internal: remove potentially slow method

Author: matklad

crates/hir/src/lib.rs

@@ -430,13 +430,6 @@ impl Module {
             .collect()
     }
 
-    /// XXX: this O(N) rather O(1) method, avoid using it if you can.
-    pub fn visibility_of(self, db: &dyn HirDatabase, def: &ModuleDef) -> Option<Visibility> {
-        let def_map = self.id.def_map(db.upcast());
-        let module_data = &def_map[self.id.local_id];
-        module_data.scope.visibility_of((*def).into())
-    }
-
     pub fn diagnostics(self, db: &dyn HirDatabase, acc: &mut Vec<AnyDiagnostic>) {
         let _p = profile::span("Module::diagnostics").detail(|| {
             format!("{:?}", self.name(db).map_or("<unknown>".into(), |name| name.to_string()))

crates/hir_def/src/item_scope.rs

@@ -109,12 +109,6 @@ impl ItemScope {
         self.values.values().copied()
     }
 
-    pub fn visibility_of(&self, def: ModuleDefId) -> Option<Visibility> {
-        self.name_of(ItemInNs::Types(def))
-            .or_else(|| self.name_of(ItemInNs::Values(def)))
-            .map(|(_, v)| v)
-    }
-
     pub fn unnamed_consts(&self) -> impl Iterator<Item = ConstId> + '_ {
         self.unnamed_consts.iter().copied()
     }
@@ -138,6 +132,7 @@ impl ItemScope {
         }
     }
 
+    /// XXX: this is O(N) rather than O(1), try to not introduce new usages.
     pub(crate) fn name_of(&self, item: ItemInNs) -> Option<(&Name, Visibility)> {
         for (name, per_ns) in self.entries() {
             if let Some(vis) = item.match_with(per_ns) {

crates/ide/src/inlay_hints.rs

@@ -1,5 +1,5 @@
 use either::Either;
-use hir::{known, Callable, HirDisplay, Semantics};
+use hir::{known, Callable, HasVisibility, HirDisplay, Semantics};
 use ide_db::helpers::FamousDefs;
 use ide_db::RootDatabase;
 use stdx::to_lower_snake_case;
@@ -221,7 +221,11 @@ fn hint_iterator(
     let iter_mod = famous_defs.core_iter()?;
 
     // Assert that this struct comes from `core::iter`.
-    iter_mod.visibility_of(db, &strukt.into()).filter(|&vis| vis == hir::Visibility::Public)?;
+    if !(strukt.visibility(db) == hir::Visibility::Public
+        && strukt.module(db).path_to_root(db).contains(&iter_mod))
+    {
+        return None;
+    }
 
     if ty.impls_trait(db, iter_trait, &[]) {
         let assoc_type_item = iter_trait.items(db).into_iter().find_map(|item| match item {