From 19f6209e5b1db295320bfbd3ef00eeaa729c1eec Mon Sep 17 00:00:00 2001 From: Lukas Rytz Date: Mon, 26 Sep 2016 22:11:40 +0200 Subject: SI-9697 / SD-229 Fix DelayedInit subclass capturing local value When a class captures an outer value, a field for that value is created in the class. The class also gets a constructor parameter for the captured value, the constructor will assign the field. LambdaLift re-writes accesses to the local value (Ident trees) to the field. However, if the statement accessing the local value will end up inside the constructor, the access is re-written to the constructor parameter instead. This is the case for constructor statements: class C { { println(capturedLocal) } } If C extends DelayedInit, the statement does not end up in C's constructor, but into a new synthetic method. The access to `capturedLocal` needs to be re-written to the field instead of the constructor parameter. LambdaLift takes the decision (field or constructor parameter) based on the owner chain of `currentOwner`. For the constructor statement block, the owner is a local dummy, for which `logicallyEnclosingMember` returns the constructor symbol. This commit introduces a special case in LambdaLift for local dummies of DelayedInit subclasses: instead of the constructor, we use a temporary symbol representing the synthetic method holding the initializer statements. --- .../scala/tools/nsc/transform/LambdaLift.scala | 44 +++++++++++++++++----- 1 file changed, 34 insertions(+), 10 deletions(-) (limited to 'src/compiler/scala/tools/nsc/transform') diff --git a/src/compiler/scala/tools/nsc/transform/LambdaLift.scala b/src/compiler/scala/tools/nsc/transform/LambdaLift.scala index 74e6c58388..1ec3d4d4cb 100644 --- a/src/compiler/scala/tools/nsc/transform/LambdaLift.scala +++ b/src/compiler/scala/tools/nsc/transform/LambdaLift.scala @@ -104,8 +104,31 @@ abstract class LambdaLift extends InfoTransform { /** Buffers for lifted out classes and methods */ private val liftedDefs = new LinkedHashMap[Symbol, List[Tree]] + val delayedInitDummies = new mutable.HashMap[Symbol, Symbol] + + /** + * For classes capturing locals, LambdaLift uses `local.logicallyEnclosingMember` to decide + * whether an access to the local is re-written to the field or constructor parameter. If the + * access is in a constructor statement, the constructor parameter is used. + * + * For DelayedInit subclasses, constructor statements end up in the synthetic init method + * instead of the constructor itself, so the access should go to the field. This method changes + * `logicallyEnclosingMember` in this case to return a temprorary symbol corresponding to that + * method. + */ + private def logicallyEnclosingMember(sym: Symbol): Symbol = { + if (sym.isLocalDummy) { + val enclClass = sym.enclClass + if (enclClass.isSubClass(DelayedInitClass)) + delayedInitDummies.getOrElseUpdate(enclClass, enclClass.newMethod(nme.delayedInit)) + else + enclClass.primaryConstructor + } else if (sym.isMethod || sym.isClass || sym == NoSymbol) sym + else logicallyEnclosingMember(sym.owner) + } + private def isSameOwnerEnclosure(sym: Symbol) = - sym.owner.logicallyEnclosingMember == currentOwner.logicallyEnclosingMember + logicallyEnclosingMember(sym.owner) == logicallyEnclosingMember(currentOwner) /** Mark symbol `sym` as being free in `enclosure`, unless `sym` * is defined in `enclosure` or there is a class between `enclosure`s owner @@ -139,9 +162,9 @@ abstract class LambdaLift extends InfoTransform { */ private def markFree(sym: Symbol, enclosure: Symbol): Boolean = { // println(s"mark free: ${sym.fullLocationString} marked free in $enclosure") - (enclosure == sym.owner.logicallyEnclosingMember) || { - debuglog("%s != %s".format(enclosure, sym.owner.logicallyEnclosingMember)) - if (enclosure.isPackageClass || !markFree(sym, enclosure.skipConstructor.owner.logicallyEnclosingMember)) false + (enclosure == logicallyEnclosingMember(sym.owner)) || { + debuglog("%s != %s".format(enclosure, logicallyEnclosingMember(sym.owner))) + if (enclosure.isPackageClass || !markFree(sym, logicallyEnclosingMember(enclosure.skipConstructor.owner))) false else { val ss = symSet(free, enclosure) if (!ss(sym)) { @@ -184,14 +207,14 @@ abstract class LambdaLift extends InfoTransform { if (sym == NoSymbol) { assert(name == nme.WILDCARD) } else if (sym.isLocalToBlock) { - val owner = currentOwner.logicallyEnclosingMember + val owner = logicallyEnclosingMember(currentOwner) if (sym.isTerm && !sym.isMethod) markFree(sym, owner) else if (sym.isMethod) markCalled(sym, owner) //symSet(called, owner) += sym } case Select(_, _) => if (sym.isConstructor && sym.owner.isLocalToBlock) - markCalled(sym, currentOwner.logicallyEnclosingMember) + markCalled(sym, logicallyEnclosingMember(currentOwner)) case _ => } super.traverse(tree) @@ -283,17 +306,18 @@ abstract class LambdaLift extends InfoTransform { private def proxy(sym: Symbol) = { def searchIn(enclosure: Symbol): Symbol = { - if (enclosure eq NoSymbol) throw new IllegalArgumentException("Could not find proxy for "+ sym.defString +" in "+ sym.ownerChain +" (currentOwner= "+ currentOwner +" )") - debuglog("searching for " + sym + "(" + sym.owner + ") in " + enclosure + " " + enclosure.logicallyEnclosingMember) + if (enclosure eq NoSymbol) + throw new IllegalArgumentException("Could not find proxy for "+ sym.defString +" in "+ sym.ownerChain +" (currentOwner= "+ currentOwner +" )") + debuglog("searching for " + sym + "(" + sym.owner + ") in " + enclosure + " " + logicallyEnclosingMember(enclosure)) val proxyName = proxyNames.getOrElse(sym, sym.name) - val ps = (proxies get enclosure.logicallyEnclosingMember).toList.flatten find (_.name == proxyName) + val ps = (proxies get logicallyEnclosingMember(enclosure)).toList.flatten find (_.name == proxyName) ps getOrElse searchIn(enclosure.skipConstructor.owner) } debuglog("proxy %s from %s has logical enclosure %s".format( sym.debugLocationString, currentOwner.debugLocationString, - sym.owner.logicallyEnclosingMember.debugLocationString) + logicallyEnclosingMember(sym.owner).debugLocationString) ) if (isSameOwnerEnclosure(sym)) sym -- cgit v1.2.3