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author | Adriaan Moors <adriaan.moors@typesafe.com> | 2014-02-05 09:47:41 -0800 |
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committer | Adriaan Moors <adriaan.moors@typesafe.com> | 2014-02-05 09:47:41 -0800 |
commit | 01770aa7ff1d5b89a6b67a964a818320c8c9d15e (patch) | |
tree | e77ffa7ed4d7370c617f3f83059c89f9768006cf | |
parent | d41e6d501b63445003867e3f4e13628a4918213b (diff) | |
parent | a02fae978bbf3a4296e7ab0baffdbe0b80d6c126 (diff) | |
download | scala-01770aa7ff1d5b89a6b67a964a818320c8c9d15e.tar.gz scala-01770aa7ff1d5b89a6b67a964a818320c8c9d15e.tar.bz2 scala-01770aa7ff1d5b89a6b67a964a818320c8c9d15e.zip |
Merge pull request #3400 from retronym/ticket/8170
SI-8170 Fix regression in TypeRef#transform w. PolyTypes
-rw-r--r-- | src/reflect/scala/reflect/internal/Types.scala | 37 | ||||
-rw-r--r-- | test/files/pos/t8170.scala | 27 | ||||
-rw-r--r-- | test/files/pos/t8170b.scala | 25 |
3 files changed, 84 insertions, 5 deletions
diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala index 2acf901d0e..53c528a2bb 100644 --- a/src/reflect/scala/reflect/internal/Types.scala +++ b/src/reflect/scala/reflect/internal/Types.scala @@ -1988,12 +1988,39 @@ trait Types // too little information is known to determine its kind, and // it later turns out not to have kind *. See SI-4070. Only // logging it for now. - if (sym.typeParams.size != args.size) + val tparams = sym.typeParams + if (tparams.size != args.size) devWarning(s"$this.transform($tp), but tparams.isEmpty and args=$args") - - val GenPolyType(tparams, result) = asSeenFromOwner(tp) - assert((tparams eq Nil) || tparams == sym.typeParams, (tparams, sym.typeParams)) - result.instantiateTypeParams(sym.typeParams, args) + def asSeenFromInstantiated(tp: Type) = + asSeenFromOwner(tp).instantiateTypeParams(tparams, args) + // If we're called with a poly type, and we were to run the `asSeenFrom`, over the entire + // type, we can end up with new symbols for the type parameters (clones from TypeMap). + // The subsequent substitution of type arguments would fail. This problem showed up during + // the fix for SI-8046, however the solution taken there wasn't quite right, and led to + // SI-8170. + // + // Now, we detect the PolyType before both the ASF *and* the substitution, and just operate + // on the result type. + // + // TODO: Revisit this and explore the questions raised: + // + // AM: I like this better than the old code, but is there any way the tparams would need the ASF treatment as well? + // JZ: I think its largely irrelevant, as they are no longer referred to in the result type. + // In fact, you can get away with returning a type of kind * here and the sky doesn't fall: + // `case PolyType(`tparams`, result) => asSeenFromInstantiated(result)` + // But I thought it was better to retain the kind. + // AM: I've been experimenting with apply-type-args-then-ASF, but running into cycles. + // In general, it seems iffy the tparams can never occur in the result + // then we might as well represent the type as a no-arg typeref. + // AM: I've also been trying to track down uses of transform (pretty generic name for something that + // does not seem that widely applicable). + // It's kind of a helper for computing baseType (since it tries to propagate our type args to some + // other type, which has to be related to this type for that to make sense). + // + tp match { + case PolyType(`tparams`, result) => PolyType(tparams, asSeenFromInstantiated(result)) + case _ => asSeenFromInstantiated(tp) + } } // note: does not go through typeRef. There's no need to because diff --git a/test/files/pos/t8170.scala b/test/files/pos/t8170.scala new file mode 100644 index 0000000000..b65f4b8572 --- /dev/null +++ b/test/files/pos/t8170.scala @@ -0,0 +1,27 @@ +object O { + trait X + trait B extends A { + override type T[F1 <: X] = F1 + } + trait A { + type T[F <: X] + } +} + +object Test { + import O._ + val a: B = ??? + val b: a.T[X] = ??? + b.ensuring(x => true) // trigger an implicit search +} + + +/* +this = {AliasArgsTypeRef@3004}"Test#7680.a#14899.T#14823[O#7702.X#7793]" + sym = type T#14823 + info = namer: [F#14824 <: O#7703.X#7793]F#14824 +result = {AbstractNoArgsTypeRef@3237}"F#24451" +tp = {PolyType@3235}"[F#14824 <: O#7703.X#7793]F#14824" +tparams = + (0) = {AbstractTypeSymbol@3247}"type F#24451" +*/
\ No newline at end of file diff --git a/test/files/pos/t8170b.scala b/test/files/pos/t8170b.scala new file mode 100644 index 0000000000..53036f6c8a --- /dev/null +++ b/test/files/pos/t8170b.scala @@ -0,0 +1,25 @@ +import language._ + +object ScalaZeee { + trait HFold[M[_], U] { + type Apply[E, A <: U] <: U + } + trait GenericCons[M[_], H, +T <: GenericList[M]] extends GenericList[M] { + val tail: T + override type Folded[N[X] >: M[X], U, F <: HFold[N, U]] = F#Apply[H, tail.Folded[N, U, F]] + } + val KNil: GenericList[Nothing] = ??? + sealed trait GenericList[+M[_]] { + type Folded[N[X] >: M[X], U, F <: HFold[N, U]] <: U + } +} + +object TypelevelUsage { + import ScalaZeee._ + type T = GenericCons[Some, String, KNil.type] + val klist1: T = ??? + type T2 = klist1.Folded[Option, Int, HFold[Option, Int]] + val count2: T2 = ??? + + count2.ensuring(x => true).toChar // trigger an implicit search +} |