Improve implicit .NET standard facade references

If you reference System.Collections.Immutable 1.4.0 in a net462 project, it picks the netstandard2.0 System.Collections.Immutable dll. Unfortunately, the build system copies not just netstandard.dll but all the .NET Standard 1.* facade assemblies as well. This means 72 unreferenced, unused System.* and Microsoft.* DLLs show up for deployment. This is decidedly unpleasant.

Would you please make the SDK smart enough to only add the netstandard1.* assemblies if there is at least one reference to a netstandard1.* assembly? And, independently, add netstandard.dll only if there is at least one reference to a netstandard2.* assembly?

Here is the target which currently lumps both 1.* and 2.* in at once or none at all:

https://github.com/dotnet/sdk/blob/83ba345017d368c80e2d24090a2507a0f4627001/src/Tasks/Microsoft.NET.Build.Extensions.Tasks/msbuildExtensions/Microsoft/Microsoft.NET.Build.Extensions/Microsoft.NET.Build.Extensions.NETFramework.targets#L90-L95

This has been the only reason I’ve backed away from using System.Collections.Immutable in many projects.

[ericstj]

Yep, that’s correct. In the future you can tag me. Sorry I didn’t see it.

[livarcocc]

Closing as the issue seem to have been addressed and new issues were filed against dotnet/standard.