I'm using Unity IAP, I've imported all the unitypackages files that come with it (IAP, Channel and UDP) and I can't compile the project. I'm using Unity 2018.3.12f1 and latest versions of Package Manager and Unity IAP. I'm in a midst of moving our code base to custom packages so I have asmdef files all over the place. I get these errors: Assets\Plugins\UDP\Editor\Analytics\EditorAnalytcisApi.cs(4,23): error CS0234: The type or namespace name 'Common' does not exist in the namespace 'UnityEngine.UDP' (are you missing an assembly reference?) Assets\Plugins\UDP\Editor\AppStoreSettingsEditor.cs(15,26): error CS0246: The type or namespace name 'AppStoreSettings' could not be found (are you missing a using directive or an assembly reference?) I have no idea why this "using UnityEngine.UDP.Common;" is nowhere to be found while "UnityEngine.UDP" namespace is totally there in the EditorAnalytcisApi.cs script. And AppStoreSettings apparently found at Assets/Plugins/UnityChannel/XiaomiSupport/AppStoreSettings.cs . I've put asmdefs at all the relevant places yet they do know refer to each other correctly. What am I missing? Is there a workaround?