Unload the project can't use any function in the project, right?

Question

My problem is that when declaring a function for a class Visual Studio said that this function was found in other projects, and although I had unloaded it all, VS still found out.

In Project A:

        class A{
        private:
            int a{};
        public:
            int getA(){
                return a;
            }
        };

After that, I unloaded project A and created new project B:

    class B{
    private:
       int a{};
    public:
       int getA(){
           return a;
        }
    };

But when I unloaded, VS informed me that getA() in B was matched with getA() in A (Really, my solution has many projects but I want to debug only one of them).

Is there any way to know that this function is no longer available or can only be scanned within the scope of the open project (ie only searching in the project containing the class with that function?