Wip: pre-diffmachine merge fork

packages/core/src/arena.rs

@@ -1,14 +1,13 @@
 use std::{
     cell::{RefCell, UnsafeCell},
     collections::HashMap,
-    sync::Arc,
+    rc::Rc,
 };
 
 use generational_arena::Arena;
 
 use crate::innerlude::*;
 
-type Rc<T> = Arc<T>;
 #[derive(Clone)]
 pub struct ScopeArena(Rc<RefCell<ScopeArenaInner>>);