SI-8244 Fix raw type regression under separate compilation #3519
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In scala#1901, handling of raw types encountered in signatures during class file parsing was changed to work in the same manner as `classExistentialType`, by using `existentialAbstraction(cls.tparms, cls.tpe_*)` But this never creates fresh existential symbols, and just sticks the class type parameters it `quantified`: scala> trait T[A <: String] defined trait T scala> val cls = typeOf[T[_]].typeSymbol cls = trait T#101864 scala> cls.typeParams res0 = List(type A#101865) scala> cls.tpe_* res1 = T#101864[A#101865] scala> classExistentialType(cls) res3 = T#101864[_ <: String#7209] scala> val ExistentialType(quantified, result) = res3 List(type A#101865) In the enclosed test case, this class type parameter was substituted during `typeOf[X] memberType sym`, which led us unsoundly thinking that `Raw[_]` was `Raw[X]`. I've added a TODO comment to review the other usages of `classExistentialType`. Test variations include joint and separate compilation, and the corresponding Scala-only code. All fail with type errors now, as we expect. I've also added a distillation of a bootstrap error that failed when I forgot to wrap the `existentialType`.
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LGTM |
adriaanm
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SI-8244 Fix raw type regression under separate compilation
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[Rebase of #3483 that also avoids overlapping test files t8244b/ became t8244e/]
In #1901, handling of raw types encountered in signatures during class
file parsing was changed to work in the same manner as
classExistentialType, by usingexistentialAbstraction(cls.tparms, cls.tpe_*)But this never creates fresh existential symbols, and just sticks
the class type parameters it
quantified:In the enclosed test case, this class type parameter was substituted
during
typeOf[X] memberType sym, which led us unsoundly thinkingthat
Raw[_]wasRaw[X].I've added a TODO comment to review the other usages of
classExistentialType.Test variations include joint and separate compilation, and the
corresponding Scala-only code. All fail with type errors now,
as we expect. I've also added a distillation of a bootstrap
error that failed when I forgot to wrap the
existentialType.