diff options
Diffstat (limited to 'src/compiler')
4 files changed, 282 insertions, 119 deletions
diff --git a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala index c6cfc317ea..0a469c9227 100644 --- a/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala +++ b/src/compiler/scala/tools/nsc/doc/model/ModelFactory.scala @@ -314,12 +314,15 @@ class ModelFactory(val global: Global, val settings: doc.Settings) { inform("Creating doc template for " + sym) override def toRoot: List[DocTemplateImpl] = this :: inTpl.toRoot - def inSource = - if (sym.sourceFile != null && ! sym.isSynthetic) - Some((sym.sourceFile, sym.pos.line)) + + protected def inSourceFromSymbol(symbol: Symbol) = + if (symbol.sourceFile != null && ! symbol.isSynthetic) + Some((symbol.sourceFile, symbol.pos.line)) else None + def inSource = inSourceFromSymbol(sym) + def sourceUrl = { def fixPath(s: String) = s.replaceAll("\\" + java.io.File.separator, "/") val assumedSourceRoot = fixPath(settings.sourcepath.value) stripSuffix "/" @@ -508,11 +511,11 @@ class ModelFactory(val global: Global, val settings: doc.Settings) { abstract class PackageImpl(sym: Symbol, inTpl: PackageImpl) extends DocTemplateImpl(sym, inTpl) with Package { override def inTemplate = inTpl override def toRoot: List[PackageImpl] = this :: inTpl.toRoot - override lazy val linearization = { - val symbol = sym.info.members.find { + override lazy val (inSource, linearization) = { + val representive = sym.info.members.find { s => s.isPackageObject } getOrElse sym - linearizationFromSymbol(symbol) + (inSourceFromSymbol(representive), linearizationFromSymbol(representive)) } def packages = members collect { case p: PackageImpl if !(droppedPackages contains p) => p } } diff --git a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala index c7ca239fa9..bc54054028 100644 --- a/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala +++ b/src/compiler/scala/tools/nsc/transform/ExtensionMethods.scala @@ -91,39 +91,42 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { matching.head } + /** Recognize a MethodType which represents an extension method. + * + * It may have a curried parameter list with the `$this` alone in the first + * parameter list, in which case that parameter list is dropped. Or, since + * the curried lists disappear during uncurry, it may have a single parameter + * list with `$this` as the first parameter, in which case that parameter is + * removed from the list. + */ + object ExtensionMethodType { + def unapply(tp: Type) = tp match { + case MethodType(thiz :: rest, restpe) if thiz.name == nme.SELF => + Some((thiz, if (rest.isEmpty) restpe else MethodType(rest, restpe) )) + case _ => + None + } + } + /** This method removes the `$this` argument from the parameter list a method. * * A method may be a `PolyType`, in which case we tear out the `$this` and the class - * type params from its nested `MethodType`. - * It may be a `MethodType`, either with a curried parameter list in which the first argument - * is a `$this` - we just return the rest of the list. - * This means that the corresponding symbol was generated during `extmethods`. - * - * It may also be a `MethodType` in which the `$this` does not appear in a curried parameter list. - * The curried lists disappear during `uncurry`, and the methods may be duplicated afterwards, - * for instance, during `specialize`. - * In this case, the first argument is `$this` and we just get rid of it. + * type params from its nested `MethodType`. Or it may be a MethodType, as + * described at the ExtensionMethodType extractor. */ private def normalize(stpe: Type, clazz: Symbol): Type = stpe match { case PolyType(tparams, restpe) => - // Split the type parameters of the extension method into two groups, - // corresponding the to class and method type parameters. - val numClassParams = clazz.typeParams.length - val methTParams = tparams dropRight numClassParams - val classTParams = tparams takeRight numClassParams - - GenPolyType(methTParams, - normalize(restpe.substSym(classTParams, clazz.typeParams), clazz)) - case MethodType(List(thiz), restpe) if thiz.name == nme.SELF => - restpe.substituteTypes(thiz :: Nil, clazz.thisType :: Nil) - case MethodType(thiz :: params, restpe) => - MethodType(params, restpe) + // method type parameters, class type parameters + val (mtparams, ctparams) = tparams splitAt (tparams.length - clazz.typeParams.length) + GenPolyType(mtparams, + normalize(restpe.substSym(ctparams, clazz.typeParams), clazz)) + case ExtensionMethodType(thiz, etpe) => + etpe.substituteTypes(thiz :: Nil, clazz.thisType :: Nil) case _ => stpe } class Extender(unit: CompilationUnit) extends TypingTransformer(unit) { - private val extensionDefs = mutable.Map[Symbol, mutable.ListBuffer[Tree]]() def checkNonCyclic(pos: Position, seen: Set[Symbol], clazz: Symbol): Unit = @@ -134,31 +137,54 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { if (unboxed.isDerivedValueClass) checkNonCyclic(pos, seen + clazz, unboxed) } + /** We will need to clone the info of the original method (which obtains clones + * of the method type parameters), clone the type parameters of the value class, + * and create a new polymethod with the union of all those type parameters, with + * their infos adjusted to be consistent with their new home. Example: + * + * class Foo[+A <: AnyRef](val xs: List[A]) extends AnyVal { + * def baz[B >: A](x: B): List[B] = x :: xs + * // baz has to be transformed into this extension method, where + * // A is cloned from class Foo and B is cloned from method baz: + * // def extension$baz[B >: A <: Any, A >: Nothing <: AnyRef]($this: Foo[A])(x: B): List[B] + * } + * + * TODO: factor out the logic for consolidating type parameters from a class + * and a method for re-use elsewhere, because nobody will get this right without + * some higher level facilities. + */ def extensionMethInfo(extensionMeth: Symbol, origInfo: Type, clazz: Symbol): Type = { - // No variance for method type parameters - var newTypeParams = cloneSymbolsAtOwner(clazz.typeParams, extensionMeth) map (_ resetFlag COVARIANT | CONTRAVARIANT) - val thisParamType = appliedType(clazz.typeConstructor, newTypeParams map (_.tpeHK)) + val GenPolyType(tparamsFromMethod, methodResult) = origInfo cloneInfo extensionMeth + // Start with the class type parameters - clones will be method type parameters + // so must drop their variance. + val tparamsFromClass = cloneSymbolsAtOwner(clazz.typeParams, extensionMeth) map (_ resetFlag COVARIANT | CONTRAVARIANT) + + val thisParamType = appliedType(clazz, tparamsFromClass map (_.tpeHK): _*) val thisParam = extensionMeth.newValueParameter(nme.SELF, extensionMeth.pos) setInfo thisParamType - def transform(clonedType: Type): Type = clonedType match { - case MethodType(params, restpe) => - // I assume it was a bug that this was dropping params... [Martin]: No, it wasn't; it's curried. - MethodType(List(thisParam), clonedType) - case NullaryMethodType(restpe) => - MethodType(List(thisParam), restpe) - } - val GenPolyType(tparams, restpe) = origInfo cloneInfo extensionMeth - val selfParamSingletonType = singleType(currentOwner.companionModule.thisType, thisParam) - GenPolyType( - tparams ::: newTypeParams, - transform(restpe) substThisAndSym (clazz, selfParamSingletonType, clazz.typeParams, newTypeParams) - ) - } + val resultType = MethodType(List(thisParam), dropNullaryMethod(methodResult)) + val selfParamType = singleType(currentOwner.companionModule.thisType, thisParam) - private def allParams(tpe: Type): List[Symbol] = tpe match { - case MethodType(params, res) => params ::: allParams(res) - case _ => List() - } + def fixres(tp: Type) = tp substThisAndSym (clazz, selfParamType, clazz.typeParams, tparamsFromClass) + def fixtparam(tp: Type) = tp substSym (clazz.typeParams, tparamsFromClass) + + // We can't substitute symbols on the entire polytype because we + // need to modify the bounds of the cloned type parameters, but we + // don't want to substitute for the cloned type parameters themselves. + val tparams = tparamsFromMethod ::: tparamsFromClass + GenPolyType(tparams map (_ modifyInfo fixtparam), fixres(resultType)) + // For reference, calling fix on the GenPolyType plays out like this: + // error: scala.reflect.internal.Types$TypeError: type arguments [B#7344,A#6966] + // do not conform to method extension$baz#16148's type parameter bounds + // + // And the difference is visible here. See how B is bounded from below by A#16149 + // in both cases, but in the failing case, the other type parameter has turned into + // a different A. (What is that A? It is a clone of the original A created in + // SubstMap during the call to substSym, but I am not clear on all the particulars.) + // + // bad: [B#16154 >: A#16149, A#16155 <: AnyRef#2189]($this#16156: Foo#6965[A#16155])(x#16157: B#16154)List#2457[B#16154] + // good: [B#16151 >: A#16149, A#16149 <: AnyRef#2189]($this#16150: Foo#6965[A#16149])(x#16153: B#16151)List#2457[B#16151] + } override def transform(tree: Tree): Tree = { tree match { case Template(_, _, _) => @@ -173,37 +199,56 @@ abstract class ExtensionMethods extends Transform with TypingTransformers { super.transform(tree) } else tree case DefDef(_, _, tparams, vparamss, _, rhs) if tree.symbol.isMethodWithExtension => - val companion = currentOwner.companionModule - val origMeth = tree.symbol - val extensionName = extensionNames(origMeth).head - val extensionMeth = companion.moduleClass.newMethod(extensionName, origMeth.pos, origMeth.flags & ~OVERRIDE & ~PROTECTED | FINAL) - .setAnnotations(origMeth.annotations) - companion.info.decls.enter(extensionMeth) - val newInfo = extensionMethInfo(extensionMeth, origMeth.info, currentOwner) + val origMeth = tree.symbol + val origThis = currentOwner + val origTpeParams = tparams.map(_.symbol) ::: origThis.typeParams // method type params ++ class type params + val origParams = vparamss.flatten map (_.symbol) + val companion = origThis.companionModule + + def makeExtensionMethodSymbol = { + val extensionName = extensionNames(origMeth).head + val extensionMeth = ( + companion.moduleClass.newMethod(extensionName, origMeth.pos, origMeth.flags & ~OVERRIDE & ~PROTECTED | FINAL) + setAnnotations origMeth.annotations + ) + companion.info.decls.enter(extensionMeth) + } + + val extensionMeth = makeExtensionMethodSymbol + val newInfo = extensionMethInfo(extensionMeth, origMeth.info, origThis) extensionMeth setInfo newInfo - log("Value class %s spawns extension method.\n Old: %s\n New: %s".format( - currentOwner, - origMeth.defString, - extensionMeth.defString)) // extensionMeth.defStringSeenAs(origInfo - - def thisParamRef = gen.mkAttributedStableRef(extensionMeth.info.params.head setPos extensionMeth.pos) - val GenPolyType(extensionTpeParams, extensionMono) = extensionMeth.info - val origTpeParams = (tparams map (_.symbol)) ::: currentOwner.typeParams - val extensionBody = rhs + + log(s"Value class $origThis spawns extension method.\n Old: ${origMeth.defString}\n New: ${extensionMeth.defString}") + + val GenPolyType(extensionTpeParams, MethodType(thiz :: Nil, extensionMono)) = newInfo + val extensionParams = allParameters(extensionMono) + val extensionThis = gen.mkAttributedStableRef(thiz setPos extensionMeth.pos) + + val extensionBody = ( + rhs .substituteSymbols(origTpeParams, extensionTpeParams) - .substituteSymbols(vparamss.flatten map (_.symbol), allParams(extensionMono).tail) - .substituteThis(currentOwner, thisParamRef) - .changeOwner((origMeth, extensionMeth)) - extensionDefs(companion) += atPos(tree.pos) { DefDef(extensionMeth, extensionBody) } - val extensionCallPrefix = Apply( - gen.mkTypeApply(gen.mkAttributedRef(companion), extensionMeth, origTpeParams map (_.tpeHK)), - List(This(currentOwner))) - val extensionCall = atOwner(origMeth) { - localTyper.typedPos(rhs.pos) { - gen.mkForwarder(extensionCallPrefix, mmap(vparamss)(_.symbol)) - } - } - deriveDefDef(tree)(_ => extensionCall) + .substituteSymbols(origParams, extensionParams) + .substituteThis(origThis, extensionThis) + .changeOwner(origMeth -> extensionMeth) + ) + + // Record the extension method ( FIXME: because... ? ) + extensionDefs(companion) += atPos(tree.pos)(DefDef(extensionMeth, extensionBody)) + + // These three lines are assembling Foo.bar$extension[T1, T2, ...]($this) + // which leaves the actual argument application for extensionCall. + val sel = Select(gen.mkAttributedRef(companion), extensionMeth) + val targs = origTpeParams map (_.tpeHK) + val callPrefix = gen.mkMethodCall(sel, targs, This(origThis) :: Nil) + + // Apply all the argument lists. + deriveDefDef(tree)(_ => + atOwner(origMeth)( + localTyper.typedPos(rhs.pos)( + gen.mkForwarder(callPrefix, mmap(vparamss)(_.symbol)) + ) + ) + ) case _ => super.transform(tree) } diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala index 0fad744506..74078a4ed3 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala @@ -411,8 +411,19 @@ trait Infer extends Checkable { /** Like weakly compatible but don't apply any implicit conversions yet. * Used when comparing the result type of a method with its prototype. + * * [Martin] I think Infer is also created by Erasure, with the default * implementation of isCoercible + * [Paulp] (Assuming the above must refer to my comment on isCoercible) + * Nope, I examined every occurrence of Inferencer in trunk. It + * appears twice as a self-type, once at its definition, and once + * where it is instantiated in Typers. There are no others. + * + % ack -A0 -B0 --no-filename '\bInferencer\b' src + self: Inferencer => + self: Inferencer => + class Inferencer(context: Context) extends InferencerContextErrors with InferCheckable { + val infer = new Inferencer(context0) { */ def isConservativelyCompatible(tp: Type, pt: Type): Boolean = context.withImplicitsDisabled(isWeaklyCompatible(tp, pt)) diff --git a/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala index b0745b4c09..4b53802d95 100644 --- a/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala +++ b/src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala @@ -409,15 +409,9 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL // example check: List[Int] <:< ::[Int] // TODO: extractor.paramType may contain unbound type params (run/t2800, run/t3530) - val (typeTestTreeMaker, patBinderOrCasted) = - if (needsTypeTest(patBinder.info.widen, extractor.paramType)) { - // chain a type-testing extractor before the actual extractor call - // it tests the type, checks the outer pointer and casts to the expected type - // TODO: the outer check is mandated by the spec for case classes, but we do it for user-defined unapplies as well [SPEC] - // (the prefix of the argument passed to the unapply must equal the prefix of the type of the binder) - val treeMaker = TypeTestTreeMaker(patBinder, patBinder, extractor.paramType, extractor.paramType)(pos, extractorArgTypeTest = true) - (List(treeMaker), treeMaker.nextBinder) - } else { + // `patBinderOrCasted` is assigned the result of casting `patBinder` to `extractor.paramType` + val (typeTestTreeMaker, patBinderOrCasted, binderKnownNonNull) = + if (patBinder.info.widen <:< extractor.paramType) { // no type test needed, but the tree maker relies on `patBinderOrCasted` having type `extractor.paramType` (and not just some type compatible with it) // SI-6624 shows this is necessary because apparently patBinder may have an unfortunate type (.decls don't have the case field accessors) // TODO: get to the bottom of this -- I assume it happens when type checking infers a weird type for an unapply call @@ -426,10 +420,21 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL if (settings.developer.value && !(patBinder.info =:= extractor.paramType)) devWarning(s"resetting info of $patBinder: ${patBinder.info} to ${extractor.paramType}") */ - (Nil, patBinder setInfo extractor.paramType) + (Nil, patBinder setInfo extractor.paramType, false) + } else { + // chain a type-testing extractor before the actual extractor call + // it tests the type, checks the outer pointer and casts to the expected type + // TODO: the outer check is mandated by the spec for case classes, but we do it for user-defined unapplies as well [SPEC] + // (the prefix of the argument passed to the unapply must equal the prefix of the type of the binder) + val treeMaker = TypeTestTreeMaker(patBinder, patBinder, extractor.paramType, extractor.paramType)(pos, extractorArgTypeTest = true) + + // check whether typetest implies patBinder is not null, + // even though the eventual null check will be on patBinderOrCasted + // it'll be equal to patBinder casted to extractor.paramType anyway (and the type test is on patBinder) + (List(treeMaker), treeMaker.nextBinder, treeMaker.impliesBinderNonNull(patBinder)) } - withSubPats(typeTestTreeMaker :+ extractor.treeMaker(patBinderOrCasted, pos), extractor.subBindersAndPatterns: _*) + withSubPats(typeTestTreeMaker :+ extractor.treeMaker(patBinderOrCasted, binderKnownNonNull, pos), extractor.subBindersAndPatterns: _*) } @@ -622,8 +627,13 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL // to which type should the previous binder be casted? def paramType : Type - // binder has been casted to paramType if necessary - def treeMaker(binder: Symbol, pos: Position): TreeMaker + /** Create the TreeMaker that embodies this extractor call + * + * `binder` has been casted to `paramType` if necessary + * `binderKnownNonNull` indicates whether the cast implies `binder` cannot be null + * when `binderKnownNonNull` is `true`, `ProductExtractorTreeMaker` does not do a (redundant) null check on binder + */ + def treeMaker(binder: Symbol, binderKnownNonNull: Boolean, pos: Position): TreeMaker // `subPatBinders` are the variables bound by this pattern in the following patterns // subPatBinders are replaced by references to the relevant part of the extractor's result (tuple component, seq element, the result as-is) @@ -637,6 +647,11 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL case bp => bp } + // never store these in local variables (for PreserveSubPatBinders) + lazy val ignoredSubPatBinders = (subPatBinders zip args).collect{ + case (b, PatternBoundToUnderscore()) => b + }.toSet + def subPatTypes: List[Type] = if(isSeq) { val TypeRef(pre, SeqClass, args) = seqTp @@ -731,17 +746,25 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL def isSeq: Boolean = rawSubPatTypes.nonEmpty && isRepeatedParamType(rawSubPatTypes.last) protected def rawSubPatTypes = constructorTp.paramTypes - // binder has type paramType - def treeMaker(binder: Symbol, pos: Position): TreeMaker = { + /** Create the TreeMaker that embodies this extractor call + * + * `binder` has been casted to `paramType` if necessary + * `binderKnownNonNull` indicates whether the cast implies `binder` cannot be null + * when `binderKnownNonNull` is `true`, `ProductExtractorTreeMaker` does not do a (redundant) null check on binder + */ + def treeMaker(binder: Symbol, binderKnownNonNull: Boolean, pos: Position): TreeMaker = { val paramAccessors = binder.constrParamAccessors // binders corresponding to mutable fields should be stored (SI-5158, SI-6070) + // make an exception for classes under the scala package as they should be well-behaved, + // to optimize matching on List val mutableBinders = - if (paramAccessors exists (_.isMutable)) + if (!binder.info.typeSymbol.hasTransOwner(ScalaPackageClass) && + (paramAccessors exists (_.isMutable))) subPatBinders.zipWithIndex.collect{ case (binder, idx) if paramAccessors(idx).isMutable => binder } else Nil // checks binder ne null before chaining to the next extractor - ProductExtractorTreeMaker(binder, lengthGuard(binder))(subPatBinders, subPatRefs(binder), mutableBinders) + ProductExtractorTreeMaker(binder, lengthGuard(binder))(subPatBinders, subPatRefs(binder), mutableBinders, binderKnownNonNull, ignoredSubPatBinders) } // reference the (i-1)th case accessor if it exists, otherwise the (i-1)th tuple component @@ -763,11 +786,21 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL def resultType = tpe.finalResultType def isSeq = extractorCall.symbol.name == nme.unapplySeq - def treeMaker(patBinderOrCasted: Symbol, pos: Position): TreeMaker = { + /** Create the TreeMaker that embodies this extractor call + * + * `binder` has been casted to `paramType` if necessary + * `binderKnownNonNull` is not used in this subclass + * + * TODO: implement review feedback by @retronym: + * Passing the pair of values around suggests: + * case class Binder(sym: Symbol, knownNotNull: Boolean). + * Perhaps it hasn't reached critical mass, but it would already clean things up a touch. + */ + def treeMaker(patBinderOrCasted: Symbol, binderKnownNonNull: Boolean, pos: Position): TreeMaker = { // the extractor call (applied to the binder bound by the flatMap corresponding to the previous (i.e., enclosing/outer) pattern) val extractorApply = atPos(pos)(spliceApply(patBinderOrCasted)) val binder = freshSym(pos, pureType(resultInMonad)) // can't simplify this when subPatBinders.isEmpty, since UnitClass.tpe is definitely wrong when isSeq, and resultInMonad should always be correct since it comes directly from the extractor's result type - ExtractorTreeMaker(extractorApply, lengthGuard(binder), binder)(subPatBinders, subPatRefs(binder), resultType.typeSymbol == BooleanClass, checkedLength, patBinderOrCasted) + ExtractorTreeMaker(extractorApply, lengthGuard(binder), binder)(subPatBinders, subPatRefs(binder), resultType.typeSymbol == BooleanClass, checkedLength, patBinderOrCasted, ignoredSubPatBinders) } override protected def seqTree(binder: Symbol): Tree = @@ -824,6 +857,16 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL } } + object PatternBoundToUnderscore { + def unapply(pat: Tree): Boolean = pat match { + case Bind(nme.WILDCARD, _) => true // don't skip when binding an interesting symbol! + case Ident(nme.WILDCARD) => true + case Alternative(ps) => ps forall (PatternBoundToUnderscore.unapply(_)) + case Typed(PatternBoundToUnderscore(), _) => true + case _ => false + } + } + object Bound { def unapply(t: Tree): Option[(Symbol, Tree)] = t match { case t@Bind(n, p) if (t.symbol ne null) && (t.symbol ne NoSymbol) => // pos/t2429 does not satisfy these conditions @@ -991,10 +1034,17 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL trait PreserveSubPatBinders extends TreeMaker { val subPatBinders: List[Symbol] val subPatRefs: List[Tree] + val ignoredSubPatBinders: Set[Symbol] // unless `debugInfoEmitVars`, this set should contain the bare minimum for correctness // mutable case class fields need to be stored regardless (SI-5158, SI-6070) -- see override in ProductExtractorTreeMaker - def storedBinders: Set[Symbol] = if (debugInfoEmitVars) subPatBinders.toSet else Set.empty + // sub patterns bound to wildcard (_) are never stored as they can't be referenced + // dirty debuggers will have to get dirty to see the wildcards + lazy val storedBinders: Set[Symbol] = + (if (debugInfoEmitVars) subPatBinders.toSet else Set.empty) ++ extraStoredBinders -- ignoredSubPatBinders + + // e.g., mutable fields of a case class in ProductExtractorTreeMaker + def extraStoredBinders: Set[Symbol] def emitVars = storedBinders.nonEmpty @@ -1015,10 +1065,22 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL Substitution(subPatBinders, subPatRefs) >> super.subPatternsAsSubstitution import CODE._ - def bindSubPats(in: Tree): Tree = if (!emitVars) in + def bindSubPats(in: Tree): Tree = + if (!emitVars) in else { - val (subPatBindersStored, subPatRefsStored) = stored.unzip - Block(map2(subPatBindersStored.toList, subPatRefsStored.toList)(VAL(_) === _), in) + // binders in `subPatBindersStored` that are referenced by tree `in` + val usedBinders = new collection.mutable.HashSet[Symbol]() + // all potentially stored subpat binders + val potentiallyStoredBinders = stored.unzip._1.toSet + // compute intersection of all symbols in the tree `in` and all potentially stored subpat binders + in.foreach(t => if (potentiallyStoredBinders(t.symbol)) usedBinders += t.symbol) + + if (usedBinders.isEmpty) in + else { + // only store binders actually used + val (subPatBindersStored, subPatRefsStored) = stored.filter{case (b, _) => usedBinders(b)}.unzip + Block(map2(subPatBindersStored.toList, subPatRefsStored.toList)(VAL(_) === _), in) + } } } @@ -1038,7 +1100,11 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL val subPatRefs: List[Tree], extractorReturnsBoolean: Boolean, val checkedLength: Option[Int], - val prevBinder: Symbol) extends FunTreeMaker with PreserveSubPatBinders { + val prevBinder: Symbol, + val ignoredSubPatBinders: Set[Symbol] + ) extends FunTreeMaker with PreserveSubPatBinders { + + def extraStoredBinders: Set[Symbol] = Set() def chainBefore(next: Tree)(casegen: Casegen): Tree = { val condAndNext = extraCond match { @@ -1081,27 +1147,35 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL case class ProductExtractorTreeMaker(prevBinder: Symbol, extraCond: Option[Tree])( val subPatBinders: List[Symbol], val subPatRefs: List[Tree], - val mutableBinders: List[Symbol]) extends FunTreeMaker with PreserveSubPatBinders { + val mutableBinders: List[Symbol], + binderKnownNonNull: Boolean, + val ignoredSubPatBinders: Set[Symbol] + ) extends FunTreeMaker with PreserveSubPatBinders { import CODE._ val nextBinder = prevBinder // just passing through // mutable binders must be stored to avoid unsoundness or seeing mutation of fields after matching (SI-5158, SI-6070) - // (the implementation could be optimized by duplicating code from `super.storedBinders`, but this seems more elegant) - override def storedBinders: Set[Symbol] = super.storedBinders ++ mutableBinders.toSet + def extraStoredBinders: Set[Symbol] = mutableBinders.toSet def chainBefore(next: Tree)(casegen: Casegen): Tree = { val nullCheck = REF(prevBinder) OBJ_NE NULL - val cond = extraCond map (nullCheck AND _) getOrElse nullCheck - casegen.ifThenElseZero(cond, bindSubPats(substitution(next))) + val cond = + if (binderKnownNonNull) extraCond + else (extraCond map (nullCheck AND _) + orElse Some(nullCheck)) + + cond match { + case Some(cond) => + casegen.ifThenElseZero(cond, bindSubPats(substitution(next))) + case _ => + bindSubPats(substitution(next)) + } } override def toString = "P"+(prevBinder.name, extraCond getOrElse "", localSubstitution) } - // typetag-based tests are inserted by the type checker - def needsTypeTest(tp: Type, pt: Type): Boolean = !(tp <:< pt) - object TypeTestTreeMaker { // factored out so that we can consistently generate other representations of the tree that implements the test // (e.g. propositions for exhaustivity and friends, boolean for isPureTypeTest) @@ -1115,12 +1189,14 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL def equalsTest(pat: Tree, testedBinder: Symbol): Result def eqTest(pat: Tree, testedBinder: Symbol): Result def and(a: Result, b: Result): Result + def tru: Result } object treeCondStrategy extends TypeTestCondStrategy { import CODE._ type Result = Tree def and(a: Result, b: Result): Result = a AND b + def tru = TRUE_typed def typeTest(testedBinder: Symbol, expectedTp: Type) = codegen._isInstanceOf(testedBinder, expectedTp) def nonNullTest(testedBinder: Symbol) = REF(testedBinder) OBJ_NE NULL def equalsTest(pat: Tree, testedBinder: Symbol) = codegen._equals(pat, testedBinder) @@ -1151,6 +1227,19 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL def equalsTest(pat: Tree, testedBinder: Symbol): Result = false def eqTest(pat: Tree, testedBinder: Symbol): Result = false def and(a: Result, b: Result): Result = false // we don't and type tests, so the conjunction must include at least one false + def tru = true + } + + def nonNullImpliedByTestChecker(binder: Symbol) = new TypeTestCondStrategy { + type Result = Boolean + + def typeTest(testedBinder: Symbol, expectedTp: Type): Result = testedBinder eq binder + def outerTest(testedBinder: Symbol, expectedTp: Type): Result = false + def nonNullTest(testedBinder: Symbol): Result = testedBinder eq binder + def equalsTest(pat: Tree, testedBinder: Symbol): Result = false // could in principle analyse pat and see if it's statically known to be non-null + def eqTest(pat: Tree, testedBinder: Symbol): Result = false // could in principle analyse pat and see if it's statically known to be non-null + def and(a: Result, b: Result): Result = a || b + def tru = false } } @@ -1220,10 +1309,16 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL // I think it's okay: // - the isInstanceOf test includes a test for the element type // - Scala's arrays are invariant (so we don't drop type tests unsoundly) - case _ if (expectedTp <:< AnyRefClass.tpe) && !needsTypeTest(testedBinder.info.widen, expectedTp) => - // do non-null check first to ensure we won't select outer on null - if (outerTestNeeded) and(nonNullTest(testedBinder), outerTest(testedBinder, expectedTp)) - else nonNullTest(testedBinder) + case _ if testedBinder.info.widen <:< expectedTp => + // if the expected type is a primitive value type, it cannot be null and it cannot have an outer pointer + // since the types conform, no further checking is required + if (expectedTp.typeSymbol.isPrimitiveValueClass) tru + // have to test outer and non-null only when it's a reference type + else if (expectedTp <:< AnyRefClass.tpe) { + // do non-null check first to ensure we won't select outer on null + if (outerTestNeeded) and(nonNullTest(testedBinder), outerTest(testedBinder, expectedTp)) + else nonNullTest(testedBinder) + } else default case _ => default } @@ -1235,6 +1330,8 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL // is this purely a type test, e.g. no outer check, no equality tests (used in switch emission) def isPureTypeTest = renderCondition(pureTypeTestChecker) + def impliesBinderNonNull(binder: Symbol) = renderCondition(nonNullImpliedByTestChecker(binder)) + override def toString = "TT"+(expectedTp, testedBinder.name, nextBinderTp) } @@ -1733,6 +1830,7 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL def nonNullTest(testedBinder: Symbol) = NonNullCond(binderToUniqueTree(testedBinder)) def equalsTest(pat: Tree, testedBinder: Symbol) = EqualityCond(binderToUniqueTree(testedBinder), unique(pat)) def eqTest(pat: Tree, testedBinder: Symbol) = EqualityCond(binderToUniqueTree(testedBinder), unique(pat)) // TODO: eq, not == + def tru = TrueCond } ttm.renderCondition(condStrategy) case EqualityTestTreeMaker(prevBinder, patTree, _) => EqualityCond(binderToUniqueTree(prevBinder), unique(patTree)) @@ -3694,11 +3792,17 @@ trait PatternMatching extends Transform with TypingTransformers with ast.TreeDSL // nextBinder: T // next == MatchMonad[U] // returns MatchMonad[U] - def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = - ifThenElseZero(cond, BLOCK( - VAL(nextBinder) === res, - next - )) + def flatMapCond(cond: Tree, res: Tree, nextBinder: Symbol, next: Tree): Tree = { + val rest = + // only emit a local val for `nextBinder` if it's actually referenced in `next` + if (next.exists(_.symbol eq nextBinder)) + BLOCK( + VAL(nextBinder) === res, + next + ) + else next + ifThenElseZero(cond, rest) + } // guardTree: Boolean // next: MatchMonad[T] |