From 5d479bf0c189eb030bc273c94a909d3708f16662 Mon Sep 17 00:00:00 2001
From: Alexey Bashtanov <alexey.bashtanov@redpanda.com>
Date: Fri, 3 Jan 2025 11:17:10 +0000
Subject: [PATCH] try making co_return strict

---
 include/seastar/core/coroutine.hh | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/seastar/core/coroutine.hh b/include/seastar/core/coroutine.hh
index 4373db5cdc..ba8377a744 100644
--- a/include/seastar/core/coroutine.hh
+++ b/include/seastar/core/coroutine.hh
@@ -49,9 +49,11 @@ public:
         promise_type(promise_type&&) = delete;
         promise_type(const promise_type&) = delete;
 
-        template<typename... U>
-        void return_value(U&&... value) {
-            _promise.set_value(std::forward<U>(value)...);
+        template<typename U>
+        void return_value(U&& value) {
+            using From = decltype(std::forward<U>(value));
+            static_assert(std::is_convertible_v<From, T>, "only implicit conversions are considered");
+            _promise.set_value(std::forward<U>(value));
         }
 
         void return_value(coroutine::exception ce) noexcept {