diff --git a/check_diff/src/lib.rs b/check_diff/src/lib.rs
index 68cb2fb88ba..7df383afc87 100644
--- a/check_diff/src/lib.rs
+++ b/check_diff/src/lib.rs
@@ -18,6 +18,7 @@ pub enum CheckDiffError {
     IO(std::io::Error),
 }
 
+// will be used in future PRs, just added to make the compiler happy
 #[allow(dead_code)]
 pub struct CheckDiffRunners {
     feature_runner: RustfmtRunner,
@@ -30,6 +31,7 @@ pub struct RustfmtRunner {
 }
 
 impl RustfmtRunner {
+    // will be used in future PRs, just added to make the compiler happy
     #[allow(dead_code)]
     fn run(&self, args: &[&str]) -> io::Result<Output> {
         Command::new(&self.binary_path)
diff --git a/check_diff/src/main.rs b/check_diff/src/main.rs
index 8aac6647db9..58b5330a994 100644
--- a/check_diff/src/main.rs
+++ b/check_diff/src/main.rs
@@ -23,7 +23,7 @@ fn main() {
     let args = CliInputs::parse();
     let tmp_dir = Builder::new().tempdir_in("").unwrap();
     info!("Created tmp_dir {:?}", tmp_dir);
-    let _ = compile_rustfmt(
+    let runner = compile_rustfmt(
         tmp_dir.path(),
         args.remote_repo_url,
         args.feature_branch,