D'oh

ScriptableRenderPipeline/Core/CoreRP/Volume/VolumeProfile.cs

             return false;
         }
 
-        public bool TryGetAllSubclassOf<T>(Type type, List<T> component)
+        public bool TryGetAllSubclassOf<T>(Type type, List<T> result)
-            int count = component.Count;
+            int count = result.Count;
-                    components.Add(comp);
+                    result.Add((T)comp);
-            return count != component.Count;
+            return count != result.Count;
         }
     }
 }