mcs/errors/cs4026.cs

   1 // CS4026: The CallerMemberName applied to parameter `x' will have no effect because it applies to a member that is used in context that do not allow optional arguments
   2 // Line: 14
   3 // Compiler options: -warnaserror
   4
   5 using System.Runtime.CompilerServices;
   6
   7 partial class D
   8 {
   9         partial void Foo (string x = "x");
  10 }
  11
  12 partial class D
  13 {
  14         partial void Foo ([CallerMemberName] string x)
  15         {
  16         }
  17 }