Registering implementation type X is not assignable to service type IX when using Generics

[ruslanss]

is this a known issue limitation?

I have added code to reproduce it here: https://github.com/ruslanss/azure-functions-dotnet-extensions/tree/service_registration_bug

this type of service registration doesn't appear to be supported:

builder.Services.AddSingleton<IValidator<WhateverCommand>, NullValidator>();

Error on host startup:

[2020-10-22T20:12:11.169] A host error has occurred during startup operation '3a905cf7-b8f9-4dad-868a-ae23c7e8c1db'.
[2020-10-22T20:12:11.170] Microsoft.Azure.WebJobs.Script.WebHost: Registering implementation type Microsoft.Azure.Functions.Samples.DependencyInjectionBasic.InjectionTest.NullValidator is not assignable to service type Microsoft.Azure.Functions.Samples.DependencyInjectionBasic.InjectionTest.IValidator<Microsoft.Azure.Functions.Samples.DependencyInjectionBasic.InjectionTest.WhateverCommand>.

[remiX-]

Hey Ruslanss, did you ever manage to resolve this? I'm having issues with this after updating my Function App from ~3 -> ~4 whilst migrating from DOTNETCORE|3.1 to DOTNET|6.0

[ruslanss]

Hi @remiX- ! yes try downgrading Scrutor nuget package to v4.1.0 if you're using it.

[remiX-]

Ah I'm not using it.

I had to resort to using Provider in the Add and create the instance

Something like this, even if I didn't need it
builder.Services.AddSingleton<IValidator<WhateverCommand>>(sp => new NullValidator());

[waynebrantley]

@fabiocav @brettsam Wondering if this project is being depreciated? No changes since 2020.
Who would we be able to get to update this type check to stop this issue - assuming this project is not dead?