小编sed*_*iel的帖子

最近我遇到了一个问题,不知何故(但只是某种程度上)对我有意义.它基于解释临时的构造作为单个(!)构造函数参数的声明.请看下面的最小例子.

#include <iostream>

class Foo0{
public:
  Foo0(int a){};
  void doStuff() {std::cout<<"maap"<<std::endl;};
};

class Foo1{
public:
  Foo1(int a){};
  void doStuff() {std::cout<<"maap"<<std::endl;};
};

class Foo2{
public:
  Foo2(int a){};
  void doStuff() {std::cout<<"maap"<<std::endl;};
};

class Bar{
public:
  Bar(Foo0 foo0, Foo1 foo1, Foo2 foo2){};
};

int main () {
  int x = 1;

  Bar bar0(Foo0(x), Foo1(x), Foo2(x)); // Does not work: conflicting declaration ‘Foo1 x’ previous declaration as ‘Foo0 x’; conflicting declaration ‘Foo2 x’ previous declaration as ‘Foo0 x’
  Bar bar1(Foo0{x}, Foo1(x), Foo2(x)); // Works …