ClassA.h

class ClassA
{
public:
    template <typename T>
    int test(int a, int b)
    {
        return a + b;
    }
};

ClassB.h

#include "ClassA.h"

class ClassB
{
    void SomeFun()
    {
        ClassA a;
        
        struct TestType
        {
            int a;
        };
        a.test<TestType>(1,2);
    }
};

gistfile1.sh

No matching function for call to 'ClassA::test(int, int)'

main.cpp

#include "ClassB.h"

int main()
{
}