3 files changed, 34 insertions, 32 deletions

diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index b27efcbe3..8af0a3176 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use ra_syntax::{SyntaxNode, TreeArc, SourceFile, ast};
+use ra_syntax::{SyntaxNode, TreeArc, SourceFile, SmolStr, ast};
 use ra_db::{SourceDatabase, salsa};
 
 use crate::{
@@ -16,7 +16,7 @@ use crate::{
     generics::{GenericParams, GenericDef},
     type_ref::TypeRef,
     traits::TraitData, Trait, ty::TraitRef,
-    lang_item::LangItems,
+    lang_item::{LangItems, LangItemTarget},
     ids
 };
 
@@ -104,6 +104,9 @@ pub trait DefDatabase: SourceDatabase {
 
     #[salsa::invoke(crate::lang_item::LangItems::lang_items_query)]
     fn lang_items(&self, krate: Crate) -> Arc<LangItems>;
+
+    #[salsa::invoke(crate::lang_item::LangItems::lang_item_query)]
+    fn lang_item(&self, start_crate: Crate, item: SmolStr) -> Option<LangItemTarget>;
 }
 
 #[salsa::query_group(HirDatabaseStorage)]
diff --git a/crates/ra_hir/src/lang_item.rs b/crates/ra_hir/src/lang_item.rs
index a25d419e7..5f3f91cba 100644
--- a/crates/ra_hir/src/lang_item.rs
+++ b/crates/ra_hir/src/lang_item.rs
@@ -40,7 +40,7 @@ impl LangItems {
         self.items.get(item)
     }
 
-    /// Salsa query. This will query a specific crate for lang items.
+    /// Salsa query. This will look for lang items in a specific crate.
     pub(crate) fn lang_items_query(db: &impl DefDatabase, krate: Crate) -> Arc<LangItems> {
         let mut lang_items = LangItems { items: FxHashMap::default() };
 
@@ -51,6 +51,29 @@ impl LangItems {
         Arc::new(lang_items)
     }
 
+    /// Salsa query. Look for a lang item, starting from the specified crate and recursively
+    /// traversing its dependencies.
+    pub(crate) fn lang_item_query(
+        db: &impl DefDatabase,
+        start_crate: Crate,
+        item: SmolStr,
+    ) -> Option<LangItemTarget> {
+        let lang_items = db.lang_items(start_crate);
+        let start_crate_target = lang_items.items.get(&item);
+        if let Some(target) = start_crate_target {
+            Some(*target)
+        } else {
+            for dep in start_crate.dependencies(db) {
+                let dep_crate = dep.krate;
+                let dep_target = db.lang_item(dep_crate, item.clone());
+                if dep_target.is_some() {
+                    return dep_target;
+                }
+            }
+            None
+        }
+    }
+
     fn collect_lang_items_recursive(&mut self, db: &impl DefDatabase, module: &Module) {
         // Look for impl targets
         let (impl_blocks, source_map) = db.impls_in_module_with_source_map(module.clone());
@@ -77,26 +100,3 @@ impl LangItems {
         }
     }
 }
-
-/// Look for a lang item, starting from the specified crate and recursively traversing its
-/// dependencies.
-pub(crate) fn lang_item_lookup(
-    db: &impl DefDatabase,
-    start_krate: Crate,
-    item: &str,
-) -> Option<LangItemTarget> {
-    let lang_items = db.lang_items(start_krate);
-    let start_krate_target = lang_items.items.get(item);
-    if start_krate_target.is_some() {
-        start_krate_target.map(|t| *t)
-    } else {
-        for dep in start_krate.dependencies(db) {
-            let dep_krate = dep.krate;
-            let dep_target = lang_item_lookup(db, dep_krate, item);
-            if dep_target.is_some() {
-                return dep_target;
-            }
-        }
-        None
-    }
-}
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index dca56a434..ea6e0dc0f 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -14,7 +14,6 @@ use crate::{
     resolve::Resolver,
     traits::TraitItem,
     generics::HasGenericParams,
-    lang_item::lang_item_lookup,
     ty::primitive::{UncertainIntTy, UncertainFloatTy}
 };
 use super::{TraitRef, Substs};
@@ -116,15 +115,15 @@ fn def_crate(db: &impl HirDatabase, cur_crate: Crate, ty: &Ty) -> Option<Crate>
     match ty {
         Ty::Apply(a_ty) => match a_ty.ctor {
             TypeCtor::Adt(def_id) => def_id.krate(db),
-            TypeCtor::Bool => lang_item_lookup(db, cur_crate, "bool")?.krate(db),
-            TypeCtor::Char => lang_item_lookup(db, cur_crate, "char")?.krate(db),
+            TypeCtor::Bool => db.lang_item(cur_crate, "bool".into())?.krate(db),
+            TypeCtor::Char => db.lang_item(cur_crate, "char".into())?.krate(db),
             TypeCtor::Float(UncertainFloatTy::Known(f)) => {
-                lang_item_lookup(db, cur_crate, f.ty_to_string())?.krate(db)
+                db.lang_item(cur_crate, f.ty_to_string().into())?.krate(db)
             }
             TypeCtor::Int(UncertainIntTy::Known(i)) => {
-                lang_item_lookup(db, cur_crate, i.ty_to_string())?.krate(db)
+                db.lang_item(cur_crate, i.ty_to_string().into())?.krate(db)
             }
-            TypeCtor::Str => lang_item_lookup(db, cur_crate, "str")?.krate(db),
+            TypeCtor::Str => db.lang_item(cur_crate, "str".into())?.krate(db),
             _ => None,
         },
         _ => None,