diff --git a/crates/formality-smir/src/lib.rs b/crates/formality-smir/src/lib.rs
index 5b40b7fd..17e928e8 100644
--- a/crates/formality-smir/src/lib.rs
+++ b/crates/formality-smir/src/lib.rs
@@ -1,5 +1,8 @@
 #![feature(rustc_private)]
 
+/// This import is needed, because `stable_mir` on its own doesn't have the `scoped_tls` rlib.
+extern crate rustc_driver;
+/// Access to the pre-0.1 stable_mir crate
 extern crate stable_mir;
 
 /// Trait used to convert from Stable MIR to Formality types.
diff --git a/rust-toolchain b/rust-toolchain
index bdbe494e..0a823a6e 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly"
+channel = "nightly-2023-10-08"
 components = [ "rustc-dev", "llvm-tools" ]
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 2a88e287..00000000
--- a/shell.nix
+++ /dev/null
@@ -1,5 +0,0 @@
-{ pkgs ? import <nixpkgs> {} }:
-  pkgs.mkShell {
-    # nativeBuildInputs is usually what you want -- tools you need to run
-    nativeBuildInputs = [ pkgs.racket ];
-}