FxCop CA1047 - Abstract and accessibility level

Question

I have this code (sample to reproduce):

public class ObjectBase<T>
{
}
public abstract class ExportBase
{
    public void ExportData<T>(string path, T data, string filename)
                where T : ObjectBase<T>
    {
        // Several verifications on data.
        // Example:
        if (data != null)
        {
            this.InnerExport(this.GetFileName<T>(path, filename), data);
        }
    }
    protected abstract void InnerExport<T>(string path, T data)
                where T : ObjectBase<T>;

    public string GetFileName<T>(string path, string filename)
    {
        // Code.
        return "TEST";
    }
}
internal sealed class XmlExport : ExportBase
{
    protected override void InnerExport<T>(string path, T data)
    {
        // Code.
    }
}

I don't want XmlExport visible (internal in my class library) nor inherits (sealed).

With FxCop 10.0, I've got an CA1047:DoNotDeclareProtectedMembersInSealedTypes:

Name: (FxCopCmd)
Do not declare protected members in sealed types.

Description: (FxCopCmd)
Sealed types cannot be extended, and protected members are only useful if you can extend the declaring type. Sealed types should not declare protected members.

How to fix: (FxCopCmd)
Make member 'XmlExport.InnerExport(string, T)' private, public, or internal (Friend in Visual Basic).

Info: (FxCop)
Sealed types cannot be extended, and protected members are only useful if you can extend the declaring type. Sealed types should not declare protected members.

But I can't change protected to private: virtual or abstract members can't be private. Nor public (does not make sense, here).

I know I can use a SuppressMessage, but I'm wondering if there is a better way (including a modification of the classes).

Thanks.

Answer 1

This appears to be due to a bug in the rule, triggered by the generic constraint ("where T : ObjectBase") on the base InnerExport method declaration. You should suppress the violation as a false positive. If you're feeling particularly keen, you could also report the bug at https://connect.microsoft.com/visualstudio/.

Answer 2

You could change protected to internal if you only will use this in the library. But you would also have to change it to internal in XmlExport when you override.