matthandlersux · August 13, 2012 23:18 · Aug 13, 2012
diff --git a/gistfile1.scala b/gistfile1.scala
@@ -0,0 +1,50 @@
+object Holder {
+    var companions = Set[AnyRef]()
+
+    def companionFor[M](m:M) = {
+        companions.find {
+            case found:M => true
+            case _ => false
+        }
+    }
+}
+
+abstract class Model {
+    def test = {
+        Holder.companionFor(this)
+    }
+}
+
+abstract trait CompanionTrait[M <: Model] { self:Model =>
+    Holder.companions = Holder.companions ++ Set(self)
+}
+
+class T1 extends Model {
+
+}
+
+object T1 extends Model with CompanionTrait[T1] {
+
+}
+
+class T2 extends Model {
+
+}
+
+object T2 extends Model with CompanionTrait[T2] {
+
+}
+
+T1
+T2
+
+val x = new T1
+val y = new T2
+
+println("testing")
+assert(x.test == Some(T1))
+println("passed 1")
+assert(y.test != Some(T1))
+println("passed 2")
+assert(y.test == Some(T2))
+println("passed 3")