diff --git a/docs/src/subsystems/rust.md b/docs/src/subsystems/rust.md
index 83e32cc1..ce861604 100644
--- a/docs/src/subsystems/rust.md
+++ b/docs/src/subsystems/rust.md
@@ -140,7 +140,7 @@ in
   # ...
   packageOverrides = {
     # for crane builder
-    "^.*".set-toolchain.overrideRustToolchain = old: {cargo = toolchain};
+    "^.*".set-toolchain.overrideRustToolchain = old: {cargo = toolchain;};
     # for build-rust-package builder
     "^.*".set-toolchain.overrideRustToolchain = old: {
       cargo = toolchain;