build: check for P2582R1 support

CMakeLists.txt

@@ -821,6 +821,14 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     -Wno-error=deprecated-declarations)
 endif ()
 
+if (CMAKE_CXX_STANDARD GREATER_EQUAL 23)
+  include (CheckP2582R1)
+  if (Cxx_Compiler_IMPLEMENTS_P2581R1)
+    target_compile_definitions (seastar
+      PUBLIC SEASTAR_P2581R1)
+  endif ()
+endif ()
+
 if (BUILD_SHARED_LIBS)
   # use initial-exec TLS, as it puts the TLS variables in the static TLS space
   # instead of allocating them using malloc. otherwise intercepting mallocs and

cmake/CheckP2582R1.cmake

@@ -0,0 +1,26 @@
+include (CheckCXXSourceCompiles)
+include (CMakePushCheckState)
+
+cmake_push_check_state (RESET)
+
+set (CMAKE_REQUIRED_FLAGS "-std=c++23")
+
+# check if the compiler implements the inherited vs non-inherited guide
+# tiebreaker specified by P2582R1, see https://wg21.link/P2582R1
+check_cxx_source_compiles ("
+template <typename T> struct B {
+    B(T) {}
+};
+
+template <typename T> struct C : public B<T> {
+    using B<T>::B;
+};
+
+B(int) -> B<char>;
+C c2(42);
+
+int main() {}
+"
+  Cxx_Compiler_IMPLEMENTS_P2581R1)
+
+cmake_pop_check_state ()

include/seastar/rpc/rpc_types.hh

@@ -403,8 +403,10 @@ public:
 
 /// @}
 
+#ifndef SEASTAR_P2581R1
 template <typename... T>
 tuple(T&&...) ->  tuple<T...>;
+#endif
 
 } // namespace rpc