3 files changed, 18 insertions, 9 deletions

diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index 0e592ac1b..658a50d15 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -73,6 +73,7 @@ pub(crate) struct GlobalState {
     pub(crate) mem_docs: FxHashMap<VfsPath, DocumentData>,
     pub(crate) semantic_tokens_cache: Arc<Mutex<FxHashMap<Url, SemanticTokens>>>,
     pub(crate) vfs: Arc<RwLock<(vfs::Vfs, FxHashMap<FileId, LineEndings>)>>,
+    pub(crate) shutdown_requested: bool,
     pub(crate) status: Status,
     pub(crate) source_root_config: SourceRootConfig,
     pub(crate) proc_macro_client: ProcMacroClient,
@@ -124,6 +125,7 @@ impl GlobalState {
             mem_docs: FxHashMap::default(),
             semantic_tokens_cache: Arc::new(Default::default()),
             vfs: Arc::new(RwLock::new((vfs::Vfs::default(), FxHashMap::default()))),
+            shutdown_requested: false,
             status: Status::default(),
             source_root_config: SourceRootConfig::default(),
             proc_macro_client: ProcMacroClient::dummy(),
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 0ac6434dd..e6cf46df2 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -337,6 +337,16 @@ impl GlobalState {
     fn on_request(&mut self, request_received: Instant, req: Request) -> Result<()> {
         self.register_request(&req, request_received);
 
+        if self.shutdown_requested {
+            self.respond(Response::new_err(
+                req.id,
+                lsp_server::ErrorCode::InvalidRequest as i32,
+                "Shutdown already requested.".to_owned(),
+            ));
+
+            return Ok(());
+        }
+
         if self.status == Status::Loading && req.method != "shutdown" {
             self.respond(lsp_server::Response::new_err(
                 req.id,
@@ -351,7 +361,10 @@ impl GlobalState {
             .on_sync::<lsp_ext::ReloadWorkspace>(|s, ()| Ok(s.fetch_workspaces()))?
             .on_sync::<lsp_ext::JoinLines>(|s, p| handlers::handle_join_lines(s.snapshot(), p))?
             .on_sync::<lsp_ext::OnEnter>(|s, p| handlers::handle_on_enter(s.snapshot(), p))?
-            .on_sync::<lsp_types::request::Shutdown>(|_, ()| Ok(()))?
+            .on_sync::<lsp_types::request::Shutdown>(|s, ()| {
+                s.shutdown_requested = true;
+                Ok(())
+            })?
             .on_sync::<lsp_types::request::SelectionRangeRequest>(|s, p| {
                 handlers::handle_selection_range(s.snapshot(), p)
             })?
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 18948cb3c..f5db55b8c 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -4,7 +4,7 @@ import * as ra from '../src/lsp_ext';
 import * as Is from 'vscode-languageclient/lib/utils/is';
 
 import { CallHierarchyFeature } from 'vscode-languageclient/lib/callHierarchy.proposed';
-import { SemanticTokensFeature, DocumentSemanticsTokensSignature } from 'vscode-languageclient/lib/semanticTokens.proposed';
+import { SemanticTokensFeature } from 'vscode-languageclient/lib/semanticTokens.proposed';
 import { assert } from './util';
 
 function renderCommand(cmd: ra.CommandLink) {
@@ -44,12 +44,6 @@ export function createClient(serverPath: string, cwd: string): lc.LanguageClient
         diagnosticCollectionName: "rustc",
         traceOutputChannel,
         middleware: {
-            // Workaround for https://github.com/microsoft/vscode-languageserver-node/issues/576
-            async provideDocumentSemanticTokens(document: vscode.TextDocument, token: vscode.CancellationToken, next: DocumentSemanticsTokensSignature) {
-                const res = await next(document, token);
-                if (res === undefined) throw new Error('busy');
-                return res;
-            },
             async provideHover(document: vscode.TextDocument, position: vscode.Position, token: vscode.CancellationToken, _next: lc.ProvideHoverSignature) {
                 return client.sendRequest(lc.HoverRequest.type, client.code2ProtocolConverter.asTextDocumentPositionParams(document, position), token).then(
                     (result) => {
@@ -135,7 +129,7 @@ export function createClient(serverPath: string, cwd: string): lc.LanguageClient
                 );
             }
 
-        } as any
+        }
     };
 
     const client = new lc.LanguageClient(