1 files changed, 41 insertions, 21 deletions

diff --git a/crates/hir_def/src/data.rs b/crates/hir_def/src/data.rs
index 1a27f7bf2..0be868ba2 100644
--- a/crates/hir_def/src/data.rs
+++ b/crates/hir_def/src/data.rs
@@ -9,7 +9,7 @@ use crate::{
     attr::Attrs,
     body::Expander,
     db::DefDatabase,
-    item_tree::{AssocItem, FunctionQualifier, ItemTreeId, ModItem},
+    item_tree::{AssocItem, FunctionQualifier, ItemTreeId, ModItem, Param},
     type_ref::{TypeBound, TypeRef},
     visibility::RawVisibility,
     AssocContainerId, AssocItemId, ConstId, ConstLoc, FunctionId, FunctionLoc, HasModule, ImplId,
@@ -36,19 +36,38 @@ impl FunctionData {
     pub(crate) fn fn_data_query(db: &dyn DefDatabase, func: FunctionId) -> Arc<FunctionData> {
         let loc = func.lookup(db);
         let krate = loc.container.module(db).krate;
-        let item_tree = db.item_tree(loc.id.file_id);
+        let crate_graph = db.crate_graph();
+        let cfg_options = &crate_graph[krate].cfg_options;
+        let item_tree = loc.id.item_tree(db);
         let func = &item_tree[loc.id.value];
 
+        let enabled_params = func
+            .params
+            .clone()
+            .filter(|&param| item_tree.attrs(db, krate, param.into()).is_cfg_enabled(cfg_options));
+
+        // If last cfg-enabled param is a `...` param, it's a varargs function.
+        let is_varargs = enabled_params
+            .clone()
+            .next_back()
+            .map_or(false, |param| matches!(item_tree[param], Param::Varargs));
+
         Arc::new(FunctionData {
             name: func.name.clone(),
-            params: func.params.iter().map(|id| item_tree[*id].clone()).collect(),
+            params: enabled_params
+                .clone()
+                .filter_map(|id| match &item_tree[id] {
+                    Param::Normal(ty) => Some(item_tree[*ty].clone()),
+                    Param::Varargs => None,
+                })
+                .collect(),
             ret_type: item_tree[func.ret_type].clone(),
             attrs: item_tree.attrs(db, krate, ModItem::from(loc.id.value).into()),
             has_self_param: func.has_self_param,
             has_body: func.has_body,
             qualifier: func.qualifier.clone(),
             is_in_extern_block: func.is_in_extern_block,
-            is_varargs: func.is_varargs,
+            is_varargs,
             visibility: item_tree[func.visibility].clone(),
         })
     }
@@ -70,7 +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 {
@@ -96,23 +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,
         );
@@ -148,21 +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,
         );
@@ -183,7 +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 {
@@ -206,7 +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 {
@@ -232,22 +251,23 @@ fn collect_items(
         return Vec::new();
     }
 
-    let item_tree = db.item_tree(file_id);
-    let cfg_options = db.crate_graph()[module.krate].cfg_options.clone();
+    let item_tree = db.file_item_tree(file_id);
+    let crate_graph = db.crate_graph();
+    let cfg_options = &crate_graph[module.krate].cfg_options;
 
     let mut items = Vec::new();
     for item in assoc_items {
+        let attrs = item_tree.attrs(db, module.krate, ModItem::from(item).into());
+        if !attrs.is_cfg_enabled(cfg_options) {
+            continue;
+        }
+
         match item {
             AssocItem::Function(id) => {
                 let item = &item_tree[id];
-                let attrs = item_tree.attrs(db, module.krate, ModItem::from(id).into());
-                if !attrs.is_cfg_enabled(&cfg_options) {
-                    continue;
-                }
                 let def = FunctionLoc { container, id: ItemTreeId::new(file_id, id) }.intern(db);
                 items.push((item.name.clone(), def.into()));
             }
-            // FIXME: cfg?
             AssocItem::Const(id) => {
                 let item = &item_tree[id];
                 let name = match item.name.clone() {
@@ -272,7 +292,7 @@ fn collect_items(
                 if let Ok(res) = res {
                     if let Some((mark, mac)) = res.value {
                         let src: InFile<ast::MacroItems> = expander.to_source(mac);
-                        let item_tree = db.item_tree(src.file_id);
+                        let item_tree = db.file_item_tree(src.file_id);
                         let iter =
                             item_tree.top_level_items().iter().filter_map(ModItem::as_assoc_item);
                         items.extend(collect_items(