diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index 00aea8feab7de..a5ccc2e89819c 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -446,35 +446,52 @@ impl Step for RustAnalyzer {
 
     /// Runs `cargo test` for rust-analyzer
     fn run(self, builder: &Builder<'_>) {
-        let host = self.compilers.target();
+        let tool_result = builder.ensure(tool::RustAnalyzer::from_compilers(self.compilers));
+        let build_compiler = tool_result.build_compiler;
+        let target = self.compilers.target();
 
-        let workspace_path = "src/tools/rust-analyzer";
-        // until the whole RA test suite runs on `i686`, we only run
-        // `proc-macro-srv` tests
-        let crate_path = "src/tools/rust-analyzer/crates/proc-macro-srv";
         let mut cargo = tool::prepare_tool_cargo(
             builder,
-            self.compilers.build_compiler(),
+            build_compiler,
             Mode::ToolRustcPrivate,
-            host,
+            target,
             Kind::Test,
-            crate_path,
+            "src/tools/rust-analyzer",
             SourceType::InTree,
             &["in-rust-tree".to_owned()],
         );
         cargo.allow_features(tool::RustAnalyzer::ALLOW_FEATURES);
 
-        let dir = builder.src.join(workspace_path);
-        // needed by rust-analyzer to find its own text fixtures, cf.
-        // https://github.com/rust-analyzer/expect-test/issues/33
-        cargo.env("CARGO_WORKSPACE_DIR", &dir);
+        // N.B. it turns out _setting_ `CARGO_WORKSPACE_DIR` actually somehow breaks `expect-test`,
+        // even though previously we actually needed to set that hack to allow `expect-test` to
+        // correctly discover the r-a workspace instead of the outer r-l/r workspace.
 
-        // RA's test suite tries to write to the source directory, that can't
-        // work in Rust CI
+        // FIXME: RA's test suite tries to write to the source directory, that can't work in Rust CI
+        // without properly wiring up the writable test dir.
         cargo.env("SKIP_SLOW_TESTS", "1");
 
+        // NOTE: we need to skip `src/tools/rust-analyzer/xtask` as they seem to exercise rustup /
+        // stable rustfmt.
+        //
+        // NOTE: you can only skip a specific workspace package via `--exclude=...` if you *also*
+        // specify `--workspace`.
+        cargo.arg("--workspace");
+        cargo.arg("--exclude=xtask");
+
+        let mut skip_tests = vec![];
+
+        // Across all platforms
+        skip_tests.extend_from_slice(&[
+            // FIXME: this test wants to find a `rustc`. We need to provide it with a path to staged
+            // in-tree `rustc`, but setting `RUSTC` env var requires some reworking of bootstrap.
+            "tests::smoke_test_real_sysroot_cargo",
+        ]);
+
+        let skip_tests = skip_tests.iter().map(|name| format!("--skip={name}")).collect::<Vec<_>>();
+        let skip_tests = skip_tests.iter().map(|s| s.as_str()).collect::<Vec<_>>();
+
         cargo.add_rustc_lib_path(builder);
-        run_cargo_test(cargo, &[], &[], "rust-analyzer", host, builder);
+        run_cargo_test(cargo, skip_tests.as_slice(), &[], "rust-analyzer", target, builder);
     }
 
     fn metadata(&self) -> Option<StepMetadata> {
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index d0429387f824e..ac7a2ef52cd24 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -2112,6 +2112,7 @@ mod snapshot {
         [build] rustc 0 <host> -> Linkchecker 1 <host>
         [test] link-check <host>
         [test] tier-check <host>
+        [build] rustc 0 <host> -> rust-analyzer 1 <host>
         [test] rustc 0 <host> -> rust-analyzer 1 <host>
         [build] rustc 0 <host> -> RustdocTheme 1 <host>
         [test] rustdoc-theme 1 <host>
@@ -2296,6 +2297,7 @@ mod snapshot {
         [build] rustc 0 <host> -> Linkchecker 1 <host>
         [test] link-check <host>
         [test] tier-check <host>
+        [build] rustc 1 <host> -> rust-analyzer 2 <host>
         [test] rustc 1 <host> -> rust-analyzer 2 <host>
         [doc] rustc (book) <host>
         [test] rustc 1 <host> -> lint-docs 2 <host>
diff --git a/src/tools/rust-analyzer/crates/base-db/Cargo.toml b/src/tools/rust-analyzer/crates/base-db/Cargo.toml
index ea06fd9c48fc1..55dfcbc7e508a 100644
--- a/src/tools/rust-analyzer/crates/base-db/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/base-db/Cargo.toml
@@ -31,5 +31,9 @@ vfs.workspace = true
 span.workspace = true
 intern.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/base-db/src/lib.rs b/src/tools/rust-analyzer/crates/base-db/src/lib.rs
index 0e411bcfae60e..bd38f20f8d7f8 100644
--- a/src/tools/rust-analyzer/crates/base-db/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/base-db/src/lib.rs
@@ -1,5 +1,10 @@
 //! base_db defines basic database traits. The concrete DB is defined by ide.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 pub use salsa;
 pub use salsa_macros;
 
diff --git a/src/tools/rust-analyzer/crates/cfg/Cargo.toml b/src/tools/rust-analyzer/crates/cfg/Cargo.toml
index ba34966614536..d48df39343f3a 100644
--- a/src/tools/rust-analyzer/crates/cfg/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/cfg/Cargo.toml
@@ -33,5 +33,9 @@ derive_arbitrary = "1.4.1"
 syntax-bridge.workspace = true
 syntax.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/cfg/src/lib.rs b/src/tools/rust-analyzer/crates/cfg/src/lib.rs
index 906106ca5db0b..c722d7daa3da5 100644
--- a/src/tools/rust-analyzer/crates/cfg/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/cfg/src/lib.rs
@@ -1,5 +1,10 @@
 //! cfg defines conditional compiling options, `cfg` attribute parser and evaluator
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod cfg_expr;
 mod dnf;
 #[cfg(test)]
diff --git a/src/tools/rust-analyzer/crates/ide-completion/Cargo.toml b/src/tools/rust-analyzer/crates/ide-completion/Cargo.toml
index 9bad21fc8e90e..bb59a60d73fab 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/ide-completion/Cargo.toml
@@ -36,5 +36,9 @@ expect-test = "1.5.1"
 test-utils.workspace = true
 test-fixture.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
index a70a1138d2f42..7bed1594fecd4 100644
--- a/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-completion/src/lib.rs
@@ -1,5 +1,10 @@
 //! `completions` crate provides utilities for generating completions of user input.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod completions;
 mod config;
 mod context;
diff --git a/src/tools/rust-analyzer/crates/ide-db/Cargo.toml b/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
index e065adb0f0baa..cb8a6e8324524 100644
--- a/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/ide-db/Cargo.toml
@@ -52,5 +52,9 @@ expect-test = "1.5.1"
 test-utils.workspace = true
 test-fixture.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
index 44bccd86d8709..9875bf9cca31f 100644
--- a/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-db/src/lib.rs
@@ -2,6 +2,11 @@
 //!
 //! It is mainly a `HirDatabase` for semantic analysis, plus a `SymbolsDatabase`, for fuzzy search.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod apply_change;
 
 pub mod active_parameter;
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/Cargo.toml b/src/tools/rust-analyzer/crates/ide-diagnostics/Cargo.toml
index 6f1e66948f42c..ddf5999036d21 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/Cargo.toml
@@ -34,5 +34,9 @@ expect-test = "1.5.1"
 test-utils.workspace = true
 test-fixture.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
index a1db92641f5ee..00a6ecb742cab 100644
--- a/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-diagnostics/src/lib.rs
@@ -23,6 +23,11 @@
 //! There are also a couple of ad-hoc diagnostics implemented directly here, we
 //! don't yet have a great pattern for how to do them properly.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod handlers {
     pub(crate) mod await_outside_of_async;
     pub(crate) mod bad_rtn;
diff --git a/src/tools/rust-analyzer/crates/ide-ssr/Cargo.toml b/src/tools/rust-analyzer/crates/ide-ssr/Cargo.toml
index 0620bd26fefd1..1900b069e00f8 100644
--- a/src/tools/rust-analyzer/crates/ide-ssr/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/ide-ssr/Cargo.toml
@@ -30,5 +30,9 @@ triomphe.workspace = true
 test-utils.workspace = true
 test-fixture.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs b/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
index 43ad12c1f699a..b3b7ffa0b9d06 100644
--- a/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/ide-ssr/src/lib.rs
@@ -63,6 +63,11 @@
 // // foo($a, $b) ==>> ($a).foo($b)
 // ```
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod fragments;
 mod from_comment;
 mod matching;
diff --git a/src/tools/rust-analyzer/crates/load-cargo/src/lib.rs b/src/tools/rust-analyzer/crates/load-cargo/src/lib.rs
index ad838a6550eca..76e53d3d4f344 100644
--- a/src/tools/rust-analyzer/crates/load-cargo/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/load-cargo/src/lib.rs
@@ -2,6 +2,12 @@
 //! for incorporating changes.
 // Note, don't remove any public api from this. This API is consumed by external tools
 // to run rust-analyzer as a library.
+
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 use std::{any::Any, collections::hash_map::Entry, mem, path::Path, sync};
 
 use crossbeam_channel::{Receiver, unbounded};
diff --git a/src/tools/rust-analyzer/crates/parser/src/lib.rs b/src/tools/rust-analyzer/crates/parser/src/lib.rs
index 7963f00bb25ce..6f5ac1af6a73a 100644
--- a/src/tools/rust-analyzer/crates/parser/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/parser/src/lib.rs
@@ -24,6 +24,8 @@
 extern crate ra_ap_rustc_lexer as rustc_lexer;
 #[cfg(feature = "in-rust-tree")]
 extern crate rustc_lexer;
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
 
 mod event;
 mod grammar;
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
index dac8e09435762..bbe72e23642b0 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/Cargo.toml
@@ -29,5 +29,9 @@ span = { path = "../span", version = "0.0.0", default-features = false}
 
 intern.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs b/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
index 97919b85b5130..7131398c3e1cf 100644
--- a/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/proc-macro-api/src/lib.rs
@@ -5,6 +5,11 @@
 //! is used to provide basic infrastructure for communication between two
 //! processes: Client (RA itself), Server (the external program)
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 pub mod legacy_protocol;
 mod process;
 
diff --git a/src/tools/rust-analyzer/crates/project-model/Cargo.toml b/src/tools/rust-analyzer/crates/project-model/Cargo.toml
index 0dbb309a62a6c..7682bd4cf049a 100644
--- a/src/tools/rust-analyzer/crates/project-model/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/project-model/Cargo.toml
@@ -38,5 +38,9 @@ toolchain.workspace = true
 [dev-dependencies]
 expect-test = "1.5.1"
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/project-model/src/lib.rs b/src/tools/rust-analyzer/crates/project-model/src/lib.rs
index e36b904881513..4c97b3f426c37 100644
--- a/src/tools/rust-analyzer/crates/project-model/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/project-model/src/lib.rs
@@ -15,6 +15,11 @@
 //!   procedural macros).
 //! * Lowering of concrete model to a [`base_db::CrateGraph`]
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 pub mod project_json;
 pub mod toolchain_info {
     pub mod rustc_cfg;
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml b/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
index b301a7189b3c9..45c16a99c2262 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/Cargo.toml
@@ -96,12 +96,16 @@ syntax-bridge.workspace = true
 jemalloc = ["jemallocator", "profile/jemalloc"]
 force-always-assert = ["stdx/force-always-assert"]
 in-rust-tree = [
-  "syntax/in-rust-tree",
-  "parser/in-rust-tree",
-  "hir/in-rust-tree",
+  "cfg/in-rust-tree",
   "hir-def/in-rust-tree",
   "hir-ty/in-rust-tree",
+  "hir/in-rust-tree",
+  "ide-ssr/in-rust-tree",
+  "ide/in-rust-tree",
   "load-cargo/in-rust-tree",
+  "parser/in-rust-tree",
+  "proc-macro-api/in-rust-tree",
+  "syntax/in-rust-tree",
 ]
 
 [lints]
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs b/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
index 0dea285e97bd4..e26b7824ac719 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/src/lib.rs
@@ -9,6 +9,11 @@
 //! The `cli` submodule implements some batch-processing analysis, primarily as
 //! a debugging aid.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 /// Any toolchain less than this version will likely not work with rust-analyzer built from this revision.
 pub const MINIMUM_SUPPORTED_TOOLCHAIN_VERSION: semver::Version = semver::Version {
     major: 1,
diff --git a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
index 8a04bc7798f8b..2b629b0868b55 100644
--- a/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
+++ b/src/tools/rust-analyzer/crates/rust-analyzer/tests/slow-tests/main.rs
@@ -9,6 +9,10 @@
 //! be sure without a real client anyway.
 
 #![allow(clippy::disallowed_types)]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
 
 mod cli;
 mod ratoml;
diff --git a/src/tools/rust-analyzer/crates/span/Cargo.toml b/src/tools/rust-analyzer/crates/span/Cargo.toml
index 966962bab381b..cfb319d688b6a 100644
--- a/src/tools/rust-analyzer/crates/span/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/span/Cargo.toml
@@ -27,6 +27,7 @@ syntax.workspace = true
 
 [features]
 default = ["salsa"]
+in-rust-tree = []
 
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/span/src/lib.rs b/src/tools/rust-analyzer/crates/span/src/lib.rs
index ae9e038459e50..be26539bc049e 100644
--- a/src/tools/rust-analyzer/crates/span/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/span/src/lib.rs
@@ -1,4 +1,10 @@
 //! File and span related types.
+
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 use std::fmt::{self, Write};
 
 mod ast_id;
diff --git a/src/tools/rust-analyzer/crates/syntax-bridge/src/lib.rs b/src/tools/rust-analyzer/crates/syntax-bridge/src/lib.rs
index 4e525be3fe3c8..387eca6f57004 100644
--- a/src/tools/rust-analyzer/crates/syntax-bridge/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/syntax-bridge/src/lib.rs
@@ -1,5 +1,10 @@
 //! Conversions between [`SyntaxNode`] and [`tt::TokenTree`].
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 use std::{fmt, hash::Hash};
 
 use intern::Symbol;
diff --git a/src/tools/rust-analyzer/crates/syntax/Cargo.toml b/src/tools/rust-analyzer/crates/syntax/Cargo.toml
index 1ee93013e3e85..8909fb423c4de 100644
--- a/src/tools/rust-analyzer/crates/syntax/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/syntax/Cargo.toml
@@ -33,6 +33,7 @@ rustc_apfloat = "0.2.3"
 test-utils.workspace = true
 
 [features]
+default = []
 in-rust-tree = []
 
 [lints]
diff --git a/src/tools/rust-analyzer/crates/syntax/src/lib.rs b/src/tools/rust-analyzer/crates/syntax/src/lib.rs
index a3c19f71fbaa7..1f02f91889655 100644
--- a/src/tools/rust-analyzer/crates/syntax/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/syntax/src/lib.rs
@@ -19,6 +19,11 @@
 //! [RFC]: <https://github.com/rust-lang/rfcs/pull/2256>
 //! [Swift]: <https://github.com/apple/swift/blob/13d593df6f359d0cb2fc81cfaac273297c539455/lib/Syntax/README.md>
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 mod parsing;
 mod ptr;
 mod syntax_error;
diff --git a/src/tools/rust-analyzer/crates/test-fixture/Cargo.toml b/src/tools/rust-analyzer/crates/test-fixture/Cargo.toml
index 353d4c312dba8..7760ae7aa0450 100644
--- a/src/tools/rust-analyzer/crates/test-fixture/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/test-fixture/Cargo.toml
@@ -21,5 +21,9 @@ intern.workspace = true
 triomphe.workspace = true
 paths.workspace = true
 
+[features]
+default = []
+in-rust-tree = []
+
 [lints]
 workspace = true
diff --git a/src/tools/rust-analyzer/crates/test-fixture/src/lib.rs b/src/tools/rust-analyzer/crates/test-fixture/src/lib.rs
index 7574d12c0cfd0..9d66283a96941 100644
--- a/src/tools/rust-analyzer/crates/test-fixture/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/test-fixture/src/lib.rs
@@ -1,4 +1,10 @@
 //! A set of high-level utility fixture methods to use in tests.
+
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 use std::{any::TypeId, mem, str::FromStr, sync};
 
 use base_db::target::TargetData;
diff --git a/src/tools/rust-analyzer/crates/tt/Cargo.toml b/src/tools/rust-analyzer/crates/tt/Cargo.toml
index 82e7c24668fe6..3183b72a6629a 100644
--- a/src/tools/rust-analyzer/crates/tt/Cargo.toml
+++ b/src/tools/rust-analyzer/crates/tt/Cargo.toml
@@ -21,6 +21,7 @@ intern.workspace = true
 ra-ap-rustc_lexer.workspace = true
 
 [features]
+default = []
 in-rust-tree = []
 
 [lints]
diff --git a/src/tools/rust-analyzer/crates/tt/src/lib.rs b/src/tools/rust-analyzer/crates/tt/src/lib.rs
index 243a27b83b0df..63289b87f8343 100644
--- a/src/tools/rust-analyzer/crates/tt/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/tt/src/lib.rs
@@ -5,6 +5,9 @@
 
 #![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
 
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 #[cfg(not(feature = "in-rust-tree"))]
 extern crate ra_ap_rustc_lexer as rustc_lexer;
 #[cfg(feature = "in-rust-tree")]