Don't recursively call impls_from_deps

It creates a big map and duplicates lots of impls that are then left
lying around

Author: Jonas Schievink

crates/ra_hir_ty/src/method_resolution.rs

@@ -72,13 +72,8 @@ impl CrateImplDefs {
             impls_by_trait: FxHashMap::default(),
         };
 
-        // For each dependency, calculate `impls_from_deps` recursively, then add its own
-        // `impls_in_crate`.
-        // As we might visit crates multiple times, `merge` has to deduplicate impls to avoid
-        // wasting memory.
-        for dep in &crate_graph[krate].dependencies {
-            res.merge(&db.impls_from_deps(dep.crate_id));
-            res.merge(&db.impls_in_crate(dep.crate_id));
+        for krate in crate_graph.transitive_deps(krate) {
+            res.merge(&db.impls_in_crate(krate));
         }
 
         Arc::new(res)
@@ -114,17 +109,13 @@ impl CrateImplDefs {
         for (fp, impls) in &other.inherent_impls {
             let vec = self.inherent_impls.entry(*fp).or_default();
             vec.extend(impls);
-            vec.sort();
-            vec.dedup();
         }
 
         for (trait_, other_map) in &other.impls_by_trait {
             let map = self.impls_by_trait.entry(*trait_).or_default();
             for (fp, impls) in other_map {
                 let vec = map.entry(*fp).or_default();
                 vec.extend(impls);
-                vec.sort();
-                vec.dedup();
             }
         }
     }