From 556277d689f64f2b4910f5ace1ed1cb5a793726c Mon Sep 17 00:00:00 2001
From: fatvlady <fatvlad.95@gmail.com>
Date: Sat, 14 Mar 2020 15:20:04 +0200
Subject: [PATCH] Fix optional dereference type deduction

---
 include/pybind11/stl.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
index 32f8d294a..77da13362 100644
--- a/include/pybind11/stl.h
+++ b/include/pybind11/stl.h
@@ -266,7 +266,8 @@ template<typename T> struct optional_caster {
     static handle cast(T_ &&src, return_value_policy policy, handle parent) {
         if (!src)
             return none().inc_ref();
-        policy = return_value_policy_override<typename T::value_type>::policy(policy);
+        using dereference_type = decltype(*std::forward<T_>(src));
+        policy = return_value_policy_override<dereference_type>::policy(policy);
         return value_conv::cast(*std::forward<T_>(src), policy, parent);
     }