text: #ifndef STAN_MATH_PRIM_SCAL_META_PARTIALS_TYPE_HPP
  #define STAN_MATH_PRIM_SCAL_META_PARTIALS_TYPE_HPP
  
  namespace stan {
  
  /**
   * This base implimentation will contain a static member function named type
   * equal to the type passed into it. When this is specialized for vars the type
   * will be double and fvar<T> will have a member type of value T.
   */
  template <typename T, typename = void>
  struct partials_type {
    using type = T;
  };
  
  /**
   * Helper alias for accessing the partial type.
   */
  template <typename T>
  using partials_type_t = typename partials_type<T>::type;
  
  }  // namespace stan
  #endif
  