// N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf 
#define msg "p286.cpp(138)12.3.1 Conversion by constructor [class.conv.ctor]"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>

struct X {
X(int);
X(const char*, int =0);
X(int, int);
};
void f(X arg) {
X a = 1; // a = X(1)
X b = "Jessie"; // b = X("Jessie",0)
a = 2; // a = X(2)
f(3); // f(X(3))
f({1, 2}); // f(X(1,2))
}

struct Z {
explicit Z();
explicit Z(int);
explicit Z(int, int);
};
Z a; // OK: default-initialization performed
Z b{}; // OK: direct initialization syntax used
Z c = {}; // error: copy-list-initialization
Z a1 = 1; // error: no implicit conversion
Z a3 = Z(1); // OK: direct initialization syntax used
Z a2(1); // OK: direct initialization syntax used
Z* p = new Z(1); // OK: direct initialization syntax used
Z a4 = (Z)1; // OK: explicit cast used
Z a5 = static_cast<Z>(1); // OK: explicit cast used
Z a6 = { 3, 4 }; // error: no implicit conversion


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

$ ./cppgl17.sh p286
$ clang++ p286.cpp
p286.cpp:29:3: error: chosen constructor is explicit in copy-initialization
Z c = {}; // error: copy-list-initialization
  ^   ~~
p286.cpp:23:10: note: explicit constructor declared here
explicit Z();
         ^
p286.cpp:30:3: error: no viable conversion from 'int' to 'Z'
Z a1 = 1; // error: no implicit conversion
  ^    ~
p286.cpp:22:8: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const Z &' for 1st
      argument
struct Z {
       ^
p286.cpp:22:8: note: candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'Z &&' for 1st
      argument
struct Z {
       ^
p286.cpp:36:3: error: chosen constructor is explicit in copy-initialization
Z a6 = { 3, 4 }; // error: no implicit conversion
  ^    ~~~~~~~~
p286.cpp:25:10: note: explicit constructor declared here
explicit Z(int, int);
         ^
3 errors generated.

$ g++-7 p286.cpp
p286.cpp:29:8: error: converting to 'Z' from initializer list would use explicit constructor 'Z::Z()'
 Z c = {}; // error: copy-list-initialization
        ^
p286.cpp:30:8: error: conversion from 'int' to non-scalar type 'Z' requested
 Z a1 = 1; // error: no implicit conversion
        ^
p286.cpp:36:15: error: converting to 'Z' from initializer list would use explicit constructor 'Z::Z(int, int)'
 Z a6 = { 3, 4 }; // error: no implicit conversion
               ^