diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index 02fdbf0ebf..37d5347fe7 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -39,6 +39,9 @@ extern crate rustc_next_trait_solver;
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_next_trait_solver as rustc_next_trait_solver;
 
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_data_structures as ena;
+
 mod builder;
 mod chalk_db;
 mod chalk_ext;
diff --git a/crates/hir-ty/src/next_solver.rs b/crates/hir-ty/src/next_solver.rs
index 0225deebe4..99a501b053 100644
--- a/crates/hir-ty/src/next_solver.rs
+++ b/crates/hir-ty/src/next_solver.rs
@@ -40,5 +40,8 @@ pub type AliasTy<'db> = rustc_type_ir::AliasTy<DbInterner<'db>>;
 pub type PolyFnSig<'db> = Binder<'db, rustc_type_ir::FnSig<DbInterner<'db>>>;
 pub type TypingMode<'db> = rustc_type_ir::TypingMode<DbInterner<'db>>;
 
+#[cfg(feature = "in-rust-tree")]
+use rustc_data_structure::sorted_map::index_map as indexmap;
+
 pub type FxIndexMap<K, V> =
     indexmap::IndexMap<K, V, std::hash::BuildHasherDefault<rustc_hash::FxHasher>>;