Index: Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/CalculationGroupExtensions.cs
===================================================================
diff -u -rce9e1d476f00cfb42ce2a8ab6c762baf5abfd97b -ra1bba29ba0d84061cca88da8324957087d564db9
--- Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/CalculationGroupExtensions.cs	(.../CalculationGroupExtensions.cs)	(revision ce9e1d476f00cfb42ce2a8ab6c762baf5abfd97b)
+++ Ringtoets/Common/src/Ringtoets.Common.Data/Calculation/CalculationGroupExtensions.cs	(.../CalculationGroupExtensions.cs)	(revision a1bba29ba0d84061cca88da8324957087d564db9)
@@ -84,7 +84,7 @@
         /// <remarks>The calculation group is enumerated recursively, also taking into account nested calculations.</remarks>
         public static void ClearCalculationOutput(this CalculationGroup calculationGroup)
         {
-            foreach (var calc in calculationGroup.GetCalculations().Where(c => c.HasOutput))
+            foreach (ICalculation calc in calculationGroup.GetCalculations().Where(c => c.HasOutput))
             {
                 calc.ClearOutput();
                 calc.NotifyObservers();