diff --git a/tasks/ast_tools/src/output/javascript.rs b/tasks/ast_tools/src/output/javascript.rs
index 0a3411ba0457f..ab5e8e60314ef 100644
--- a/tasks/ast_tools/src/output/javascript.rs
+++ b/tasks/ast_tools/src/output/javascript.rs
@@ -3,22 +3,14 @@ use std::{
     process::{Command, Stdio},
 };
 
+use super::add_header;
+
 /// Format Javascript/Typescript code, and add header.
 pub fn print_javascript(code: &str, generator_path: &str) -> String {
-    let header = generate_header(generator_path);
-    let code = format!("{header}{code}");
+    let code = add_header(code, generator_path, "//");
     format(&code)
 }
 
-/// Creates a generated file warning + required information for a generated file.
-fn generate_header(generator_path: &str) -> String {
-    // TODO: Add generation date, AST source hash, etc here.
-    format!(
-        "// Auto-generated code, DO NOT EDIT DIRECTLY!\n\
-        // To edit this generated file you have to edit `{generator_path}`\n\n"
-    )
-}
-
 /// Format JS/TS code with dprint.
 fn format(source_text: &str) -> String {
     let mut dprint = Command::new("dprint")
diff --git a/tasks/ast_tools/src/output/mod.rs b/tasks/ast_tools/src/output/mod.rs
index d93f557d82f81..f61d2c70e81e3 100644
--- a/tasks/ast_tools/src/output/mod.rs
+++ b/tasks/ast_tools/src/output/mod.rs
@@ -21,6 +21,16 @@ pub fn output_path(krate: &str, path: &str) -> String {
     format!("{krate}/src/generated/{path}")
 }
 
+/// Add a generated file warning to top of file.
+fn add_header(code: &str, generator_path: &str, comment_start: &str) -> String {
+    // TODO: Add generation date, AST source hash, etc here.
+    format!(
+        "{comment_start} Auto-generated code, DO NOT EDIT DIRECTLY!\n\
+        {comment_start} To edit this generated file you have to edit `{generator_path}`\n\n\
+        {code}"
+    )
+}
+
 /// An output from codegen.
 ///
 /// Can be Rust, Javascript, or other formats.
diff --git a/tasks/ast_tools/src/output/rust.rs b/tasks/ast_tools/src/output/rust.rs
index 8776e0d1c06a6..f862f13676dfd 100644
--- a/tasks/ast_tools/src/output/rust.rs
+++ b/tasks/ast_tools/src/output/rust.rs
@@ -5,32 +5,17 @@ use std::{
 
 use lazy_static::lazy_static;
 use proc_macro2::TokenStream;
-use quote::quote;
 use regex::{Captures, Regex, Replacer};
 use syn::parse_file;
 
+use super::add_header;
+
 /// Format Rust code, and add header.
 pub fn print_rust(tokens: &TokenStream, generator_path: &str) -> String {
-    let header = generate_header(generator_path);
-    let tokens = quote! {
-        #header
-        #tokens
-    };
-
-    let result = prettyplease::unparse(&parse_file(tokens.to_string().as_str()).unwrap());
-    let result = COMMENT_REGEX.replace_all(&result, CommentReplacer).to_string();
-    rust_fmt(&result)
-}
-
-/// Creates a generated file warning + required information for a generated file.
-fn generate_header(generator_path: &str) -> TokenStream {
-    // TODO: Add generation date, AST source hash, etc here.
-    let edit_comment = format!("@ To edit this generated file you have to edit `{generator_path}`");
-    quote! {
-        //!@ Auto-generated code, DO NOT EDIT DIRECTLY!
-        #![doc = #edit_comment]
-        //!@@line_break
-    }
+    let code = prettyplease::unparse(&parse_file(tokens.to_string().as_str()).unwrap());
+    let code = COMMENT_REGEX.replace_all(&code, CommentReplacer).to_string();
+    let code = add_header(&code, generator_path, "//");
+    rust_fmt(&code)
 }
 
 fn rust_fmt(source_text: &str) -> String {
diff --git a/tasks/ast_tools/src/output/yaml.rs b/tasks/ast_tools/src/output/yaml.rs
index 529877b270d64..2518dc59774f8 100644
--- a/tasks/ast_tools/src/output/yaml.rs
+++ b/tasks/ast_tools/src/output/yaml.rs
@@ -1,14 +1,6 @@
+use super::add_header;
+
 /// Add header to YAML.
 pub fn print_yaml(code: &str, generator_path: &str) -> String {
-    let header = generate_header(generator_path);
-    format!("{header}{code}")
-}
-
-/// Creates a generated file warning + required information for a generated file.
-fn generate_header(generator_path: &str) -> String {
-    // TODO: Add generation date, AST source hash, etc here.
-    format!(
-        "# Auto-generated code, DO NOT EDIT DIRECTLY!\n\
-        # To edit this generated file you have to edit `{generator_path}`\n\n"
-    )
+    add_header(code, generator_path, "#")
 }