// N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf 
#define msg "p269.cpp(126)11 Member access control [class.access]"

#include <iostream>


class X {
int a; // X::a is private by default
};
struct S {
int a; // S::a is public by default
};

class A {
class B { };
public:
typedef B BB;
};
void f() {
A::BB x; // OK, typedef name A::BB is public
A::B y; // access error, A::B is private
}

class A2 {
typedef int I; // private member
I f();
friend I g(I);
static I x;
template<int> struct Q;
template<int> friend struct R;
protected:
struct B2 { };
};
A2::I A2::f() { return 0; }
A2::I g(A2::I p = A2::x);
A2::I g(A2::I p) { return 0; }
A2::I A2::x = 0;
template<A2::I> struct A2::Q { };
template<A2::I> struct R { };
struct D: A2::B2, A2 { };


class B3 { };
template <class T> class C3 {
protected:
typedef T TT;
};
template <class U, class V = typename U::TT>
class D3 : public U { };
D3 <C<B3> >* d; // access error, C3::TT is protected

int main(){
  std::cout<< msg << std::endl;
  return EXIT_SUCCESS;
}

$ ./cppgl17.sh p269
$ clang++ p269.cpp
p269.cpp:22:4: error: 'B' is a private member of 'A'
A::B y; // access error, A::B is private
   ^
p269.cpp:16:7: note: implicitly declared private here
class B { };
      ^
p269.cpp:41:15: error: 'B2' is a protected member of 'A2'
struct D: A2::B2, A2 { };
              ^
p269.cpp:33:8: note: declared protected here
struct B2 { };
       ^
p269.cpp:51:5: error: use of undeclared identifier 'C'
D3 <C<B3> >* d; // access error, C3::TT is protected
    ^
p269.cpp:51:7: error: 'B3' does not refer to a value
D3 <C<B3> >* d; // access error, C3::TT is protected
      ^
p269.cpp:44:7: note: declared here
class B3 { };
      ^
p269.cpp:51:11: error: expected unqualified-id
D3 <C<B3> >* d; // access error, C3::TT is protected
          ^
5 errors generated.

$ g++-7 p269.cpp
p269.cpp: In function 'void f()':
p269.cpp:22:4: error: 'class A::B' is private within this context
 A::B y; // access error, A::B is private
    ^
p269.cpp:16:7: note: declared private here
 class B { };
       ^
p269.cpp: At global scope:
p269.cpp:39:14: error: 'typedef int A2::I' is private within this context
 template<A2::I> struct A2::Q { };
              ^
p269.cpp:26:13: note: declared private here
 typedef int I; // private member
             ^
p269.cpp:40:14: error: 'typedef int A2::I' is private within this context
 template<A2::I> struct R { };
              ^
p269.cpp:26:13: note: declared private here
 typedef int I; // private member
             ^
p269.cpp:41:15: error: 'struct A2::B2' is protected within this context
 struct D: A2::B2, A2 { };
               ^~
p269.cpp:33:8: note: declared protected here
 struct B2 { };
        ^~
p269.cpp:51:5: error: 'C' was not declared in this scope
 D3 <C<B3> >* d; // access error, C3::TT is protected
     ^
p269.cpp:51:5: note: suggested alternative: 'C3'
 D3 <C<B3> >* d; // access error, C3::TT is protected
     ^
     C3
p269.cpp:51:9: error: template argument 1 is invalid
 D3 <C<B3> >* d; // access error, C3::TT is protected
         ^
p269.cpp:51:9: error: template argument 2 is invalid
p269.cpp:51:11: error: expected unqualified-id before '>' token
 D3 <C<B3> >* d; // access error, C3::TT is protected
           ^