Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresFailureMechanism.cs
===================================================================
diff -u -rab20c4eb4ca81bd3845d50210d2bdb301177af6a -r183d1e7ed095ea4e8024068bc4ddfcf3ac6997d3
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresFailureMechanism.cs	(.../HeightStructuresFailureMechanism.cs)	(revision ab20c4eb4ca81bd3845d50210d2bdb301177af6a)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresFailureMechanism.cs	(.../HeightStructuresFailureMechanism.cs)	(revision 183d1e7ed095ea4e8024068bc4ddfcf3ac6997d3)
@@ -55,7 +55,7 @@
         {
             get
             {
-                return CalculationsGroup.GetCalculations().OfType<StructuresCalculation<HeightStructuresInput>>();
+                return CalculationsGroup.GetCalculations().Cast<StructuresCalculation<HeightStructuresInput>>();
             }
         }