diff options
-rw-r--r-- | src/compiler/scala/tools/nsc/Global.scala | 2 | ||||
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Contexts.scala | 42 | ||||
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Infer.scala | 57 | ||||
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 7 | ||||
-rw-r--r-- | src/reflect/scala/reflect/internal/SymbolTable.scala | 10 | ||||
-rw-r--r-- | src/reflect/scala/reflect/internal/Types.scala | 73 |
6 files changed, 105 insertions, 86 deletions
diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala index fea9e72512..4e5f4faf51 100644 --- a/src/compiler/scala/tools/nsc/Global.scala +++ b/src/compiler/scala/tools/nsc/Global.scala @@ -263,6 +263,8 @@ class Global(var currentSettings: Settings, var reporter: Reporter) @inline final override def devWarning(msg: => String) { if (settings.developer.value || settings.debug.value) warning("!!! " + msg) + else + log("!!! " + msg) // such warnings always at least logged } private def elapsedMessage(msg: String, start: Long) = diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala index eb91251930..26e39d3d1b 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala @@ -8,6 +8,7 @@ package typechecker import scala.collection.mutable import scala.annotation.tailrec +import scala.reflect.internal.util.shortClassOfInstance /** * @author Martin Odersky @@ -175,6 +176,7 @@ trait Contexts { self: Analyzer => if ((owner eq NoSymbol) || (owner.isClass) || (owner.isMethod)) this else outer.enclClassOrMethod + def enclosingCaseDef = nextEnclosing(_.tree.isInstanceOf[CaseDef]) def undetparamsString = if (undetparams.isEmpty) "" else undetparams.mkString("undetparams=", ", ", "") @@ -584,23 +586,39 @@ trait Contexts { self: Analyzer => } def pushTypeBounds(sym: Symbol) { + sym.info match { + case tb: TypeBounds => if (!tb.isEmptyBounds) log(s"Saving $sym info=$tb") + case info => devWarning(s"Something other than a TypeBounds seen in pushTypeBounds: $info is a ${shortClassOfInstance(info)}") + } savedTypeBounds ::= ((sym, sym.info)) } def restoreTypeBounds(tp: Type): Type = { - var current = tp - for ((sym, info) <- savedTypeBounds) { - debuglog("resetting " + sym + " to " + info) - sym.info match { - case TypeBounds(lo, hi) if (hi <:< lo && lo <:< hi) => - current = current.instantiateTypeParams(List(sym), List(lo)) -//@M TODO: when higher-kinded types are inferred, probably need a case PolyType(_, TypeBounds(...)) if ... => - case _ => - } - sym.setInfo(info) + def restore(): Type = savedTypeBounds.foldLeft(tp) { case (current, (sym, savedInfo)) => + def bounds_s(tb: TypeBounds) = if (tb.isEmptyBounds) "<empty bounds>" else s"TypeBounds(lo=${tb.lo}, hi=${tb.hi})" + //@M TODO: when higher-kinded types are inferred, probably need a case PolyType(_, TypeBounds(...)) if ... => + val tb @ TypeBounds(lo, hi) = sym.info.bounds + val isUnique = lo <:< hi && hi <:< lo + val isPresent = current contains sym + def saved_s = bounds_s(savedInfo.bounds) + def current_s = bounds_s(sym.info.bounds) + + if (isUnique && isPresent) + devWarningResult(s"Preserving inference: ${sym.nameString}=$hi in $current (based on $current_s) before restoring $sym to saved $saved_s")( + current.instantiateTypeParams(List(sym), List(hi)) + ) + else if (isPresent) + devWarningResult(s"Discarding inferred $current_s because it does not uniquely determine $sym in")(current) + else + logResult(s"Discarding inferred $current_s because $sym does not appear in")(current) + } + try restore() + finally { + for ((sym, savedInfo) <- savedTypeBounds) + sym setInfo debuglogResult(s"Discarding inferred $sym=${sym.info}, restoring saved info")(savedInfo) + + savedTypeBounds = Nil } - savedTypeBounds = List() - current } private var implicitsCache: List[List[ImplicitInfo]] = null diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala index db3759d65f..a29cc93b6d 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala @@ -1317,15 +1317,18 @@ trait Infer extends Checkable { } } - def instBounds(tvar: TypeVar): (Type, Type) = { - val tparam = tvar.origin.typeSymbol - val instType = toOrigin(tvar.constr.inst) + def instBounds(tvar: TypeVar): TypeBounds = { + val tparam = tvar.origin.typeSymbol + val instType = toOrigin(tvar.constr.inst) + val TypeBounds(lo, hi) = tparam.info.bounds val (loBounds, hiBounds) = - if (instType != NoType && isFullyDefined(instType)) (List(instType), List(instType)) + if (isFullyDefined(instType)) (List(instType), List(instType)) else (tvar.constr.loBounds, tvar.constr.hiBounds) - val lo = lub(tparam.info.bounds.lo :: loBounds map toOrigin) - val hi = glb(tparam.info.bounds.hi :: hiBounds map toOrigin) - (lo, hi) + + TypeBounds( + lub(lo :: loBounds map toOrigin), + glb(hi :: hiBounds map toOrigin) + ) } def isInstantiatable(tvars: List[TypeVar]) = { @@ -1335,33 +1338,25 @@ trait Infer extends Checkable { solve(tvars1, tvars1 map (_.origin.typeSymbol), tvars1 map (_ => Variance.Covariant), false) } - // this is quite nasty: it destructively changes the info of the syms of e.g., method type params (see #3692, where the type param T's bounds were set to >: T <: T, so that parts looped) + // this is quite nasty: it destructively changes the info of the syms of e.g., method type params + // (see #3692, where the type param T's bounds were set to > : T <: T, so that parts looped) // the changes are rolled back by restoreTypeBounds, but might be unintentially observed in the mean time def instantiateTypeVar(tvar: TypeVar) { - val tparam = tvar.origin.typeSymbol - if (false && - tvar.constr.inst != NoType && - isFullyDefined(tvar.constr.inst) && - (tparam.info.bounds containsType tvar.constr.inst)) { - context.nextEnclosing(_.tree.isInstanceOf[CaseDef]).pushTypeBounds(tparam) - tparam setInfo tvar.constr.inst - tparam resetFlag DEFERRED - debuglog("new alias of " + tparam + " = " + tparam.info) - } else { - val (lo, hi) = instBounds(tvar) - if (lo <:< hi) { - if (!((lo <:< tparam.info.bounds.lo) && (tparam.info.bounds.hi <:< hi)) // bounds were improved - && tparam != lo.typeSymbolDirect && tparam != hi.typeSymbolDirect) { // don't create illegal cycles - context.nextEnclosing(_.tree.isInstanceOf[CaseDef]).pushTypeBounds(tparam) - tparam setInfo TypeBounds(lo, hi) - debuglog("new bounds of " + tparam + " = " + tparam.info) - } else { - debuglog("redundant: "+tparam+" "+tparam.info+"/"+lo+" "+hi) - } - } else { - debuglog("inconsistent: "+tparam+" "+lo+" "+hi) + val tparam = tvar.origin.typeSymbol + val TypeBounds(lo0, hi0) = tparam.info.bounds + val tb @ TypeBounds(lo1, hi1) = instBounds(tvar) + + if (lo1 <:< hi1) { + if (lo1 <:< lo0 && hi0 <:< hi1) // bounds unimproved + log(s"redundant bounds: discarding TypeBounds($lo1, $hi1) for $tparam, no improvement on TypeBounds($lo0, $hi0)") + else if (tparam == lo1.typeSymbolDirect || tparam == hi1.typeSymbolDirect) + log(s"cyclical bounds: discarding TypeBounds($lo1, $hi1) for $tparam because $tparam appears as bounds") + else { + context.enclosingCaseDef pushTypeBounds tparam + tparam setInfo logResult(s"updated bounds: $tparam from ${tparam.info} to")(tb) } } + else log(s"inconsistent bounds: discarding TypeBounds($lo1, $hi1)") } /** Type intersection of simple type tp1 with general type tp2. @@ -1524,7 +1519,7 @@ trait Infer extends Checkable { // todo: missing test case for bests.isEmpty bests match { case best :: Nil => tree setSymbol best setType (pre memberType best) - case best :: competing :: _ if alts0.nonEmpty => + case best :: competing :: _ if alts0.nonEmpty => // SI-6912 Don't give up and leave an OverloadedType on the tree. // Originally I wrote this as `if (secondTry) ... `, but `tryTwice` won't attempt the second try // unless an error is issued. We're not issuing an error, in the assumption that it would be diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index c40b69bc7a..9680b911e0 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -2438,16 +2438,13 @@ trait Typers extends Adaptations with Tags { else typed(cdef.guard, BooleanClass.tpe) var body1: Tree = typed(cdef.body, pt) - val contextWithTypeBounds = context.nextEnclosing(_.tree.isInstanceOf[CaseDef]) - if (contextWithTypeBounds.savedTypeBounds.nonEmpty) { - body1 modifyType (contextWithTypeBounds restoreTypeBounds _) - + if (context.enclosingCaseDef.savedTypeBounds.nonEmpty) { + body1 modifyType context.enclosingCaseDef.restoreTypeBounds // insert a cast if something typechecked under the GADT constraints, // but not in real life (i.e., now that's we've reset the method's type skolems' // infos back to their pre-GADT-constraint state) if (isFullyDefined(pt) && !(body1.tpe <:< pt)) body1 = typedPos(body1.pos)(gen.mkCast(body1, pt.dealiasWiden)) - } // body1 = checkNoEscaping.locals(context.scope, pt, body1) diff --git a/src/reflect/scala/reflect/internal/SymbolTable.scala b/src/reflect/scala/reflect/internal/SymbolTable.scala index 9b5778b9da..03ec59f0fe 100644 --- a/src/reflect/scala/reflect/internal/SymbolTable.scala +++ b/src/reflect/scala/reflect/internal/SymbolTable.scala @@ -87,6 +87,16 @@ abstract class SymbolTable extends macros.Universe result } @inline + final private[scala] def debuglogResult[T](msg: => String)(result: T): T = { + debuglog(msg + ": " + result) + result + } + @inline + final private[scala] def devWarningResult[T](msg: => String)(result: T): T = { + devWarning(msg + ": " + result) + result + } + @inline final private[scala] def logResultIf[T](msg: => String, cond: T => Boolean)(result: T): T = { if (cond(result)) log(msg + ": " + result) diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala index 15883bb8a9..22ba6d43e9 100644 --- a/src/reflect/scala/reflect/internal/Types.scala +++ b/src/reflect/scala/reflect/internal/Types.scala @@ -2250,7 +2250,7 @@ trait Types extends api.Types { self: SymbolTable => else ErrorType } - // isHKSubType0 introduces synthetic type params so that + // isHKSubType introduces synthetic type params so that // betaReduce can first apply sym.info to typeArgs before calling // asSeenFrom. asSeenFrom then skips synthetic type params, which // are used to reduce HO subtyping to first-order subtyping, but @@ -5746,44 +5746,41 @@ trait Types extends api.Types { self: SymbolTable => case _ => false } - // @assume tp1.isHigherKinded || tp2.isHigherKinded - def isHKSubType0(tp1: Type, tp2: Type, depth: Int): Boolean = ( - tp1.typeSymbol == NothingClass - || - tp2.typeSymbol == AnyClass // @M Any and Nothing are super-type resp. subtype of every well-kinded type - || // @M! normalize reduces higher-kinded case to PolyType's - ((tp1.normalize.withoutAnnotations , tp2.normalize.withoutAnnotations) match { - case (PolyType(tparams1, res1), PolyType(tparams2, res2)) => // @assume tp1.isHigherKinded && tp2.isHigherKinded (as they were both normalized to PolyType) - sameLength(tparams1, tparams2) && { - if (tparams1.head.owner.isMethod) { // fast-path: polymorphic method type -- type params cannot be captured - (tparams1 corresponds tparams2)((p1, p2) => p2.info.substSym(tparams2, tparams1) <:< p1.info) && - res1 <:< res2.substSym(tparams2, tparams1) - } else { // normalized higher-kinded type - //@M for an example of why we need to generate fresh symbols, see neg/tcpoly_ticket2101.scala - val tpsFresh = cloneSymbols(tparams1) - - (tparams1 corresponds tparams2)((p1, p2) => - p2.info.substSym(tparams2, tpsFresh) <:< p1.info.substSym(tparams1, tpsFresh)) && - res1.substSym(tparams1, tpsFresh) <:< res2.substSym(tparams2, tpsFresh) - - //@M the forall in the previous test could be optimised to the following, - // but not worth the extra complexity since it only shaves 1s from quick.comp - // (List.forall2(tpsFresh/*optimisation*/, tparams2)((p1, p2) => - // p2.info.substSym(tparams2, tpsFresh) <:< p1.info /*optimisation, == (p1 from tparams1).info.substSym(tparams1, tpsFresh)*/) && - // this optimisation holds because inlining cloneSymbols in `val tpsFresh = cloneSymbols(tparams1)` gives: - // val tpsFresh = tparams1 map (_.cloneSymbol) - // for (tpFresh <- tpsFresh) tpFresh.setInfo(tpFresh.info.substSym(tparams1, tpsFresh)) - } - } && annotationsConform(tp1.normalize, tp2.normalize) + private def isPolySubType(tp1: PolyType, tp2: PolyType): Boolean = { + val PolyType(tparams1, res1) = tp1 + val PolyType(tparams2, res2) = tp2 + + sameLength(tparams1, tparams2) && { + // fast-path: polymorphic method type -- type params cannot be captured + val isMethod = tparams1.head.owner.isMethod + //@M for an example of why we need to generate fresh symbols otherwise, see neg/tcpoly_ticket2101.scala + val substitutes = if (isMethod) tparams1 else cloneSymbols(tparams1) + def sub1(tp: Type) = if (isMethod) tp else tp.substSym(tparams1, substitutes) + def sub2(tp: Type) = tp.substSym(tparams2, substitutes) + def cmp(p1: Symbol, p2: Symbol) = sub2(p2.info) <:< sub1(p1.info) - case (PolyType(_, _), MethodType(params, _)) if params exists (_.tpe.isWildcard) => - false // don't warn on HasMethodMatching on right hand side + (tparams1 corresponds tparams2)(cmp) && (sub1(res1) <:< sub2(res2)) + } + } - case (ntp1, ntp2) => - devWarning(s"isHKSubType0($tp1, $tp2, _) is ${tp1.getClass}, ${tp2.getClass}: ($ntp1, $ntp2)") - false // @assume !tp1.isHigherKinded || !tp2.isHigherKinded - // --> thus, cannot be subtypes (Any/Nothing has already been checked) - })) + // @assume tp1.isHigherKinded || tp2.isHigherKinded + def isHKSubType(tp1: Type, tp2: Type, depth: Int): Boolean = { + def isSub(ntp1: Type, ntp2: Type) = (ntp1.withoutAnnotations, ntp2.withoutAnnotations) match { + case (TypeRef(_, AnyClass, _), _) => false // avoid some warnings when Nothing/Any are on the other side + case (_, TypeRef(_, NothingClass, _)) => false + case (pt1: PolyType, pt2: PolyType) => isPolySubType(pt1, pt2) // @assume both .isHigherKinded (both normalized to PolyType) + case (_: PolyType, MethodType(ps, _)) if ps exists (_.tpe.isWildcard) => false // don't warn on HasMethodMatching on right hand side + case _ => // @assume !(both .isHigherKinded) thus cannot be subtypes + def tp_s(tp: Type): String = f"$tp%-20s ${util.shortClassOfInstance(tp)}%s" + devWarning(s"HK subtype check on $tp1 and $tp2, but both don't normalize to polytypes:\n tp1=${tp_s(ntp1)}\n tp2=${tp_s(ntp2)}") + false + } + + ( tp1.typeSymbol == NothingClass // @M Nothing is subtype of every well-kinded type + || tp2.typeSymbol == AnyClass // @M Any is supertype of every well-kinded type (@PP: is it? What about continuations plugin?) + || isSub(tp1.normalize, tp2.normalize) && annotationsConform(tp1, tp2) // @M! normalize reduces higher-kinded case to PolyType's + ) + } def isSubArgs(tps1: List[Type], tps2: List[Type], tparams: List[Symbol], depth: Int): Boolean = { def isSubArg(t1: Type, t2: Type, variance: Variance) = ( @@ -5801,7 +5798,7 @@ trait Types extends api.Types { self: SymbolTable => if (tp1 eq NoPrefix) return (tp2 eq NoPrefix) || tp2.typeSymbol.isPackageClass // !! I do not see how the "isPackageClass" would be warranted by the spec if (tp2 eq NoPrefix) return tp1.typeSymbol.isPackageClass if (isSingleType(tp1) && isSingleType(tp2) || isConstantType(tp1) && isConstantType(tp2)) return tp1 =:= tp2 - if (tp1.isHigherKinded || tp2.isHigherKinded) return isHKSubType0(tp1, tp2, depth) + if (tp1.isHigherKinded || tp2.isHigherKinded) return isHKSubType(tp1, tp2, depth) /** First try, on the right: * - unwrap Annotated types, BoundedWildcardTypes, |