diff --git a/src/main/scala/config/Config.scala b/src/main/scala/config/Config.scala
index 45fec790..5ae84865 100644
--- a/src/main/scala/config/Config.scala
+++ b/src/main/scala/config/Config.scala
@@ -10,8 +10,10 @@ abstract class Field[T] private (val default: Option[T])
 
 abstract class View {
   final def apply[T](pname: Field[T]): T = apply(pname, this)
-  final def apply[T](pname: Field[T], site: View): T = find(pname, site) match {
-    case Some(x) => x.asInstanceOf[T]
+  final def apply[T](pname: Field[T], site: View): T = {
+    val out = find(pname, site)
+    require (out.isDefined, s"Key ${pname} is not defined in Parameters")
+    out.get
   }
 
   final def lift[T](pname: Field[T]): Option[T] = lift(pname, this)