Compiler Error C2871

'name' : does not exist or is not a namespace

You did one of the following:

• You tried to extend an item that is not a namespace.
  
  
• You tried to add a namespace with a using declaration that does not exist.
  
  
• You tried to add a namespace with a using declaration that is not a namespace.

The following code shows all three errors:

int A;
int i;

namespace A { \\ error: cannot extend; A is not a namespace
   using namespace B; \\ error: namespace B does not exist
   using namespace i; \\ error: i is not a namespace
}