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Fix #2117: bug in typechecking super prefix with invalid enclosing class #2118

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Merged
merged 1 commit into from
Mar 20, 2017
Merged

Fix #2117: bug in typechecking super prefix with invalid enclosing class #2118

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40 changes: 21 additions & 19 deletions compiler/src/dotty/tools/dotc/typer/TypeAssigner.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -291,26 +291,28 @@ trait TypeAssigner {

def assignType(tree: untpd.Super, qual: Tree, inConstrCall: Boolean, mixinClass: Symbol = NoSymbol)(implicit ctx: Context) = {
val mix = tree.mix
val qtype @ ThisType(_) = qual.tpe
val cls = qtype.cls

def findMixinSuper(site: Type): Type = site.parents filter (_.name == mix.name) match {
case p :: Nil =>
p
case Nil =>
errorType(SuperQualMustBeParent(mix, cls), tree.pos)
case p :: q :: _ =>
errorType("ambiguous parent class qualifier", tree.pos)
qual.tpe match {
case err: ErrorType => untpd.cpy.Super(tree)(qual, mix).withType(err)
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Is this necessary, or can I just do tree.withType(err)?
In general, when I should I be using the tree copier?

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Tree copier provides structural sharing and is used when you think that the tree might stay the same after your changes.

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Thanks. In this case, would it be ok/better to do tree.withType(err)?

case qtype @ ThisType(_) =>
val cls = qtype.cls
def findMixinSuper(site: Type): Type = site.parents filter (_.name == mix.name) match {
case p :: Nil =>
p
case Nil =>
errorType(SuperQualMustBeParent(mix, cls), tree.pos)
case p :: q :: _ =>
errorType("ambiguous parent class qualifier", tree.pos)
}
val owntype =
if (mixinClass.exists) mixinClass.typeRef
else if (!mix.isEmpty) findMixinSuper(cls.info)
else if (inConstrCall || ctx.erasedTypes) cls.info.firstParent
else {
val ps = cls.classInfo.parentsWithArgs
if (ps.isEmpty) defn.AnyType else ps.reduceLeft((x: Type, y: Type) => x & y)
}
tree.withType(SuperType(cls.thisType, owntype))
}
val owntype =
if (mixinClass.exists) mixinClass.typeRef
else if (!mix.isEmpty) findMixinSuper(cls.info)
else if (inConstrCall || ctx.erasedTypes) cls.info.firstParent
else {
val ps = cls.classInfo.parentsWithArgs
if (ps.isEmpty) defn.AnyType else ps.reduceLeft((x: Type, y: Type) => x & y)
}
tree.withType(SuperType(cls.thisType, owntype))
}

def assignType(tree: untpd.Apply, fn: Tree, args: List[Tree])(implicit ctx: Context) = {
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3 changes: 3 additions & 0 deletions tests/neg/i2117.scala
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@@ -0,0 +1,3 @@
class A {
C.super.foo() // error: C isn't an enclosing class
}