From 0819cfbe7b84a1398dc755c813dcae94a5eb7976 Mon Sep 17 00:00:00 2001
From: fakeshadow <24548779@qq.com>
Date: Mon, 18 Jan 2021 09:16:14 +0800
Subject: [PATCH] add panic and comment

---
 actix-http/src/message.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/actix-http/src/message.rs b/actix-http/src/message.rs
index 6c07e8993..7daffef79 100644
--- a/actix-http/src/message.rs
+++ b/actix-http/src/message.rs
@@ -343,9 +343,17 @@ impl ResponseHead {
 }
 
 pub struct Message<T: Head> {
+    // Rc here should not be cloned by anyone.
+    // It's used to reuse allocation of T and no shared ownership is allowed.
     head: Rc<T>,
 }
 
+impl<T: Head> Clone for Message<T> {
+    fn clone(&self) -> Self {
+        panic!("Message<T> type should not be Clone.")
+    }
+}
+
 impl<T: Head> Message<T> {
     /// Get new message from the pool of objects
     pub fn new() -> Self {