3 files changed, 8 insertions, 3 deletions

diff --git a/crates/ra_batch/src/lib.rs b/crates/ra_batch/src/lib.rs
index 2db038063..c6d10107d 100644
--- a/crates/ra_batch/src/lib.rs
+++ b/crates/ra_batch/src/lib.rs
@@ -99,7 +99,7 @@ impl BatchDatabase {
         let ws = ProjectWorkspace::discover(root.as_ref())?;
         let mut roots = Vec::new();
         roots.push(root.clone());
-        ws.add_roots(&mut roots);
+        roots.extend(ws.to_roots());
         let (mut vfs, roots) = Vfs::new(roots);
         let mut load = |path: &Path| {
             let vfs_file = vfs.load(path);
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index 4625a26a7..7163568b9 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -40,7 +40,7 @@ impl ServerWorldState {
         let mut roots = Vec::new();
         roots.push(root.clone());
         for ws in workspaces.iter() {
-            ws.add_roots(&mut roots);
+            roots.extend(ws.to_roots());
         }
         let (mut vfs, roots) = Vfs::new(roots);
         let roots_to_scan = roots.len();
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index ded222446..c566ec0fb 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -50,20 +50,25 @@ impl ProjectWorkspace {
         }
     }
 
-    pub fn add_roots(&self, roots: &mut Vec<PathBuf>) {
+    pub fn to_roots(&self) -> Vec<PathBuf> {
         match self {
             ProjectWorkspace::Json { project } => {
+                let mut roots = Vec::with_capacity(project.roots.len());
                 for root in &project.roots {
                     roots.push(root.path.clone());
                 }
+                roots
             }
             ProjectWorkspace::Cargo { cargo, sysroot } => {
+                let mut roots =
+                    Vec::with_capacity(cargo.packages().count() + sysroot.crates().count());
                 for pkg in cargo.packages() {
                     roots.push(pkg.root(&cargo).to_path_buf());
                 }
                 for krate in sysroot.crates() {
                     roots.push(krate.root_dir(&sysroot).to_path_buf())
                 }
+                roots
             }
         }
     }