1 files changed, 12 insertions, 2 deletions

diff --git a/crates/ra_hir_ty/src/traits.rs b/crates/ra_hir_ty/src/traits.rs
index 9fef9240d..892fbd6d1 100644
--- a/crates/ra_hir_ty/src/traits.rs
+++ b/crates/ra_hir_ty/src/traits.rs
@@ -2,7 +2,9 @@
 use std::{panic, sync::Arc};
 
 use chalk_ir::cast::Cast;
-use hir_def::{expr::ExprId, DefWithBodyId, ImplId, TraitId, TypeAliasId};
+use hir_def::{
+    expr::ExprId, lang_item::LangItemTarget, DefWithBodyId, ImplId, TraitId, TypeAliasId,
+};
 use ra_db::{impl_intern_key, salsa, CrateId};
 use ra_prof::profile;
 use rustc_hash::FxHashSet;
@@ -14,7 +16,7 @@ use super::{Canonical, GenericPredicate, HirDisplay, ProjectionTy, TraitRef, Ty,
 use self::chalk::{from_chalk, Interner, ToChalk};
 
 pub(crate) mod chalk;
-pub(crate) mod builtin;
+mod builtin;
 
 // This controls the maximum size of types Chalk considers. If we set this too
 // high, we can run into slow edge cases; if we set it too low, Chalk won't
@@ -298,6 +300,14 @@ impl FnTrait {
             FnTrait::Fn => "fn",
         }
     }
+
+    pub fn get_id(&self, db: &dyn HirDatabase, krate: CrateId) -> Option<TraitId> {
+        let target = db.lang_item(krate, self.lang_item_name().into())?;
+        match target {
+            LangItemTarget::TraitId(t) => Some(t),
+            _ => None,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]