diff --git a/crates/gen_lsp_server/src/msg.rs b/crates/gen_lsp_server/src/msg.rs
index d2ce20a114..42241194da 100644
--- a/crates/gen_lsp_server/src/msg.rs
+++ b/crates/gen_lsp_server/src/msg.rs
@@ -9,7 +9,7 @@ use languageserver_types::{
 
 use Result;
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 #[serde(untagged)]
 pub enum RawMessage {
     Request(RawRequest),
@@ -17,14 +17,14 @@ pub enum RawMessage {
     Response(RawResponse),
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct RawRequest {
     pub id: u64,
     pub method: String,
     pub params: Value,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct RawResponse {
     // JSON RPC allows this to be null if it was impossible
     // to decode the request's id. Ignore this special case
@@ -36,7 +36,7 @@ pub struct RawResponse {
     pub error: Option<RawResponseError>,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct RawResponseError {
     pub code: i32,
     pub message: String,
@@ -44,6 +44,7 @@ pub struct RawResponseError {
     pub data: Option<Value>,
 }
 
+#[derive(Clone, Copy, Debug)]
 #[allow(unused)]
 pub enum ErrorCode {
     ParseError = -32700,
@@ -58,7 +59,7 @@ pub enum ErrorCode {
     RequestCancelled = -32800,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize, Clone)]
 pub struct RawNotification {
     pub method: String,
     pub params: Value,
diff --git a/crates/server/tests/heavy_tests/support.rs b/crates/server/tests/heavy_tests/support.rs
index 113ef4c542..36ca56af33 100644
--- a/crates/server/tests/heavy_tests/support.rs
+++ b/crates/server/tests/heavy_tests/support.rs
@@ -1,7 +1,7 @@
 use std::{
     fs,
     thread,
-    cell::Cell,
+    cell::{Cell, RefCell},
     path::PathBuf,
 };
 
@@ -56,6 +56,7 @@ pub fn project(fixture: &str) -> Server {
 
 pub struct Server {
     req_id: Cell<u64>,
+    messages: RefCell<Vec<RawMessage>>,
     dir: TempDir,
     sender: Option<Sender<RawMessage>>,
     receiver: Receiver<RawMessage>,
@@ -71,6 +72,7 @@ impl Server {
         let res = Server {
             req_id: Cell::new(1),
             dir,
+            messages: Default::default(),
             sender: Some(client_sender),
             receiver: client_receiver,
             server: Some(server),
@@ -129,7 +131,7 @@ impl Server {
             .unwrap()
             .send(RawMessage::Request(r));
 
-        while let Some(msg) = self.receiver.recv() {
+        while let Some(msg) = self.recv() {
             match msg {
                 RawMessage::Request(req) => panic!("unexpected request: {:?}", req),
                 RawMessage::Notification(_) => (),
@@ -144,6 +146,13 @@ impl Server {
         }
         panic!("no response");
     }
+    fn recv(&self) -> Option<RawMessage> {
+        self.receiver.recv()
+            .map(|msg| {
+                self.messages.borrow_mut().push(msg.clone());
+                msg
+            })
+    }
     fn send_notification(&self, not: RawNotification) {
 
         self.sender.as_ref()