Deduplicate getting the path of a lib candidate

Author: bjorn3

compiler/rustc_metadata/src/locator.rs

@@ -495,13 +495,11 @@ impl<'a> CrateLocator<'a> {
             0 => Ok(None),
             1 => Ok(Some(libraries.into_iter().next().unwrap().1)),
             _ => {
-                let mut libraries: Vec<_> = libraries.into_values().collect();
-
-                libraries.sort_by_cached_key(|lib| lib.source.paths().next().unwrap().clone());
-                let candidates = libraries
-                    .iter()
+                let mut candidates: Vec<PathBuf> = libraries
+                    .into_values()
                     .map(|lib| lib.source.paths().next().unwrap().clone())
-                    .collect::<Vec<_>>();
+                    .collect();
+                candidates.sort();
 
                 Err(CrateError::MultipleCandidates(
                     self.crate_name,