fix eval delete bindings

core/ast/src/scope_analyzer.rs

@@ -2284,10 +2284,10 @@ pub struct EvalDeclarationBindings {
     pub new_annex_b_function_names: Vec<IdentifierReference>,
 
     /// New function names created during the declaration of an eval ast node.
-    pub new_function_names: FxHashMap<Identifier, (IdentifierReference, bool)>,
+    pub new_function_names: FxHashMap<Identifier, IdentifierReference>,
 
-    /// New variable names created during the declaration of an eval ast node.
-    pub new_var_names: Vec<IdentifierReference>,
+    /// Variable names declared during the declaration of an eval ast node.
+    pub declared_var_names: Vec<IdentifierReference>,
 }
 
 /// `EvalDeclarationInstantiation ( body, varEnv, lexEnv, privateEnv, strict )`
@@ -2532,10 +2532,7 @@ pub(crate) fn eval_declaration_instantiation_scope(
                 let binding = var_env.set_mutable_binding(n).expect("must not fail");
                 result.new_function_names.insert(
                     name,
-                    (
-                        IdentifierReference::new(binding.locator(), !var_env.is_function(), true),
-                        true,
-                    ),
+                    IdentifierReference::new(binding.locator(), !var_env.is_function(), true),
                 );
             } else {
                 // 1. NOTE: The following invocation cannot return an abrupt completion because of the validation preceding step 14.
@@ -2544,10 +2541,7 @@ pub(crate) fn eval_declaration_instantiation_scope(
                 let binding = var_env.create_mutable_binding(n, !strict);
                 result.new_function_names.insert(
                     name,
-                    (
-                        IdentifierReference::new(binding, !var_env.is_function(), true),
-                        false,
-                    ),
+                    IdentifierReference::new(binding, !var_env.is_function(), true),
                 );
             }
         }
@@ -2568,13 +2562,17 @@ pub(crate) fn eval_declaration_instantiation_scope(
                 // 1. NOTE: The following invocation cannot return an abrupt completion because of the validation preceding step 14.
                 // 2. Perform ! varEnv.CreateMutableBinding(vn, true).
                 // 3. Perform ! varEnv.InitializeBinding(vn, undefined).
-                let binding = var_env.create_mutable_binding(name, true);
-                result.new_var_names.push(IdentifierReference::new(
-                    binding,
-                    !var_env.is_function(),
-                    true,
-                ));
+                drop(var_env.create_mutable_binding(name.clone(), true));
             }
+
+            let binding = var_env
+                .get_binding_reference(&name)
+                .expect("binding must exist");
+            result.declared_var_names.push(IdentifierReference::new(
+                binding.locator(),
+                !var_env.is_function(),
+                true,
+            ));
         }
     }
 

core/engine/src/bytecompiler/declarations.rs

@@ -838,24 +838,19 @@ impl ByteCompiler<'_> {
                 self.emit_get_function(&dst, index);
 
                 // i. Let bindingExists be ! varEnv.HasBinding(fn).
-                let (binding, binding_exists) = bindings
+                let binding = bindings
                     .new_function_names
                     .get(&name)
                     .expect("binding must exist");
 
                 // ii. If bindingExists is false, then
+                // 1. NOTE: The following invocation cannot return an abrupt completion because of the validation preceding step 14.
+                // 2. Perform ! varEnv.CreateMutableBinding(fn, true).
+                // 3. Perform ! varEnv.InitializeBinding(fn, fo).
                 // iii. Else,
-                if *binding_exists {
-                    // 1. Perform ! varEnv.SetMutableBinding(fn, fo, false).
-                    let index = self.insert_binding(binding.clone());
-                    self.emit_binding_access(BindingAccessOpcode::SetName, &index, &dst);
-                } else {
-                    // 1. NOTE: The following invocation cannot return an abrupt completion because of the validation preceding step 14.
-                    // 2. Perform ! varEnv.CreateMutableBinding(fn, true).
-                    // 3. Perform ! varEnv.InitializeBinding(fn, fo).
-                    let index = self.insert_binding(binding.clone());
-                    self.emit_binding_access(BindingAccessOpcode::DefInitVar, &index, &dst);
-                }
+                // 1. Perform ! varEnv.SetMutableBinding(fn, fo, false).
+                let index = self.insert_binding(binding.clone());
+                self.emit_binding_access(BindingAccessOpcode::DefInitVar, &index, &dst);
                 self.register_allocator.dealloc(dst);
             }
         }
@@ -872,15 +867,15 @@ impl ByteCompiler<'_> {
             }
         }
         // 18.b
-        for binding in bindings.new_var_names {
+        for binding in bindings.declared_var_names {
             // i. Let bindingExists be ! varEnv.HasBinding(vn).
             // ii. If bindingExists is false, then
             // 1. NOTE: The following invocation cannot return an abrupt completion because of the validation preceding step 14.
             // 2. Perform ! varEnv.CreateMutableBinding(vn, true).
             // 3. Perform ! varEnv.InitializeBinding(vn, undefined).
             let index = self.insert_binding(binding);
             self.emit_binding_access(
-                BindingAccessOpcode::DefInitVar,
+                BindingAccessOpcode::DefEvalVar,
                 &index,
                 &CallFrame::undefined_register(),
             );

core/engine/src/bytecompiler/mod.rs

@@ -449,6 +449,7 @@ pub(crate) enum BindingAccessOpcode {
     DeleteName,
     GetLocator,
     DefVar,
+    DefEvalVar,
 }
 
 /// Manages the source position scope, push on creation, pop on drop.
@@ -918,6 +919,9 @@ impl<'ctx> ByteCompiler<'ctx> {
                 }
                 BindingAccessOpcode::GetLocator => self.bytecode.emit_get_locator((*index).into()),
                 BindingAccessOpcode::DefVar => self.bytecode.emit_def_var((*index).into()),
+                BindingAccessOpcode::DefEvalVar => {
+                    self.bytecode.emit_def_eval_var((*index).into());
+                }
                 BindingAccessOpcode::PutLexicalValue => self
                     .bytecode
                     .emit_put_lexical_value(value.variable(), (*index).into()),
@@ -943,6 +947,9 @@ impl<'ctx> ByteCompiler<'ctx> {
                 }
                 BindingAccessOpcode::GetLocator => self.bytecode.emit_get_locator((*index).into()),
                 BindingAccessOpcode::DefVar => self.bytecode.emit_def_var((*index).into()),
+                BindingAccessOpcode::DefEvalVar => {
+                    self.bytecode.emit_def_eval_var((*index).into());
+                }
                 BindingAccessOpcode::PutLexicalValue => self
                     .bytecode
                     .emit_put_lexical_value(value.variable(), (*index).into()),
@@ -978,7 +985,9 @@ impl<'ctx> ByteCompiler<'ctx> {
                 | BindingAccessOpcode::GetNameAndLocator => {
                     self.bytecode.emit_move(value.variable(), (*index).into());
                 }
-                BindingAccessOpcode::GetLocator | BindingAccessOpcode::DefVar => {}
+                BindingAccessOpcode::GetLocator
+                | BindingAccessOpcode::DefVar
+                | BindingAccessOpcode::DefEvalVar => {}
                 BindingAccessOpcode::SetName
                 | BindingAccessOpcode::DefInitVar
                 | BindingAccessOpcode::PutLexicalValue

core/engine/src/environments/runtime/declarative/function.rs

@@ -1,11 +1,16 @@
 use boa_ast::scope::Scope;
 use boa_gc::{Finalize, GcRefCell, Trace, custom_trace};
+use std::cell::RefCell;
 
 use crate::{JsNativeError, JsObject, JsResult, JsValue, builtins::function::OrdinaryFunction};
 
 #[derive(Debug, Trace, Finalize)]
 pub(crate) struct FunctionEnvironment {
     bindings: GcRefCell<Vec<Option<JsValue>>>,
+    #[unsafe_ignore_trace]
+    deletable_bindings: RefCell<Vec<bool>>,
+    #[unsafe_ignore_trace]
+    deleted_bindings: RefCell<Vec<bool>>,
     slots: Box<FunctionSlots>,
 
     // Safety: Nothing in `Scope` needs tracing.
@@ -18,6 +23,8 @@ impl FunctionEnvironment {
     pub(crate) fn new(bindings_count: u32, slots: FunctionSlots, scope: Scope) -> Self {
         Self {
             bindings: GcRefCell::new(vec![None; bindings_count as usize]),
+            deletable_bindings: RefCell::new(vec![false; bindings_count as usize]),
+            deleted_bindings: RefCell::new(vec![false; bindings_count as usize]),
             slots: Box::new(slots),
             scope,
         }
@@ -53,9 +60,69 @@ impl FunctionEnvironment {
         self.bindings.borrow_mut()[index as usize] = Some(value);
     }
 
-    /// Gets the bindings of this poisonable environment.
-    pub(crate) const fn bindings(&self) -> &GcRefCell<Vec<Option<JsValue>>> {
-        &self.bindings
+    pub(crate) fn extend_from_compile(&self) {
+        let compile_bindings_len = self.scope.num_bindings() as usize;
+        let mut bindings = self.bindings.borrow_mut();
+        let bindings_len = bindings.len();
+
+        if compile_bindings_len <= bindings_len {
+            return;
+        }
+
+        bindings.resize(compile_bindings_len, None);
+
+        let mut deletable_bindings = self.deletable_bindings.borrow_mut();
+        deletable_bindings.resize(compile_bindings_len, false);
+        deletable_bindings[bindings_len..].fill(true);
+
+        self.deleted_bindings
+            .borrow_mut()
+            .resize(compile_bindings_len, false);
+    }
+
+    pub(crate) fn is_deleted_binding(&self, index: u32) -> bool {
+        self.deleted_bindings
+            .borrow()
+            .get(index as usize)
+            .copied()
+            .unwrap_or_default()
+    }
+
+    #[track_caller]
+    pub(crate) fn restore_deleted_binding(&self, index: u32) {
+        let index = index as usize;
+        if let Some(deleted) = self.deleted_bindings.borrow_mut().get_mut(index) {
+            *deleted = false;
+        }
+    }
+
+    #[track_caller]
+    pub(crate) fn delete_binding(&self, index: u32) -> bool {
+        let index = index as usize;
+
+        if self
+            .deleted_bindings
+            .borrow()
+            .get(index)
+            .copied()
+            .unwrap_or_default()
+        {
+            return true;
+        }
+
+        if !self
+            .deletable_bindings
+            .borrow()
+            .get(index)
+            .copied()
+            .unwrap_or_default()
+        {
+            return false;
+        }
+
+        self.bindings.borrow_mut()[index] = None;
+        self.deleted_bindings.borrow_mut()[index] = true;
+        true
     }
 
     /// `BindThisValue`

core/engine/src/environments/runtime/declarative/mod.rs

@@ -90,6 +90,21 @@ impl DeclarativeEnvironment {
         self.kind.set(index, value);
     }
 
+    #[track_caller]
+    pub(crate) fn delete_binding(&self, index: u32) -> bool {
+        self.kind.delete_binding(index)
+    }
+
+    #[track_caller]
+    pub(crate) fn is_deleted_binding(&self, index: u32) -> bool {
+        self.kind.is_deleted_binding(index)
+    }
+
+    #[track_caller]
+    pub(crate) fn restore_deleted_binding(&self, index: u32) {
+        self.kind.restore_deleted_binding(index);
+    }
+
     /// `GetThisBinding`
     ///
     /// Returns the `this` binding of this environment.
@@ -132,11 +147,7 @@ impl DeclarativeEnvironment {
     /// Extends the environment with the bindings from the compile time environment.
     pub(crate) fn extend_from_compile(&self) {
         if let Some(env) = self.kind().as_function() {
-            let compile_bindings_number = env.compile().num_bindings() as usize;
-            let mut bindings = env.bindings().borrow_mut();
-            if compile_bindings_number > bindings.len() {
-                bindings.resize(compile_bindings_number, None);
-            }
+            env.extend_from_compile();
         }
     }
 }
@@ -212,6 +223,29 @@ impl DeclarativeEnvironmentKind {
         }
     }
 
+    #[track_caller]
+    pub(crate) fn delete_binding(&self, index: u32) -> bool {
+        match self {
+            Self::Function(inner) => inner.delete_binding(index),
+            Self::Lexical(_) | Self::Global(_) | Self::Module(_) => false,
+        }
+    }
+
+    #[track_caller]
+    pub(crate) fn is_deleted_binding(&self, index: u32) -> bool {
+        match self {
+            Self::Function(inner) => inner.is_deleted_binding(index),
+            Self::Lexical(_) | Self::Global(_) | Self::Module(_) => false,
+        }
+    }
+
+    #[track_caller]
+    pub(crate) fn restore_deleted_binding(&self, index: u32) {
+        if let Self::Function(inner) = self {
+            inner.restore_deleted_binding(index);
+        }
+    }
+
     /// `GetThisBinding`
     ///
     /// Returns the `this` binding of this environment.