Ambiguous type 'FormatterAssemblyStyle' when using Json.NET 10.0.1 with netcoreapp2.0 or netstandard2.0

Newtonsoft.Json defines System.Runtime.Serialization.Formatters.FormatterAssemblyStyle in it, while this type is brought back in NetStandard2.0 in System.Runtime.Serialization.Formatters.dll. So when using this type in a project that targets netcoreapp2.0 or netstandard2.0 and references Json.NET 10.0.1, you will get the following error at compilation:

Program.cs(18,31): error CS0433: The type 'FormatterAssemblyStyle' exists in both 'Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' and 'System.Runtime.Serialization.Formatters, Version=4.0.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' [D:\apps\netcore2\test\test.csproj]

[abock]

We are now running into this in Xamarin Workbooks trying to port from some rather involved [Serializable], ISerializable, IObjectReference, SerializationBinder code to Newtonsoft.Json now that we can move all of our targets to netstandard2.0.

Given that targeting netstandard2.0 will provide the type, I do not see why you could not remove your version in the netstandard2.0 copy of Newtonsoft.Json.dll as part of the 10.x major release series?

[tmitchel2]

In case anyone else is trying to use this assembly in a NetStandard2.0 libary, here are the options:

• Use an assembly Alias so that two types with the same namespace and assembly can co-exist and be referenced. Not currently possible, has a DEPENDENCY ON https://github.com/NuGet/Home/issues/4989
• Remove Newtonsoft.Json and use something else
• Use explicit int values such as 0 and 1 instead of the enum values.