diff --git a/Cargo.toml b/Cargo.toml
index 0ad5d75411ec3..f0db99020a02f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -73,6 +73,7 @@ doc_markdown = "allow"
 missing_const_for_fn = "allow"
 significant_drop_in_scrutinee = "warn"
 iter_on_single_items = "warn"
+unused_peekable = "warn"
 # cargo
 cargo = { level = "warn", priority = -1 }
 multiple_crate_versions = "allow"
diff --git a/crates/oxc_codegen/src/gen.rs b/crates/oxc_codegen/src/gen.rs
index 901c13deec597..f5c82000fac53 100644
--- a/crates/oxc_codegen/src/gen.rs
+++ b/crates/oxc_codegen/src/gen.rs
@@ -73,7 +73,7 @@ impl Gen for Directive<'_> {
         // See https://github.com/babel/babel/blob/v7.26.2/packages/babel-generator/src/generators/base.ts#L64
         let directive = self.directive.as_str();
 
-        let mut chars = directive.chars().peekable();
+        let mut chars = directive.chars();
         let mut quote = p.quote;
         while let Some(c) = chars.next() {
             match c {