C++ 17 any variable being set to "not empty (Small)" rather than actual value

Question

I am currently working on a project to handle RPN equations and solve them. This includes *, /, +, -, sin, cos, tan, parenthesis, integers, and doubles. I am attempting to use a stack of any-s to handle every variable type. However, when I set my any variable to a value, Visual Studio 2019 shows it is set to "not empty (Small)", and I cannot access the correct value. Here is my code:

#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <any>

using namespace std;

int main() 
{
    stack<any> equation;
    any temp;

    string input;
    getline(cin, input);

    int inputLength = input.length();

    for (int i = 0; i < inputLength; i++) {
        if (input[i] == '(' && input[i + 1] != ' ') {
            input.insert(input.begin() + i + 1, ' ');
            inputLength++;
        }
        else if (input[i] == ')' && input[i - 1] != ' ') {
            input.insert(input.begin() + i, ' ');
            inputLength++;
        }
        else if (i < inputLength - 2 && input[i] == ')' && (input[i + 2] == '(' || (input[i + 2] >= 0 && input[i + 2] <= 9))) {
            input.insert(input.begin() + i + 2, '*');
            input.insert(input.begin() + i + 3, ' ');
            inputLength += 2;
        }
    }

    stringstream ss;
    string temp2;
    ss << input;
    while (ss >> temp2) {
        if (temp2[0] < 0 || temp2[0] > 9) {
            temp = "char";
        }
        else {
            temp = 1.0;
        }
        equation.push(temp);
    }
    
    equation.push(temp);

    cout << input;

}