diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index 4d2d3b48a0c..a8d6466eac1 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -337,15 +337,11 @@ pub fn get(&self, env: &str) -> Option<String> {
 }
 
 impl ExternSource {
-    pub fn extern_path(&self, path: impl AsRef<Path>) -> Option<(ExternSourceId, RelativePathBuf)> {
-        let path = path.as_ref();
+    pub fn extern_path(&self, path: &Path) -> Option<(ExternSourceId, RelativePathBuf)> {
         self.extern_paths.iter().find_map(|(root_path, id)| {
-            if let Ok(rel_path) = path.strip_prefix(root_path) {
-                let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
-                Some((*id, rel_path))
-            } else {
-                None
-            }
+            let rel_path = path.strip_prefix(root_path).ok()?;
+            let rel_path = RelativePathBuf::from_path(rel_path).ok()?;
+            Some((*id, rel_path))
         })
     }
 
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
index 91e0ee61947..2ab3148840f 100644
--- a/crates/ra_db/src/lib.rs
+++ b/crates/ra_db/src/lib.rs
@@ -158,7 +158,7 @@ fn resolve_path(&self, anchor: FileId, path: &str) -> Option<FileId> {
         if std::path::Path::new(path).is_absolute() {
             let krate = *self.relevant_crates(anchor).get(0)?;
             let (extern_source_id, relative_file) =
-                self.0.crate_graph()[krate].extern_source.extern_path(path)?;
+                self.0.crate_graph()[krate].extern_source.extern_path(path.as_ref())?;
 
             let source_root = self.0.source_root(SourceRootId(extern_source_id.0));
             source_root.file_by_relative_path(&relative_file)