I've noticed a warning in Visual Studio in a few projects where it gives me the following warning after building,
The predefined type "System.Runtime.CompilerServices.ExtensionAttribute" is defined in multiple assemblies in the global alias
I don't like leaving warnings in my build but I didn't have time to look into it until today. This handy tip from Remco te Wierik led me to the root of the issue. The .net Lucene contrib nuget package contains a reference Lucene.Net.FastVectorHighlighter which defines an ExtensionAttribute
class in the System.Runtime.CompilerServices
namespace.
Updating the assembly reference alias
from "global" to a custom one, fixed the warning.