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legacy-svn-scala
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refined type checking rules wrt selftypes for new's in valdefs. 

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@14658 5e8d7ff9-d8ef-0310-90f0-a4852d11357a
This commit is contained in:
odersky 2008-04-15 15:10:29 +00:00
parent f1e886a5db
commit 0e837d1fb9
1 changed files with 17 additions and 2 deletions
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19
src/compiler/scala/tools/nsc/typechecker/Typers.scala
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@ -2364,14 +2364,29 @@ trait Typers { self: Analyzer =>
.setOriginal(tpt1) /* .setPos(tpt1.pos) */
.setType(appliedType(tpt1.tpe, context.undetparams map (_.tpe)))
}
def narrowRhs(tp: Type) = {
var sym = context.tree.symbol
if (sym != null && sym != NoSymbol && sym.owner.isClass && sym.getter(sym.owner) != NoSymbol)
sym = sym.getter(sym.owner)
context.tree match {
case ValDef(_, _, _, Apply(Select(`tree`, _), _)) if (sym.isStable) =>
// println("narrowing...")
val pre = if (sym.owner.isClass) sym.owner.thisType else NoPrefix
intersectionType(List(tp, singleType(pre, sym)))
case _ =>
// println("no narrow: "+sym+" "+sym.isStable+" "+context.tree+"//"+tree)
tp
}
}
if (tpt1.tpe.typeSymbol.isAbstractType || (tpt1.tpe.typeSymbol hasFlag ABSTRACT))
error(tree.pos, tpt1.tpe.typeSymbol + " is abstract; cannot be instantiated")
else if (tpt1.tpe.typeSymbol.initialize.thisSym != tpt1.tpe.typeSymbol &&
!(tpt1.tpe <:< tpt1.tpe.typeOfThis) &&
!phase.erasedTypes)
!(narrowRhs(tpt1.tpe) <:< tpt1.tpe.typeOfThis) &&
!phase.erasedTypes) {
error(tree.pos, tpt1.tpe.typeSymbol +
" cannot be instantiated because it does not conform to its self-type "+
tpt1.tpe.typeOfThis)
}
copy.New(tree, tpt1).setType(tpt1.tpe)
}