From 9d69a712ac8ed1e70374470bb58fafa52b4064e1 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Thu, 26 Mar 2026 11:33:00 +0100
Subject: [PATCH] Does SWIG prefer std::conditional_t over auto return type?

---
 src/ifcparse/express.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/ifcparse/express.h b/src/ifcparse/express.h
index 293cc30e2f..02f4aa1268 100644
--- a/src/ifcparse/express.h
+++ b/src/ifcparse/express.h
@@ -226,7 +226,11 @@ constexpr bool is_std_vector_vector_v = is_std_vector_vector<T>::value;
 }
 
 template <typename T, typename U>
-auto cast_vector(const std::vector<U>& vs) {
+typename std::conditional_t<
+    is_std_vector<U>::value,
+    std::vector<std::vector<T>>,
+    std::vector<T>>
+cast_vector(const std::vector<U>& vs) {
     if constexpr (is_std_vector<U>::value) {
         using V = typename U::value_type;
         std::vector<std::vector<T>> result;