diff --git a/html5ever/src/tree_builder/generated.rs b/html5ever/src/tree_builder/generated.rs
index 08f66014..78e1182f 100644
--- a/html5ever/src/tree_builder/generated.rs
+++ b/html5ever/src/tree_builder/generated.rs
@@ -1,3 +1,5 @@
+// This code is @generated. See tests/codegen.rs for more information.
+
use super::*;
use crate::tendril::SliceExt;
use crate::tokenizer::states::{Plaintext, Rawtext, Rcdata, ScriptData};
diff --git a/html5ever/tests/codegen.rs b/html5ever/tests/codegen.rs
index 61168435..86c0d44c 100644
--- a/html5ever/tests/codegen.rs
+++ b/html5ever/tests/codegen.rs
@@ -34,7 +34,7 @@ fn generated_code_is_fresh() {
.stack_size(128 * 1024 * 1024)
.spawn(move || {
let generated = expand(&input);
- let formatted = reformat(&generated);
+ let formatted = reformat(&format!("{}{}", PREAMBLE, generated));
let current = fs::read_to_string(&output).unwrap_or_default();
if formatted == current {
@@ -70,6 +70,8 @@ fn reformat(code: &str) -> String {
String::from_utf8(output.stdout).unwrap()
}
+const PREAMBLE: &str = "// This code is @generated. See tests/codegen.rs for more information.\n\n";
+
/*
Implements the `match_token!()` macro for use by the HTML tree builder