diff --git a/core/util.rs b/core/util.rs
index d3684750a..d87b2df97 100644
--- a/core/util.rs
+++ b/core/util.rs
@@ -1,7 +1,6 @@
-pub fn normalize_ident(ident: &str) -> String {
+pub fn normalize_ident(mut ident: &str) -> String {
     if ident.starts_with('"') && ident.ends_with('"') {
-        ident[1..ident.len() - 1].to_string().to_lowercase()
-    } else {
-        ident.to_lowercase()
+        ident = &ident[1..ident.len() - 1];
     }
+    ident.to_lowercase()
 }