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// A bunch of ridiculous seeming tests until you realize much
// of this didn't work until the commit which accompanies this.
object Test {
def f1(x: AnyRef with Singleton): AnyRef with Singleton = x
def f2[T <: AnyRef with Singleton](x: T): T = x
val x1: AnyRef with Singleton = "abc"
val x2 = "def"
final val x3 = "ghi"
val x4: String = "jkl"
// compiles...
def narrow1(x: AnyRef): AnyRef with Singleton = x
// compiles, still doesn't help.
def narrow2(x: AnyRef): AnyRef with Singleton = x.asInstanceOf[x.type]
// fails, wait, what? This fails and narrow1 compiles?
def narrow3(x: AnyRef): AnyRef with Singleton = x.asInstanceOf[AnyRef with Singleton]
// ok
def narrow4[T <: AnyRef](x: T): AnyRef with Singleton = x
object imp {
implicit def narrow4[T <: AnyRef](x: T): AnyRef with Singleton = x
val x5: String = "mno"
def imp1 = f1(x5)
// f2(x5) // doesn't work but I think it should
def imp2 = f2(narrow4(x5))
}
def main(args: Array[String]): Unit = {
// compiles
f1(x1)
f1(x2)
f1(x3)
f1(x4)
f2(x1)
// f2(x2)
// f2(x3) // maybe this one should work
// f2(x4)
f1(narrow1(x4))
f1(narrow2(x4))
f1(narrow3(x4))
f1(narrow4(x4))
f2(narrow1(x4))
f2(narrow2(x4))
f2(narrow3(x4))
f2(narrow4(x4))
}
}
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