Why do we need to register IPipelineBehavior<,> manually with Scrutor's scan?

[FDUdannychen]

Line 30 in the example of ASP.NET CORE

services.AddScoped(typeof(IPipelineBehavior<,>), typeof(GenericPipelineBehavior<,>));

IMO GenericPipelineBehavior<,> is registered by Scrutor's scan:

services.Scan(scan => scan
                .FromAssembliesOf(typeof(IMediator), typeof(Ping))
                .AddClasses()
                .AsImplementedInterfaces());

Unfortunately it isn't, which means line 30 is necessary. Why?

[lilasquared]

@FDUdannychen this might be due to it being a generic? I know with structuremap you have to explicitly call .ConnectImplementationsToTypesClosing()

[jbogard]

Open generics are treated differently in the ASP.NET Core container. Behaviors might not have any explicitly defined closed types, so T is not known until runtime.