Coded workflows - namespace created within same library - unable to publish

I’m not sure if I follow you.

I’ve rewritten the classes into each of their own Coded Source File:

using System.Collections.Generic;

namespace API_Library.RegisterCenter.CodedWorkflows.DeserializeVehicles
{
    public class VehicleData
    {
        public List<VehicleInfo> VehicleInfos { get; set; }
    }
}
namespace API_Library.RegisterCenter.CodedWorkflows.DeserializeVehicles
{
    public class VehicleInfo
    {
        public string LicenseNumber { get; set; }
        public string Brand { get; set; }
        public string Model { get; set; }
        public int Year { get; set; }
        public string UnregisteredDate { get; set; }
    }
}

This is in a coded workflow

using System.Collections.Generic;
using UiPath.CodedWorkflows;
using Newtonsoft.Json;

namespace API_Library.RegisterCenter.CodedWorkflows.DeserializeVehicles
{

    public class DeserializeResponse : CodedWorkflow
    {
        [Workflow]
        public List<VehicleInfo> Execute(string JSONInput)
        {
     
            return JsonConvert.DeserializeObject<VehicleData>(JSONInput).VehicleInfos;
            
        }
    }
    
}

This still yields

Error Could not load file C:.…\API_Library_RegisterCenter\Vehicles\POST Vehicles.xaml. Reason: Cannot create unknown type ‘{http://schemas.microsoft.com/netfx/2009/xaml/activities}Variable({clr-namespace:System.Collections.Generic;assembly=System.Private.CoreLib}List({clr-namespace:API_Library.RegisterCenter.CodedWorkflows.DeserializeVehicles;assembly=API_Library.RegisterCenter.Core}VehicleInfo))’.

But if I create the Coded Source File in a separate library and then import that library it works.