diff --git a/xtask/src/codegen/gen_assists_docs.rs b/xtask/src/codegen/gen_assists_docs.rs
index 6da5ca89e7f..31d606535fb 100644
--- a/xtask/src/codegen/gen_assists_docs.rs
+++ b/xtask/src/codegen/gen_assists_docs.rs
@@ -4,7 +4,7 @@ use std::{fs, path::Path};
 
 use crate::{
     codegen::{self, extract_comment_blocks_with_empty_lines, Mode},
-    project_root, Result,
+    project_root, rust_files, Result,
 };
 
 pub fn generate_assists_docs(mode: Mode) -> Result<()> {
@@ -46,12 +46,8 @@ fn reveal_hash_comments(text: &str) -> String {
 
 fn collect_assists() -> Result<Vec<Assist>> {
     let mut res = Vec::new();
-    for entry in fs::read_dir(project_root().join(codegen::ASSISTS_DIR))? {
-        let entry = entry?;
-        let path = entry.path();
-        if path.is_file() {
-            collect_file(&mut res, path.as_path())?;
-        }
+    for path in rust_files(&project_root().join(codegen::ASSISTS_DIR)) {
+        collect_file(&mut res, path.as_path())?;
     }
     res.sort_by(|lhs, rhs| lhs.id.cmp(&rhs.id));
     return Ok(res);
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index e1472e85d89..4f01f84fb41 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -17,6 +17,7 @@ use std::{
     path::{Path, PathBuf},
     process::{Command, Stdio},
 };
+use walkdir::{DirEntry, WalkDir};
 
 use crate::{
     codegen::Mode,
@@ -37,6 +38,21 @@ pub fn project_root() -> PathBuf {
     .to_path_buf()
 }
 
+pub fn rust_files(path: &Path) -> impl Iterator<Item = PathBuf> {
+    let iter = WalkDir::new(path);
+    return iter
+        .into_iter()
+        .filter_entry(|e| !is_hidden(e))
+        .map(|e| e.unwrap())
+        .filter(|e| !e.file_type().is_dir())
+        .map(|e| e.into_path())
+        .filter(|path| path.extension().map(|it| it == "rs").unwrap_or(false));
+
+    fn is_hidden(entry: &DirEntry) -> bool {
+        entry.file_name().to_str().map(|s| s.starts_with('.')).unwrap_or(false)
+    }
+}
+
 pub fn run_rustfmt(mode: Mode) -> Result<()> {
     let _dir = pushd(project_root());
     ensure_rustfmt()?;
diff --git a/xtask/tests/tidy-tests/main.rs b/xtask/tests/tidy-tests/main.rs
index 5ae86c87c94..80911a68e8b 100644
--- a/xtask/tests/tidy-tests/main.rs
+++ b/xtask/tests/tidy-tests/main.rs
@@ -5,13 +5,12 @@ use std::{
     path::{Path, PathBuf},
 };
 
-use walkdir::{DirEntry, WalkDir};
-use xtask::{not_bash::fs2, project_root};
+use xtask::{not_bash::fs2, project_root, rust_files};
 
 #[test]
 fn rust_files_are_tidy() {
     let mut tidy_docs = TidyDocs::default();
-    for path in rust_files() {
+    for path in rust_files(&project_root().join("crates")) {
         let text = fs2::read_to_string(&path).unwrap();
         check_todo(&path, &text);
         check_trailing_ws(&path, &text);
@@ -142,19 +141,3 @@ fn is_exclude_dir(p: &Path, dirs_to_exclude: &[&str]) -> bool {
 
     false
 }
-
-fn rust_files() -> impl Iterator<Item = PathBuf> {
-    let crates = project_root().join("crates");
-    let iter = WalkDir::new(crates);
-    return iter
-        .into_iter()
-        .filter_entry(|e| !is_hidden(e))
-        .map(|e| e.unwrap())
-        .filter(|e| !e.file_type().is_dir())
-        .map(|e| e.into_path())
-        .filter(|path| path.extension().map(|it| it == "rs").unwrap_or(false));
-
-    fn is_hidden(entry: &DirEntry) -> bool {
-        entry.file_name().to_str().map(|s| s.starts_with('.')).unwrap_or(false)
-    }
-}