feat: class 私有成员语义（字段/方法/访问器 + brand 检查 + 契约修复）

crates/oxide_emit/src/expr/assignment.rs

@@ -207,12 +207,15 @@ impl Emitter {
             }
             let obj_reg = self.emit_expression(&member.object, ctx)?;
             let val_reg = self.emit_expression(&assign.right, ctx)?;
-            let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
-            ctx.inst(Inst::new(
-                OpCode::SET_PRIVATE,
+            let name = member.field.name.as_str();
+            let (brand_reg, brand_id) = self.private_access_brand(obj_reg, name, ctx)?;
+            let key_reg = self.emit_private_id_reg(name, ctx)?;
+            ctx.inst(Inst::set_private(
                 Operand::Reg(obj_reg),
                 Operand::Reg(val_reg),
                 Operand::Reg(key_reg),
+                brand_reg,
+                brand_id,
             ));
             Ok(val_reg)
         } else if let oxide_parser::AssignmentTarget::AssignmentTargetIdentifier(id_ref) = &assign.left {

crates/oxide_emit/src/expr/call.rs

@@ -39,13 +39,16 @@ impl Emitter {
         let (callee_reg, this_reg) = match &call.callee {
             Expression::PrivateFieldExpression(member) => {
                 let obj_reg = self.emit_expression(&member.object, ctx)?;
-                let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+                let name = member.field.name.as_str();
+                let (brand_reg, brand_id) = self.private_access_brand(obj_reg, name, ctx)?;
+                let key_reg = self.emit_private_id_reg(name, ctx)?;
                 let callee_reg = ctx.alloc_reg();
-                ctx.inst(Inst::new(
-                    OpCode::GET_PRIVATE,
+                ctx.inst(Inst::get_private(
                     Operand::Reg(callee_reg),
                     Operand::Reg(obj_reg),
                     Operand::Reg(key_reg),
+                    brand_reg,
+                    brand_id,
                 ));
                 (callee_reg, obj_reg)
             }

crates/oxide_emit/src/expr/identifier.rs

@@ -54,12 +54,7 @@ impl Emitter {
         ctx.inst(Inst::load_const(Operand::Reg(key_reg), key_idx));
 
         let has_reg = ctx.alloc_reg();
-        ctx.inst(Inst::new(
-            OpCode::IN,
-            Operand::Reg(has_reg),
-            Operand::Reg(key_reg),
-            Operand::Reg(obj_reg),
-        ));
+        ctx.inst(Inst::new(OpCode::IN, Operand::Reg(has_reg), Operand::Reg(key_reg), Operand::Reg(obj_reg)));
 
         let fallback_label = ctx.next_label_id();
         let end_label = ctx.next_label_id();
@@ -101,12 +96,7 @@ impl Emitter {
                 ));
             }
         } else if let Some(reg) = ctx.scopes.symbols.lookup_any(name) {
-            ctx.inst(Inst::new(
-                OpCode::LOAD_VAR,
-                Operand::Reg(result_reg),
-                Operand::Reg(reg),
-                Operand::None,
-            ));
+            ctx.inst(Inst::new(OpCode::LOAD_VAR, Operand::Reg(result_reg), Operand::Reg(reg), Operand::None));
         } else {
             let undef_idx = ctx.add_constant(Constant::Undefined);
             ctx.inst(Inst::load_const(Operand::Reg(result_reg), undef_idx));
@@ -164,12 +154,7 @@ impl Emitter {
         ctx.inst(Inst::load_const(Operand::Reg(key_reg), key_idx));
 
         let has_reg = ctx.alloc_reg();
-        ctx.inst(Inst::new(
-            OpCode::IN,
-            Operand::Reg(has_reg),
-            Operand::Reg(key_reg),
-            Operand::Reg(obj_reg),
-        ));
+        ctx.inst(Inst::new(OpCode::IN, Operand::Reg(has_reg), Operand::Reg(key_reg), Operand::Reg(obj_reg)));
 
         let fallback_label = ctx.next_label_id();
         let end_label = ctx.next_label_id();

crates/oxide_emit/src/expr/literal.rs

@@ -70,9 +70,7 @@ impl Emitter {
                 // 非法正则字面量须在编译期报 SyntaxError（负面测试期望编译失败）。
                 // 用 regress（ECMAScript 语法）校验，避免误报 backreference/lookaround 等合法模式。
                 if regress::Regex::with_flags(&pattern, flags.as_str()).is_err() {
-                    return Err(format!(
-                        "SyntaxError: Invalid regular expression: /{pattern}/{flags}"
-                    ));
+                    return Err(format!("SyntaxError: Invalid regular expression: /{pattern}/{flags}"));
                 }
                 let pat_ci = ctx.add_constant(Constant::String(pattern));
                 let pat_reg = ctx.alloc_reg();
@@ -96,5 +94,3 @@ impl Emitter {
         }
     }
 }
-
-

crates/oxide_emit/src/expr/member/mod.rs

@@ -60,13 +60,16 @@ impl Emitter {
         &self, member: &oxide_parser::PrivateFieldExpression, ctx: &mut CompileCtx,
     ) -> Result<u32, String> {
         let obj_reg = self.emit_expression(&member.object, ctx)?;
-        let key_reg = self.emit_private_id_reg(member.field.name.as_str(), ctx)?;
+        let name = member.field.name.as_str();
+        let (brand_reg, brand_id) = self.private_access_brand(obj_reg, name, ctx)?;
+        let key_reg = self.emit_private_id_reg(name, ctx)?;
         let r = ctx.alloc_reg();
-        ctx.inst(Inst::new(
-            OpCode::GET_PRIVATE,
+        ctx.inst(Inst::get_private(
             Operand::Reg(r),
             Operand::Reg(obj_reg),
             Operand::Reg(key_reg),
+            brand_reg,
+            brand_id,
         ));
         Ok(r)
     }

crates/oxide_emit/src/expr/operator/mod.rs

@@ -343,12 +343,7 @@ impl Emitter {
                     } else {
                         OpCode::SUB
                     };
-                    ctx.inst(Inst::new(
-                        op,
-                        Operand::Reg(new_reg),
-                        Operand::Reg(old_reg),
-                        Operand::Reg(one_reg),
-                    ));
+                    ctx.inst(Inst::new(op, Operand::Reg(new_reg), Operand::Reg(old_reg), Operand::Reg(one_reg)));
                     ctx.inst(Inst::new(
                         OpCode::SET_PROP_DYNAMIC,
                         Operand::Reg(obj_reg),