llvm-project/clang/test/CXX/class.access/class.friend/p1.cpp

// RUN: %clang_cc1 -fsyntax-only -verify %s

// C++'0x [class.friend] p1:
//   A friend of a class is a function or class that is given permission to use
//   the private and protected member names from the class. A class specifies
//   its friends, if any, by way of friend declarations. Such declarations give
//   special access rights to the friends, but they do not make the nominated
//   friends members of the befriending class.

struct S { static void f(); }; // expected-note 2 {{'S' declared here}}
S* g() { return 0; } // expected-note 2 {{'g' declared here}}

struct X {
  friend struct S;
  friend S* g();
};

void test1() {
  S s;
  g()->f();
  S::f();
  X::g(); // expected-error{{no member named 'g' in 'X'; did you mean simply 'g'?}}
  X::S x_s; // expected-error{{no type named 'S' in 'X'; did you mean simply 'S'?}}
  X x;
  x.g(); // expected-error{{no member named 'g' in 'X'}}
}

// Test that we recurse through namespaces to find already declared names, but
// new names are declared within the enclosing namespace.
namespace N {
  struct X {
    friend struct S;
    friend S* g();

    friend struct S2;
    friend struct S2* g2();
  };

  struct S2 { static void f2(); }; // expected-note 2 {{'S2' declared here}}
  S2* g2() { return 0; } // expected-note 2 {{'g2' declared here}}

  void test() {
    g()->f();
    S s;
    S::f();
    X::g(); // expected-error{{no member named 'g' in 'N::X'; did you mean simply 'g'?}}
    X::S x_s; // expected-error{{no type named 'S' in 'N::X'; did you mean simply 'S'?}}
    X x;
    x.g(); // expected-error{{no member named 'g' in 'N::X'}}

    g2();
    S2 s2;
    ::g2(); // expected-error{{no member named 'g2' in the global namespace; did you mean simply 'g2'?}}
    ::S2 g_s2; // expected-error{{no type named 'S2' in the global namespace; did you mean simply 'S2'?}}
    X::g2(); // expected-error{{no member named 'g2' in 'N::X'; did you mean simply 'g2'?}}
    X::S2 x_s2; // expected-error{{no type named 'S2' in 'N::X'; did you mean simply 'S2'?}}
    x.g2(); // expected-error{{no member named 'g2' in 'N::X'}}
  }
}

namespace test0 {
  class ClassFriend {
    void test();
  };

  class MemberFriend {
  public:
    void test();
  };

  void declared_test();

  class Class {
    static void member(); // expected-note 2 {{declared private here}}

    friend class ClassFriend;
    friend class UndeclaredClassFriend;

    friend void undeclared_test();
    friend void declared_test();
    friend void MemberFriend::test();
  };

  void declared_test() {
    Class::member();
  }

  void undeclared_test() {
    Class::member();
  }

  void unfriended_test() {
    Class::member(); // expected-error {{'member' is a private member of 'test0::Class'}}
  }

  void ClassFriend::test() {
    Class::member();
  }

  void MemberFriend::test() {
    Class::member();
  }

  class UndeclaredClassFriend {
    void test() {
      Class::member();
    }
  };

  class ClassNonFriend {
    void test() {
      Class::member(); // expected-error {{'member' is a private member of 'test0::Class'}}
    }
  };
}

// Make sure that friends have access to inherited protected members.
namespace test2 {
  struct X;

  class ilist_half_node {
    friend struct ilist_walker_bad;
    X *Prev;
  protected:
    X *getPrev() { return Prev; } // expected-note{{member is declared here}}
  };

  class ilist_node : private ilist_half_node { // expected-note {{declared private here}} expected-note {{constrained by private inheritance here}}
    friend struct ilist_walker;
    X *Next;
    X *getNext() { return Next; } // expected-note {{declared private here}}
  };

  struct X : ilist_node {};

  struct ilist_walker {
    static X *getPrev(X *N) { return N->getPrev(); }
    static X *getNext(X *N) { return N->getNext(); }
  };  

  struct ilist_walker_bad {
    static X *getPrev(X *N) { return N->getPrev(); } // \
    // expected-error {{'getPrev' is a private member of 'test2::ilist_half_node'}} \
    // expected-error {{cannot cast 'test2::X' to its private base class 'test2::ilist_half_node'}}

    static X *getNext(X *N) { return N->getNext(); } // \
    // expected-error {{'getNext' is a private member of 'test2::ilist_node'}}
  };  
}

namespace test3 {
  class A { protected: int x; }; // expected-note {{declared protected here}}

  class B : public A {
    friend int foo(B*);
  };

  int foo(B *p) {
    return p->x;
  }

  int foo(const B *p) {
    return p->x; // expected-error {{'x' is a protected member of 'test3::A'}}
  }
}

namespace test3a {
  class A { protected: int x; };

  class B : public A {
    friend int foo(B*);
  };

  int foo(B * const p) {
    return p->x;
  }
}

namespace test4 {
  template <class T> class Holder {
    T object;
    friend bool operator==(Holder &a, Holder &b) {
      return a.object == b.object; // expected-error {{invalid operands to binary expression}}
    }
  };

  struct Inequal {};
  bool test() {
    Holder<Inequal> a, b;
    return a == b;  // expected-note {{requested here}}
  }
}


// PR6174
namespace test5 {
  namespace ns {
    class A;
  }

  class ns::A {
  private: int x;
    friend class B;
  };

  namespace ns {
    class B {
      int test(A *p) { return p->x; }
    };
  }
}

// PR6207
namespace test6 {
  struct A {};

  struct B {
    friend A::A();
    friend A::~A();
    friend A &A::operator=(const A&);
  };
}

namespace test7 {
  template <class T> struct X {
    X();
    ~X();
    void foo();
    void bar();
  };

  class A {
    friend void X<int>::foo();
    friend X<int>::X();
    friend X<int>::X(const X&);

  private:
    A(); // expected-note 2 {{declared private here}}
  };

  template<> void X<int>::foo() {
    A a;
  }

  template<> void X<int>::bar() {
    A a; // expected-error {{calling a private constructor}}
  }

  template<> X<int>::X() {
    A a;
  }

  template<> X<int>::~X() {
    A a; // expected-error {{calling a private constructor}}
  }
}

// Return types, parameters and default arguments to friend functions.
namespace test8 {
  class A {
    typedef int I; // expected-note 4 {{declared private here}}
    static const I x = 0; // expected-note {{implicitly declared private here}}
    friend I f(I i);
    template<typename T> friend I g(I i);
  };

  const A::I A::x;
  A::I f(A::I i = A::x) {}
  template<typename T> A::I g(A::I i) {
    T t;
  }
  template A::I g<A::I>(A::I i);

  A::I f2(A::I i = A::x) {} // expected-error 3 {{is a private member of}}
  template<typename T> A::I g2(A::I i) { // expected-error 2 {{is a private member of}}
    T t;
  }
  template A::I g2<A::I>(A::I i);
}

// PR6885
namespace test9 {
  class B {
    friend class test9;
  };
}

// PR7230
namespace test10 {
  extern "C" void test10_f(void);
  extern "C" void test10_g(void);

  namespace NS {
    class C {
      void foo(void); // expected-note {{declared private here}}
      friend void test10::test10_f(void);
    };
    static C* bar;
  }

  void test10_f(void) {
    NS::bar->foo();
  }

  void test10_g(void) {
    NS::bar->foo(); // expected-error {{private member}}
  }
}

// PR8705
namespace test11 {
  class A {
  public:
    void test0(int);
    void test1(int);
    void test2(int);
    void test3(int);
  };

  class B {
    typedef int private_type; // expected-note 2 {{implicitly declared private here}}
    friend void A::test0(int);
    friend void A::test1(int);
  };

  void A::test0(B::private_type x) {}
  void A::test1(int x = B::private_type()) {}
  void A::test2(B::private_type x) {} // expected-error {{'private_type' is a private member of 'test11::B'}}
  void A::test3(int x = B::private_type()) {} // expected-error {{'private_type' is a private member of 'test11::B'}}
}


// PR9221
namespace test12 {
  struct A {
    void foo();
  };
  class B : private A {
    friend void A::foo();
    void *mem;
  };
  void A::foo() {
    void *var = static_cast<B*>(this)->mem;
  }
}

namespace PR9103 {
  struct base {
  protected:
    static void foo(void) {}
  };

  struct cls: base {
    friend void bar(void) {
      base::foo();
    }
  };
}

// PR13642.  When computing the effective context, we were walking up
// the DC chain for the canonical decl, which is unfortunate if that's
// (e.g.) a friend declaration.
namespace test14 {
  class A {
    class B { // expected-note {{implicitly declared private here}}
      static int i;
      friend void c();
    };
  };

  void c() {
    A::B::i = 5; // expected-error {{'B' is a private member of 'test14::A'}}
  }
}