Clean up ItemTree lowering now that it's 1:1

1 files changed, 26 insertions, 53 deletions

diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index a59a3dc37..798ab46dd 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -3,7 +3,6 @@
 use std::{collections::hash_map::Entry, mem, sync::Arc};
 
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, name::known, HirFileId};
-use smallvec::SmallVec;
 use syntax::{
     ast::{self, ModuleItemOwner},
     SyntaxNode, WalkEvent,
@@ -20,17 +19,6 @@ fn id<N: ItemTreeNode>(index: Idx<N>) -> FileItemTreeId<N> {
     FileItemTreeId { index, _p: PhantomData }
 }
 
-struct ModItems(SmallVec<[ModItem; 1]>);
-
-impl<T> From<T> for ModItems
-where
-    T: Into<ModItem>,
-{
-    fn from(t: T) -> Self {
-        ModItems(SmallVec::from_buf([t.into(); 1]))
-    }
-}
-
 pub(super) struct Ctx<'a> {
     db: &'a dyn DefDatabase,
     tree: ItemTree,
@@ -53,11 +41,8 @@ impl<'a> Ctx<'a> {
     }
 
     pub(super) fn lower_module_items(mut self, item_owner: &dyn ModuleItemOwner) -> ItemTree {
-        self.tree.top_level = item_owner
-            .items()
-            .flat_map(|item| self.lower_mod_item(&item, false))
-            .flat_map(|items| items.0)
-            .collect();
+        self.tree.top_level =
+            item_owner.items().flat_map(|item| self.lower_mod_item(&item, false)).collect();
         self.tree
     }
 
@@ -69,7 +54,6 @@ impl<'a> Ctx<'a> {
                 _ => None,
             })
             .flat_map(|item| self.lower_mod_item(&item, false))
-            .flat_map(|items| items.0)
             .collect();
 
         // Non-items need to have their inner items collected.
@@ -96,7 +80,7 @@ impl<'a> Ctx<'a> {
         self.tree.data_mut()
     }
 
-    fn lower_mod_item(&mut self, item: &ast::Item, inner: bool) -> Option<ModItems> {
+    fn lower_mod_item(&mut self, item: &ast::Item, inner: bool) -> Option<ModItem> {
         // Collect inner items for 1-to-1-lowered items.
         match item {
             ast::Item::Struct(_)
@@ -127,34 +111,28 @@ impl<'a> Ctx<'a> {
         };
 
         let attrs = RawAttrs::new(self.db, item, &self.hygiene);
-        let items = match item {
-            ast::Item::Struct(ast) => self.lower_struct(ast).map(Into::into),
-            ast::Item::Union(ast) => self.lower_union(ast).map(Into::into),
-            ast::Item::Enum(ast) => self.lower_enum(ast).map(Into::into),
-            ast::Item::Fn(ast) => self.lower_function(ast).map(Into::into),
-            ast::Item::TypeAlias(ast) => self.lower_type_alias(ast).map(Into::into),
-            ast::Item::Static(ast) => self.lower_static(ast).map(Into::into),
-            ast::Item::Const(ast) => Some(self.lower_const(ast).into()),
-            ast::Item::Module(ast) => self.lower_module(ast).map(Into::into),
-            ast::Item::Trait(ast) => self.lower_trait(ast).map(Into::into),
-            ast::Item::Impl(ast) => self.lower_impl(ast).map(Into::into),
-            ast::Item::Use(ast) => Some(ModItems(
-                self.lower_use(ast).into_iter().map(Into::into).collect::<SmallVec<_>>(),
-            )),
-            ast::Item::ExternCrate(ast) => self.lower_extern_crate(ast).map(Into::into),
-            ast::Item::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
-            ast::Item::MacroRules(ast) => self.lower_macro_rules(ast).map(Into::into),
-            ast::Item::MacroDef(ast) => self.lower_macro_def(ast).map(Into::into),
-            ast::Item::ExternBlock(ast) => Some(self.lower_extern_block(ast).into()),
+        let item: ModItem = match item {
+            ast::Item::Struct(ast) => self.lower_struct(ast)?.into(),
+            ast::Item::Union(ast) => self.lower_union(ast)?.into(),
+            ast::Item::Enum(ast) => self.lower_enum(ast)?.into(),
+            ast::Item::Fn(ast) => self.lower_function(ast)?.into(),
+            ast::Item::TypeAlias(ast) => self.lower_type_alias(ast)?.into(),
+            ast::Item::Static(ast) => self.lower_static(ast)?.into(),
+            ast::Item::Const(ast) => self.lower_const(ast).into(),
+            ast::Item::Module(ast) => self.lower_module(ast)?.into(),
+            ast::Item::Trait(ast) => self.lower_trait(ast)?.into(),
+            ast::Item::Impl(ast) => self.lower_impl(ast)?.into(),
+            ast::Item::Use(ast) => self.lower_use(ast)?.into(),
+            ast::Item::ExternCrate(ast) => self.lower_extern_crate(ast)?.into(),
+            ast::Item::MacroCall(ast) => self.lower_macro_call(ast)?.into(),
+            ast::Item::MacroRules(ast) => self.lower_macro_rules(ast)?.into(),
+            ast::Item::MacroDef(ast) => self.lower_macro_def(ast)?.into(),
+            ast::Item::ExternBlock(ast) => self.lower_extern_block(ast).into(),
         };
 
-        if !attrs.is_empty() {
-            for item in items.iter().flat_map(|items| &items.0) {
-                self.add_attrs((*item).into(), attrs.clone());
-            }
-        }
+        self.add_attrs(item.into(), attrs.clone());
 
-        items
+        Some(item)
     }
 
     fn add_attrs(&mut self, item: AttrOwner, attrs: RawAttrs) {
@@ -188,12 +166,10 @@ impl<'a> Ctx<'a> {
                             },
                             ast::Item(item) => {
                                 // FIXME: This triggers for macro calls in expression/pattern/type position
-                                let mod_items = self.lower_mod_item(&item, true);
+                                let mod_item = self.lower_mod_item(&item, true);
                                 let current_block = block_stack.last();
-                                if let (Some(mod_items), Some(block)) = (mod_items, current_block) {
-                                    if !mod_items.0.is_empty() {
-                                        self.data().inner_items.entry(*block).or_default().extend(mod_items.0.iter().copied());
-                                    }
+                                if let (Some(mod_item), Some(block)) = (mod_item, current_block) {
+                                        self.data().inner_items.entry(*block).or_default().push(mod_item);
                                 }
                             },
                             _ => {}
@@ -478,10 +454,7 @@ impl<'a> Ctx<'a> {
                 items: module
                     .item_list()
                     .map(|list| {
-                        list.items()
-                            .flat_map(|item| self.lower_mod_item(&item, false))
-                            .flat_map(|items| items.0)
-                            .collect()
+                        list.items().flat_map(|item| self.lower_mod_item(&item, false)).collect()
                     })
                     .unwrap_or_else(|| {
                         cov_mark::hit!(name_res_works_for_broken_modules);