<violates the constraint of type parameter 'TSettings'> error in paymentSettings (Payment Plugin)

Hi,

I encounter a problem when creating a new Payment Plugin.
I tried to "decouple" my dependencies and decided to create an interface for all my concrete classes. I then use autofac in Nop in order to resolve the correct service/implementation to use.

A problem occurs in the paymentsettings model.
I created following Interface for my paymentsettings model:

using Nop.Core.Configuration;

namespace Nop.Plugin.Payments.Mollie.BankContact
{
    public interface IMollieBankContactPaymentSettings : ISettings
    {
        decimal AdditionalHandlingFeeFixed { get; set; }
        decimal AdditionalHandlingFeePercentage { get; set; }
        string ApiProduction { get; set; }
        string ApiTest { get; set; }
......

My concrete class is as followed:

namespace Nop.Plugin.Payments.Mollie.BankContact
{
    public class MollieBankContactPaymentSettings : IMollieBankContactPaymentSettings
    {
        public bool UseSandbox { get; set; }
        public string ApiTest { get; set; }
        public string ApiProduction { get; set; }
        //
        // RedirectURL : URL which is used access the mollie API        
        //

    
Because my interface IMollieBankContactPaymentSettings extends ISettings, I expected all to go fine, but I get following error:

Method Nop.Web.Framework.SettingsSource.BuildRegistration: type argument 'Nop.Plugin.Payments.Mollie.BankContact.IMollieBankContactPaymentSettings' violates the constraint of type parameter 'TSettings'.
Exception Details: System.Security.VerificationException: Method Nop.Web.Framework.SettingsSource.BuildRegistration: type argument 'Nop.Plugin.Payments.Mollie.BankContact.IMollieBankContactPaymentSettings' violates the constraint of type parameter 'TSettings'.
Source Error: 
Line 385:            if (ts != null && typeof(ISettings).IsAssignableFrom(ts.ServiceType))
Line 386:            {
Line 387:                var buildMethod = BuildMethod.MakeGenericMethod(ts.ServiceType);
Line 388:                yield return (IComponentRegistration)buildMethod.Invoke(null, null);
Line 389:            }
Source File: C:\Data\Ecommerce\nop390\Presentation\Nop.Web.Framework\DependencyRegistrar.cs    Line: 387 

Any thought on this ?
Thanks in advance.

The reason for that exception could be this line of code

static IComponentRegistration BuildRegistration<TSettings>() where TSettings : ISettings, new()

If i understand your code right you are using IMobileBankContactPaymentSettings for resolving your settings.
So it fits the constraint ISettings, but not the new() constraint.