simplify

crates/ra_arena/src/map.rs

@@ -29,6 +29,10 @@ impl<ID: ArenaId, T> ArenaMap<ID, T> {
         self.v.get(Self::to_idx(id)).and_then(|it| it.as_ref())
     }
 
+    pub fn get_mut(&mut self, id: ID) -> Option<&mut T> {
+        self.v.get_mut(Self::to_idx(id)).and_then(|it| it.as_mut())
+    }
+
     pub fn values(&self) -> impl Iterator<Item = &T> {
         self.v.iter().filter_map(|o| o.as_ref())
     }

crates/ra_hir/src/code_model_api.rs

@@ -165,7 +165,7 @@ impl Module {
 
     /// Returns a `ModuleScope`: a set of items, visible in this module.
     pub fn scope(&self, db: &impl HirDatabase) -> ModuleScope {
-        self.scope_impl(db)
+        db.item_map(self.krate)[self.module_id].clone()
     }
 
     pub fn resolve_path(&self, db: &impl HirDatabase, path: &Path) -> PerNs<ModuleDef> {

crates/ra_hir/src/code_model_impl/module.rs

@@ -2,10 +2,10 @@ use ra_db::FileId;
 use ra_syntax::{ast, SyntaxNode, TreeArc};
 
 use crate::{
-    Module, ModuleSource, Problem, ModuleDef,
+    Module, ModuleSource, Problem,
-    Crate, Name, Path, PerNs,
+    Crate, Name,
     module_tree::ModuleId,
-    nameres::{ModuleScope, lower::ImportId},
+    nameres::{lower::ImportId},
     db::HirDatabase,
 };
 
@@ -90,12 +90,6 @@ impl Module {
         Some(self.with_module_id(parent_id))
     }
 
-    /// Returns a `ModuleScope`: a set of items, visible in this module.
-    pub(crate) fn scope_impl(&self, db: &impl HirDatabase) -> ModuleScope {
-        let item_map = db.item_map(self.krate);
-        item_map.per_module[&self.module_id].clone()
-    }
-
     pub(crate) fn problems_impl(
         &self,
         db: &impl HirDatabase,

crates/ra_hir/src/nameres.rs

@@ -19,6 +19,7 @@ pub(crate) mod lower;
 use std::sync::Arc;
 
 use ra_db::CrateId;
+use ra_arena::map::ArenaMap;
 use test_utils::tested_by;
 use rustc_hash::{FxHashMap, FxHashSet};
 
@@ -37,7 +38,14 @@ use crate::{
 // FIXME: currenty we compute item map per source-root. We should do it per crate instead.
 #[derive(Default, Debug, PartialEq, Eq)]
 pub struct ItemMap {
-    pub per_module: FxHashMap<ModuleId, ModuleScope>,
+    per_module: ArenaMap<ModuleId, ModuleScope>,
+}
+
+impl std::ops::Index<ModuleId> for ItemMap {
+    type Output = ModuleScope;
+    fn index(&self, id: ModuleId) -> &ModuleScope {
+        &self.per_module[id]
+    }
 }
 
 #[derive(Debug, Default, PartialEq, Eq, Clone)]
@@ -308,7 +316,7 @@ where
     }
 
     fn update(&mut self, module_id: ModuleId, f: impl FnOnce(&mut ModuleScope)) {
-        let module_items = self.result.per_module.get_mut(&module_id).unwrap();
+        let module_items = self.result.per_module.get_mut(module_id).unwrap();
         f(module_items)
     }
 }
@@ -380,7 +388,7 @@ impl ItemMap {
                         return (def, ReachedFixedPoint::Yes);
                     }
 
-                    match self.per_module[&module.module_id].items.get(&segment.name) {
+                    match self[module.module_id].items.get(&segment.name) {
                         Some(res) if !res.def.is_none() => res.def,
                         _ => {
                             log::debug!("path segment {:?} not found", segment.name);

crates/ra_hir/src/nameres/tests.rs

@@ -20,7 +20,7 @@ fn item_map(fixture: &str) -> (Arc<ItemMap>, ModuleId) {
 }
 
 fn check_module_item_map(map: &ItemMap, module_id: ModuleId, expected: &str) {
-    let mut lines = map.per_module[&module_id]
+    let mut lines = map[module_id]
         .items
         .iter()
         .map(|(name, res)| format!("{}: {}", name, dump_resolution(res)))