diff --git a/rust-toolchain b/rust-toolchain
index a8a61591..925656db 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2022-01-01
+nightly-2022-01-19
diff --git a/user/src/bin/race_adder_arg.rs b/user/src/bin/race_adder_arg.rs
index 8d7758c4..4c386be2 100644
--- a/user/src/bin/race_adder_arg.rs
+++ b/user/src/bin/race_adder_arg.rs
@@ -29,7 +29,7 @@ unsafe fn f(count:usize) -> ! {
 
 #[no_mangle]
 pub fn main(argc: usize, argv: &[&str]) -> i32 {
-    let mut count = 0;
+    let count: usize;
     if argc == 1 {
         count = THREAD_COUNT;
     } else if argc == 2 {