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author | Paul Phillips <paulp@improving.org> | 2013-01-31 22:44:12 -0800 |
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committer | Paul Phillips <paulp@improving.org> | 2013-01-31 22:44:12 -0800 |
commit | 110b54a575278cfdd04672b5ff170a68060ff245 (patch) | |
tree | dd8298895522d6fe5a679379bdcae2d0b1597d63 /src | |
parent | d1b6d8b20f55d0b11102ced679b54ec5ea208f8f (diff) | |
parent | f6d90a8a2502c0e1f0ecf72a2fd4258c4f52ec84 (diff) | |
download | scala-110b54a575278cfdd04672b5ff170a68060ff245.tar.gz scala-110b54a575278cfdd04672b5ff170a68060ff245.tar.bz2 scala-110b54a575278cfdd04672b5ff170a68060ff245.zip |
Merge pull request #2000 from adriaanm/backport-pr-1873
[backport] SI-5378, unsoundness with type bounds in refinements.
Diffstat (limited to 'src')
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 79 |
1 files changed, 50 insertions, 29 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index 2816015671..3e1a4631ac 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -2210,37 +2210,58 @@ trait Typers extends Modes with Adaptations with Tags { */ def checkMethodStructuralCompatible(ddef: DefDef): Unit = { val meth = ddef.symbol - def fail(pos: Position, msg: String) = unit.error(pos, msg) - val tp: Type = meth.tpe match { - case mt @ MethodType(_, _) => mt - case NullaryMethodType(restpe) => restpe // TODO_NMT: drop NullaryMethodType from resultType? - case PolyType(_, restpe) => restpe - case _ => NoType - } - def nthParamPos(n: Int) = ddef.vparamss match { - case xs :: _ if xs.length > n => xs(n).pos - case _ => meth.pos - } - def failStruct(pos: Position, what: String, where: String = "Parameter") = - fail(pos, s"$where type in structural refinement may not refer to $what") - - foreachWithIndex(tp.paramTypes) { (paramType, idx) => - val sym = paramType.typeSymbol - def paramPos = nthParamPos(idx) - - if (sym.isAbstractType) { - if (!sym.hasTransOwner(meth.owner)) - failStruct(paramPos, "an abstract type defined outside that refinement") - else if (!sym.hasTransOwner(meth)) - failStruct(paramPos, "a type member of that refinement") + def parentString = meth.owner.parentSymbols filterNot (_ == ObjectClass) match { + case Nil => "" + case xs => xs.map(_.nameString).mkString(" (of ", " with ", ")") + } + def fail(pos: Position, msg: String): Boolean = { + unit.error(pos, msg) + false + } + /** Have to examine all parameters in all lists. + */ + def paramssTypes(tp: Type): List[List[Type]] = tp match { + case mt @ MethodType(_, restpe) => mt.paramTypes :: paramssTypes(restpe) + case PolyType(_, restpe) => paramssTypes(restpe) + case _ => Nil + } + def resultType = meth.tpe.finalResultType + def nthParamPos(n1: Int, n2: Int) = + try ddef.vparamss(n1)(n2).pos catch { case _: IndexOutOfBoundsException => meth.pos } + + def failStruct(pos: Position, what: String, where: String = "Parameter type") = + fail(pos, s"$where in structural refinement may not refer to $what") + + foreachWithIndex(paramssTypes(meth.tpe)) { (paramList, listIdx) => + foreachWithIndex(paramList) { (paramType, paramIdx) => + val sym = paramType.typeSymbol + def paramPos = nthParamPos(listIdx, paramIdx) + + /** Not enough to look for abstract types; have to recursively check the bounds + * of each abstract type for more abstract types. Almost certainly there are other + * exploitable type soundness bugs which can be seen by bounding a type parameter + * by an abstract type which itself is bounded by an abstract type. + */ + def checkAbstract(tp0: Type, what: String): Boolean = { + def check(sym: Symbol): Boolean = !sym.isAbstractType || { + log(s"""checking $tp0 in refinement$parentString at ${meth.owner.owner.fullLocationString}""") + ( (!sym.hasTransOwner(meth.owner) && failStruct(paramPos, "an abstract type defined outside that refinement", what)) + || (!sym.hasTransOwner(meth) && failStruct(paramPos, "a type member of that refinement", what)) + || checkAbstract(sym.info.bounds.hi, "Type bound") + ) + } + tp0.dealiasWidenChain forall (t => check(t.typeSymbol)) + } + checkAbstract(paramType, "Parameter type") + + if (sym.isDerivedValueClass) + failStruct(paramPos, "a user-defined value class") + if (paramType.isInstanceOf[ThisType] && sym == meth.owner) + failStruct(paramPos, "the type of that refinement (self type)") } - if (sym.isDerivedValueClass) - failStruct(paramPos, "a user-defined value class") - if (paramType.isInstanceOf[ThisType] && sym == meth.owner) - failStruct(paramPos, "the type of that refinement (self type)") } - if (tp.resultType.typeSymbol.isDerivedValueClass) - failStruct(ddef.tpt.pos, "a user-defined value class", where = "Result") + if (resultType.typeSymbol.isDerivedValueClass) + failStruct(ddef.tpt.pos, "a user-defined value class", where = "Result type") } def typedUseCase(useCase: UseCase) { |