Run flycheck only on crate if target is binary.

crates/rust-analyzer/src/flycheck.rs

@@ -118,14 +118,14 @@ impl FlycheckHandle {
     }
 
     /// Schedule a re-start of the cargo check worker to do a workspace wide check.
-    pub(crate) fn restart_workspace(&self, saved_file: Option<AbsPathBuf>) {
-        self.sender.send(StateChange::Restart { package: None, saved_file }).unwrap();
+    pub(crate) fn restart_workspace(&self, saved_file: Option<AbsPathBuf>, target: Option<String>) {
+        self.sender.send(StateChange::Restart { package: None, saved_file, target }).unwrap();
     }
 
     /// Schedule a re-start of the cargo check worker to do a package wide check.
-    pub(crate) fn restart_for_package(&self, package: String) {
+    pub(crate) fn restart_for_package(&self, package: String, target: Option<String>) {
         self.sender
-            .send(StateChange::Restart { package: Some(package), saved_file: None })
+            .send(StateChange::Restart { package: Some(package), saved_file: None, target })
             .unwrap();
     }
 
@@ -183,7 +183,7 @@ pub(crate) enum Progress {
 }
 
 enum StateChange {
-    Restart { package: Option<String>, saved_file: Option<AbsPathBuf> },
+    Restart { package: Option<String>, saved_file: Option<AbsPathBuf>, target: Option<String> },
     Cancel,
 }
 
@@ -271,7 +271,7 @@ impl FlycheckActor {
                     tracing::debug!(flycheck_id = self.id, "flycheck cancelled");
                     self.cancel_check_process();
                 }
-                Event::RequestStateChange(StateChange::Restart { package, saved_file }) => {
+                Event::RequestStateChange(StateChange::Restart { package, saved_file, target }) => {
                     // Cancel the previously spawned process
                     self.cancel_check_process();
                     while let Ok(restart) = inbox.recv_timeout(Duration::from_millis(50)) {
@@ -281,8 +281,11 @@ impl FlycheckActor {
                         }
                     }
 
-                    let command =
-                        match self.check_command(package.as_deref(), saved_file.as_deref()) {
+                    let command = match self.check_command(
+                        package.as_deref(),
+                        saved_file.as_deref(),
+                        target.as_deref(),
+                    ) {
                         Some(c) => c,
                         None => continue,
                     };
@@ -381,6 +384,7 @@ impl FlycheckActor {
         &self,
         package: Option<&str>,
         saved_file: Option<&AbsPath>,
+        bin_target: Option<&str>,
     ) -> Option<Command> {
         match &self.config {
             FlycheckConfig::CargoCommand { command, options, ansi_color_output } => {
@@ -396,6 +400,10 @@ impl FlycheckActor {
                     None => cmd.arg("--workspace"),
                 };
 
+                if let Some(tgt) = bin_target {
+                    cmd.arg("--bin").arg(tgt);
+                }
+
                 cmd.arg(if *ansi_color_output {
                     "--message-format=json-diagnostic-rendered-ansi"
                 } else {

crates/rust-analyzer/src/handlers/notification.rs

@@ -20,6 +20,7 @@ use crate::{
     lsp_ext::{self, RunFlycheckParams},
     mem_docs::DocumentData,
     reload,
+    target_spec::TargetSpec,
 };
 
 pub(crate) fn handle_cancel(state: &mut GlobalState, params: CancelParams) -> anyhow::Result<()> {
@@ -185,7 +186,7 @@ pub(crate) fn handle_did_save_text_document(
     } else if state.config.check_on_save() {
         // No specific flycheck was triggered, so let's trigger all of them.
         for flycheck in state.flycheck.iter() {
-            flycheck.restart_workspace(None);
+            flycheck.restart_workspace(None, None);
         }
     }
     Ok(())
@@ -287,16 +288,33 @@ fn run_flycheck(state: &mut GlobalState, vfs_path: VfsPath) -> bool {
         let world = state.snapshot();
         let mut updated = false;
         let task = move || -> std::result::Result<(), ide::Cancelled> {
+            // Is the target binary? If so we let flycheck run only for the workspace that contains the crate.
+            let target_is_bin = TargetSpec::for_file(&world, file_id)?.and_then(|x| {
+                if x.target_kind() == project_model::TargetKind::Bin {
+                    return match x {
+                        TargetSpec::Cargo(c) => Some(c.target),
+                        TargetSpec::ProjectJson(p) => Some(p.label),
+                    };
+                }
+
+                None
+            });
+
+            let crate_ids = if target_is_bin.is_some() {
+                // Trigger flychecks for the only workspace which the binary crate belongs to
+                world.analysis.crates_for(file_id)?.into_iter().unique().collect::<Vec<_>>()
+            } else {
                 // Trigger flychecks for all workspaces that depend on the saved file
                 // Crates containing or depending on the saved file
-            let crate_ids: Vec<_> = world
+                world
                     .analysis
                     .crates_for(file_id)?
                     .into_iter()
                     .flat_map(|id| world.analysis.transitive_rev_deps(id))
                     .flatten()
                     .unique()
-                .collect();
+                    .collect::<Vec<_>>()
+            };
 
             let crate_root_paths: Vec<_> = crate_ids
                 .iter()
@@ -347,8 +365,11 @@ fn run_flycheck(state: &mut GlobalState, vfs_path: VfsPath) -> bool {
                     if id == flycheck.id() {
                         updated = true;
                         match package.filter(|_| !world.config.flycheck_workspace()) {
-                            Some(package) => flycheck.restart_for_package(package),
-                            None => flycheck.restart_workspace(saved_file.clone()),
+                            Some(package) => {
+                                flycheck.restart_for_package(package, target_is_bin.clone())
+                            }
+                            None => flycheck
+                                .restart_workspace(saved_file.clone(), target_is_bin.clone()),
                         }
                         continue;
                     }
@@ -357,7 +378,7 @@ fn run_flycheck(state: &mut GlobalState, vfs_path: VfsPath) -> bool {
             // No specific flycheck was triggered, so let's trigger all of them.
             if !updated {
                 for flycheck in world.flycheck.iter() {
-                    flycheck.restart_workspace(saved_file.clone());
+                    flycheck.restart_workspace(saved_file.clone(), None);
                 }
             }
             Ok(())
@@ -399,7 +420,7 @@ pub(crate) fn handle_run_flycheck(
     }
     // No specific flycheck was triggered, so let's trigger all of them.
     for flycheck in state.flycheck.iter() {
-        flycheck.restart_workspace(None);
+        flycheck.restart_workspace(None, None);
     }
     Ok(())
 }

crates/rust-analyzer/src/main_loop.rs

@@ -406,7 +406,9 @@ impl GlobalState {
             if became_quiescent {
                 if self.config.check_on_save() {
                     // Project has loaded properly, kick off initial flycheck
-                    self.flycheck.iter().for_each(|flycheck| flycheck.restart_workspace(None));
+                    self.flycheck
+                        .iter()
+                        .for_each(|flycheck| flycheck.restart_workspace(None, None));
                 }
                 if self.config.prefill_caches() {
                     self.prime_caches_queue.request_op("became quiescent".to_owned(), ());