NS3002 false positive when nested returns

[andrewdmoreno]

#118 was closed so did not want to add onto it, however, I am running into this issue still.

var provider = Substitute.For<IOptionProvider>();

provider
    .GetOptions(Arg.Any<EnrollmentDetail>())
    .Returns(_ =>
        {
            //  NS3002 Can not find an argument of type ... to this call
            var enrollment = _.Arg<EnrollmentDetail>();
            return new List<OptionSummary>();
       });

IOptionProvider:

List<OptionSummary> GetOptions(EnrollmentDetail enrollment);

I tried with versions 1.0.11, 1.0.13, and 1.0.14. Am I doing something wrong possibly?

[tpodolak]

Hi @andrewdmoreno
I am not able to repro this. Here is my code based on your snippet

using System.Collections.Generic;
using NSubstitute;

namespace TestProject6
{
    public class FooTests
    {
        public void Test()
        {
            var provider = Substitute.For<IOptionProvider>();

            provider
                .GetOptions(Arg.Any<EnrollmentDetail>())
                .Returns(_ =>
                {
                    var enrollment = _.Arg<EnrollmentDetail>();
                    return new List<OptionSummary>();
                });
        }
    }

    public interface IOptionProvider
    {
        List<OptionSummary> GetOptions(EnrollmentDetail enrollment);
    }

    public class OptionSummary
    {
    }

    public class EnrollmentDetail
    {
    }
}

no warnings were reported with

<PackageReference Include="NSubstitute" Version="4.2.1" />
<PackageReference Include="NSubstitute.Analyzers.CSharp" Version="1.0.14" />

Can you provide small solution with repro?

[andrewdmoreno]

Thanks @tpodolak. I will double check both package versions and see if I can repro it in a smaller solution.

[andrewdmoreno]

@tpodolak At first I could not repro in a fresh solution so I started looking at what else was unique about the setup and was finally able to repro. I reduced it down to the minimum needed to repro. Basically it was only when I introduced the IProviderFactory substitution setup was I able to repro.

    public class FooTests
    {
        public void Test()
        {
            var providerFactory = Substitute.For<IProviderFactory>();
            providerFactory.GetProvider().Returns(info =>
            {
                var provider = Substitute.For<IOptionProvider>();
                provider
                    .GetOptions(Arg.Any<string>())
                    .Returns(_ =>
                    {
                        // Warning	NS3002	Can not find an argument of type string to this call.
                        var input = _.Arg<string>();
                        return new List<string> {input};
                    });
                return provider;
            });
        }
    }

    public interface IProviderFactory
    {
        IOptionProvider GetProvider();
    }

    public interface IOptionProvider
    {
        List<string> GetOptions(string input);
    }

[dtchepak]

@andrewdmoreno Thanks for taking the time to refine the reproduction case!

@tpodolak I'm guessing the issue is the nested Returns here?

[andrewdmoreno]

Now that we know that the nested Returns caused this false positive I have mitigated the issue on my end by moving the provider setup outside and just returning the provider instance like so:

    public class FooTests
    {
        public void Test()
        {
            var provider = Substitute.For<IOptionProvider>();
            provider
                .GetOptions(Arg.Any<string>())
                .Returns(_ =>
                {
                    var input = _.Arg<string>();
                    return new List<string> {input};
                });

            var providerFactory = Substitute.For<IProviderFactory>();
            providerFactory.GetProvider().Returns(provider);
        }
    }

    public interface IProviderFactory
    {
        IOptionProvider GetProvider();
    }

    public interface IOptionProvider
    {
        List<string> GetOptions(string input);
    }

However, I imagine there could be valid use cases for having nested Returns

[tpodolak]

@tpodolak I'm guessing the issue is the nested Returns here?

@dtchepak yes, there is a missing check if given Arg<T> belongs to given callInfo parameter.