can you give a derived class object as a function parameter in place of a base class object

I am trying to do matrix addition using expression templates and for this task I have base class: Exp

template<typename subtype>
class Exp{
public:
  inline const subtype& self(void) const{
    return *static_cast<const subtype*>(this);
  }

};

a derived class: matrix

template<typename T,unsigned rows_,unsigned cols_ >
class matrix : public Exp<matrix<T,rows_,cols_>>{
   //some members
};

and another derived class: addExp

template<typename T, typename Op1 , typename Op2>
class addExp: public Exp< addExp<T,Op1,Op2> >{
  const Op1& op1;
  const Op2& op2;

public:
  addExp(const Op1& a, const Op2& b): op1(a), op2(b){}

  T& operator()(const std::size_t i,const std::size_t j) const{ 
    return op1(i,j) + op2(i,j); 
  }
}; 

I am now trying to do operator overloading on addExp for adding matrices.

template<typename T,typename Lhs, typename Rhs>
inline addExp<T,Lhs, Rhs>
operator+(const Exp<Lhs> &lhs, const Exp<Rhs> &rhs) {
  return addExp<T,Lhs, Rhs>(lhs.self(), rhs.self());
}

later in my code I try to put two matrix objects(which should have Exp as base class) as function parameters here but I get an error:

prog.cpp: In function ‘int main()’:
prog.cpp:76:25: error: no match for ‘operator+’ (operand types are ‘matrix<int, 3u, 3u>’ and ‘matrix<int, 3u, 3u>’)
  matrix<int,3,3> m3 = m1+m2;
                       ~~^~~
prog.cpp:69:1: note: candidate: template<class T, class Lhs, class Rhs> addExp<T, Lhs, Rhs> operator+(const Exp<Lhs>&, const Exp<Rhs>&)
 operator+(const Exp<Lhs> &lhs, const Exp<Rhs> &rhs) {
 ^~~~~~~~
prog.cpp:69:1: note:   template argument deduction/substitution failed:
prog.cpp:76:26: note:   couldn't deduce template parameter ‘T’
  matrix<int,3,3> m3 = m1+m2;  

where did I go wrong here and how do I fix this?