函数重载

当一种类型可以隐式转换为多种类型并且该特定类型没有匹配函数时，可能会出现歧义。

例如：

 placeholderCopyvoid foo(double, double);
void foo(long, long);

//Call foo with 2 ints
foo(1, 2); //Function call is ambiguous - int can be converted into a double/long at the same time