diff --git a/Scripts/NodePort.cs b/Scripts/NodePort.cs
index 6bcc638..14c3b7d 100644
--- a/Scripts/NodePort.cs
+++ b/Scripts/NodePort.cs
@@ -279,6 +279,9 @@ namespace XNode {
             if (output.typeConstraint == XNode.Node.TypeConstraint.Strict && input.ValueType != output.ValueType) return false;
             if (output.typeConstraint == XNode.Node.TypeConstraint.InheritedInverse && !output.ValueType.IsAssignableFrom(input.ValueType)) return false;
             if (output.typeConstraint == XNode.Node.TypeConstraint.InheritedAny && !input.ValueType.IsAssignableFrom(output.ValueType) && !output.ValueType.IsAssignableFrom(input.ValueType)) return false;
+            if (output.typeConstraint == XNode.Node.TypeConstraint.Castable && !input.ValueType.IsCastableFrom(output.ValueType)) return false;
+            if (output.typeConstraint == XNode.Node.TypeConstraint.CastableInverse && !output.ValueType.IsCastableFrom(input.ValueType)) return false;
+            if (output.typeConstraint == XNode.Node.TypeConstraint.CastableAny && !input.ValueType.IsCastableFrom(output.ValueType) && !output.ValueType.IsCastableFrom(input.ValueType)) return false;
             // Success
             return true;
         }