Wrote this title has arisen in a class in the header file this warning, the constructor defined inside the class, ordinary class also won't appear this kind of situation, this exactly is what reason? How to solve?
# pragma once
#include

Template
Class A
{
Public:
(A)=default;
A (STD: : initializer_list & lt; T> Li);
~ (A)=default;

Private:
STD: : vector v;
};

Template
A : : A (STD: : initializer_list & lt; T> Li)
: v (li)
{
}