Warning “The type X in Y.cs conflicts with the imported type X in Z.dll”

Question

The main.cs of my project returns the following warning:

Warning 1 The type \'Extensions.MessageDetails\' in \'PATH\\Extensions.cs\'

Answer 1

It seems like Extensions.cs is both part of the project that builds lib.dll and your main.exe

Remove it from one of the project to fix this issue.