How to handle class name collision in nuget package

The easiest way I'm aware of to avoid this problem and make sure you always consume your class which is inside of your own namespace is to move your using directives to inside your namespace declaration.

If you have this:

using YourNamespaceWhereYourGlobalIs;

namespace SomeOtherNamespaceYouOwn;

internal class Consumer
{
    public void M()
    {
        Console.WriteLine(Global.Y);
    }
}

It will attempt to use the global-scoped Global class. But if you move the using inside, like this:

namespace SomeOtherNamespaceYouOwn;

using YourNamespaceWhereYourGlobalIs;

internal class Consumer
{
    public void M()
    {
        Console.WriteLine(Global.Y);
    }
}

It will now default to using the Global class inside of the YourNamespaceWhereYourGlobalIs namespace.

Couple of notes on this:

1. Using declarations inside of the namespace like this are actually a good standard, and encouraged by StyleCop. It is not the default setting in Visual Studio, however
2. I'd still rename your Global class regardless since that's a very poor name for a class (or even a namespace) because global is an existing reserved keyword in the language and one should avoid reusing those.

To disambiguate between two like-names types (fully qualified names) in two packages, you need "external alias". First, in your package reference, add an alias to one of the packages, for example Aliases="foo" as an attribute on the <Package reference...>. Now add extern alias foo; in an individual C# file to tell the compiler to include that alias, but that isn't enough by itself; now you can use foo::Global.Whatever to explicitly mean that type.