1 files changed, 21 insertions, 37 deletions

diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index 5a0a87ed7..4f098b706 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -88,46 +88,28 @@ impl ProjectRoot {
     }
 
     pub fn discover(path: &Path) -> io::Result<Vec<ProjectRoot>> {
-        if let Some(project_json) = find_rust_project_json(path) {
+        if let Some(project_json) = find_in_parent_dirs(path, "rust-project.json") {
             return Ok(vec![ProjectRoot::ProjectJson(project_json)]);
         }
         return find_cargo_toml(path)
             .map(|paths| paths.into_iter().map(ProjectRoot::CargoToml).collect());
 
-        fn find_rust_project_json(path: &Path) -> Option<PathBuf> {
-            if path.ends_with("rust-project.json") {
-                return Some(path.to_path_buf());
-            }
-
-            let mut curr = Some(path);
-            while let Some(path) = curr {
-                let candidate = path.join("rust-project.json");
-                if candidate.exists() {
-                    return Some(candidate);
-                }
-                curr = path.parent();
-            }
-
-            None
-        }
-
         fn find_cargo_toml(path: &Path) -> io::Result<Vec<PathBuf>> {
-            if path.ends_with("Cargo.toml") {
-                return Ok(vec![path.to_path_buf()]);
+            match find_in_parent_dirs(path, "Cargo.toml") {
+                Some(it) => Ok(vec![it]),
+                None => Ok(find_cargo_toml_in_child_dir(read_dir(path)?)),
             }
+        }
 
-            if let Some(p) = find_cargo_toml_in_parent_dir(path) {
-                return Ok(vec![p]);
+        fn find_in_parent_dirs(path: &Path, target_file_name: &str) -> Option<PathBuf> {
+            if path.ends_with(target_file_name) {
+                return Some(path.to_owned());
             }
 
-            let entities = read_dir(path)?;
-            Ok(find_cargo_toml_in_child_dir(entities))
-        }
-
-        fn find_cargo_toml_in_parent_dir(path: &Path) -> Option<PathBuf> {
             let mut curr = Some(path);
+
             while let Some(path) = curr {
-                let candidate = path.join("Cargo.toml");
+                let candidate = path.join(target_file_name);
                 if candidate.exists() {
                     return Some(candidate);
                 }
@@ -139,14 +121,11 @@ impl ProjectRoot {
 
         fn find_cargo_toml_in_child_dir(entities: ReadDir) -> Vec<PathBuf> {
             // Only one level down to avoid cycles the easy way and stop a runaway scan with large projects
-            let mut valid_canditates = vec![];
-            for entity in entities.filter_map(Result::ok) {
-                let candidate = entity.path().join("Cargo.toml");
-                if candidate.exists() {
-                    valid_canditates.push(candidate)
-                }
-            }
-            valid_canditates
+            entities
+                .filter_map(Result::ok)
+                .map(|it| it.path().join("Cargo.toml"))
+                .filter(|it| it.exists())
+                .collect()
         }
     }
 }
@@ -600,7 +579,12 @@ pub fn get_rustc_cfg_options(target: Option<&String>) -> CfgOptions {
 fn output(mut cmd: Command) -> Result<Output> {
     let output = cmd.output().with_context(|| format!("{:?} failed", cmd))?;
     if !output.status.success() {
-        bail!("{:?} failed, {}", cmd, output.status)
+        match String::from_utf8(output.stderr) {
+            Ok(stderr) if !stderr.is_empty() => {
+                bail!("{:?} failed, {}\nstderr:\n{}", cmd, output.status, stderr)
+            }
+            _ => bail!("{:?} failed, {}", cmd, output.status),
+        }
     }
     Ok(output)
 }