feat: lookup at downgrade time

works, but leaks memory

src/builtins/mod.rs

@@ -1,13 +1,18 @@
 use gc_arena::{Gc, Mutation};
 use hashbrown::HashMap;
 
-use crate::env::{IrEnv, VmEnv};
+use crate::env::VmEnv;
+use crate::ir::{DowngradeContext, Ir};
+use crate::ty::common::Const;
 use crate::ty::internal::{AttrSet, CoW, PrimOp, Value};
 use crate::vm::VM;
 
-pub fn ir_env<'gc>(mc: &Mutation<'gc>) -> Gc<'gc, IrEnv<'gc>> {
-    // TODO:
-    IrEnv::new(Gc::new(mc, HashMap::new()), mc)
+pub fn ir_env(ctx: &mut DowngradeContext) -> HashMap<usize, Ir> {
+    let mut map = HashMap::new();
+    map.insert(ctx.new_sym("true"), ctx.new_const(Const::Bool(true)).ir());
+    map.insert(ctx.new_sym("false"), ctx.new_const(Const::Bool(false)).ir());
+
+    map
 }
 
 pub fn vm_env<'gc>(vm: &VM, mc: &Mutation<'gc>) -> Gc<'gc, VmEnv<'gc>> {
@@ -78,15 +83,16 @@ pub fn vm_env<'gc>(vm: &VM, mc: &Mutation<'gc>) -> Gc<'gc, VmEnv<'gc>> {
         map.insert(vm.new_sym(primop.name), Value::PrimOp(primop));
     }
     let sym = vm.new_sym("builtins");
-    let attrs = CoW::new_cyclic(
-        |this| {
-            map.insert(sym, Value::AttrSet(this));
-            AttrSet::from_inner(map)
-        },
-        mc,
-    );
+    let mut attrs = CoW::new(AttrSet::new(map), mc);
+    unsafe {
+        attrs.make_cyclic(|attrs, this| {
+            let _ = attrs.push_attr(sym, Value::AttrSet(this));
+        }, mc);
+    }
     let builtins = Value::AttrSet(attrs);
 
     env_map.insert(sym, builtins);
-    VmEnv::new(Gc::new(mc, env_map), mc)
+    // TODO:
+    // VmEnv::new(Gc::new(mc, env_map), mc)
+    VmEnv::new(Vec::new(), mc)
 }