diff --git a/src/vm.rs b/src/vm.rs
index f26abf2..3706173 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -219,31 +219,25 @@ pub(crate) struct Environment {
 }
 
 impl Environment {
-    pub fn get_global(&mut self, key: &Constant) -> Option<StackValue> {
+    fn get_global(&mut self, key: &Constant) -> Option<StackValue> {
         let value = self.globals.get_mut(key)?;
         Some(match &*value.borrow() {
             _ => StackValue::Value(value.borrow().clone()),
         })
     }
 
-    pub fn set_global(&mut self, key: Constant, value: StackValue) {
+    fn set_global(&mut self, key: Constant, value: StackValue) {
         if let Some(existing) = self.globals.get_mut(&key) {
             match value {
                 StackValue::Value(value) => {
                     *existing.borrow_mut() = value;
                 }
-                StackValue::Ref(reference) => {
-                    *existing = reference;
-                }
             }
         } else {
             match value {
                 StackValue::Value(value) => {
                     self.globals.insert(key, Rc::new(RefCell::new(value)));
                 }
-                StackValue::Ref(reference) => {
-                    self.globals.insert(key, reference);
-                }
             }
         }
     }
@@ -556,7 +550,6 @@ pub struct ClosureRunner {
 #[derive(Clone, Debug)]
 enum StackValue {
     Value(Value),
-    Ref(Rc<RefCell<Value>>),
 }
 
 impl ClosureRunner {
@@ -566,16 +559,12 @@ impl ClosureRunner {
                 StackValue::Value(value) => {
                     *stack_slot.borrow_mut() = value;
                 }
-                StackValue::Ref(ref_cell) => *stack_slot = ref_cell,
             }
         } else {
             match value {
                 StackValue::Value(value) => {
                     self.stack.insert(idx, Rc::new(RefCell::new(value)));
                 }
-                StackValue::Ref(reference) => {
-                    self.stack.insert(idx, reference);
-                }
             }
         }
     }