generated error message
Error ModManager.cpp:1469: Error while running setup for item prototype "picker-naked-rail" (rail-planner): curved_rail entity (picker-naked-curved-rail) first item-to-place must be this item but is rail.
Assume this may be due to new validation done as part of the fix for https://forums.factorio.com/84047 deployed in 0.18.20
This error was not observed with 0.18.19
