diff --git a/src/bytecode.rs b/src/bytecode.rs
index 2592755..17c311a 100644
--- a/src/bytecode.rs
+++ b/src/bytecode.rs
@@ -1,5 +1,3 @@
-use std::fmt::{Debug, Formatter, Result};
-
 use ecow::EcoString;
 
 use crate::ty::internal::Const;
diff --git a/src/ty/common.rs b/src/ty/common.rs
index 58913b1..34002db 100644
--- a/src/ty/common.rs
+++ b/src/ty/common.rs
@@ -1,6 +1,8 @@
 use std::fmt::{Display, Formatter, Result as FmtResult};
 use std::ops::Deref;
 
+use std::sync::LazyLock;
+
 use derive_more::Constructor;
 use ecow::EcoString;
 use regex::Regex;
@@ -39,9 +41,10 @@ impl Display for Symbol {
     }
 }
 
+static REGEX: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"^[a-zA-Z\_][a-zA-Z0-9\_\'\-]*$"#).unwrap());
 impl Symbol {
     fn normal(&self) -> bool {
-        !Regex::new(r#"^[a-zA-Z\_][a-zA-Z0-9\_\'\-]*$"#).unwrap().is_match(self)
+        !REGEX.is_match(self)
     }
 }