Spawn a flycheck instance per workspace

crates/rust-analyzer/src/global_state.rs

@@ -63,7 +63,7 @@ pub(crate) struct GlobalState {
     req_queue: ReqQueue,
     pub(crate) task_pool: Handle<TaskPool<Task>, Receiver<Task>>,
     pub(crate) loader: Handle<Box<dyn vfs::loader::Handle>, Receiver<vfs::loader::Message>>,
-    pub(crate) flycheck: Option<FlycheckHandle>,
+    pub(crate) flycheck: Vec<FlycheckHandle>,
     pub(crate) flycheck_sender: Sender<flycheck::Message>,
     pub(crate) flycheck_receiver: Receiver<flycheck::Message>,
     pub(crate) config: Config,
@@ -115,7 +115,7 @@ impl GlobalState {
             req_queue: ReqQueue::default(),
             task_pool,
             loader,
-            flycheck: None,
+            flycheck: Vec::new(),
             flycheck_sender,
             flycheck_receiver,
             config,