Describe the bug
$ cat a.js
function f(s) { return eval(s); };
console.log(f("eval('var x = 1;'); typeof x")); // should be: number
console.log(f("typeof x")); // should be: undefined
$ ./boa a.js
number
Uncaught Error: ReferenceError: x is not defined (a.js:3:14)
at <eval> (eval at :?:?)
at f (a.js:1:28)
at <main> (a.js:3:14)
Build environment (please complete the following information):
- OS: Linux
- Version: 352ec3d
- Target triple: aarch64-unknown-linux-gnu
- Rustc version: rustc 1.94.1 (e408947bf 2026-03-25)
Additional context
Potential fix that codex came up with - add a deep clone of scope to FunctionEnvironment
Details
diff --git a/core/ast/src/scope.rs b/core/ast/src/scope.rs
index c1728774..7c98df8a 100644
--- a/core/ast/src/scope.rs
+++ b/core/ast/src/scope.rs
@@ -110,6 +110,28 @@ pub(crate) struct Inner {
}
impl Scope {
+ /// Creates a deep clone of this scope chain, preserving indices, unique IDs and bindings,
+ /// but without sharing the underlying `Rc` storage.
+ #[must_use]
+ pub fn deep_clone(&self) -> Self {
+ fn clone_inner(scope: &Scope) -> Scope {
+ let outer = scope.inner.outer.as_ref().map(clone_inner);
+ Scope {
+ inner: Rc::new(Inner {
+ unique_id: scope.inner.unique_id,
+ outer,
+ index: Cell::new(scope.inner.index.get()),
+ bindings: RefCell::new(scope.inner.bindings.borrow().clone()),
+ function: scope.inner.function,
+ this_escaped: Cell::new(scope.inner.this_escaped.get()),
+ context: scope.inner.context.clone(),
+ }),
+ }
+ }
+
+ clone_inner(self)
+ }
+
/// Creates a new global scope.
#[must_use]
pub fn new_global() -> Self {
diff --git a/core/engine/src/environments/runtime/declarative/function.rs b/core/engine/src/environments/runtime/declarative/function.rs
index 9e198882..38aba0b6 100644
--- a/core/engine/src/environments/runtime/declarative/function.rs
+++ b/core/engine/src/environments/runtime/declarative/function.rs
@@ -19,7 +19,7 @@ impl FunctionEnvironment {
Self {
bindings: GcRefCell::new(vec![None; bindings_count as usize]),
slots: Box::new(slots),
- scope,
+ scope: scope.deep_clone(),
}
}Affects some ~15 tests in test262's test/staging/sm/
Describe the bug
Build environment (please complete the following information):
Additional context
Potential fix that codex came up with - add a deep clone of scope to FunctionEnvironment
Details
Affects some ~15 tests in test262's
test/staging/sm/