Type parameter ignored in selectDynamic invocation #6663
Description
As noticed by Dinko Srkoc in http://thread.gmane.org/gmane.comp.lang.scala.user/58246 sometimes the type parameter on a selectDynamic call gets lost.
With this definition:
import language.dynamics
class C(v: Any) extends Dynamic {
def selectDynamic[T](n: String): Option[T] = Option(v.asInstanceOf[T])
def applyDynamic[T](n: String)(): Option[T] = Option(v.asInstanceOf[T])
}
one gets this behaviour:
scala> new C(42).foo[Int].get
java.lang.ClassCastException: java.lang.Integer cannot be cast to scala.runtime.Nothing$
This happens because in Typers.scala, mkInvoke is called with the following cxTree:
new C.(42).foo[Int].get
Note that the outer element of that tree is a Select(..., "get"), and that's not handled by mkInvoke:
val (outer, explicitTargs) = cxTree1 match {
case TypeApply(fun, targs) => (fun, targs)
case Apply(TypeApply(fun, targs), args) => (Apply(fun, args), targs)
case t => (t, Nil)
}
That can be fixed by adding another case:
val (outer, explicitTargs) = cxTree1 match {
case TypeApply(fun, targs) => (fun, targs)
case Apply(TypeApply(fun, targs), args) => (Apply(fun, args), targs)
case Select(TypeApply(fun, targs), nme) => (Select(fun, nme), targs)
case t => (t, Nil)
}
With that change, the examples work as expected:
scala> new C(42).foo[Int]().get
res0: Int = 42
scala> new C(42).foo[Int].get
res1: Int = 42