8 files changed, 77 insertions, 37 deletions

diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index e0eb2a66d..15651bb22 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -574,7 +574,7 @@ impl<'db> SemanticsImpl<'db> {
     }
 
     fn scope_for_def(&self, def: Trait) -> SemanticsScope<'db> {
-        let file_id = self.db.lookup_intern_trait(def.id).id.file_id;
+        let file_id = self.db.lookup_intern_trait(def.id).id.file_id();
         let resolver = def.id.resolver(self.db.upcast());
         SemanticsScope { db: self.db, file_id, resolver }
     }
diff --git a/crates/hir_def/src/adt.rs b/crates/hir_def/src/adt.rs
index 1b9bb8235..58e35353b 100644
--- a/crates/hir_def/src/adt.rs
+++ b/crates/hir_def/src/adt.rs
@@ -94,7 +94,7 @@ impl StructData {
     pub(crate) fn struct_data_query(db: &dyn DefDatabase, id: StructId) -> Arc<StructData> {
         let loc = id.lookup(db);
         let krate = loc.container.krate;
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let repr = repr_from_value(db, krate, &item_tree, ModItem::from(loc.id.value).into());
         let cfg_options = db.crate_graph()[loc.container.krate].cfg_options.clone();
 
@@ -110,7 +110,7 @@ impl StructData {
     pub(crate) fn union_data_query(db: &dyn DefDatabase, id: UnionId) -> Arc<StructData> {
         let loc = id.lookup(db);
         let krate = loc.container.krate;
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let repr = repr_from_value(db, krate, &item_tree, ModItem::from(loc.id.value).into());
         let cfg_options = db.crate_graph()[loc.container.krate].cfg_options.clone();
 
@@ -130,7 +130,7 @@ impl EnumData {
     pub(crate) fn enum_data_query(db: &dyn DefDatabase, e: EnumId) -> Arc<EnumData> {
         let loc = e.lookup(db);
         let krate = loc.container.krate;
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let cfg_options = db.crate_graph()[krate].cfg_options.clone();
 
         let enum_ = &item_tree[loc.id.value];
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index b7353d868..e4c84afbf 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -530,7 +530,7 @@ where
 }
 
 fn attrs_from_item_tree<N: ItemTreeNode>(id: ItemTreeId<N>, db: &dyn DefDatabase) -> RawAttrs {
-    let tree = db.item_tree(id.file_id);
+    let tree = id.item_tree(db);
     let mod_item = N::id_to_mod_item(id.value);
     tree.raw_attrs(mod_item.into()).clone()
 }
diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index fefc31129..f1772ea3d 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -38,7 +38,7 @@ impl FunctionData {
         let krate = loc.container.module(db).krate;
         let crate_graph = db.crate_graph();
         let cfg_options = &crate_graph[krate].cfg_options;
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let func = &item_tree[loc.id.value];
 
         let enabled_params = func
@@ -89,7 +89,7 @@ impl TypeAliasData {
         typ: TypeAliasId,
     ) -> Arc<TypeAliasData> {
         let loc = typ.lookup(db);
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let typ = &item_tree[loc.id.value];
 
         Arc::new(TypeAliasData {
@@ -115,23 +115,23 @@ pub struct TraitData {
 impl TraitData {
     pub(crate) fn trait_data_query(db: &dyn DefDatabase, tr: TraitId) -> Arc<TraitData> {
         let tr_loc = tr.lookup(db);
-        let item_tree = db.item_tree(tr_loc.id.file_id);
+        let item_tree = tr_loc.id.item_tree(db);
         let tr_def = &item_tree[tr_loc.id.value];
         let name = tr_def.name.clone();
         let is_auto = tr_def.is_auto;
         let is_unsafe = tr_def.is_unsafe;
         let module_id = tr_loc.container;
         let container = AssocContainerId::TraitId(tr);
-        let mut expander = Expander::new(db, tr_loc.id.file_id, module_id);
         let visibility = item_tree[tr_def.visibility].clone();
         let bounds = tr_def.bounds.clone();
+        let mut expander = Expander::new(db, tr_loc.id.file_id(), module_id);
 
         let items = collect_items(
             db,
             module_id,
             &mut expander,
             tr_def.items.iter().copied(),
-            tr_loc.id.file_id,
+            tr_loc.id.file_id(),
             container,
             100,
         );
@@ -167,21 +167,21 @@ impl ImplData {
         let _p = profile::span("impl_data_query");
         let impl_loc = id.lookup(db);
 
-        let item_tree = db.item_tree(impl_loc.id.file_id);
+        let item_tree = impl_loc.id.item_tree(db);
         let impl_def = &item_tree[impl_loc.id.value];
         let target_trait = impl_def.target_trait.map(|id| item_tree[id].clone());
         let target_type = item_tree[impl_def.target_type].clone();
         let is_negative = impl_def.is_negative;
         let module_id = impl_loc.container;
         let container = AssocContainerId::ImplId(id);
-        let mut expander = Expander::new(db, impl_loc.id.file_id, module_id);
+        let mut expander = Expander::new(db, impl_loc.id.file_id(), module_id);
 
         let items = collect_items(
             db,
             module_id,
             &mut expander,
             impl_def.items.iter().copied(),
-            impl_loc.id.file_id,
+            impl_loc.id.file_id(),
             container,
             100,
         );
@@ -202,7 +202,7 @@ pub struct ConstData {
 impl ConstData {
     pub(crate) fn const_data_query(db: &dyn DefDatabase, konst: ConstId) -> Arc<ConstData> {
         let loc = konst.lookup(db);
-        let item_tree = db.item_tree(loc.id.file_id);
+        let item_tree = loc.id.item_tree(db);
         let konst = &item_tree[loc.id.value];
 
         Arc::new(ConstData {
@@ -225,7 +225,7 @@ pub struct StaticData {
 impl StaticData {
     pub(crate) fn static_data_query(db: &dyn DefDatabase, konst: StaticId) -> Arc<StaticData> {
         let node = konst.lookup(db);
-        let item_tree = db.item_tree(node.id.file_id);
+        let item_tree = node.id.item_tree(db);
         let statik = &item_tree[node.id.value];
 
         Arc::new(StaticData {
diff --git a/crates/hir_def/src/generics.rs b/crates/hir_def/src/generics.rs
index a056ab797..7c6cbff11 100644
--- a/crates/hir_def/src/generics.rs
+++ b/crates/hir_def/src/generics.rs
@@ -97,43 +97,43 @@ impl GenericParams {
         let generics = match def {
             GenericDefId::FunctionId(id) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::AdtId(AdtId::StructId(id)) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::AdtId(AdtId::EnumId(id)) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::AdtId(AdtId::UnionId(id)) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::TraitId(id) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::TypeAliasId(id) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
             GenericDefId::ImplId(id) => {
                 let id = id.lookup(db).id;
-                let tree = db.item_tree(id.file_id);
+                let tree = id.item_tree(db);
                 let item = &tree[id.value];
                 tree[item.generic_params].clone()
             }
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 90df3d929..8383780e0 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -401,7 +401,47 @@ impl<N: ItemTreeNode> fmt::Debug for FileItemTreeId<N> {
     }
 }
 
-pub type ItemTreeId<N> = InFile<FileItemTreeId<N>>;
+#[derive(Debug)]
+pub struct ItemTreeId<N: ItemTreeNode> {
+    file: HirFileId,
+    pub value: FileItemTreeId<N>,
+}
+
+impl<N: ItemTreeNode> ItemTreeId<N> {
+    pub fn new(file: HirFileId, idx: FileItemTreeId<N>) -> Self {
+        Self { file, value: idx }
+    }
+
+    pub fn file_id(self) -> HirFileId {
+        self.file
+    }
+
+    pub fn item_tree(self, db: &dyn DefDatabase) -> Arc<ItemTree> {
+        db.item_tree(self.file)
+    }
+}
+
+impl<N: ItemTreeNode> Copy for ItemTreeId<N> {}
+impl<N: ItemTreeNode> Clone for ItemTreeId<N> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<N: ItemTreeNode> PartialEq for ItemTreeId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.file == other.file && self.value == other.value
+    }
+}
+
+impl<N: ItemTreeNode> Eq for ItemTreeId<N> {}
+
+impl<N: ItemTreeNode> Hash for ItemTreeId<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.file.hash(state);
+        self.value.hash(state);
+    }
+}
 
 macro_rules! mod_items {
     ( $( $typ:ident in $fld:ident -> $ast:ty ),+ $(,)? ) => {
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index b5ae5a9e4..7ca4299b9 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -951,21 +951,21 @@ impl DefCollector<'_> {
         let mut diagnosed_extern_crates = FxHashSet::default();
         for directive in &self.unresolved_imports {
             if let ImportSource::ExternCrate(krate) = directive.import.source {
-                let item_tree = self.db.item_tree(krate.file_id);
+                let item_tree = krate.item_tree(self.db);
                 let extern_crate = &item_tree[krate.value];
 
                 diagnosed_extern_crates.insert(extern_crate.name.clone());
 
                 self.def_map.diagnostics.push(DefDiagnostic::unresolved_extern_crate(
                     directive.module_id,
-                    InFile::new(krate.file_id, extern_crate.ast_id),
+                    InFile::new(krate.file_id(), extern_crate.ast_id),
                 ));
             }
         }
 
         for directive in &self.unresolved_imports {
             if let ImportSource::Import(import) = &directive.import.source {
-                let item_tree = self.db.item_tree(import.file_id);
+                let item_tree = import.item_tree(self.db);
                 let import_data = &item_tree[import.value];
 
                 match (import_data.path.segments().first(), &import_data.path.kind) {
@@ -979,7 +979,7 @@ impl DefCollector<'_> {
 
                 self.def_map.diagnostics.push(DefDiagnostic::unresolved_import(
                     directive.module_id,
-                    InFile::new(import.file_id, import_data.ast_id),
+                    InFile::new(import.file_id(), import_data.ast_id),
                     import_data.index,
                 ));
             }
@@ -1055,7 +1055,7 @@ impl ModCollector<'_, '_> {
                             self.def_collector.db,
                             krate,
                             &self.item_tree,
-                            InFile::new(self.file_id, import_id),
+                            ItemTreeId::new(self.file_id, import_id),
                         ),
                         status: PartialResolvedImport::Unresolved,
                     })
@@ -1067,7 +1067,7 @@ impl ModCollector<'_, '_> {
                             self.def_collector.db,
                             krate,
                             &self.item_tree,
-                            InFile::new(self.file_id, import_id),
+                            ItemTreeId::new(self.file_id, import_id),
                         ),
                         status: PartialResolvedImport::Unresolved,
                     })
diff --git a/crates/hir_def/src/src.rs b/crates/hir_def/src/src.rs
index 751d4c052..24e57b469 100644
--- a/crates/hir_def/src/src.rs
+++ b/crates/hir_def/src/src.rs
@@ -14,12 +14,12 @@ impl<N: ItemTreeNode> HasSource for AssocItemLoc<N> {
     type Value = N::Source;
 
     fn source(&self, db: &dyn DefDatabase) -> InFile<N::Source> {
-        let tree = db.item_tree(self.id.file_id);
-        let ast_id_map = db.ast_id_map(self.id.file_id);
-        let root = db.parse_or_expand(self.id.file_id).unwrap();
+        let tree = self.id.item_tree(db);
+        let ast_id_map = db.ast_id_map(self.id.file_id());
+        let root = db.parse_or_expand(self.id.file_id()).unwrap();
         let node = &tree[self.id.value];
 
-        InFile::new(self.id.file_id, ast_id_map.get(node.ast_id()).to_node(&root))
+        InFile::new(self.id.file_id(), ast_id_map.get(node.ast_id()).to_node(&root))
     }
 }
 
@@ -27,12 +27,12 @@ impl<N: ItemTreeNode> HasSource for ItemLoc<N> {
     type Value = N::Source;
 
     fn source(&self, db: &dyn DefDatabase) -> InFile<N::Source> {
-        let tree = db.item_tree(self.id.file_id);
-        let ast_id_map = db.ast_id_map(self.id.file_id);
-        let root = db.parse_or_expand(self.id.file_id).unwrap();
+        let tree = self.id.item_tree(db);
+        let ast_id_map = db.ast_id_map(self.id.file_id());
+        let root = db.parse_or_expand(self.id.file_id()).unwrap();
         let node = &tree[self.id.value];
 
-        InFile::new(self.id.file_id, ast_id_map.get(node.ast_id()).to_node(&root))
+        InFile::new(self.id.file_id(), ast_id_map.get(node.ast_id()).to_node(&root))
     }
 }