make and use static interned storage in one fn

Author: Eh2406

src/cargo/util/interning.rs

@@ -13,7 +13,10 @@ use std::str;
 use std::sync::Mutex;
 use std::sync::OnceLock;
 
-static STRING_CACHE: OnceLock<Mutex<HashSet<&'static str>>> = OnceLock::new();
+fn interned_storage() -> std::sync::MutexGuard<'static, HashSet<&'static str>> {
+    static STRING_CACHE: OnceLock<Mutex<HashSet<&'static str>>> = OnceLock::new();
+    STRING_CACHE.get_or_init(Default::default).lock().unwrap()
+}
 
 #[derive(Clone, Copy)]
 pub struct InternedString {
@@ -60,8 +63,8 @@ impl Eq for InternedString {}
 
 impl InternedString {
     pub fn new(str: &str) -> InternedString {
-        let mut cache = STRING_CACHE.get_or_init(Default::default).lock().unwrap();
-        let s = cache.get(str).cloned().unwrap_or_else(|| {
+        let mut cache = interned_storage();
+        let s = cache.get(str).copied().unwrap_or_else(|| {
             let s = str.to_string().leak();
             cache.insert(s);
             s