Group dependencies with duplicate transitive dependencies may fail compiler

[agross]

depfile:

nuget Nancy.Bootstrappers.Windsor

group test
  nuget Nancy.Testing

group hosting
  nuget Nancy.Owin

references:

Nancy.Bootstrappers.Windsor

group test
  Nancy.Testing

group hosting
  Nancy.Owin

Because Nancy (nuget) is a transitive dependency of all of the packages above, three references to Nancy.dll will be added to the projects next to the references file:

packages\test\Nancy\lib\net40\Nancy.dll
packages\hosting\Nancy\lib\net40\Nancy.dll
packages\Nancy\lib\net40\Nancy.dll

CSC output:

warning MSB3243: No way to resolve conflict between "Nancy, Version=1.4.2.0, Culture=neutral, PublicKeyToken=null" and "Nancy, Version=1.4.1.0, Culture=neutral, PublicKeyToken=null". Choosing "Nancy, Version=1.4.2.0, Culture=neutral, PublicKeyToken=null" arbitrarily.

error CS1704: An assembly with the same simple name 'Nancy' has already been imported. Try removing one of the references (e.g. 'packages\Nancy\lib\net40\Nancy.dll') or sign them to enable side-by-side.
Build has been canceled.

[forki]

sorry for delay.