diff --git a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
index 405bb001b5d..c14339f6afe 100644
--- a/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir-ty/src/lib.rs
@@ -1,6 +1,7 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
 #[allow(unused)]
 macro_rules! eprintln {
diff --git a/src/tools/rust-analyzer/crates/hir/Cargo.toml b/src/tools/rust-analyzer/crates/hir/Cargo.toml
index f860ee94845..09ab60dd549 100644
--- a/src/tools/rust-analyzer/crates/hir/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/hir/Cargo.toml
@@ -30,3 +30,6 @@ profile.workspace = true
 stdx.workspace = true
 syntax.workspace = true
 tt.workspace = true
+
+[features]
+in-rust-tree = []
diff --git a/src/tools/rust-analyzer/crates/hir/src/lib.rs b/src/tools/rust-analyzer/crates/hir/src/lib.rs
index 17ffb9acbd1..93859611668 100644
--- a/src/tools/rust-analyzer/crates/hir/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/lib.rs
@@ -18,6 +18,7 @@
 //! <https://www.tedinski.com/2018/02/06/system-boundaries.html>.
 
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 #![recursion_limit = "512"]
 
 mod semantics;
diff --git a/src/tools/rust-analyzer/crates/ide/src/lib.rs b/src/tools/rust-analyzer/crates/ide/src/lib.rs
index aee03d218ad..2320c95b4a1 100644
--- a/src/tools/rust-analyzer/crates/ide/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/lib.rs
@@ -8,8 +8,9 @@
 //! in this crate.
 
 // For proving that RootDatabase is RefUnwindSafe.
-#![recursion_limit = "128"]
 #![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+#![recursion_limit = "128"]
 
 #[allow(unused)]
 macro_rules! eprintln {
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml b/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
index ee5df984b68..c85b3e53cda 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
@@ -97,6 +97,7 @@ in-rust-tree = [
     "syntax/in-rust-tree",
     "parser/in-rust-tree",
     "rustc-dependencies/in-rust-tree",
+    "hir/in-rust-tree",
     "hir-def/in-rust-tree",
     "hir-ty/in-rust-tree",
 ]