The missing compiler requires a member of 'System.Runtime.CompilerServices.ExtensionAttribute..ctor'

Question

I have a project focused on .Net 4.0. It used to be built until yesterday. I looked at the code and assembly links. I can define an extension attribute. Does anyone know about this.

I asked the following questions, but did not help - "A required compiler member is missing" error that occurs several times with almost no code changes

* UPDATE 1: * I see that Npgsql defines ExtensionAttribute in the same namespace. When I removed and added an older version of Npgsql, it was built. What to do to use the latest Npgsql?

Answer 1

, JSON.Net, .

, .config, . NuGet .