Implement rough symbol interning infra

Author: Veykril

.typos.toml

@@ -14,6 +14,8 @@ extend-ignore-re = [
     "\\w*\\.{3,4}\\w*",
     '"flate2"',
     "raison d'être",
+    "inout",
+    "optin"
 ]
 
 [default.extend-words]

Cargo.lock

@@ -18,6 +18,7 @@ dashmap.workspace = true
 hashbrown.workspace = true
 rustc-hash.workspace = true
 triomphe.workspace = true
+sptr = "0.3.2"
 
 [lints]
-workspace = true
+workspace = true

crates/intern/Cargo.toml

@@ -20,6 +20,9 @@ type Guard<T> = dashmap::RwLockWriteGuard<
     HashMap<Arc<T>, SharedValue<()>, BuildHasherDefault<FxHasher>>,
 >;
 
+mod symbol;
+pub use self::symbol::{symbols, Symbol};
+
 pub struct Interned<T: Internable + ?Sized> {
     arc: Arc<T>,
 }