Cannot use qualified namespace names in nested namespace declarations
A qualified namespace is not permitted in a namespace declaration.
The following sample generates CS0134:
namespace MyNameSpace { namespace MyNameSpace.DottedNamespace { // CS0134, qualified namespace // try the following line instead // namespace NotRoot { public class MyClass { public static void Main() { } } namespace DottedNamespace { public class MyClass2 { public static void f1() { MyNameSpace.NotRoot.MyClass.Main(); // legal use of qualified namespace } } } } }