scala.tools.nsc.Reporting.WarningCategory
import scala.util.chaining._
/** This trait declares methods to create symbols and to enter them into scopes.
*
* @author Martin Odersky
*/
trait Namers extends MethodSynthesis {
self: Analyzer =>
import global._
import definitions._
/** 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 AstTransformer {
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): Unit = { }
def expandMacroAnnotations(stats: List[Tree]): List[Tree] = stats
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 =>
enterInScope(assignMemberSymbol(param, mask = ValueParameterFlags)) 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 if !global.propagateCyclicReferences =>
// 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.isTrait || (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 an 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) sym
else {
val qualClass = if (mods.hasAccessBoundary)
typer.qualifyingClass(tree, mods.privateWithin, packageOK = true, immediate = false)
else
NoSymbol
sym setPrivateWithin qualClass
}
def setPrivateWithin(tree: MemberDef, sym: Symbol): Symbol =
setPrivateWithin(tree, sym, tree.mods)
def inConstructorFlag: Long = {
@tailrec def go(context: Context): Long =
if (context eq NoContext) 0L else {
val owner = context.owner
if (!owner.isTerm || owner.isAnonymousFunction) 0L
else if (owner.isConstructor) if (context.inConstructorSuffix) 0L else INCONSTRUCTOR
else if (owner.isEarlyInitialized) INCONSTRUCTOR
else go(context.outer)
}
go(context)
}
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 context.scope.lookupSymbolEntry(m) match {
case null => false
case entry => entry.owner eq context.scope
}
}
/** 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?
}
}
if (sym.isModule && sym.isSynthetic && sym.owner.isClass && !sym.isTopLevel) {
val entry = scope.lookupEntry(sym.name.toTypeName)
if (entry eq null)
scope enter sym
else
scope.enterBefore(sym, entry)
} else
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(_, _) => enterImport(tree); returnContext = context.makeImportContext(tree)
case _ =>
}
returnContext
}
tree.symbol match {
case NoSymbol => try dispatch() catch typeErrorHandler(tree, this.context)
case sym =>
tree match {
case tree@Import(_, _) => enterExistingSym(sym, tree).make(tree)
case _ => enterExistingSym(sym, tree)
}
}
}
def assignMemberSymbol(tree: MemberDef, mask: Long = -1L): Symbol = {
val sym = createMemberSymbol(tree, tree.name, mask)
setPrivateWithin(tree, sym)
tree.symbol = sym
sym
}
def assignAndEnterFinishedSymbol(tree: MemberDef): Symbol = {
val sym = enterInScope(assignMemberSymbol(tree))
sym setInfo completerOf(tree)
// log("[+info] " + sym.fullLocationString)
sym
}
def createMethod(accessQual: MemberDef, name: TermName, pos: Position, flags: Long): MethodSymbol = {
val sym = owner.newMethod(name, pos, flags)
setPrivateWithin(accessQual, 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 createImportSymbol(tree: Import) =
NoSymbol.newImport(tree.pos) setInfo (namerOf(tree.symbol) importTypeCompleter 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
case x => throw new MatchError(x)
}
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 = {
var sourceFile = clazz.sourceFile
if (sourceFile != null && sourceFile != contextFile)
devWarning(s"Source file mismatch in $clazz: ${sourceFile} vs. $contextFile")
clazz.associatedFile = contextFile
sourceFile = clazz.sourceFile
if (sourceFile != null) {
assert(currentRun.canRedefine(clazz) || sourceFile == currentRun.symSource(clazz), sourceFile)
currentRun.symSource(clazz) = sourceFile
}
registerTopLevelSym(clazz)
assert(clazz.name.toString.indexOf('(') < 0, clazz.name) // )
clazz
}
def enterClassSymbol(tree: ClassDef): Symbol = {
val existing = context.scope.lookup(tree.name)
val isRedefinition = (
existing.isType
&& existing.isTopLevel
&& context.scope == existing.owner.info.decls
&& currentRun.canRedefine(existing)
)
val clazz: Symbol = {
if (isRedefinition) {
updatePosFlags(existing, tree.pos, tree.mods.flags)
setPrivateWithin(tree, existing)
clearRenamedCaseAccessors(existing)
existing
}
else enterInScope(assignMemberSymbol(tree)) setFlag inConstructorFlag
}
clazz match {
case csym: ClassSymbol if csym.isTopLevel => enterClassSymbol(tree, csym)
case _ => clazz
}
}
/** Given a ClassDef or ModuleDef, verifies there isn't a companion which
* has been defined in a separate file.
*/
def validateCompanionDefs(tree: ImplDef): Unit = {
val sym = tree.symbol
if (sym != NoSymbol) {
val ctx = if (context.owner.isPackageObjectClass) context.outer else context
val module = if (sym.isModule) sym else ctx.scope.lookupModule(tree.name)
val clazz = if (sym.isClass) sym else ctx.scope.lookupClass(tree.name)
val fails = (
module.isModule
&& clazz.isClass
&& !module.isSynthetic
&& !clazz.isSynthetic
&& (clazz.sourceFile ne null)
&& (module.sourceFile ne null)
&& !module.isCoDefinedWith(clazz)
&& module.exists
&& clazz.exists
&& currentRun.compiles(clazz) == currentRun.compiles(module)
)
if (fails) reporter.error(tree.pos,
sm"""|Companions '$clazz' and '$module' must be defined in same file:
| 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 = {
val moduleFlags = tree.mods.flags | MODULE
val existingModule = context.scope lookupModule tree.name
if (existingModule.isModule && !existingModule.hasPackageFlag && inCurrentScope(existingModule) && (currentRun.canRedefine(existingModule) || existingModule.isSynthetic)) {
updatePosFlags(existingModule, tree.pos, moduleFlags)
setPrivateWithin(tree, existingModule)
existingModule.moduleClass andAlso (setPrivateWithin(tree, _))
context.unit.synthetics -= existingModule
tree.symbol = existingModule
}
else {
enterInScope(assignMemberSymbol(tree))
val m = tree.symbol
m.moduleClass setFlag moduleClassFlags(moduleFlags)
setPrivateWithin(tree, m.moduleClass)
}
val m = tree.symbol
if (m.isTopLevel && !m.hasPackageFlag) {
// TODO: I've seen crashes where m.moduleClass == NoSymbol
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
// warn proactively if specific import loses to definition in scope,
// since it may result in desired implicit not imported into scope.
def checkNotRedundant(pos: Position, from: Name, to0: Name): Unit = {
def check(to: Name): Unit = {
val e = context.scope.lookupEntry(to)
if (e != null && e.owner == context.scope && e.sym.exists) {
if (!context.isPackageOwnedInDifferentUnit(e.sym))
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).exists)
check(to0)
if (base.member(from.toTypeName).exists)
check(to0.toTypeName)
}
}
def checkSelector(s: ImportSelector) = {
val ImportSelector(from, fromPos, to, _) = s
def isValid(original: Name, base: Type) = {
def lookup(name: Name) =
if (context.unit.isJava)
NoContext.javaFindMember(base, name, _ => true)._2
else
base.nonLocalMember(name)
lookup(original.toTermName) != NoSymbol || lookup(original.toTypeName) != NoSymbol
}
if (!s.isWildcard && base != ErrorType) {
val okay = isValid(from, base) || context.unit.isJava && ( // Java code...
(nme.isModuleName(from) && isValid(from.dropModule, base)) // - importing Scala module classes
|| isValid(from, base.companion) // - importing type members from types
)
if (!okay) typer.TyperErrorGen.NotAMemberError(tree, expr, from, context.outer)
// 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 (scala/bug#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)
}
}
selectors foreach checkSelector
def noDuplicates(): Unit = {
def loop(xs: List[ImportSelector]): Unit = xs match {
case Nil => ()
case hd :: tl =>
if (!hd.isWildcard && tl.exists(x => !x.isWildcard && x.name == hd.name))
DuplicatesError(tree, hd.name, RenamedTwice)
else if (hd.isRename && tl.exists(x => x.isRename && x.rename == hd.rename))
DuplicatesError(tree, hd.rename, AppearsTwice)
else loop(tl)
}
loop(selectors)
}
// checks on the whole set
noDuplicates()
}
def copyMethodCompleter(copyDef: DefDef): TypeCompleter = {
/* Assign the types of the class parameters to the parameters of the
* copy method. See comment in `Unapplies.caseClassCopyMeth`
*/
def assignParamTypes(copyDef: DefDef, sym: Symbol): Unit = {
val clazz = sym.owner
val constructorType = clazz.primaryConstructor.tpe
val subst = SubstSymMap(clazz.typeParams, copyDef.tparams.map(_.symbol))
val classParamss = constructorType.paramss
foreach2(copyDef.vparamss, classParamss)((copyParams, classParams) =>
foreach2(copyParams, classParams)((copyP, classP) =>
copyP.tpt setType subst(classP.tpe)
)
)
}
new CompleterWrapper(completerOf(copyDef)) {
override def complete(sym: Symbol): Unit = {
assignParamTypes(tree.asInstanceOf[DefDef], sym)
super.complete(sym)
}
}
}
// for apply/unapply, which may need to disappear when they clash with a user-defined method of matching signature
def applyUnapplyMethodCompleter(un_applyDef: DefDef, companionContext: Context): TypeCompleter =
new CompleterWrapper(completerOf(un_applyDef)) {
override def complete(sym: Symbol): Unit = {
assert(sym hasAllFlags CASE | SYNTHETIC, sym.defString)
super.complete(sym)
// don't propagate e.g. @volatile annot to apply's argument
def retainOnlyParamAnnots(param: Symbol) =
param setAnnotations (param.annotations filter AnnotationInfo.mkFilter(ParamTargetClass, defaultRetention = false))
sym.info.paramss.foreach(_.foreach(retainOnlyParamAnnots))
// owner won't be locked
val ownerInfo = companionContext.owner.info
// If there's a same-named locked symbol, we're currently completing its signature.
// If `scopePartiallyCompleted`, the program is known to have a type error, since
// this means a user-defined method is missing a result type while its rhs refers to `sym` or an overload.
// This is an error because overloaded/recursive methods must have a result type.
// The method would be overloaded if its signature, once completed, would not match the synthetic method's,
// or recursive if it turned out we should unlink our synthetic method (matching sig).
// In any case, error out. We don't unlink the symbol so that `symWasOverloaded` says yes,
// which would be wrong if the method is in fact recursive, but it seems less confusing.
val scopePartiallyCompleted = new HasMember(ownerInfo, sym.name, BridgeFlags | SYNTHETIC, LOCKED).apply()
// Check `scopePartiallyCompleted` first to rule out locked symbols from the owner.info.member call,
// as FindMember will call info on a locked symbol (while checking type matching to assemble an overloaded type),
// and throw a TypeError, so that we are aborted.
// Do not consider deferred symbols, as suppressing our concrete implementation would be an error regardless
// of whether the signature matches (if it matches, we omitted a valid implementation, if it doesn't,
// we would get an error for the missing implementation it isn't implemented by some overload other than our synthetic one)
val suppress = scopePartiallyCompleted || {
// can't exclude deferred members using DEFERRED flag here (TODO: why?)
val userDefined = ownerInfo.memberBasedOnName(sym.name, BridgeFlags | SYNTHETIC)
(userDefined != NoSymbol) && {
assert(userDefined != sym, "userDefined symbol cannot be the same as symbol of which it is a member")
val alts = userDefined.alternatives // could be just the one, if this member isn't overloaded
// don't compute any further `memberInfo`s if there's an error somewhere
alts.exists(_.isErroneous) || {
val self = companionContext.owner.thisType
val memberInfo = self.memberInfo(sym)
alts.exists(alt => !alt.isDeferred && (self.memberInfo(alt) matches memberInfo))
}
}
}
if (suppress) {
sym setInfo ErrorType
// There are two ways in which we exclude the symbol from being added in typedStats::addSynthetics,
// because we don't know when the completer runs with respect to this loop in addSynthetics
// for (sym <- scope)
// for (tree <- context.unit.synthetics.get(sym) if shouldAdd(sym)) {
// if (!sym.initialize.hasFlag(IS_ERROR))
// newStats += typedStat(tree)
// If we're already in the loop, set the IS_ERROR flag and trigger the condition `sym.initialize.hasFlag(IS_ERROR)`
sym setFlag IS_ERROR
// Or, if we are not yet in the addSynthetics loop, we can just retract our symbol from the synthetics for this unit.
companionContext.unit.synthetics -= sym
// Don't unlink in an error situation to generate less confusing error messages.
// Ideally, our error reporting would distinguish overloaded from recursive user-defined apply methods without signature,
// but this would require some form of partial-completion of method signatures, so that we can
// know what the argument types were, even though we can't complete the result type, because
// we hit a cycle while trying to compute it (when we get here with locked user-defined symbols, we
// are in the complete for that symbol, and thus the locked symbol has not yet received enough info;
// I hesitate to provide more info, because it would involve a WildCard or something for its result type,
// which could upset other code paths)
if (!scopePartiallyCompleted)
companionContext.scope.unlink(sym)
for (a <- sym.attachments.get[CaseApplyDefaultGetters]; defaultGetter <- a.defaultGetters) {
companionContext.unit.synthetics -= defaultGetter
companionContext.scope.unlink(defaultGetter)
}
}
sym.removeAttachment[CaseApplyDefaultGetters] // no longer needed once the completer is done
}
}
def completerOf(tree: MemberDef): 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 enterPackage(tree: PackageDef): Unit = {
val sym = createPackageSymbol(tree.pos, tree.pid)
tree.symbol = sym
newNamer(context.make(tree, sym.moduleClass, sym.info.decls)) enterSyms tree.stats
}
private def enterImport(tree: Import) = {
val sym = createImportSymbol(tree)
tree.symbol = sym
}
def enterTypeDef(tree: TypeDef) = assignAndEnterFinishedSymbol(tree)
def enterDefDef(tree: DefDef): Unit = {
tree match {
case DefDef(_, nme.CONSTRUCTOR, _, _, _, _) =>
assignAndEnterFinishedSymbol(tree)
case DefDef(mods, name, _, _, _, _) =>
val sym = enterInScope(assignMemberSymbol(tree))
val completer =
if (sym hasFlag SYNTHETIC) {
if (name == nme.copy) copyMethodCompleter(tree)
else if (sym hasFlag CASE) applyUnapplyMethodCompleter(tree, context)
else completerOf(tree)
} else completerOf(tree)
sym setInfo completer
}
if (mexists(tree.vparamss)(_.mods.hasDefault))
enterDefaultGetters(tree.symbol, tree, tree.vparamss, tree.tparams)
}
def enterClassDef(tree: ClassDef): Unit = {
val ClassDef(mods, _, _, impl) = tree
val primaryConstructorArity = treeInfo.firstConstructorArgs(impl.body).size
tree.symbol = enterClassSymbol(tree)
tree.symbol setInfo completerOf(tree)
if (tree.symbol.isJava) patmat.javaClassesByUnit.get(tree.symbol.pos.source).foreach(_.addOne(tree.symbol))
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) {
context.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.",
WarningCategory.LintPackageObjectClasses)
}
// 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): Unit = { }
def enterSyntheticSym(tree: Tree): Symbol = {
enterSym(tree)
context.unit.synthetics(tree.symbol) = tree
tree.symbol
}
// --- Lazy Type Assignment --------------------------------------------------
@nowarn("cat=lint-nonlocal-return")
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.value) {
if (!sym.maybeInitialize) {
log(s"Cycle inspecting $lo for possible f-bounds: ${sym.fullLocationString}")
return sym
}
}
else sym.initialize
}
case _ =>
}
NoSymbol
}
def monoTypeCompleter(tree: MemberDef) = new MonoTypeCompleter(tree)
class MonoTypeCompleter(tree: MemberDef) extends TypeCompleterBase(tree) {
override def completeImpl(sym: Symbol): Unit = {
// 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
val annotations = annotSig(tree.mods.annotations, tree, _ => true)
val tp = typeSig(tree, annotations)
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) tp else RestrictJavaArraysMap(tp))
if (needsCycleCheck) {
log(s"Needs cycle check: ${sym.debugLocationString}")
if (!typer.checkNonCyclic(tree.pos, tp))
sym setInfo ErrorType
}
validate(sym)
}
}
def moduleClassTypeCompleter(tree: ModuleDef) = new ModuleClassTypeCompleter(tree)
class ModuleClassTypeCompleter(tree: ModuleDef) extends TypeCompleterBase(tree) {
override def completeImpl(sym: Symbol): Unit = {
val moduleSymbol = tree.symbol
assert(moduleSymbol.moduleClass == sym, moduleSymbol.moduleClass)
moduleSymbol.info // sets moduleClass info as a side effect.
}
}
def importTypeCompleter(tree: Import) = new ImportTypeCompleter(tree)
class ImportTypeCompleter(imp: Import) extends TypeCompleterBase(imp) {
override def completeImpl(sym: Symbol): Unit = {
sym setInfo importSig(imp)
}
}
import AnnotationInfo.{mkFilter => annotationFilter}
def implicitFactoryMethodCompleter(tree: DefDef, classSym: Symbol) = new CompleterWrapper(completerOf(tree)) {
override def complete(methSym: Symbol): Unit = {
super.complete(methSym)
val annotations = classSym.initialize.annotations
methSym setAnnotations (annotations filter annotationFilter(MethodTargetClass, defaultRetention = false))
classSym setAnnotations (annotations filter annotationFilter(ClassTargetClass, defaultRetention = true))
}
}
// complete the type of a value definition (may have a method symbol, for those valdefs that never receive a field,
// as specified by Field.noFieldFor)
def valTypeCompleter(tree: ValDef) = new ValTypeCompleter(tree)
class ValTypeCompleter(tree: ValDef) extends TypeCompleterBase(tree) {
override def completeImpl(fieldOrGetterSym: Symbol): Unit = {
val mods = tree.mods
val isGetter = fieldOrGetterSym.isMethod
val annots =
if (mods.annotations.isEmpty) Nil
else {
// if this is really a getter, retain annots targeting either field/getter
val pred: AnnotationInfo => Boolean =
if (isGetter) accessorAnnotsFilter(tree.mods)
else annotationFilter(FieldTargetClass, !mods.isParamAccessor)
annotSig(mods.annotations, tree, pred)
}
// must use typeSig, not memberSig (TODO: when do we need to switch namers?)
val sig = typeSig(tree, annots)
fieldOrGetterSym setInfo (if (isGetter) NullaryMethodType(sig) else sig)
checkBeanAnnot(tree, annots)
validate(fieldOrGetterSym)
}
}
// knowing `isBean`, we could derive `isSetter` from `valDef.name`
def accessorTypeCompleter(valDef: ValDef, missingTpt: Boolean, isBean: Boolean, isSetter: Boolean) = new AccessorTypeCompleter(valDef, missingTpt, isBean, isSetter)
class AccessorTypeCompleter(valDef: ValDef, missingTpt: Boolean, isBean: Boolean, isSetter: Boolean) extends TypeCompleterBase(valDef) {
override def completeImpl(accessorSym: Symbol): Unit = {
context.unit.synthetics get accessorSym match {
case Some(ddef: DefDef) =>
// `accessorSym` is the accessor for which we're completing the info (tree == ddef),
// while `valDef` is the field definition that spawned the accessor
// NOTE: `valTypeCompleter` handles abstract vals, trait vals and lazy vals, where the ValDef carries the getter's symbol
valDef.symbol.rawInfo match {
case c: ValTypeCompleter =>
// If the field and accessor symbols are distinct, i.e., we're not in a trait, invoke the
// valTypeCompleter. This ensures that field annotations are set correctly (scala/bug#10471).
c.completeImpl(valDef.symbol)
case _ =>
}
val valSig =
if (valDef.symbol.isInitialized) valDef.symbol.info // re-use an already computed type
else typeSig(valDef, Nil) // Don't pass any annotations to set on the valDef.symbol, just compute the type sig (TODO: dig deeper and see if we can use memberSig)
// patch up the accessor's tree if the valdef's tpt was not known back when the tree was synthesized
// can't look at `valDef.tpt` here because it may have been completed by now (this is why we pass in `missingTpt`)
// HACK: a param accessor `ddef.tpt.tpe` somehow gets out of whack with `accessorSym.info`, so always patch it back...
// (the tpt is typed in the wrong namer, using the class as owner instead of the outer context, which is where param accessors should be typed)
if (missingTpt || accessorSym.isParamAccessor) {
if (!isSetter) ddef.tpt setType valSig
else if (ddef.vparamss.nonEmpty && ddef.vparamss.head.nonEmpty) ddef.vparamss.head.head.tpt setType valSig
else throw new TypeError(valDef.pos, s"Internal error: could not complete parameter/return type for $ddef from $accessorSym")
}
val mods = valDef.mods
val annots =
if (mods.annotations.isEmpty) Nil
else annotSig(mods.annotations, valDef, accessorAnnotsFilter(valDef.mods, isSetter, isBean))
// for a setter, call memberSig to attribute the parameter (for a bean, we always use the regular method sig completer since they receive method types)
// for a regular getter, make sure it gets a NullaryMethodType (also, no need to recompute it: we already have the valSig)
val sig =
if (isSetter || isBean) typeSig(ddef, annots)
else {
if (annots.nonEmpty) annotate(accessorSym, annots)
NullaryMethodType(valSig)
}