diff options
Diffstat (limited to 'src/compiler')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index bc8a8a31b5..6f6edc62c7 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -2844,7 +2844,34 @@ trait Typers extends Modes with Adaptations with PatMatVirtualiser { def isRawParameter(sym: Symbol) = // is it a type parameter leaked by a raw type? sym.isTypeParameter && sym.owner.isJavaDefined + + /** If we map a set of hidden symbols to their existential bounds, we + * have a problem: the bounds may themselves contain references to the + * hidden symbols. So this recursively calls existentialBound until + * the typeSymbol is not amongst the symbols being hidden. + */ + def existentialBoundsExcludingHidden(hidden: List[Symbol]): Map[Symbol, Type] = { + def safeBound(t: Type): Type = + if (hidden contains t.typeSymbol) safeBound(t.typeSymbol.existentialBound.bounds.hi) else t + + def hiBound(s: Symbol): Type = safeBound(s.existentialBound.bounds.hi) match { + case tp @ RefinedType(parents, decls) => + val parents1 = parents mapConserve safeBound + if (parents eq parents1) tp + else copyRefinedType(tp, parents1, decls) + case tp => tp + } + (hidden map { s => + // Hanging onto lower bound in case anything interesting + // happens with it. + (s, s.existentialBound match { + case TypeBounds(lo, hi) => TypeBounds(lo, hiBound(s)) + case _ => hiBound(s) + }) + }).toMap + } + /** Given a set `rawSyms` of term- and type-symbols, and a type * `tp`, produce a set of fresh type parameters and a type so that * it can be abstracted to an existential type. Every type symbol @@ -2862,12 +2889,13 @@ trait Typers extends Modes with Adaptations with PatMatVirtualiser { * only the type of the Ident is changed. */ protected def existentialTransform[T](rawSyms: List[Symbol], tp: Type)(creator: (List[Symbol], Type) => T): T = { + val allBounds = existentialBoundsExcludingHidden(rawSyms) val typeParams: List[Symbol] = rawSyms map { sym => val name = sym.name match { case x: TypeName => x - case x => newTypeName(x + ".type") + case x => nme.singletonName(x) } - val bound = sym.existentialBound + val bound = allBounds(sym) val sowner = if (isRawParameter(sym)) context.owner else sym.owner val quantified = sowner.newExistential(name, sym.pos) |