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object test {
class Foo[a](val arg : a)
object Foo {
def apply [a](arg : a, right :a) = new Foo[a](arg)
def unapply [a](m : Foo[a]) = Some (m.arg)
}
def matchAndGetArgFromFoo[a]( e:Foo[a]):a = {e match { case Foo(x) => x }}
// Unapply node here will have type argument [a] instantiated to scala.Nothing:
// UnApply(TypeApply(Select(Ident(Foo),unapply),List(TypeTree[TypeVar(PolyParam(a) -> TypeRef(ThisType(TypeRef(NoPrefix,scala)),Nothing))])),List(),List(Bind(x,Ident(_))))
// but the type of the UnApply node itself is correct: RefinedType(TypeRef(ThisType(TypeRef(ThisType(TypeRef(NoPrefix,<empty>)),test$)),Foo), test$$Foo$$a, TypeAlias(TypeRef(NoPrefix,a)))
//
// Try the same thing as above but use function as argument to Bar
// constructor
type FunIntToA [a] = (Int) => a
class Bar[a] (var f: FunIntToA[a])
object Bar {
def apply[a](f: FunIntToA[a]) = new Bar[a](f)
def unapply[a](m: Bar[a]) = Some (m.f)
}
def matchAndGetFunFromBar[a](b:Bar[a]) : FunIntToA[a] = { b match { case Bar(x) => x}}
}
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