6 files changed, 127 insertions, 157 deletions

diff --git a/crates/flycheck/src/lib.rs b/crates/flycheck/src/lib.rs
index 4dcab7a61..92ec4f92e 100644
--- a/crates/flycheck/src/lib.rs
+++ b/crates/flycheck/src/lib.rs
@@ -7,7 +7,7 @@ use std::{
     io::{self, BufReader},
     path::PathBuf,
     process::{Command, Stdio},
-    time::Instant,
+    time::Duration,
 };
 
 use crossbeam_channel::{never, select, unbounded, Receiver, Sender};
@@ -74,9 +74,6 @@ impl FlycheckHandle {
 
 #[derive(Debug)]
 pub enum Message {
-    /// Request a clearing of all cached diagnostics from the check watcher
-    ClearDiagnostics,
-
     /// Request adding a diagnostic with fixes included to a file
     AddDiagnostic { workspace_root: PathBuf, diagnostic: Diagnostic },
 
@@ -86,9 +83,10 @@ pub enum Message {
 
 #[derive(Debug)]
 pub enum Progress {
-    Being,
+    DidStart,
     DidCheckCrate(String),
-    End,
+    DidFinish,
+    DidCancel,
 }
 
 struct Restart;
@@ -97,19 +95,18 @@ struct FlycheckActor {
     sender: Box<dyn Fn(Message) + Send>,
     config: FlycheckConfig,
     workspace_root: PathBuf,
-    last_update_req: Option<Instant>,
     /// WatchThread exists to wrap around the communication needed to be able to
     /// run `cargo check` without blocking. Currently the Rust standard library
     /// doesn't provide a way to read sub-process output without blocking, so we
     /// have to wrap sub-processes output handling in a thread and pass messages
     /// back over a channel.
     // XXX: drop order is significant
-    check_process: Option<(Receiver<CheckEvent>, jod_thread::JoinHandle)>,
+    check_process: Option<(Receiver<cargo_metadata::Message>, jod_thread::JoinHandle)>,
 }
 
 enum Event {
     Restart(Restart),
-    CheckEvent(Option<CheckEvent>),
+    CheckEvent(Option<cargo_metadata::Message>),
 }
 
 impl FlycheckActor {
@@ -118,7 +115,7 @@ impl FlycheckActor {
         config: FlycheckConfig,
         workspace_root: PathBuf,
     ) -> FlycheckActor {
-        FlycheckActor { sender, config, workspace_root, last_update_req: None, check_process: None }
+        FlycheckActor { sender, config, workspace_root, check_process: None }
     }
     fn next_event(&self, inbox: &Receiver<Restart>) -> Option<Event> {
         let check_chan = self.check_process.as_ref().map(|(chan, _thread)| chan);
@@ -128,65 +125,48 @@ impl FlycheckActor {
         }
     }
     fn run(&mut self, inbox: Receiver<Restart>) {
-        // If we rerun the thread, we need to discard the previous check results first
-        self.send(Message::ClearDiagnostics);
-        self.send(Message::Progress(Progress::End));
-
         while let Some(event) = self.next_event(&inbox) {
             match event {
-                Event::Restart(Restart) => self.last_update_req = Some(Instant::now()),
+                Event::Restart(Restart) => {
+                    while let Ok(Restart) = inbox.recv_timeout(Duration::from_millis(50)) {}
+                    self.cancel_check_process();
+                    self.check_process = Some(self.start_check_process());
+                    self.send(Message::Progress(Progress::DidStart));
+                }
                 Event::CheckEvent(None) => {
                     // Watcher finished, replace it with a never channel to
                     // avoid busy-waiting.
-                    self.check_process = None;
+                    assert!(self.check_process.take().is_some());
+                    self.send(Message::Progress(Progress::DidFinish));
                 }
-                Event::CheckEvent(Some(event)) => match event {
-                    CheckEvent::Begin => {
-                        self.send(Message::Progress(Progress::Being));
-                    }
-
-                    CheckEvent::End => {
-                        self.send(Message::Progress(Progress::End));
-                    }
-
-                    CheckEvent::Msg(cargo_metadata::Message::CompilerArtifact(msg)) => {
+                Event::CheckEvent(Some(message)) => match message {
+                    cargo_metadata::Message::CompilerArtifact(msg) => {
                         self.send(Message::Progress(Progress::DidCheckCrate(msg.target.name)));
                     }
 
-                    CheckEvent::Msg(cargo_metadata::Message::CompilerMessage(msg)) => {
+                    cargo_metadata::Message::CompilerMessage(msg) => {
                         self.send(Message::AddDiagnostic {
                             workspace_root: self.workspace_root.clone(),
                             diagnostic: msg.message,
                         });
                     }
 
-                    CheckEvent::Msg(cargo_metadata::Message::BuildScriptExecuted(_))
-                    | CheckEvent::Msg(cargo_metadata::Message::BuildFinished(_))
-                    | CheckEvent::Msg(cargo_metadata::Message::TextLine(_))
-                    | CheckEvent::Msg(cargo_metadata::Message::Unknown) => {}
+                    cargo_metadata::Message::BuildScriptExecuted(_)
+                    | cargo_metadata::Message::BuildFinished(_)
+                    | cargo_metadata::Message::TextLine(_)
+                    | cargo_metadata::Message::Unknown => {}
                 },
             }
-            if self.should_recheck() {
-                self.last_update_req = None;
-                self.send(Message::ClearDiagnostics);
-                self.restart_check_process();
-            }
         }
+        // If we rerun the thread, we need to discard the previous check results first
+        self.cancel_check_process();
     }
-    fn should_recheck(&mut self) -> bool {
-        if let Some(_last_update_req) = &self.last_update_req {
-            // We currently only request an update on save, as we need up to
-            // date source on disk for cargo check to do it's magic, so we
-            // don't really need to debounce the requests at this point.
-            return true;
+    fn cancel_check_process(&mut self) {
+        if self.check_process.take().is_some() {
+            self.send(Message::Progress(Progress::DidCancel));
         }
-        false
     }
-
-    fn restart_check_process(&mut self) {
-        // First, clear and cancel the old thread
-        self.check_process = None;
-
+    fn start_check_process(&self) -> (Receiver<cargo_metadata::Message>, jod_thread::JoinHandle) {
         let mut cmd = match &self.config {
             FlycheckConfig::CargoCommand {
                 command,
@@ -223,8 +203,6 @@ impl FlycheckActor {
         let thread = jod_thread::spawn(move || {
             // If we trigger an error here, we will do so in the loop instead,
             // which will break out of the loop, and continue the shutdown
-            let _ = message_send.send(CheckEvent::Begin);
-
             let res = run_cargo(cmd, &mut |message| {
                 // Skip certain kinds of messages to only spend time on what's useful
                 match &message {
@@ -237,7 +215,7 @@ impl FlycheckActor {
                 }
 
                 // if the send channel was closed, we want to shutdown
-                message_send.send(CheckEvent::Msg(message)).is_ok()
+                message_send.send(message).is_ok()
             });
 
             if let Err(err) = res {
@@ -245,12 +223,8 @@ impl FlycheckActor {
                 // to display user-caused misconfiguration errors instead of just logging them here
                 log::error!("Cargo watcher failed {:?}", err);
             }
-
-            // We can ignore any error here, as we are already in the progress
-            // of shutting down.
-            let _ = message_send.send(CheckEvent::End);
         });
-        self.check_process = Some((message_recv, thread))
+        (message_recv, thread)
     }
 
     fn send(&self, check_task: Message) {
@@ -258,12 +232,6 @@ impl FlycheckActor {
     }
 }
 
-enum CheckEvent {
-    Begin,
-    Msg(cargo_metadata::Message),
-    End,
-}
-
 fn run_cargo(
     mut command: Command,
     on_message: &mut dyn FnMut(cargo_metadata::Message) -> bool,
diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index f224c69e7..384e1f0d2 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -21,7 +21,6 @@ use crate::{
     main_loop::Task,
     reload::SourceRootConfig,
     request_metrics::{LatestRequests, RequestMetrics},
-    show_message,
     thread_pool::TaskPool,
     to_proto::url_from_abs_path,
     Result,
@@ -182,9 +181,6 @@ impl GlobalState {
             self.send(response.into());
         }
     }
-    pub(crate) fn show_message(&self, typ: lsp_types::MessageType, message: String) {
-        show_message(typ, message, &self.sender)
-    }
 }
 
 impl Drop for GlobalState {
diff --git a/crates/rust-analyzer/src/lib.rs b/crates/rust-analyzer/src/lib.rs
index a24dfe58c..407944d85 100644
--- a/crates/rust-analyzer/src/lib.rs
+++ b/crates/rust-analyzer/src/lib.rs
@@ -39,7 +39,7 @@ pub mod config;
 use serde::de::DeserializeOwned;
 
 pub type Result<T, E = Box<dyn std::error::Error + Send + Sync>> = std::result::Result<T, E>;
-pub use crate::{caps::server_capabilities, lsp_utils::show_message, main_loop::main_loop};
+pub use crate::{caps::server_capabilities, main_loop::main_loop};
 use std::fmt;
 
 pub fn from_json<T: DeserializeOwned>(what: &'static str, json: serde_json::Value) -> Result<T> {
diff --git a/crates/rust-analyzer/src/lsp_utils.rs b/crates/rust-analyzer/src/lsp_utils.rs
index 35917030c..fd793a17c 100644
--- a/crates/rust-analyzer/src/lsp_utils.rs
+++ b/crates/rust-analyzer/src/lsp_utils.rs
@@ -1,24 +1,13 @@
 //! Utilities for LSP-related boilerplate code.
 use std::{error::Error, ops::Range};
 
-use crossbeam_channel::Sender;
-use lsp_server::{Message, Notification};
+use lsp_server::Notification;
+use lsp_types::request::Request;
 use ra_db::Canceled;
 use ra_ide::LineIndex;
 use serde::Serialize;
 
-use crate::from_proto;
-
-pub fn show_message(
-    typ: lsp_types::MessageType,
-    message: impl Into<String>,
-    sender: &Sender<Message>,
-) {
-    let message = message.into();
-    let params = lsp_types::ShowMessageParams { typ, message };
-    let not = notification_new::<lsp_types::notification::ShowMessage>(params);
-    sender.send(not.into()).unwrap();
-}
+use crate::{from_proto, global_state::GlobalState};
 
 pub(crate) fn is_canceled(e: &(dyn Error + 'static)) -> bool {
     e.downcast_ref::<Canceled>().is_some()
@@ -38,6 +27,74 @@ where
     Notification::new(N::METHOD.to_string(), params)
 }
 
+#[derive(Debug, Eq, PartialEq)]
+pub(crate) enum Progress {
+    Begin,
+    Report,
+    End,
+}
+
+impl Progress {
+    pub(crate) fn percentage(done: usize, total: usize) -> f64 {
+        (done as f64 / total.max(1) as f64) * 100.0
+    }
+}
+
+impl GlobalState {
+    pub(crate) fn show_message(&mut self, typ: lsp_types::MessageType, message: String) {
+        let message = message.into();
+        let params = lsp_types::ShowMessageParams { typ, message };
+        let not = notification_new::<lsp_types::notification::ShowMessage>(params);
+        self.send(not.into());
+    }
+
+    pub(crate) fn report_progress(
+        &mut self,
+        title: &str,
+        state: Progress,
+        message: Option<String>,
+        percentage: Option<f64>,
+    ) {
+        if !self.config.client_caps.work_done_progress {
+            return;
+        }
+        let token = lsp_types::ProgressToken::String(format!("rustAnalyzer/{}", title));
+        let work_done_progress = match state {
+            Progress::Begin => {
+                let work_done_progress_create = self.req_queue.outgoing.register(
+                    lsp_types::request::WorkDoneProgressCreate::METHOD.to_string(),
+                    lsp_types::WorkDoneProgressCreateParams { token: token.clone() },
+                    |_, _| (),
+                );
+                self.send(work_done_progress_create.into());
+
+                lsp_types::WorkDoneProgress::Begin(lsp_types::WorkDoneProgressBegin {
+                    title: title.into(),
+                    cancellable: None,
+                    message,
+                    percentage,
+                })
+            }
+            Progress::Report => {
+                lsp_types::WorkDoneProgress::Report(lsp_types::WorkDoneProgressReport {
+                    cancellable: None,
+                    message,
+                    percentage,
+                })
+            }
+            Progress::End => {
+                lsp_types::WorkDoneProgress::End(lsp_types::WorkDoneProgressEnd { message })
+            }
+        };
+        let notification =
+            notification_new::<lsp_types::notification::Progress>(lsp_types::ProgressParams {
+                token,
+                value: lsp_types::ProgressParamsValue::WorkDone(work_done_progress),
+            });
+        self.send(notification.into());
+    }
+}
+
 pub(crate) fn apply_document_changes(
     old_text: &mut String,
     content_changes: Vec<lsp_types::TextDocumentContentChangeEvent>,
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 8fc816cbd..ae3c7e30e 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -18,7 +18,7 @@ use crate::{
     from_proto,
     global_state::{file_id_to_url, url_to_file_id, GlobalState, Status},
     handlers, lsp_ext,
-    lsp_utils::{apply_document_changes, is_canceled, notification_is, notification_new},
+    lsp_utils::{apply_document_changes, is_canceled, notification_is, notification_new, Progress},
     Result,
 };
 
@@ -181,18 +181,15 @@ impl GlobalState {
                         became_ready = true;
                         Progress::End
                     };
-                    report_progress(
-                        self,
+                    self.report_progress(
                         "roots scanned",
                         state,
                         Some(format!("{}/{}", n_done, n_total)),
-                        Some(percentage(n_done, n_total)),
+                        Some(Progress::percentage(n_done, n_total)),
                     )
                 }
             },
             Event::Flycheck(task) => match task {
-                flycheck::Message::ClearDiagnostics => self.diagnostics.clear_check(),
-
                 flycheck::Message::AddDiagnostic { workspace_root, diagnostic } => {
                     let diagnostics = crate::diagnostics::to_proto::map_rust_diagnostic_to_lsp(
                         &self.config.diagnostics,
@@ -215,14 +212,19 @@ impl GlobalState {
 
                 flycheck::Message::Progress(status) => {
                     let (state, message) = match status {
-                        flycheck::Progress::Being => (Progress::Begin, None),
+                        flycheck::Progress::DidStart => {
+                            self.diagnostics.clear_check();
+                            (Progress::Begin, None)
+                        }
                         flycheck::Progress::DidCheckCrate(target) => {
                             (Progress::Report, Some(target))
                         }
-                        flycheck::Progress::End => (Progress::End, None),
+                        flycheck::Progress::DidFinish | flycheck::Progress::DidCancel => {
+                            (Progress::End, None)
+                        }
                     };
 
-                    report_progress(self, "cargo check", state, message, None);
+                    self.report_progress("cargo check", state, message, None);
                 }
             },
         }
@@ -465,60 +467,3 @@ impl GlobalState {
         });
     }
 }
-
-#[derive(Eq, PartialEq)]
-enum Progress {
-    Begin,
-    Report,
-    End,
-}
-
-fn percentage(done: usize, total: usize) -> f64 {
-    (done as f64 / total.max(1) as f64) * 100.0
-}
-
-fn report_progress(
-    global_state: &mut GlobalState,
-    title: &str,
-    state: Progress,
-    message: Option<String>,
-    percentage: Option<f64>,
-) {
-    if !global_state.config.client_caps.work_done_progress {
-        return;
-    }
-    let token = lsp_types::ProgressToken::String(format!("rustAnalyzer/{}", title));
-    let work_done_progress = match state {
-        Progress::Begin => {
-            let work_done_progress_create = global_state.req_queue.outgoing.register(
-                lsp_types::request::WorkDoneProgressCreate::METHOD.to_string(),
-                lsp_types::WorkDoneProgressCreateParams { token: token.clone() },
-                |_, _| (),
-            );
-            global_state.send(work_done_progress_create.into());
-
-            lsp_types::WorkDoneProgress::Begin(lsp_types::WorkDoneProgressBegin {
-                title: title.into(),
-                cancellable: None,
-                message,
-                percentage,
-            })
-        }
-        Progress::Report => {
-            lsp_types::WorkDoneProgress::Report(lsp_types::WorkDoneProgressReport {
-                cancellable: None,
-                message,
-                percentage,
-            })
-        }
-        Progress::End => {
-            lsp_types::WorkDoneProgress::End(lsp_types::WorkDoneProgressEnd { message })
-        }
-    };
-    let notification =
-        notification_new::<lsp_types::notification::Progress>(lsp_types::ProgressParams {
-            token,
-            value: lsp_types::ProgressParamsValue::WorkDone(work_done_progress),
-        });
-    global_state.send(notification.into());
-}
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index a22d3e262..fece6176e 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -36,27 +36,31 @@ impl GlobalState {
             self.config
                 .linked_projects
                 .iter()
-                .filter_map(|project| match project {
+                .map(|project| match project {
                     LinkedProject::ProjectManifest(manifest) => {
                         ra_project_model::ProjectWorkspace::load(
                             manifest.clone(),
                             &self.config.cargo,
                             self.config.with_sysroot,
                         )
-                        .map_err(|err| {
-                            log::error!("failed to load workspace: {:#}", err);
-                            self.show_message(
-                                lsp_types::MessageType::Error,
-                                format!("rust-analyzer failed to load workspace: {:#}", err),
-                            );
-                        })
-                        .ok()
                     }
                     LinkedProject::InlineJsonProject(it) => {
-                        Some(ra_project_model::ProjectWorkspace::Json { project: it.clone() })
+                        Ok(ra_project_model::ProjectWorkspace::Json { project: it.clone() })
                     }
                 })
                 .collect::<Vec<_>>()
+                .into_iter()
+                .filter_map(|res| {
+                    res.map_err(|err| {
+                        log::error!("failed to load workspace: {:#}", err);
+                        self.show_message(
+                            lsp_types::MessageType::Error,
+                            format!("rust-analyzer failed to load workspace: {:#}", err),
+                        );
+                    })
+                    .ok()
+                })
+                .collect::<Vec<_>>()
         };
 
         if let FilesWatcher::Client = self.config.files.watcher {