// N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf 
#define msg "p295.cpp(143)12.6.2 Initializing bases and members [class.base.init]"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>

struct A { A(); };
typedef A global_A;
struct B { };
struct C: public A, public B { C(); };
C::C(): global_A() { } // mem-initializer for base A

struct A2 { A2(); };
struct B2: public virtual A2 { };
struct C2: public A2, public B2 { C2(); };
C2::C2(): A2() { } // ill-formed: which A?
C( int ) { } // #1: non-delegating constructor
C(): C(42) { } // #2: delegates to #1
C( char c ) : C(42.0) { } // #3: ill-formed due to recursion with #4
C( double d ) : C(’a’) { } // #4: ill-formed due to recursion with #3
};

struct B1a { B1a(int); /* ... */ };
struct B2a { B2a(int); /* ... */ };
struct Da : B1a, B2a {
Da(int);
B1a b;
const int c;
};
Da::Da(int a) : B2a(a+1), B1a(a+2), c(a+3), b(a+4)
{ /* ... */ }
Da d(10);


struct A3 {
A3() : v(42) { } // error
const int& v;
};

struct A4 {
A4();
};
struct B4 {
B4(int);
};
struct C4 {
C4() { } // initializes members as follows:
A4 a; // OK: calls A4::A4()
const B4 b; // error: B4 has no default constructor
int i; // OK: i has indeterminate value
int j = 5; // OK: j has the value 5
};

struct A5 {
int i = /* some integer expression with side effects */ 3 ;
A5(int arg) : i(arg) { }
// ...
};

struct A6 {
A6() = default; // OK
A6(int v) : v(v) { } // OK
const int& v = 42; // OK
};
A6 a1; // error: ill-formed binding of temporary to reference
A6 a2(1); // OK, unfortunately

struct V {
V();
V(int);
};
struct A7 : virtual V {
A7();
A7(int);
};
struct B7 : virtual V {
B7();
B7(int);
};

struct C7 : A7, B7, virtual V {
C7();
C7(int);
};
A7::A7(int i) : V(i) { /* ... */ }
B7::B7(int i) { /* ... */ }
C7::C7(int i) { /* ... */ }
V v(1); // use V(int)
A7 a(2); // use V(int)
B7 b(3); // use V()
C7 c(4); // use V()

class X {
int a;
int b;
int i;
int j;
public:
const int& r;
X(int i): r(a), b(i), i(i), j(this->i) { }
};


class A8 {
public:
A8(int);
};
class B8 : public A8 {
int j;
public:
int f();
B8() : A8(f()), // undefined: calls member function
// but base A not yet initialized
j(f()) { } // well-defined: bases are all initialized
};
class C8 {
public:
C8(int);
};
class D8 : public B8, C8 {
int i;
public:
D8() : C8(f()), // undefined: calls member function
// but base C not yet initialized
i(f()) { } // well-defined: bases are all initialized
};

template<class... Mixins>
class X2 : public Mixins... {
public:
X2:(const Mixins&... mixins) : Mixins(mixins)... { }
};

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

$ ./cppgl17.sh p295
$ clang++ p295.cpp
p295.cpp:16:12: warning: direct base 'A2' is inaccessible due to ambiguity:
    struct C2 -> struct A2
    struct C2 -> struct B2 -> struct A2 [-Winaccessible-base]
struct C2: public A2, public B2 { C2(); };
           ^~~~~~~~~
p295.cpp:17:11: error: base class initializer 'A2' names both a direct base class and an inherited virtual base class
C2::C2(): A2() { } // ill-formed: which A?
          ^~
p295.cpp:39:10: warning: binding reference member 'v' to a temporary value [-Wdangling-field]
A3() : v(42) { } // error
         ^~
p295.cpp:40:12: note: reference member declared here
const int& v;
           ^
p295.cpp:50:1: error: constructor for 'C4' must explicitly initialize the member 'b' which does not have a default constructor
C4() { } // initializes members as follows:
^
p295.cpp:52:10: note: member is declared here
const B4 b; // error: B4 has no default constructor
         ^
p295.cpp:46:8: note: 'B4' declared here
struct B4 {
       ^
p295.cpp:66:16: warning: binding reference member 'v' to a temporary value [-Wdangling-field]
const int& v = 42; // OK
               ^~
p295.cpp:66:12: note: reference member declared here
const int& v = 42; // OK
           ^
p295.cpp:23:18: error: constructor for 'C3' creates a delegation cycle [-Wdelegating-ctor-cycles]
C3( double d ) : C3('a') { } // #4: ill-formed due to recursion with #3
                 ^
p295.cpp:22:1: note: it delegates to
C3( char c ) : C3(42.0) { } // #3: ill-formed due to recursion with #4
^
p295.cpp:23:1: note: which delegates to
C3( double d ) : C3('a') { } // #4: ill-formed due to recursion with #3
^
3 warnings and 3 errors generated.

$ g++-7 p295.cpp
p295.cpp:16:8: warning: direct base 'A2' inaccessible in 'C2' due to ambiguity
 struct C2: public A2, public B2 { C2(); };
        ^~
p295.cpp: In constructor 'C2::C2()':
p295.cpp:17:11: error: 'struct A2' is both a direct base and an indirect virtual base
 C2::C2(): A2() { } // ill-formed: which A?
           ^~
p295.cpp: In constructor 'C4::C4()':
p295.cpp:50:6: error: no matching function for call to 'B4::B4()'
 C4() { } // initializes members as follows:
      ^
p295.cpp:47:1: note: candidate: B4::B4(int)
 B4(int);
 ^~
p295.cpp:47:1: note:   candidate expects 1 argument, 0 provided
p295.cpp:46:8: note: candidate: constexpr B4::B4(const B4&)
 struct B4 {
        ^~
p295.cpp:46:8: note:   candidate expects 1 argument, 0 provided
p295.cpp:46:8: note: candidate: constexpr B4::B4(B4&&)
p295.cpp:46:8: note:   candidate expects 1 argument, 0 provided