1 files changed, 74 insertions, 31 deletions

diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index a35ac1024..28b7a20c5 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -36,6 +36,10 @@ use crate::{
     TraitLoc, TypeAliasLoc, UnionLoc,
 };
 
+const GLOB_RECURSION_LIMIT: usize = 100;
+const EXPANSION_DEPTH_LIMIT: usize = 128;
+const FIXED_POINT_LIMIT: usize = 8192;
+
 pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
     let crate_graph = db.crate_graph();
 
@@ -166,7 +170,7 @@ struct MacroDirective {
 #[derive(Clone, Debug, Eq, PartialEq)]
 struct DeriveDirective {
     module_id: LocalModuleId,
-    ast_id: AstIdWithPath<ast::ModuleItem>,
+    ast_id: AstIdWithPath<ast::Item>,
 }
 
 struct DefData<'a> {
@@ -217,7 +221,7 @@ impl DefCollector<'_> {
                 ReachedFixedPoint::Yes => break,
                 ReachedFixedPoint::No => i += 1,
             }
-            if i == 10000 {
+            if i == FIXED_POINT_LIMIT {
                 log::error!("name resolution is stuck");
                 break;
             }
@@ -306,7 +310,7 @@ impl DefCollector<'_> {
         if export {
             self.update(
                 self.def_map.root,
-                &[(name, PerNs::macros(macro_, Visibility::Public))],
+                &[(Some(name), PerNs::macros(macro_, Visibility::Public))],
                 Visibility::Public,
                 ImportType::Named,
             );
@@ -332,7 +336,7 @@ impl DefCollector<'_> {
     fn define_proc_macro(&mut self, name: Name, macro_: MacroDefId) {
         self.update(
             self.def_map.root,
-            &[(name, PerNs::macros(macro_, Visibility::Public))],
+            &[(Some(name), PerNs::macros(macro_, Visibility::Public))],
             Visibility::Public,
             ImportType::Named,
         );
@@ -530,7 +534,7 @@ impl DefCollector<'_> {
                             let name = variant_data.name.clone();
                             let variant = EnumVariantId { parent: e, local_id };
                             let res = PerNs::both(variant.into(), variant.into(), vis);
-                            (name, res)
+                            (Some(name), res)
                         })
                         .collect::<Vec<_>>();
                     self.update(module_id, &resolutions, vis, ImportType::Glob);
@@ -546,15 +550,15 @@ impl DefCollector<'_> {
             match import.path.segments.last() {
                 Some(last_segment) => {
                     let name = match &import.alias {
-                        Some(ImportAlias::Alias(name)) => name.clone(),
-                        Some(ImportAlias::Underscore) => last_segment.clone(), // FIXME rust-analyzer#2736
-                        None => last_segment.clone(),
+                        Some(ImportAlias::Alias(name)) => Some(name.clone()),
+                        Some(ImportAlias::Underscore) => None,
+                        None => Some(last_segment.clone()),
                     };
                     log::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
 
                     // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
                     if import.is_extern_crate && module_id == self.def_map.root {
-                        if let Some(def) = def.take_types() {
+                        if let (Some(def), Some(name)) = (def.take_types(), name.as_ref()) {
                             self.def_map.extern_prelude.insert(name.clone(), def);
                         }
                     }
@@ -569,36 +573,73 @@ impl DefCollector<'_> {
     fn update(
         &mut self,
         module_id: LocalModuleId,
-        resolutions: &[(Name, PerNs)],
+        resolutions: &[(Option<Name>, PerNs)],
         vis: Visibility,
         import_type: ImportType,
     ) {
+        self.db.check_canceled();
         self.update_recursive(module_id, resolutions, vis, import_type, 0)
     }
 
     fn update_recursive(
         &mut self,
         module_id: LocalModuleId,
-        resolutions: &[(Name, PerNs)],
+        resolutions: &[(Option<Name>, PerNs)],
         // All resolutions are imported with this visibility; the visibilies in
         // the `PerNs` values are ignored and overwritten
         vis: Visibility,
         import_type: ImportType,
         depth: usize,
     ) {
-        if depth > 100 {
+        if depth > GLOB_RECURSION_LIMIT {
             // prevent stack overflows (but this shouldn't be possible)
             panic!("infinite recursion in glob imports!");
         }
-        let scope = &mut self.def_map.modules[module_id].scope;
         let mut changed = false;
+
         for (name, res) in resolutions {
-            changed |= scope.push_res_with_import(
-                &mut self.from_glob_import,
-                (module_id, name.clone()),
-                res.with_visibility(vis),
-                import_type,
-            );
+            match name {
+                Some(name) => {
+                    let scope = &mut self.def_map.modules[module_id].scope;
+                    changed |= scope.push_res_with_import(
+                        &mut self.from_glob_import,
+                        (module_id, name.clone()),
+                        res.with_visibility(vis),
+                        import_type,
+                    );
+                }
+                None => {
+                    let tr = match res.take_types() {
+                        Some(ModuleDefId::TraitId(tr)) => tr,
+                        Some(other) => {
+                            log::debug!("non-trait `_` import of {:?}", other);
+                            continue;
+                        }
+                        None => continue,
+                    };
+                    let old_vis = self.def_map.modules[module_id].scope.unnamed_trait_vis(tr);
+                    let should_update = match old_vis {
+                        None => true,
+                        Some(old_vis) => {
+                            let max_vis = old_vis.max(vis, &self.def_map).unwrap_or_else(|| {
+                                panic!("`Tr as _` imports with unrelated visibilities {:?} and {:?} (trait {:?})", old_vis, vis, tr);
+                            });
+
+                            if max_vis == old_vis {
+                                false
+                            } else {
+                                mark::hit!(upgrade_underscore_visibility);
+                                true
+                            }
+                        }
+                    };
+
+                    if should_update {
+                        changed = true;
+                        self.def_map.modules[module_id].scope.push_unnamed_trait(tr, vis);
+                    }
+                }
+            }
         }
 
         if !changed {
@@ -609,14 +650,15 @@ impl DefCollector<'_> {
             .get(&module_id)
             .into_iter()
             .flat_map(|v| v.iter())
+            .filter(|(glob_importing_module, _)| {
+                // we know all resolutions have the same visibility (`vis`), so we
+                // just need to check that once
+                vis.is_visible_from_def_map(&self.def_map, *glob_importing_module)
+            })
             .cloned()
             .collect::<Vec<_>>();
+
         for (glob_importing_module, glob_import_vis) in glob_imports {
-            // we know all resolutions have the same visibility (`vis`), so we
-            // just need to check that once
-            if !vis.is_visible_from_def_map(&self.def_map, glob_importing_module) {
-                continue;
-            }
             self.update_recursive(
                 glob_importing_module,
                 resolutions,
@@ -677,10 +719,6 @@ impl DefCollector<'_> {
         self.unexpanded_attribute_macros = attribute_macros;
 
         for (module_id, macro_call_id, depth) in resolved {
-            if depth > 1024 {
-                log::debug!("Max macro expansion depth reached");
-                continue;
-            }
             self.collect_macro_expansion(module_id, macro_call_id, depth);
         }
 
@@ -717,6 +755,11 @@ impl DefCollector<'_> {
         macro_call_id: MacroCallId,
         depth: usize,
     ) {
+        if depth > EXPANSION_DEPTH_LIMIT {
+            mark::hit!(macro_expansion_overflow);
+            log::warn!("macro expansion is too deep");
+            return;
+        }
         let file_id: HirFileId = macro_call_id.as_file();
         let item_tree = self.db.item_tree(file_id);
         let mod_dir = self.mod_dirs[&module_id].clone();
@@ -943,7 +986,7 @@ impl ModCollector<'_, '_> {
                         .unwrap_or(Visibility::Public);
                     self.def_collector.update(
                         self.module_id,
-                        &[(name.clone(), PerNs::from_def(id, vis, has_constructor))],
+                        &[(Some(name.clone()), PerNs::from_def(id, vis, has_constructor))],
                         vis,
                         ImportType::Named,
                     )
@@ -1050,14 +1093,14 @@ impl ModCollector<'_, '_> {
         self.def_collector.def_map.modules[self.module_id].scope.define_def(def);
         self.def_collector.update(
             self.module_id,
-            &[(name, PerNs::from_def(def, vis, false))],
+            &[(Some(name), PerNs::from_def(def, vis, false))],
             vis,
             ImportType::Named,
         );
         res
     }
 
-    fn collect_derives(&mut self, attrs: &Attrs, ast_id: FileAstId<ast::ModuleItem>) {
+    fn collect_derives(&mut self, attrs: &Attrs, ast_id: FileAstId<ast::Item>) {
         for derive_subtree in attrs.by_key("derive").tt_values() {
             // for #[derive(Copy, Clone)], `derive_subtree` is the `(Copy, Clone)` subtree
             for tt in &derive_subtree.token_trees {