diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/transform/Mixin.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/transform/Mixin.scala | 132 |
1 files changed, 66 insertions, 66 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/Mixin.scala b/src/compiler/scala/tools/nsc/transform/Mixin.scala index b5084cffe1..d98daf0ffb 100644 --- a/src/compiler/scala/tools/nsc/transform/Mixin.scala +++ b/src/compiler/scala/tools/nsc/transform/Mixin.scala @@ -45,8 +45,8 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { * methods in the impl class (because they can have arbitrary initializers) */ private def isImplementedStatically(sym: Symbol) = ( - sym.isMethod - && (!sym.hasFlag(DEFERRED | SUPERACCESSOR) || (sym hasFlag lateDEFERRED)) + sym.isMethod + && notDeferredOrLate(sym) && sym.owner.isTrait && (!sym.isModule || sym.hasFlag(PRIVATE | LIFTED)) && (!(sym hasFlag (ACCESSOR | SUPERACCESSOR)) || sym.isLazy) @@ -109,16 +109,16 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { // --------- type transformation ----------------------------------------------- - def isConcreteAccessor(member: Symbol) = - member.hasAccessorFlag && (!member.isDeferred || (member hasFlag lateDEFERRED)) + private def notDeferredOrLate(sym: Symbol) = !sym.hasFlag(DEFERRED) || sym.hasFlag(lateDEFERRED) /** Is member overridden (either directly or via a bridge) in base class sequence `bcs`? */ def isOverriddenAccessor(member: Symbol, bcs: List[Symbol]): Boolean = beforeOwnPhase { def hasOverridingAccessor(clazz: Symbol) = { clazz.info.nonPrivateDecl(member.name).alternatives.exists( sym => - isConcreteAccessor(sym) && + sym.hasFlag(ACCESSOR) && !sym.hasFlag(MIXEDIN) && + notDeferredOrLate(sym) && matchesType(sym.tpe, member.tpe, alwaysMatchSimple = true)) } ( bcs.head != member.owner @@ -126,6 +126,8 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { ) } + private def isUnitGetter(sym: Symbol) = sym.tpe.resultType.typeSymbol == UnitClass + /** Add given member to given class, and mark member as mixed-in. */ def addMember(clazz: Symbol, member: Symbol): Symbol = { @@ -202,6 +204,8 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { clazz.info // make sure info is up to date, so that implClass is set. + // TODO: is this needed? can there be fields in a class that don't have accessors yet but need them??? + // can we narrow this down to just getters for lazy vals? param accessors? for (member <- clazz.info.decls) { if (!member.isMethod && !member.isModule && !member.isModuleVar) { assert(member.isTerm && !member.isDeferred, member) @@ -297,49 +301,7 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { def mixinTraitMembers(mixinClass: Symbol) { // For all members of a trait's interface do: for (mixinMember <- mixinClass.info.decls) { - if (isConcreteAccessor(mixinMember)) { - if (isOverriddenAccessor(mixinMember, clazz.info.baseClasses)) - devWarning(s"Overridden concrete accessor: ${mixinMember.fullLocationString}") - else { - // mixin field accessors - val mixedInAccessor = cloneAndAddMixinMember(mixinClass, mixinMember) - if (mixinMember.isLazy) { - initializer(mixedInAccessor) = ( - mixinClass.info.decl(mixinMember.name) - orElse abort("Could not find initializer for " + mixinMember.name) - ) - } - if (!mixinMember.isSetter) - mixinMember.tpe match { - case MethodType(Nil, ConstantType(_)) => - // mixinMember is a constant; only getter is needed - ; - case MethodType(Nil, TypeRef(_, UnitClass, _)) => - // mixinMember is a value of type unit. No field needed - ; - case _ => // otherwise mixin a field as well - // enteringPhase: the private field is moved to the implementation class by erasure, - // so it can no longer be found in the mixinMember's owner (the trait) - val accessed = enteringPickler(mixinMember.accessed) - // #3857, need to retain info before erasure when cloning (since cloning only - // carries over the current entry in the type history) - val sym = enteringErasure { - // so we have a type history entry before erasure - clazz.newValue(mixinMember.localName, mixinMember.pos).setInfo(mixinMember.tpe.resultType) - } - sym updateInfo mixinMember.tpe.resultType // info at current phase - - val newFlags = ( - ( PrivateLocal ) - | ( mixinMember getFlag MUTABLE | LAZY) - | ( if (mixinMember.hasStableFlag) 0 else MUTABLE ) - ) - - addMember(clazz, sym setFlag newFlags setAnnotations accessed.annotations) - } - } - } - else if (mixinMember.isSuperAccessor) { // mixin super accessors + if (mixinMember.hasFlag(SUPERACCESSOR)) { // mixin super accessors val superAccessor = addMember(clazz, mixinMember.cloneSymbol(clazz)) setPos clazz.pos assert(superAccessor.alias != NoSymbol, superAccessor) @@ -355,10 +317,53 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { superAccessor.asInstanceOf[TermSymbol] setAlias alias1 } } - else if (mixinMember.isMethod && mixinMember.isModule && mixinMember.hasNoFlags(LIFTED | BRIDGE)) { + else if (mixinMember.hasAllFlags(METHOD | MODULE) && mixinMember.hasNoFlags(LIFTED | BRIDGE)) { // mixin objects: todo what happens with abstract objects? addMember(clazz, mixinMember.cloneSymbol(clazz, mixinMember.flags & ~(DEFERRED | lateDEFERRED)) setPos clazz.pos) } + else if (mixinMember.hasFlag(ACCESSOR) && notDeferredOrLate(mixinMember) + && (mixinMember hasFlag (LAZY | PARAMACCESSOR)) + && !isOverriddenAccessor(mixinMember, clazz.info.baseClasses)) { + // pick up where `fields` left off -- it already mixed in fields and accessors for regular vals. + // but has ignored lazy vals and constructor parameter accessors + // TODO: captures added by lambdalift for local traits? + // + // mixin accessor for lazy val or constructor parameter + // (note that a paramaccessor cannot have a constant type as it must have a user-defined type) + val mixedInAccessor = cloneAndAddMixinMember(mixinClass, mixinMember) + val name = mixinMember.name + + if (mixinMember.isLazy) + initializer(mixedInAccessor) = + (mixinClass.info.decl(name) orElse abort(s"Could not find initializer for lazy val $name!")) + + // Add field while we're mixing in the getter (unless it's a Unit-typed lazy val) + // + // lazy val of type Unit doesn't need a field -- the bitmap is enough. + // TODO: constant-typed lazy vals... it's an extreme corner case, but we could also suppress the field in: + // `trait T { final lazy val a = "a" }; class C extends T`, but who writes code like that!? :) + // we'd also have to change the lazyvals logic if we do this + if (!nme.isSetterName(name) && !(mixinMember.isLazy && isUnitGetter(mixinMember))) { + // enteringPhase: the private field is moved to the implementation class by erasure, + // so it can no longer be found in the mixinMember's owner (the trait) + val accessed = enteringPickler(mixinMember.accessed) + // #3857, need to retain info before erasure when cloning (since cloning only + // carries over the current entry in the type history) + val sym = enteringErasure { + // so we have a type history entry before erasure + clazz.newValue(mixinMember.localName, mixinMember.pos).setInfo(mixinMember.tpe.resultType) + } + sym updateInfo mixinMember.tpe.resultType // info at current phase + + val newFlags = ( + (PrivateLocal) + | (mixinMember getFlag MUTABLE | LAZY) + | (if (mixinMember.hasStableFlag) 0 else MUTABLE) + ) + + addMember(clazz, sym setFlag newFlags setAnnotations accessed.annotations) + } + } } } @@ -478,8 +483,7 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { tree - case _ => - tree + case _ => tree } } @@ -763,13 +767,12 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { def addCheckedGetters(clazz: Symbol, stats: List[Tree]): List[Tree] = { def dd(stat: DefDef) = { val sym = stat.symbol - def isUnit = sym.tpe.resultType.typeSymbol == UnitClass def isEmpty = stat.rhs == EmptyTree if (!clazz.isTrait && sym.isLazy && !isEmpty) { assert(fieldOffset contains sym, sym) deriveDefDef(stat) { - case t if isUnit => mkLazyDef(clazz, sym, List(t), UNIT, fieldOffset(sym)) + case t if isUnitGetter(sym) => mkLazyDef(clazz, sym, List(t), UNIT, fieldOffset(sym)) case Block(stats, res) => mkLazyDef(clazz, sym, stats, Select(This(clazz), res.symbol), fieldOffset(sym)) @@ -781,8 +784,7 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { assert(fieldOffset contains sym, sym) deriveDefDef(stat)(rhs => (mkCheckedAccessor(clazz, _: Tree, fieldOffset(sym), stat.pos, sym))( - if (sym.tpe.resultType.typeSymbol == UnitClass) UNIT - else rhs + if (isUnitGetter(sym)) UNIT else rhs ) ) } @@ -908,7 +910,6 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { } } - def isUnitGetter(getter: Symbol) = getter.tpe.resultType.typeSymbol == UnitClass def fieldAccess(accessor: Symbol) = Select(This(clazz), accessor.accessed) def isOverriddenSetter(sym: Symbol) = @@ -924,7 +925,12 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { addDefDef(sym) } else { // if class is not a trait add accessor definitions - if (isConcreteAccessor(sym)) { + // used to include `sym` with `sym hasFlag lateDEFERRED` as not deferred, + // but I don't think MIXEDIN members ever get this flag + assert(!sym.hasFlag(lateDEFERRED), s"mixedin $sym from $clazz has lateDEFERRED flag?!") + if (sym.hasFlag(ACCESSOR) && !sym.hasFlag(DEFERRED)) { + assert(sym hasFlag (LAZY | PARAMACCESSOR), s"mixed in $sym from $clazz is not lazy/param?!?") + // add accessor definitions addDefDef(sym, { if (sym.isSetter) { @@ -1006,20 +1012,14 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL { val parents1 = currentOwner.info.parents map (t => TypeTree(t) setPos tree.pos) // mark fields which can be nulled afterward lazyValNullables = nullableFields(templ) withDefaultValue Set() - // Remove bodies of accessors in traits - TODO: after PR #5141 (fields refactoring), this might be a no-op - val bodyEmptyAccessors = if (!sym.enclClass.isTrait) body else body mapConserve { - case dd: DefDef if dd.symbol.isAccessor && !dd.symbol.isLazy => - deriveDefDef(dd)(_ => EmptyTree) - case tree => tree - } // add all new definitions to current class or interface - val body1 = addNewDefs(currentOwner, bodyEmptyAccessors) - body1 foreach { + val statsWithNewDefs = addNewDefs(currentOwner, body) + statsWithNewDefs foreach { case dd: DefDef if isTraitMethodRequiringStaticImpl(dd) => dd.symbol.updateAttachment(NeedStaticImpl) case _ => } - treeCopy.Template(tree, parents1, self, body1) + treeCopy.Template(tree, parents1, self, statsWithNewDefs) case Select(qual, name) if sym.owner.isTrait && !sym.isMethod => // refer to fields in some trait an abstract getter in the interface. |