Enable nullable annotations for Volo.Abp.Autofac

framework/src/Volo.Abp.Autofac/Autofac/Extensions/DependencyInjection/AutofacRegistration.cs

@@ -87,7 +87,7 @@ public static class AutofacRegistration
     public static void Populate(
         this ContainerBuilder builder,
         IServiceCollection services,
-        object lifetimeScopeTagForSingletons)
+        object? lifetimeScopeTagForSingletons)
     {
         if (services == null)
         {
@@ -134,7 +134,7 @@ public static class AutofacRegistration
     private static IRegistrationBuilder<object, TActivatorData, TRegistrationStyle> ConfigureLifecycle<TActivatorData, TRegistrationStyle>(
         this IRegistrationBuilder<object, TActivatorData, TRegistrationStyle> registrationBuilder,
         ServiceLifetime lifecycleKind,
-        object lifetimeScopeTagForSingleton)
+        object? lifetimeScopeTagForSingleton)
     {
         switch (lifecycleKind)
         {
@@ -179,7 +179,7 @@ public static class AutofacRegistration
     private static void Register(
         ContainerBuilder builder,
         IServiceCollection services,
-        object lifetimeScopeTagForSingletons)
+        object? lifetimeScopeTagForSingletons)
     {
         var moduleContainer = services.GetSingletonInstance<IModuleContainer>();
         var registrationActionList = services.GetRegistrationActionList();
@@ -223,7 +223,7 @@ public static class AutofacRegistration
             else
             {
                 builder
-                    .RegisterInstance(descriptor.ImplementationInstance)
+                    .RegisterInstance(descriptor.ImplementationInstance!)
                     .As(descriptor.ServiceType)
                     .ConfigureLifecycle(descriptor.Lifetime, null);
             }

framework/src/Volo.Abp.Autofac/Microsoft/Extensions/DependencyInjection/AbpAutofacServiceCollectionExtensions.cs

@@ -21,7 +21,7 @@ public static class AbpAutofacServiceCollectionExtensions
         return builder;
     }
 
-    public static IServiceProvider BuildAutofacServiceProvider([NotNull] this IServiceCollection services, Action<ContainerBuilder> builderAction = null)
+    public static IServiceProvider BuildAutofacServiceProvider([NotNull] this IServiceCollection services, Action<ContainerBuilder>? builderAction = null)
     {
         return services.BuildServiceProviderFromFactory(builderAction);
     }

framework/src/Volo.Abp.Autofac/Volo.Abp.Autofac.csproj

@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.Autofac</AssemblyName>
     <PackageId>Volo.Abp.Autofac</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>

framework/src/Volo.Abp.Autofac/Volo/Abp/Autofac/AbpAutofacServiceProviderFactory.cs

@@ -11,7 +11,7 @@ namespace Volo.Abp.Autofac;
 public class AbpAutofacServiceProviderFactory : IServiceProviderFactory<ContainerBuilder>
 {
     private readonly ContainerBuilder _builder;
-    private IServiceCollection _services;
+    private IServiceCollection _services = default!;
 
     public AbpAutofacServiceProviderFactory(ContainerBuilder builder)
     {