using namespace std;

namespace ui      { class CClass; }              // Expected to stay as-is
namespace ui::dlg { class CClassDlg; }           // Expected to stay as-is (new in C++17)

namespace ui {              // Brace should be on the next line
class CClass1;              // Should be indented
class CClass2;
class CClass3;
class CClass4;
class CClass5;
class CClass6;
class CClass7;
}
