Inferring FromServices optionality based on nullability information

[brunolins16]

Current design

Currently, when binding FromServices always is called the ServiceProviderServiceExtensions.GetRequiredService (that throws an InvalidOperationException when the service is not found)

aspnetcore/src/Mvc/Mvc.Core/src/ModelBinding/Binders/ServicesModelBinder.cs

Line 26 in 6bbd520

var model = requestServices.GetRequiredService(bindingContext.ModelType);

Proposed Change

The proposal is following the same approach apply in Minimal APIs, that basically evaluates the default value and nullability context to decide if the parameter is optional or not and call the ServiceProviderServiceExtensions.GetService instead when the parameter is optional.

aspnetcore/src/Http/Http.Extensions/src/RequestDelegateFactory.cs

Line 866 in 6bbd520

private static Expression BindParameterFromService(ParameterInfo parameter, FactoryContext factoryContext)

[ghost]

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