VScode C++ 编译error:‘XXX‘ was not declared in this scope, template argument 1 is invalid解决方法

VScode C++ 编译error

一、报错信息：

1. ‘XXX’ was not declared in this scope
2. template argument 1 is invalid

二、文件结构：

//A.h
#ifndef __A__
#define __A__
#include"B.h"
#include<vector>
class A{
   
public:
    std::vector<B> myB;
    ...
}
#endif

//B.h