Do I have to include all System.Collections.Immutable dependencies?

Question

I just switched from (an older) Microsoft.Bcl.Immutable NuGet package to System.Collections.Immutable and was surprised to find all these new package dependencies in my project:

System.Collections
System.Diagnostics.Debug
System.Globalization
System.Linq
System.Resources.ResourceManager
System.Runtime
System.Runtime.Extensions
System.Threading

They are listed as dependencies of the NuGet package, so they have a right to be there, yet they are obviously also already installed on my PC and my target environment (Azure btw) as they come with the framework.

I already have a large number of packages in my project and would like to avoid the additional overhead caused by these 8 packages, if possible (and without shooting myself in the foot).

Is it safe to remove these dependencies?
Do I now have to use these packages throughout my project because they might differ from their installed versions and some portion of my project might now use the wrong ones? (due to some DLL linking madness?)

Edit: Just for completeness, as there was a comment before: The dependencies are actual packages (not namespaces) and have to be downloaded, I'm targeting and compiling with .NET 4.6, working in VS2015. It's entirely possible though that something is outdated and the packages do not have to be loaded normally?

Solution

You are just seeing a side-effect of the Nuget package having to keep a lot of people happy. The package supports an enormous number of targets, it is proliferating rapidly as of late. I see support for Xamarin for OSX and iOS, Windows Phone 8.0 and 8.1, Windows Store, CoreCLR (the open source project), .NET 4.5, MonoTouch for iOS and Android and .NETCore (Silverlight).

These dependent packages just contain reference assemblies, the kind that are normally installed in your c:\program files x86\reference assemblies directory. The Nuget package doesn't take the chance that such a reference assembly might be missing and includes the whole kit and kaboodle.

After it is all downloaded, the package installer runs and adds the references you actually need in your project. Easy to see what happened, just open the References node of your project. If your targeted the desktop version of .NET 4.5 and up, the grand total of added references is one, just System.Collections.Immutable. Yes, you can remove them.