Sending object as IRequest throws

Hello, I just upgraded from MediatR 11.1.0 to 12.0.0 and found that you cannot send requests as IRequest anymore. Sending them using their concrete type, or IBaseRequest, or object still works.

Is this a bug or a feature?

Regards, Philip

Here is a minimal reproducing example:

Program.cs:

using MediatR;
using Microsoft.Extensions.DependencyInjection;
using System.Reflection;

var services = new ServiceCollection();
services.AddMediatR(o => o.RegisterServicesFromAssembly(Assembly.GetExecutingAssembly()));
var sp = services.BuildServiceProvider();
var mediator = sp.GetRequiredService<IMediator>();

// Sending as MyCommand, IBaseRequest, or object works:
MyCommand cmd0 = new MyCommand() { TypeName = "MyCommand" };
await mediator.Send(cmd0);
IBaseRequest cmd1 = new MyCommand() { TypeName = "IBaseRequest" };
await mediator.Send(cmd1);
object cmd2 = new MyCommand() { TypeName = "object" };
await mediator.Send(cmd2);

// Sending as IRequest throws:
IRequest cmd3 = new MyCommand() { TypeName = "IRequest" };
await mediator.Send(cmd3);


class MyCommand : IRequest
{
    public string? TypeName { get; set; }
}

class MyCommandHandler : IRequestHandler<MyCommand>
{
    public Task Handle(MyCommand request, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Handling command. Sent as {request.TypeName}");
        return Task.CompletedTask;
    }
}

Project file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="MediatR" Version="12.0.0" />
    <PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.1" />
  </ItemGroup>

</Project>

[jbogard]

Now!

[knopa]

Thanks for quick update. any ETA on release?