c++ - Memberspaces may access private members of parent class -

i've been reading this article, , playing around memberspace idiom while when noticed surprised me within snippet (which compiles without problems: http://ideone.com/hriv5b):

class hugeclass {     public:         struct memberspace         {             int f() const { return parent.f; }              private:                 friend hugeclass;                 explicit memberspace(hugeclass & parent)                 : parent(parent) {}                 hugeclass & parent;         } memberspace;          hugeclass() : memberspace(*this), f(42) {}      private:         int f; }; 

i have expected compiler error access of hugeclass::f not allowed because f private in context.

hugeclass friend of memberspace, hugeclass may call private constructor of memberspace, why work other way around without explicitly declaring memberspace friend of hugeclass?

by language rules in c++11.

nested class member , such has same access rights other member. example:

class e {    int x;    class b { };    class {      b b; // ok: e::i can access e::b      void f(e* p, int i)       {         p->x = i; // ok: e::i can access e::x      }    }; }; 

and in c++03 was

members of nested class have no special access members of enclosing class, nor classes or functions have granted friendship enclosing class; usual access rules (clause 11) shall obeyed.

so, example c++11 should not work c++03 compilers.