Scalar type

Author: andrjohns

stan/math/prim/fun/serializer.hpp

@@ -1,6 +1,7 @@
 #ifndef STAN_MATH_PRIM_FUN_SERIALIZER_HPP
 #define STAN_MATH_PRIM_FUN_SERIALIZER_HPP
 
+#include <stan/math/prim/meta/promote_scalar_type.hpp>
 #include <stan/math/prim/fun/to_vector.hpp>
 #include <stan/math/prim/fun/to_array_1d.hpp>
 #include <complex>
@@ -95,8 +96,8 @@ struct deserializer {
    */
   template <typename U, require_std_vector_t<U>* = nullptr,
             require_not_st_complex<U>* = nullptr>
-  typename promote_scalar_type<T, U>::type read(const U& x) {
-    typename promote_scalar_type<T, U>::type y;
+  promote_scalar_t<T, U> read(const U& x) {
+    promote_scalar_t<T, U> y;
     y.reserve(x.size());
     for (size_t i = 0; i < x.size(); ++i)
       y.push_back(read(x[i]));
@@ -114,8 +115,8 @@ struct deserializer {
    * @return deserialized value with shape and size matching argument
    */
   template <typename U, require_std_vector_st<is_complex, U>* = nullptr>
-  typename promote_scalar_type<std::complex<T>, U>::type read(const U& x) {
-    typename promote_scalar_type<std::complex<T>, U>::type y;
+  promote_scalar_t<std::complex<T>, U> read(const U& x) {
+    promote_scalar_t<std::complex<T>, U> y;
     y.reserve(x.size());
     for (size_t i = 0; i < x.size(); ++i)
       y.push_back(read(x[i]));