From 1e08001971526a8598a616daa56d59fbf1a75099 Mon Sep 17 00:00:00 2001
From: Steve Bronder <sbronder@flatironinstitute.org>
Date: Mon, 14 Aug 2023 17:18:24 -0400
Subject: [PATCH] bug fix in multi_student_t mix test

---
 stan/math/prim/prob/multi_normal_prec_lpdf.hpp   | 4 ++--
 test/unit/math/mix/prob/multi_student_t_test.cpp | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/stan/math/prim/prob/multi_normal_prec_lpdf.hpp b/stan/math/prim/prob/multi_normal_prec_lpdf.hpp
index b2f2639e7be..37aa52baf0c 100644
--- a/stan/math/prim/prob/multi_normal_prec_lpdf.hpp
+++ b/stan/math/prim/prob/multi_normal_prec_lpdf.hpp
@@ -35,8 +35,8 @@ return_type_t<T_y, T_loc, T_covar> multi_normal_prec_lpdf(
   auto&& y_ref = to_ref(y);
   auto&& mu_ref = to_ref(mu);
   lp_type lp(0);
-  vector_seq_view<T_y> y_vec(y_ref);
-  vector_seq_view<T_loc> mu_vec(mu_ref);
+  vector_seq_view<std::decay_t<decltype(y_ref)>> y_vec(y_ref);
+  vector_seq_view<std::decay_t<decltype(mu_ref)>> mu_vec(mu_ref);
   size_t size_vec = max_size_mvt(y_ref, mu_ref);
 
   int size_y = y_vec[0].size();
diff --git a/test/unit/math/mix/prob/multi_student_t_test.cpp b/test/unit/math/mix/prob/multi_student_t_test.cpp
index acf97298591..350d9583e4d 100644
--- a/test/unit/math/mix/prob/multi_student_t_test.cpp
+++ b/test/unit/math/mix/prob/multi_student_t_test.cpp
@@ -12,7 +12,7 @@ TEST(ProbDistributionsMultiStudentT, matvar) {
   auto f_const_y = [](const auto& y) {
     return [&y](const auto& nu, const auto& mu, const auto& sigma) {
       auto&& sigma_ref = stan::math::to_ref(sigma);
-      auto sigma_sym = stan::math::multiply(0.5, sigma + sigma.transpose());
+      auto sigma_sym = stan::math::multiply(0.5, sigma_ref + sigma_ref.transpose());
       return stan::math::multi_student_t_lpdf(y, nu, mu, sigma_sym);
     };
   };
@@ -20,7 +20,7 @@ TEST(ProbDistributionsMultiStudentT, matvar) {
   auto f_const_nu = [](const auto& nu) {
     return [&nu](const auto& y, const auto& mu, const auto& sigma) {
       auto&& sigma_ref = stan::math::to_ref(sigma);
-      auto sigma_sym = stan::math::multiply(0.5, sigma + sigma.transpose());
+      auto sigma_sym = stan::math::multiply(0.5, sigma_ref + sigma_ref.transpose());
       return stan::math::multi_student_t_lpdf(y, nu, mu, sigma_sym);
     };
   };