From 5fc898906a08dfde0665498792110a0fbe1821dd Mon Sep 17 00:00:00 2001
From: pjh456 <147148383@qq.com>
Date: Sat, 10 Oct 2026 03:15:38 +0000
Subject: [PATCH] =?UTF-8?q?feat:=20=E7=A7=81=E6=9C=89=E5=90=8D=E6=96=B9?=
 =?UTF-8?q?=E6=B3=95=E5=90=8D=E5=8A=A0=E4=BA=95=E5=8F=B7=E5=89=8D=E7=BC=80?=
 =?UTF-8?q?=E5=8A=A0=E5=B5=8C=E5=A5=97=E7=B1=BB=E7=8B=AC=E7=AB=8B=E4=BD=9C?=
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---
 Cargo.lock                                  | 38 ++++-----
 Cargo.toml                                  |  2 +-
 crates/oxide_emit/src/class/emit.rs         | 50 ++++++++----
 crates/oxide_emit/src/class/method.rs       | 19 ++---
 crates/oxide_emit/src/compile_ctx.rs        |  7 ++
 crates/oxide_emit/src/emit_ctx.rs           |  8 +-
 crates/oxide_emit/src/function_body.rs      | 38 +++++++--
 crates/oxide_emit/src/shared/class_field.rs |  5 +-
 crates/oxide_emit/src/shared/class_key.rs   | 15 ++--
 crates/oxide_vm/tests/class_tests.rs        | 87 +++++++++++++++++++++
 10 files changed, 210 insertions(+), 59 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 85a92dd6..d9f19de0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1160,7 +1160,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_builtins"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "chrono",
  "fast-float",
@@ -1185,7 +1185,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_bytecode"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "num-bigint",
  "oxide_log",
@@ -1193,7 +1193,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cfg"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_emit",
@@ -1204,7 +1204,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cli"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "ansi_term",
  "bumpalo",
@@ -1226,7 +1226,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_code_cache"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "lru",
  "oxide_bytecode",
@@ -1235,7 +1235,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_compiler"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1255,7 +1255,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_dce"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1269,7 +1269,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_emit"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "num-bigint",
  "oxc_allocator",
@@ -1284,7 +1284,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_engine"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1296,7 +1296,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_ir"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_log",
@@ -1305,7 +1305,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_kernel"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1319,7 +1319,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_liveness"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1331,7 +1331,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_log"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "tracing",
  "tracing-appender",
@@ -1340,7 +1340,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_parser"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxc_allocator",
  "oxc_ast",
@@ -1355,7 +1355,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_regalloc"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1371,7 +1371,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_runtime_api"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "num-bigint",
  "num-traits",
@@ -1384,7 +1384,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_test262"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1402,7 +1402,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_types"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1415,7 +1415,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_vm"
-version = "0.13.26"
+version = "0.13.27"
 dependencies = [
  "bumpalo",
  "chrono",
diff --git a/Cargo.toml b/Cargo.toml
index f9a58f68..6c11185b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.13.26"
+version = "0.13.27"
 edition = "2021"
 license = "MIT"
 rust-version = "1.80"
diff --git a/crates/oxide_emit/src/class/emit.rs b/crates/oxide_emit/src/class/emit.rs
index 9d983176..d8305f21 100644
--- a/crates/oxide_emit/src/class/emit.rs
+++ b/crates/oxide_emit/src/class/emit.rs
@@ -147,12 +147,8 @@ impl Emitter {
         let saved_private_names = ctx.scopes.private_name_map.clone();
         let saved_private_kinds = ctx.scopes.private_element_kinds.clone();
         let saved_brand_id = ctx.scopes.private_brand_id;
+        let saved_brand_chain = ctx.brand_chain.clone();
         ctx.in_derived_constructor = is_derived;
-        ctx.scopes.private_name_map = private_names.iter().map(|(n, id, _, _)| (n.clone(), *id)).collect();
-        ctx.scopes.private_element_kinds = private_names
-            .iter()
-            .map(|(n, _, kind, is_static)| (n.clone(), *kind, *is_static))
-            .collect();
 
         // 类 brand：有私有元素时分配 brand 私有名 id，并创建 brand 对象（= 类原型）。
         // 构造器把 brand 槽写入实例 own；私有方法/访问器/静态字段访问（GET/SET）据
@@ -166,6 +162,19 @@ impl Emitter {
         };
         ctx.scopes.private_brand_id = private_brand_id;
 
+        // 私有名环境是词法环境链：内类条目遮蔽外类同名条目，外类其余名字保持
+        // 可解析（内类方法体可访问外类声明的私有名）。
+        let mut stacked_names = saved_private_names.clone();
+        let mut stacked_kinds = saved_private_kinds.clone();
+        for (n, id, kind, is_static) in &private_names {
+            stacked_names.retain(|(en, _)| en != n);
+            stacked_kinds.retain(|(en, _, _, _)| en != n);
+            stacked_names.push((n.clone(), *id));
+            stacked_kinds.push((n.clone(), *kind, *is_static, private_brand_id.unwrap_or(0)));
+        }
+        ctx.scopes.private_name_map = stacked_names;
+        ctx.scopes.private_element_kinds = stacked_kinds;
+
         // 实例公有字段 computed key 求值于构造器帧外，须类定义期存入数组。构造器以
         // upvalue 捕获该数组：父作用域登记 `@@field_keys`（索引经共享计数器追加，
         // 与块级遮蔽绑定的追加索引不碰撞）。
@@ -181,9 +190,12 @@ impl Emitter {
             None
         };
         // 类 brand 对象（= proto）由类定义期 MAKE_CELL 写入，构造器经 upvalue 捕获。
-        let brand_cell: Option<u8> = private_brand_id.map(|_| {
+        // 捕获名按本类 brand id 编号：嵌套类各自登记 brand，内类方法体沿 brand 链
+        // 保持外类 brand 条目可见，跨类 brand 检查据此定位声明类的 brand 对象。
+        let brand_cell: Option<u8> = private_brand_id.map(|bid| {
             let cell_idx = ctx.alloc_cell_idx();
-            ctx.captured_bindings.insert("@@class_brand".to_string(), cell_idx);
+            ctx.captured_bindings.insert(format!("@@class_brand_{bid}"), cell_idx);
+            ctx.brand_chain.push((bid, cell_idx, None));
             cell_idx
         });
         // 字段值表达式运行于构造器帧：其自由变量须纳入构造器 upvalue 捕获。
@@ -194,13 +206,15 @@ impl Emitter {
                 _ => None,
             })
             .collect();
-        let mut extra_upvalue_names: Vec<(&str, u8)> =
-            field_key_cell.map(|c| ("@@field_keys", c)).into_iter().collect();
-        if let Some(c) = brand_cell {
-            extra_upvalue_names.push(("@@class_brand", c));
+        let mut extra_upvalue_names: Vec<(String, u8)> = Vec::new();
+        if let Some(c) = field_key_cell {
+            extra_upvalue_names.push(("@@field_keys".to_string(), c));
+        }
+        if let (Some(c), Some(bid)) = (brand_cell, private_brand_id) {
+            extra_upvalue_names.push((format!("@@class_brand_{bid}"), c));
         }
         if let (Some(name), Some(c)) = (ctor_name.as_deref(), class_self_cell) {
-            extra_upvalue_names.push((name, c));
+            extra_upvalue_names.push((name.to_string(), c));
         }
 
         let emit_instance_fields = |compiler: &Emitter, field_ctx: &mut CompileCtx| -> Result<(), String> {
@@ -210,10 +224,11 @@ impl Emitter {
                     return Err("class brand cell missing".into());
                 }
                 let brand_reg = field_ctx.alloc_reg();
+                let brand_name = format!("@@class_brand_{bid}");
                 let uv_idx = field_ctx
                     .current_upvalue_captures
                     .iter()
-                    .position(|u| u.name == "@@class_brand")
+                    .position(|u| u.name == brand_name)
                     .ok_or("class brand upvalue missing")? as u16;
                 field_ctx.inst(Inst::new(
                     OpCode::LOAD_UPVALUE,
@@ -299,9 +314,13 @@ impl Emitter {
                 // 字段初始化直接重发：构造器 upvalue/内置槽引用须与首轮编译产物对齐。
                 let mut field_ctx = CompileCtx::new();
                 // 字段表达式运行于构造器帧，构造器恒 strict，字段 ctx 同步置位。
+                // 私有名环境按堆叠口径整表继承（字段初始化器内的嵌套类需要外类
+                // 私有名与 brand 链保持可解析）。
                 field_ctx.is_strict = true;
-                field_ctx.scopes.private_name_map =
-                    private_names.iter().map(|(n, id, _, _)| (n.clone(), *id)).collect();
+                field_ctx.scopes.private_name_map = ctx.scopes.private_name_map.clone();
+                field_ctx.scopes.private_element_kinds = ctx.scopes.private_element_kinds.clone();
+                field_ctx.scopes.private_brand_id = ctx.scopes.private_brand_id;
+                field_ctx.brand_chain = ctx.brand_chain.clone();
                 field_ctx.scopes.builtin_reg_map = module.builtin_reg_map.clone();
                 field_ctx.current_upvalue_captures = module.upvalue_captures.clone();
                 field_ctx.field_keys_uv = module
@@ -443,6 +462,7 @@ impl Emitter {
         ctx.scopes.private_name_map = saved_private_names;
         ctx.scopes.private_element_kinds = saved_private_kinds;
         ctx.scopes.private_brand_id = saved_brand_id;
+        ctx.brand_chain = saved_brand_chain;
         // 类编译结束恢复外层 strict 标志：类在 sloppy 上下文时不得泄漏 strict 到类后代码。
         ctx.is_strict = saved_strict;
         Ok(ctor_reg)
diff --git a/crates/oxide_emit/src/class/method.rs b/crates/oxide_emit/src/class/method.rs
index 991db92a..7eab2fd0 100644
--- a/crates/oxide_emit/src/class/method.rs
+++ b/crates/oxide_emit/src/class/method.rs
@@ -109,16 +109,17 @@ impl Emitter {
         let saved_static = ctx.in_static_method;
         ctx.in_instance_method = !method.r#static;
         ctx.in_static_method = method.r#static;
-        // 私有方法/访问器访问需对接收者做 brand 检查：方法函数捕获类 brand 对象
-        // （@@class_brand upvalue，值 = 类原型）。
-        let mut extra_uv: Vec<(&str, u8)> = ctx
-            .captured_bindings
-            .get("@@class_brand")
-            .map(|c| ("@@class_brand", *c))
-            .into_iter()
-            .collect();
+        // 私有方法/访问器访问需对接收者做 brand 检查：方法函数捕获本类 brand 对象
+        // （@@class_brand_<id> upvalue，值 = 类原型）。
+        let mut extra_uv: Vec<(String, u8)> = Vec::new();
+        if let Some(bid) = ctx.scopes.private_brand_id {
+            let brand_name = format!("@@class_brand_{bid}");
+            if let Some(&cell_idx) = ctx.captured_bindings.get(&brand_name) {
+                extra_uv.push((brand_name, cell_idx));
+            }
+        }
         if let (Some((name, _)), Some(c)) = (self_binding.first(), class_self_cell) {
-            extra_uv.push((name, c));
+            extra_uv.push(((*name).to_string(), c));
         }
         let method_value = method.value.as_ref();
         // 生成器/异步/异步生成器方法与普通方法统一走带标志入口：`*m` 置 is_generator，
diff --git a/crates/oxide_emit/src/compile_ctx.rs b/crates/oxide_emit/src/compile_ctx.rs
index ec286fe4..dce7ce0e 100644
--- a/crates/oxide_emit/src/compile_ctx.rs
+++ b/crates/oxide_emit/src/compile_ctx.rs
@@ -74,6 +74,12 @@ pub struct CompileCtx {
     /// 类定义期全部 computed key 数组寄存器（方法/静态字段阶段按 slot 读取）。
     pub(crate) class_keys_reg: Option<u32>,
     pub(crate) current_upvalue_captures: Vec<UpvalueCapture>,
+    /// 嵌套类私有 brand 链：每类一条 `(brand_id, cell_idx, parent_uv_idx)`，
+    /// 描述本帧如何到达该类的 brand cell——`parent_uv_idx` 为 None 时 cell 在
+    /// 本帧 own cell 表（cell_idx），为 Some(k) 时经本帧第 k 个 upvalue 可达。
+    /// 子函数体编译时按父链逐条追加为链式 upvalue 捕获，使内类方法能对
+    /// 外类声明的私有名做跨类 brand 检查。
+    pub(crate) brand_chain: Vec<(u32, u8, Option<u8>)>,
     /// 本函数作用域声明的绑定名（参数 + 变量/函数声明，AST 收集，emit 前确定）。
     pub(crate) own_bindings: HashSet<String>,
     /// 本函数形参名集（含解构形参叶子与 rest，编译入口收集）：块级函数名与
@@ -283,6 +289,7 @@ impl CompileCtx {
             field_keys_uv: None,
             class_keys_reg: None,
             current_upvalue_captures: Vec::new(),
+            brand_chain: Vec::new(),
             own_bindings: HashSet::new(),
             param_names: HashSet::new(),
             param_tdz_names: HashSet::new(),
diff --git a/crates/oxide_emit/src/emit_ctx.rs b/crates/oxide_emit/src/emit_ctx.rs
index 0394a787..318a3e29 100644
--- a/crates/oxide_emit/src/emit_ctx.rs
+++ b/crates/oxide_emit/src/emit_ctx.rs
@@ -148,9 +148,11 @@ pub(crate) struct ScopeCtx {
     pub(crate) symbols: SymbolTable,
     pub(crate) builtin_reg_map: Vec<(String, u32)>,
     pub(crate) private_name_map: Vec<(String, u32)>,
-    /// 私有元素类型（name, kind，static 标志）。kind=None 表示字段；
-    /// instance 字段的私有访问走 PrivateFieldFind 原型链查找，不加 brand 检查。
-    pub(crate) private_element_kinds: Vec<(String, Option<MethodDefinitionKind>, bool)>,
+    /// 私有元素类型（name, kind，static 标志，声明类 brand id）。kind=None 表示
+    /// 字段；instance 字段的私有访问走 PrivateFieldFind 原型链查找，不加 brand
+    /// 检查。brand_id 是声明该私有名的类的 brand id：跨类访问时 brand 检查须
+    /// 定位声明类（而非访问发生处类）的 brand 对象。
+    pub(crate) private_element_kinds: Vec<(String, Option<MethodDefinitionKind>, bool, u32)>,
     /// 当前类的私有 brand 私有名 id：私有方法/访问器访问时对实例做 brand 检查。
     pub(crate) private_brand_id: Option<u32>,
     pub(crate) next_private_name_id: u32,
diff --git a/crates/oxide_emit/src/function_body.rs b/crates/oxide_emit/src/function_body.rs
index 0b44c272..f802f391 100644
--- a/crates/oxide_emit/src/function_body.rs
+++ b/crates/oxide_emit/src/function_body.rs
@@ -280,7 +280,7 @@ impl Emitter {
         &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
         is_expression_body: bool, extra_bindings: &[(&str, u32)], body_context: FunctionBodyContext,
         emit_fields: Option<E>, fields_after_super: bool, extra_capture_exprs: &[&'a Expression<'a>],
-        extra_upvalue_names: &[(&str, u8)], own_strict: bool, name: Option<&str>,
+        extra_upvalue_names: &[(String, u8)], own_strict: bool, name: Option<&str>,
     ) -> Result<IRFunction, String>
     where
         E: FnMut(&Emitter, &mut CompileCtx) -> Result<(), String>,
@@ -308,7 +308,7 @@ impl Emitter {
         &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
         is_expression_body: bool, extra_bindings: &[(&str, u32)], body_context: FunctionBodyContext,
         mut emit_fields: Option<E>, fields_after_super: bool, extra_capture_exprs: &[&'a Expression<'a>],
-        extra_upvalue_names: &[(&str, u8)], is_generator: bool, is_async: bool, own_strict: bool, name: Option<&str>,
+        extra_upvalue_names: &[(String, u8)], is_generator: bool, is_async: bool, own_strict: bool, name: Option<&str>,
     ) -> Result<IRFunction, String>
     where
         E: FnMut(&Emitter, &mut CompileCtx) -> Result<(), String>,
@@ -655,7 +655,7 @@ impl Emitter {
     fn emit_params_prologue<'a>(
         &self, param_specs: &[ParamSpec<'a>], body_stmts: &[Statement<'a>], parent_ctx: &CompileCtx,
         ctx: &mut CompileCtx, body_context: FunctionBodyContext, extra_capture_exprs: &[&'a Expression<'a>],
-        extra_upvalue_names: &[(&str, u8)], name: Option<&str>,
+        extra_upvalue_names: &[(String, u8)], name: Option<&str>,
     ) -> Result<u32, String> {
         ctx.push_scope_with_kind(ScopeKind::FunctionScope);
         let param_base = ctx.next_reg;
@@ -852,15 +852,43 @@ impl Emitter {
                 .collect();
             // 类字段 computed key 数组等合成捕获：直接追加 upvalue（cell_idx 由父分配）。
             for (name, cell_idx) in extra_upvalue_names {
-                if !ctx.own_bindings.contains(*name) && !ctx.current_upvalue_captures.iter().any(|u| u.name == *name) {
+                if !ctx.own_bindings.contains(name) && !ctx.current_upvalue_captures.iter().any(|u| u.name == *name) {
                     ctx.current_upvalue_captures.push(UpvalueCapture {
-                        name: (*name).to_string(),
+                        name: name.clone(),
                         enclosing_reg: 0,
                         cell_idx: *cell_idx,
                         parent_uv_idx: None,
                     });
                 }
             }
+            // 私有 brand 链随函数体继承：父帧每条 brand 链条目按同形态追加为
+            // upvalue 捕获（父条目描述父帧如何到达 brand cell，子帧 upvalue 以
+            // 同一方式指向父帧）。子帧 brand 链记录各条目在子捕获列表中的位置，
+            // 嵌套类逐层继承，跨类 brand 检查据此定位声明类的 brand 对象。
+            for (brand_id, cell_idx, parent_uv_idx) in &parent_ctx.brand_chain {
+                let name = format!("@@class_brand_{brand_id}");
+                if !ctx.own_bindings.contains(&name) && !ctx.current_upvalue_captures.iter().any(|u| u.name == name) {
+                    ctx.current_upvalue_captures.push(UpvalueCapture {
+                        name,
+                        enclosing_reg: 0,
+                        cell_idx: *cell_idx,
+                        parent_uv_idx: *parent_uv_idx,
+                    });
+                }
+            }
+            ctx.brand_chain = parent_ctx
+                .brand_chain
+                .iter()
+                .map(|(brand_id, _, _)| {
+                    let name = format!("@@class_brand_{brand_id}");
+                    let pos = ctx
+                        .current_upvalue_captures
+                        .iter()
+                        .position(|u| u.name == name)
+                        .expect("brand 链条目已追加或已存在捕获列表");
+                    (*brand_id, 0, Some(pos as u8))
+                })
+                .collect();
         }
 
         // 创建 arguments 对象：指令须在默认参数求值前发出（默认参数可引用 arguments）。
diff --git a/crates/oxide_emit/src/shared/class_field.rs b/crates/oxide_emit/src/shared/class_field.rs
index 16424833..4ef48ee5 100644
--- a/crates/oxide_emit/src/shared/class_field.rs
+++ b/crates/oxide_emit/src/shared/class_field.rs
@@ -75,7 +75,10 @@ impl Emitter {
             return Err("expected private method key".into());
         };
         let name = private.name.as_str();
-        let method_reg = self.emit_class_method_function(method, name, home_reg, ctx, self_binding, class_self_cell)?;
+        // 私有方法/访问器的函数名带 `#` 前缀（SetFunctionName 语义：私有键的
+        // 字符串值即 `#name`，访问器另加 `get `/`set ` 前缀）。
+        let method_reg =
+            self.emit_class_method_function(method, &format!("#{name}"), home_reg, ctx, self_binding, class_self_cell)?;
         match method.kind {
             MethodDefinitionKind::Method => {
                 let key_reg = self.emit_private_id_reg(name, ctx)?;
diff --git a/crates/oxide_emit/src/shared/class_key.rs b/crates/oxide_emit/src/shared/class_key.rs
index 37728836..121c8b35 100644
--- a/crates/oxide_emit/src/shared/class_key.rs
+++ b/crates/oxide_emit/src/shared/class_key.rs
@@ -29,20 +29,23 @@ impl Emitter {
     /// dispatch 做 brand 检查。
     ///
     /// instance 字段：dispatch 靠 own 槽存在性 + 不跨原型判定（PrivateFieldFind 只查 own），
-    /// 不需要 brand 值比较（返回 `(0,0)`）；方法/访问器/静态字段须验证接收者属于当前类
-    /// （brand 对象同一性），返回 brand 编码。brand 对象由方法函数捕获的 `@@class_brand`
-    /// upvalue 提供；嵌套函数未捕获该 upvalue 时跳过检查（保持语法合法，brand 语义受限）。
+    /// 不需要 brand 值比较（返回 `(0,0)`）；方法/访问器/静态字段须验证接收者属于声明类
+    /// （brand 对象同一性），返回 brand 编码。brand 对象按声明类的 brand id 定位
+    /// （`@@class_brand_<id>` upvalue，跨类访问时即外类 brand）；当前函数未捕获该
+    /// upvalue 时跳过检查（保持语法合法，brand 语义受限）。
     pub(crate) fn private_access_brand(
         &self, _obj_reg: u32, name: &str, ctx: &mut CompileCtx,
     ) -> Result<(u32, u32), String> {
-        let Some(brand_id) = ctx.scopes.private_brand_id else { return Ok((0, 0)) };
-        let Some((_, kind, is_static)) = ctx.scopes.private_element_kinds.iter().find(|(n, _, _)| n == name) else {
+        let entry = ctx.scopes.private_element_kinds.iter().find(|(n, _, _, _)| n == name);
+        let Some((_, kind, is_static, brand_id)) = entry else {
             return Ok((0, 0));
         };
         if kind.is_none() && !is_static {
             return Ok((0, 0));
         }
-        let Some(uv_idx) = ctx.current_upvalue_captures.iter().position(|u| u.name == "@@class_brand") else {
+        let brand_id = *brand_id;
+        let brand_name = format!("@@class_brand_{brand_id}");
+        let Some(uv_idx) = ctx.current_upvalue_captures.iter().position(|u| u.name == brand_name) else {
             return Ok((0, 0));
         };
         let brand_reg = ctx.alloc_reg();
diff --git a/crates/oxide_vm/tests/class_tests.rs b/crates/oxide_vm/tests/class_tests.rs
index a4cd3189..22d12116 100644
--- a/crates/oxide_vm/tests/class_tests.rs
+++ b/crates/oxide_vm/tests/class_tests.rs
@@ -1044,3 +1044,90 @@ fn computed_accessor_symbol_key() {
     .unwrap();
     assert_num(result, 43.0);
 }
+
+// ── 嵌套类私有名作用域：内类方法可访问外类声明的私有名 ──
+
+// 内类方法访问外类私有字段：字段走 PrivateFieldFind 原型链查找，不加 brand 检查。
+#[test]
+fn nested_class_method_reads_outer_private_field() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #x = 1; B = class { method(o) { return o.#x; } } }; var c = new C(); new c.B().method(c)",
+    )
+    .unwrap();
+    assert_eq!(result.as_int(), 1);
+}
+
+// 内类方法访问外类私有方法：brand 检查经外类 brand upvalue（跨类定位声明类 brand 对象）。
+#[test]
+fn nested_class_method_calls_outer_private_method() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #m() { return 4; } B = class { method(o) { return o.#m(); } } }; var c = new C(); new c.B().method(c)",
+    )
+    .unwrap();
+    assert_eq!(result.as_int(), 4);
+}
+
+// 内类自有同名私有名遮蔽外类：内类方法解析到内类 id，外类方法不受影响。
+#[test]
+fn nested_class_same_name_private_shadows_outer() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #v = 1; outer() { return this.#v; } B = class { #v = 2; get() { return this.#v; } } }; var c = new C(); var b = new c.B(); b.get() * 10 + c.outer()",
+    )
+    .unwrap();
+    assert_num(result, 21.0);
+}
+
+// 跨类 brand 负例：内类对象访问外类私有方法抛 TypeError（brand 对象不同一）。
+#[test]
+fn nested_class_cross_brand_access_throws_type_error() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #m() { return 1; } B = class { method(o) { return o.#m(); } } }; var c = new C(); var b = new c.B(); var r = 0; try { b.method(b); } catch (e) { r = (e.name === 'TypeError') ? 1 : 2; } r",
+    )
+    .unwrap();
+    assert_eq!(result.as_int(), 1);
+}
+
+// 私有方法函数名带 `#` 前缀（SetFunctionName 语义）。
+#[test]
+fn private_method_name_has_hash_prefix() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { static #m() {} static getM() { return this.#m; } }; C.getM().name",
+    )
+    .unwrap();
+    let name = vm.lookup_str(result).expect("name should be string");
+    assert_eq!(name, "#m");
+}
+
+// 私有访问器行为：getter 读、setter 写，经内类方法跨类访问外类私有访问器。
+#[test]
+fn nested_class_method_uses_outer_private_accessor() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #v = 0; get #x() { return this.#v; } set #x(v) { this.#v = v; } B = class { use(o) { o.#x = 5; return o.#x; } } }; var c = new C(); new c.B().use(c)",
+    )
+    .unwrap();
+    assert_eq!(result.as_int(), 5);
+}
+
+// 三级类嵌套（类内类内类）：brand 链经多层类编译保存/恢复后仍指向最外层声明类。
+#[test]
+fn triple_nested_class_reaches_outermost_private_method() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "var C = class { #m() { return 7; } B = class { D = class { method(o) { return o.#m(); } } } }; var c = new C(); var b = new c.B(); var d = new b.D(); d.method(c)",
+    )
+    .unwrap();
+    assert_eq!(result.as_int(), 7);
+}