From b1cea212f36b27636ef6aab76bf8992210a4426e Mon Sep 17 00:00:00 2001 From: Adriaan Moors Date: Sun, 6 Jan 2013 01:43:20 -0800 Subject: SI-6925 use concrete type in applyOrElse's match's selector Fix a regression introduced in 28483739c3: PartialFunction synthesis was broken so that we'd get: ``` scala> def f[T](xs: Set[T]) = xs collect { case x => x } f: [T](xs: Set[T])scala.collection.immutable.Set[_ <: T] ``` rather than ``` scala> def f[T](xs: Set[T]) = xs collect { case x => x } f: [T](xs: Set[T])scala.collection.immutable.Set[T] ``` --- test/files/pos/t6925.scala | 9 +++++++++ 1 file changed, 9 insertions(+) create mode 100644 test/files/pos/t6925.scala (limited to 'test/files') diff --git a/test/files/pos/t6925.scala b/test/files/pos/t6925.scala new file mode 100644 index 0000000000..862a6e9d0e --- /dev/null +++ b/test/files/pos/t6925.scala @@ -0,0 +1,9 @@ +class Test { + def f[T](xs: Set[T]) /* no expected type to trigger inference */ = + xs collect { case x => x } + + def g[T](xs: Set[T]): Set[T] = f[T](xs) // check that f's inferred type is Set[T] + + // check that this type checks: + List(1).flatMap(n => Set(1).collect { case w => w }) +} \ No newline at end of file -- cgit v1.2.3 From e314ff1621ee26e1e4ec65abc6e360a7731bf488 Mon Sep 17 00:00:00 2001 From: Adriaan Moors Date: Sun, 6 Jan 2013 20:41:23 -0800 Subject: rework partial function synthesis no behavioral changes, just highly overdue cleanup some TODOs for further improvements --- .../scala/tools/nsc/typechecker/Typers.scala | 291 ++++++++++----------- test/files/pos/t6925b.scala | 18 ++ 2 files changed, 163 insertions(+), 146 deletions(-) create mode 100644 test/files/pos/t6925b.scala (limited to 'test/files') diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 49c7181787..441ea6898b 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -996,7 +996,10 @@ trait Typers extends Modes with Adaptations with Tags { object variantToSkolem extends VariantTypeMap { def apply(tp: Type) = mapOver(tp) match { case TypeRef(NoPrefix, tpSym, Nil) if variance != 0 && tpSym.isTypeParameterOrSkolem && tpSym.owner.isTerm => - tpSym.initialize // must initialize or tpSym.tpe might see random type params!! TODO: why is that?? + // must initialize or tpSym.tpe might see random type params!! + // without this, we'll get very weird types inferred in test/scaladoc/run/SI-5933.scala + // TODO: why is that?? + tpSym.initialize val bounds = if (variance == 1) TypeBounds.upper(tpSym.tpe) else TypeBounds.lower(tpSym.tpe) // origin must be the type param so we can deskolemize val skolem = context.owner.newGADTSkolem(unit.freshTypeName("?"+tpSym.name), tpSym, bounds) @@ -1019,7 +1022,7 @@ trait Typers extends Modes with Adaptations with Tags { newTyper(ctorContext).infer.inferConstructorInstance(tree1, clazz.typeParams, ptSafe) // simplify types without losing safety, - // so that error messages don't unnecessarily refer to skolems + // so that we get rid of unnecessary type slack, and so that error messages don't unnecessarily refer to skolems val extrapolate = new ExistentialExtrapolation(freeVars) extrapolate (_: Type) val extrapolated = tree1.tpe match { case MethodType(ctorArgs, res) => // ctorArgs are actually in a covariant position, since this is the type of the subpatterns of the pattern represented by this Apply node @@ -2586,182 +2589,174 @@ trait Typers extends Modes with Adaptations with Tags { match_ // will be translated in phase `patmat` } - // synthesize and type check a PartialFunction implementation based on a match specified by `cases` - // Match(EmptyTree, cases) ==> new PartialFunction { def apply(params) = `translateMatch('`(param1,...,paramN)` match { cases }')` } - // for fresh params, the selector of the match we'll translated simply gathers those in a tuple - // NOTE: restricted to PartialFunction -- leave Function trees if the expected type does not demand a partial function - class MatchFunTyper(tree: Tree, cases: List[CaseDef], mode: Int, pt0: Type) { - // TODO: remove FunctionN support -- this is currently designed so that it can emit FunctionN and PartialFunction subclasses - // however, we should leave Function nodes until Uncurry so phases after typer can still detect normal Function trees - // we need to synthesize PartialFunction impls, though, to avoid nastiness in Uncurry in transforming&duplicating generated pattern matcher trees - // TODO: remove PartialFunction support from UnCurry - private val pt = deskolemizeGADTSkolems(pt0) - private val targs = pt.normalize.typeArgs - private val arity = if (isFunctionType(pt)) targs.length - 1 else 1 // TODO pt should always be a (Partial)Function, right? - private val ptRes = if (targs.isEmpty) WildcardType else targs.last // may not be fully defined - - private val isPartial = pt.typeSymbol == PartialFunctionClass - assert(isPartial) - - private val anonClass = context.owner.newAnonymousFunctionClass(tree.pos) - private val funThis = This(anonClass) - - anonClass addAnnotation AnnotationInfo(SerialVersionUIDAttr.tpe, List(Literal(Constant(0))), List()) - - def deriveFormals = - if (targs.isEmpty) Nil - else targs.init - - def mkParams(methodSym: Symbol, formals: List[Type] = deriveFormals) = - if (formals.isEmpty || !formals.forall(isFullyDefined)) { MissingParameterTypeAnonMatchError(tree, pt); Nil } - else methodSym newSyntheticValueParams formals - - def mkSel(params: List[Symbol]) = - if (params.isEmpty) EmptyTree - else { - val ids = params map (p => Ident(p.name)) - atPos(tree.pos.focusStart) { if (arity == 1) ids.head else gen.mkTuple(ids) } - } + /** synthesize and type check a PartialFunction implementation based on the match in `tree` + * + * `param => sel match { cases }` becomes: + * + * new AbstractPartialFunction[$argTp, $matchResTp] { + * def applyOrElse[A1 <: $argTp, B1 >: $matchResTp]($param: A1, default: A1 => B1): B1 = + * $selector match { $cases } + * def isDefinedAt(x: $argTp): Boolean = + * $selector match { $casesTrue } + * } + * + * TODO: it would be nicer to generate the tree specified above at once and type it as a whole, + * there are two gotchas: + * - matchResTp may not be known until we've typed the match (can only use resTp when it's fully defined), + * - if we typed the match in isolation first, you'd know its result type, but would have to re-jig the owner structure + * - could we use a type variable for matchResTp and backpatch it? + * - occurrences of `this` in `cases` or `sel` must resolve to the this of the class originally enclosing the match, + * not of the anonymous partial function subclass + * + * an alternative TODO: add partial function AST node or equivalent and get rid of this synthesis --> do everything in uncurry (or later) + * however, note that pattern matching codegen is designed to run *before* uncurry + */ + def synthesizePartialFunction(paramName: TermName, paramPos: Position, tree: Tree, mode: Int, pt0: Type): Tree = { + assert(pt0.typeSymbol == PartialFunctionClass) - import CODE._ + val pt = deskolemizeGADTSkolems(pt0) + val targs = pt.normalize.typeArgs - // need to duplicate the cases before typing them to generate the apply method, or the symbols will be all messed up - val casesTrue = if (isPartial) cases map (c => deriveCaseDef(c)(x => atPos(x.pos.focus)(TRUE_typed)).duplicate.asInstanceOf[CaseDef]) else Nil - // println("casesTrue "+ casesTrue) - def parentsPartial(targs: List[Type]) = addSerializable(appliedType(AbstractPartialFunctionClass.typeConstructor, targs)) + // if targs.head isn't fully defined, we can't translate --> error + if (targs.isEmpty || !isFullyDefined(targs.head)) { + MissingParameterTypeAnonMatchError(tree, pt) + return setError(tree) + } - def applyMethod = { - // rig the show so we can get started typing the method body -- later we'll correct the infos... - anonClass setInfo ClassInfoType(addSerializable(ObjectClass.tpe, pt), newScope, anonClass) - val methodSym = anonClass.newMethod(nme.apply, tree.pos, if(isPartial) (FINAL | OVERRIDE) else FINAL) - val paramSyms = mkParams(methodSym) - val selector = mkSel(paramSyms) + val argTp = targs.head - if (selector eq EmptyTree) EmptyTree - else { - methodSym setInfoAndEnter MethodType(paramSyms, AnyClass.tpe) + // NOTE: targs.last still might not be fully defined + val resTp = targs.last - val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) - paramSyms foreach (methodBodyTyper.context.scope enter _) + // targs must conform to Any for us to synthesize an applyOrElse (fallback to apply otherwise -- typically for @cps annotated targs) + val targsValidParams = targs forall (_ <:< AnyClass.tpe) - val match_ = methodBodyTyper.typedMatch(gen.mkUnchecked(selector), cases, mode, ptRes) - val resTp = match_.tpe + val anonClass = (context.owner + newAnonymousFunctionClass tree.pos + addAnnotation AnnotationInfo(SerialVersionUIDAttr.tpe, List(Literal(Constant(0))), List())) - val methFormals = paramSyms map (_.tpe) - val parents = ( - if (isPartial) parentsPartial(List(methFormals.head, resTp)) - else addSerializable(abstractFunctionType(methFormals, resTp)) - ) - anonClass setInfo ClassInfoType(parents, newScope, anonClass) - methodSym setInfoAndEnter MethodType(paramSyms, resTp) + import CODE._ - DefDef(methodSym, methodBodyTyper.virtualizedMatch(match_, mode, resTp)) - } - } + val Match(sel, cases) = tree - // def applyOrElse[A1 <: A, B1 >: B](x: A1, default: A1 => B1): B1 = + // need to duplicate the cases before typing them to generate the apply method, or the symbols will be all messed up + val casesTrue = cases map (c => deriveCaseDef(c)(x => atPos(x.pos.focus)(TRUE_typed)).duplicate.asInstanceOf[CaseDef]) + + // must generate a new tree every time + def selector: Tree = gen.mkUnchecked( + if (sel != EmptyTree) sel.duplicate + else atPos(tree.pos.focusStart)( + // SI-6925: subsume type of the selector to `argTp` + // we don't want/need the match to see the `A1` type that we must use for variance reasons in the method signature + // + // this failed: replace `selector` by `Typed(selector, TypeTree(argTp))` -- as it's an upcast, this should never fail, + // `(x: A1): A` doesn't always type check, even though `A1 <: A`, due to singleton types + // hence the cast, which will be erased in posterasure + Typed(gen.mkAsInstanceOf(Ident(paramName), argTp.withoutAnnotations, true, false), TypeTree(argTp))) + ) + + def mkParam(methodSym: Symbol, tp: Type = argTp) = + methodSym.newValueParameter(paramName, paramPos.focus, SYNTHETIC) setInfo tp + + // `def applyOrElse[A1 <: $argTp, B1 >: $matchResTp](x: A1, default: A1 => B1): B1 = + // ${`$selector match { $cases }` updateAttachment DefaultOverrideMatchAttachment(REF(default) APPLY (REF(x)))}` def applyOrElseMethodDef = { - // rig the show so we can get started typing the method body -- later we'll correct the infos... - // targs were type arguments for PartialFunction, so we know they will work for AbstractPartialFunction as well - anonClass setInfo ClassInfoType(parentsPartial(targs), newScope, anonClass) val methodSym = anonClass.newMethod(nme.applyOrElse, tree.pos, FINAL | OVERRIDE) // create the parameter that corresponds to the function's parameter - val List(argTp) = deriveFormals - val A1 = methodSym newTypeParameter(newTypeName("A1")) setInfo TypeBounds.upper(argTp) - val paramSyms@List(x) = mkParams(methodSym, List(A1.tpe)) - val selector = mkSel(paramSyms) - - if (selector eq EmptyTree) EmptyTree - else { - // applyOrElse's default parameter: - val B1 = methodSym newTypeParameter(newTypeName("B1")) setInfo TypeBounds.empty //lower(resTp) - val default = methodSym newValueParameter(newTermName("default"), tree.pos.focus, SYNTHETIC) setInfo functionType(List(A1.tpe), B1.tpe) + val A1 = methodSym newTypeParameter (newTypeName("A1")) setInfo TypeBounds.upper(argTp) + val x = mkParam(methodSym, A1.tpe) - val paramSyms = List(x, default) - methodSym setInfoAndEnter polyType(List(A1, B1), MethodType(paramSyms, B1.tpe)) + // applyOrElse's default parameter: + val B1 = methodSym newTypeParameter (newTypeName("B1")) setInfo TypeBounds.empty //lower(resTp) + val default = methodSym newValueParameter (newTermName("default"), tree.pos.focus, SYNTHETIC) setInfo functionType(List(A1.tpe), B1.tpe) - val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) - paramSyms foreach (methodBodyTyper.context.scope enter _) + val paramSyms = List(x, default) + methodSym setInfo polyType(List(A1, B1), MethodType(paramSyms, B1.tpe)) - // SI-6925: subsume type of the selector to `argTp` - // we don't want/need the match to see the `A1` type that we must use for variance reasons in the method signature - // the cast is safe: it's an upcast -- the cast is needed because `(x: A1): A` doesn't always type check, even though `A1 <: A` - // specifically, it's needed when dealing with singleton types due to limitations/bugs? with SingletonClass - // (I first tried to use singletonBounds for A1's info when argTp.iStable -- didn't work) - // I decided to always do the cast, as posterasure will detect it's redundant and remove it - val selectorSubsumed = - Typed(gen.mkAsInstanceOf(selector, argTp.withoutAnnotations, true, false), TypeTree(argTp)) // TODO: factor this out -- mkCastTyped? - val match_ = methodBodyTyper.typedMatch(gen.mkUnchecked(selectorSubsumed), cases, mode, ptRes) - val resTp = match_.tpe + val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) + // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) + paramSyms foreach (methodBodyTyper.context.scope enter _) - anonClass setInfo ClassInfoType(parentsPartial(List(argTp, resTp)), newScope, anonClass) - B1 setInfo TypeBounds.lower(resTp) - anonClass.info.decls enter methodSym // methodSym's info need not change (B1's bound has been updated instead) + val match_ = methodBodyTyper.typedMatch(selector, cases, mode, resTp) - match_ setType B1.tpe + val matchResTp = match_.tpe + B1 setInfo TypeBounds.lower(matchResTp) // patch info - // the default uses applyOrElse's first parameter since the scrut's type has been widened - val body = methodBodyTyper.virtualizedMatch(match_ updateAttachment DefaultOverrideMatchAttachment(REF(default) APPLY (REF(x))), mode, B1.tpe) + match_ setType B1.tpe - DefDef(methodSym, body) - } + // the default uses applyOrElse's first parameter since the scrut's type has been widened + val matchWithDefault = match_ updateAttachment DefaultOverrideMatchAttachment(REF(default) APPLY (REF(x))) + (DefDef(methodSym, methodBodyTyper.virtualizedMatch(matchWithDefault, mode, B1.tpe)), matchResTp) } + // `def isDefinedAt(x: $argTp): Boolean = ${`$selector match { $casesTrue ` updateAttachment DefaultOverrideMatchAttachment(FALSE_typed)}` def isDefinedAtMethod = { val methodSym = anonClass.newMethod(nme.isDefinedAt, tree.pos.makeTransparent, FINAL) - val paramSyms = mkParams(methodSym) - val selector = mkSel(paramSyms) + val paramSym = mkParam(methodSym) - if (selector eq EmptyTree) EmptyTree - else { - val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) - paramSyms foreach (methodBodyTyper.context.scope enter _) - methodSym setInfoAndEnter MethodType(paramSyms, BooleanClass.tpe) + val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) + methodBodyTyper.context.scope enter paramSym + methodSym setInfo MethodType(List(paramSym), BooleanClass.tpe) - val match_ = methodBodyTyper.typedMatch(gen.mkUnchecked(selector), casesTrue, mode, BooleanClass.tpe) - val body = methodBodyTyper.virtualizedMatch(match_ updateAttachment DefaultOverrideMatchAttachment(FALSE_typed), mode, BooleanClass.tpe) + val match_ = methodBodyTyper.typedMatch(selector, casesTrue, mode, BooleanClass.tpe) - DefDef(methodSym, body) - } + val matchWithDefault = match_ updateAttachment DefaultOverrideMatchAttachment(FALSE_typed) + DefDef(methodSym, methodBodyTyper.virtualizedMatch(matchWithDefault, mode, BooleanClass.tpe)) } - lazy val members = if (isPartial) { - // somehow @cps annotations upset the typer when looking at applyOrElse's signature, but not apply's - // TODO: figure out the details (T @cps[U] is not a subtype of Any, but then why does it work for the apply method?) - if (targs forall (_ <:< AnyClass.tpe)) List(applyOrElseMethodDef, isDefinedAtMethod) - else List(applyMethod, isDefinedAtMethod) - } else List(applyMethod) + // only used for @cps annotated partial functions + def applyMethod = { + val methodSym = anonClass.newMethod(nme.apply, tree.pos, FINAL | OVERRIDE) + val paramSym = mkParam(methodSym) - def translated = - if (members.head eq EmptyTree) setError(tree) - else { - val typedBlock = typedPos(tree.pos, mode, pt) { - Block(ClassDef(anonClass, NoMods, ListOfNil, members, tree.pos.focus), atPos(tree.pos.focus)(New(anonClass.tpe))) - } - // Don't leak implementation details into the type, see SI-6575 - if (isPartial && !typedBlock.isErrorTyped) - typedPos(tree.pos, mode, pt) { - Typed(typedBlock, TypeTree(typedBlock.tpe baseType PartialFunctionClass)) - } - else typedBlock - } - } + methodSym setInfo MethodType(List(paramSym), AnyClass.tpe) + + val methodBodyTyper = newTyper(context.makeNewScope(context.tree, methodSym)) + // should use the DefDef for the context's tree, but it doesn't exist yet (we need the typer we're creating to create it) + methodBodyTyper.context.scope enter paramSym + + val match_ = methodBodyTyper.typedMatch(selector, cases, mode, resTp) - // Function(params, Match(sel, cases)) ==> new Function { def apply(params) = `translateMatch('sel match { cases }')` } - class MatchFunTyperBetaReduced(fun: Function, sel: Tree, cases: List[CaseDef], mode: Int, pt: Type) extends MatchFunTyper(fun, cases, mode, pt) { - override def deriveFormals = - fun.vparams map { p => if(p.tpt.tpe == null) typedType(p.tpt).tpe else p.tpt.tpe } + val matchResTp = match_.tpe + methodSym setInfo MethodType(List(paramSym), matchResTp) // patch info - // the only difference from the super class is that we must preserve the names of the parameters - override def mkParams(methodSym: Symbol, formals: List[Type] = deriveFormals) = - (fun.vparams, formals).zipped map { (p, tp) => - methodSym.newValueParameter(p.name, p.pos.focus, SYNTHETIC) setInfo tp + (DefDef(methodSym, methodBodyTyper.virtualizedMatch(match_, mode, matchResTp)), matchResTp) + } + + def parents(resTp: Type) = addSerializable(appliedType(AbstractPartialFunctionClass.typeConstructor, List(argTp, resTp))) + + val members = { + val (applyMeth, matchResTp) = { + // rig the show so we can get started typing the method body -- later we'll correct the infos... + // targs were type arguments for PartialFunction, so we know they will work for AbstractPartialFunction as well + anonClass setInfo ClassInfoType(parents(resTp), newScope, anonClass) + + // somehow @cps annotations upset the typer when looking at applyOrElse's signature, but not apply's + // TODO: figure out the details (T @cps[U] is not a subtype of Any, but then why does it work for the apply method?) + if (targsValidParams) applyOrElseMethodDef + else applyMethod } - override def mkSel(params: List[Symbol]) = sel.duplicate + // patch info to the class's definitive info + anonClass setInfo ClassInfoType(parents(matchResTp), newScope, anonClass) + List(applyMeth, isDefinedAtMethod) + } + + members foreach (m => anonClass.info.decls enter m.symbol) + + val typedBlock = typedPos(tree.pos, mode, pt) { + Block(ClassDef(anonClass, NoMods, ListOfNil, members, tree.pos.focus), atPos(tree.pos.focus)(New(anonClass.tpe))) + } + + if (typedBlock.isErrorTyped) typedBlock + else // Don't leak implementation details into the type, see SI-6575 + typedPos(tree.pos, mode, pt) { + Typed(typedBlock, TypeTree(typedBlock.tpe baseType PartialFunctionClass)) + } } + /** * @param fun ... * @param mode ... @@ -2813,14 +2808,17 @@ trait Typers extends Modes with Adaptations with Tags { } fun.body match { - // later phase indicates scaladoc is calling (where shit is messed up, I tell you) - // -- so fall back to old patmat, which is more forgiving + // translate `x => x match { }` : PartialFunction to + // `new PartialFunction { def applyOrElse(x, default) = x match { } def isDefinedAt(x) = ... }` case Match(sel, cases) if (sel ne EmptyTree) && newPatternMatching && (pt.typeSymbol == PartialFunctionClass) => // go to outer context -- must discard the context that was created for the Function since we're discarding the function // thus, its symbol, which serves as the current context.owner, is not the right owner // you won't know you're using the wrong owner until lambda lift crashes (unless you know better than to use the wrong owner) val outerTyper = newTyper(context.outer) - (new outerTyper.MatchFunTyperBetaReduced(fun, sel, cases, mode, pt)).translated + val p = fun.vparams.head + if (p.tpt.tpe == null) p.tpt setType outerTyper.typedType(p.tpt).tpe + + outerTyper.synthesizePartialFunction(p.name, p.pos, fun.body, mode, pt) case _ => val vparamSyms = fun.vparams map { vparam => enterSym(context, vparam) @@ -4353,7 +4351,8 @@ trait Typers extends Modes with Adaptations with Tags { val selector = tree.selector val cases = tree.cases if (selector == EmptyTree) { - if (newPatternMatching && (pt.typeSymbol == PartialFunctionClass)) (new MatchFunTyper(tree, cases, mode, pt)).translated + if (newPatternMatching && (pt.typeSymbol == PartialFunctionClass)) + synthesizePartialFunction(newTermName(context.unit.fresh.newName("x")), tree.pos, tree, mode, pt) else { val arity = if (isFunctionType(pt)) pt.normalize.typeArgs.length - 1 else 1 val params = for (i <- List.range(0, arity)) yield diff --git a/test/files/pos/t6925b.scala b/test/files/pos/t6925b.scala new file mode 100644 index 0000000000..ca25146dfc --- /dev/null +++ b/test/files/pos/t6925b.scala @@ -0,0 +1,18 @@ +// code *generated* by test/scaladoc/run/SI-5933.scala +// duplicated here because it's related to SI-6925 + +import language.higherKinds + +abstract class Base[M[_, _]] { + def foo[A, B]: M[(A, B), Any] +} + +class Derived extends Base[PartialFunction] { + def foo[AA, BB] /*: PartialFunction[(A, B) => Any]*/ = { case (a, b) => (a: AA, b: BB) } +} + +object Test { + lazy val lx = { println("hello"); 3 } + def test1(x: Int = lx) = ??? + def test2(x: Int = lx match { case 0 => 1; case 3 => 4 }) = ??? +} \ No newline at end of file -- cgit v1.2.3