fix: IC 快速路径 symbol 原始值走 Symbol.prototype 链

crates/oxide_builtins/src/symbol.rs

@@ -24,23 +24,30 @@ pub fn symbol_constructor<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
         }
     }
 
-    // 描述符按规范 ToString(description)：对象经 ToPrimitive(string hint) 强制转换，
+    // 描述符按规范 ToString(description)：缺省参数与 undefined 对应无描述
-    // Symbol 抛 TypeError，对象方法抛出的原始异常原样传播。
+    // （[[Description]] 为 undefined，`symbol.description` 返回 undefined）；
+    // 对象经 ToPrimitive(string hint) 强制转换，Symbol 抛 TypeError，
+    // 对象方法抛出的原始异常原样传播。
     let description = if args.len() > 1 {
-        match oxide_runtime_api::to_string_full(vm.reg(args[1]), vm) {
+        let desc_val = vm.reg(args[1]);
-            Ok(s) => s,
+        if desc_val.is_undefined() {
-            Err(_) => {
+            None
-                if let Some(exc) = vm.take_uncaught_value() {
+        } else {
-                    return NativeResult::Err(exc);
+            match oxide_runtime_api::to_string_full(desc_val, vm) {
+                Ok(s) => Some(s),
+                Err(_) => {
+                    if let Some(exc) = vm.take_uncaught_value() {
+                        return NativeResult::Err(exc);
+                    }
+                    return NativeResult::Err(crate::error::create_type_error(vm, "Cannot convert value to a string"));
                 }
-                return NativeResult::Err(crate::error::create_type_error(vm, "Cannot convert value to a string"));
             }
         }
     } else {
-        String::new()
+        None
     };
 
-    let idx = vm.symbol_intern(Some(description));
+    let idx = vm.symbol_intern(description);
     NativeResult::Ok(JsValue::symbol(idx))
 }
 
@@ -96,6 +103,22 @@ pub fn symbol_value_of<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
     }
 }
 
+/// `Symbol.prototype.description` getter：返回该 Symbol 的 description 字符串；
+/// 无 description 的 Symbol 返回 undefined。this 必须是 Symbol 或 Symbol 包装对象，
+/// 否则抛 TypeError（规范 `SymbolDescriptiveString` 的 thisSymbolValue 校验）。
+pub fn symbol_description_getter<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {
+    let this_val = vm.reg(if args.is_empty() { 0 } else { args[0] });
+    let sym = match this_symbol_value(vm, this_val) {
+        Ok(v) => v,
+        Err(e) => return NativeResult::Err(e),
+    };
+    let idx = sym.as_symbol_index();
+    match vm.symbol_description(idx) {
+        Some(desc) => NativeResult::Ok(vm.new_string_owned(desc.to_string())),
+        None => NativeResult::Ok(JsValue::undefined()),
+    }
+}
+
 /// `Symbol.for(key)`：在全局 symbol 注册表中查找并返回同 key 的 Symbol；
 /// 不存在则新建并登记。同 key 的 Symbol 在全局唯一。
 pub fn symbol_for<H: VmHost>(vm: &mut H, args: &[u8]) -> NativeResult {

crates/oxide_test262/src/main.rs

@@ -729,7 +729,6 @@ fn classify_vm_error(e: &str, neg: Option<&Negative>, no_skip: bool) -> TestOutc
         || e.contains("unsupported")
         || e.contains("step limit")
         || e.contains("NEW_EXPRESSION")
-        || e.contains("IC_GET_PROP on non-object")
         || e.contains("GET_PROP_DYNAMIC on non-object")
         || e.contains("SET_PROP_DYNAMIC on non-object")
         || e.contains("private field brand check")
@@ -1634,6 +1633,7 @@ mod tests {
             "TypeError: Cannot convert object to primitive value",
             "TypeError: Cannot create property on non-object",
             "TypeError: Property description must be an object",
+            "IC_GET_PROP on non-object",
         ] {
             assert_outcome(e, None, false, &TestOutcome::Fail("".into()));
         }
@@ -1647,7 +1647,6 @@ mod tests {
             "feature is not supported",
             "unsupported syntax",
             "vm error: NEW_EXPRESSION not supported",
-            "IC_GET_PROP on non-object",
             "GET_PROP_DYNAMIC on non-object",
             "SET_PROP_DYNAMIC on non-object",
             "private field brand check",

crates/oxide_vm/src/bindings/bind_symbol.rs

@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use crate::bindings::{apply_binding_table, configure_native_constructor};
+use crate::bindings::{apply_binding_table, bind_accessor_getter, configure_native_constructor};
 use oxide_kernel::kernel::{KernelCore, KernelSession};
 use oxide_types::object::JsObject;
 use oxide_types::value::JsValue;
@@ -36,6 +36,15 @@ pub fn bind_symbol(core: &Arc<KernelCore>, session: &KernelSession, global: &mut
         ],
     );
 
+    // description 是访问器 getter（Symbol 原始值成员访问经 Symbol.prototype 链命中）。
+    bind_accessor_getter(
+        core,
+        session,
+        proto,
+        "description",
+        oxide_builtins::symbol::symbol_description_getter::<crate::vm::Vm> as *const (),
+    );
+
     for (name, val) in [
         (
             "match",

crates/oxide_vm/src/dispatch/property.rs

@@ -70,6 +70,11 @@ impl Vm {
             let proto = unsafe { &*proto_ptr };
             return self.ordinary_get(proto, prop_name_si, val).map(Some);
         }
+        if val.is_symbol() {
+            let proto_ptr = self.session.builtin_world().symbol_proto.as_ptr() as *mut JsObject;
+            let proto = unsafe { &*proto_ptr };
+            return self.ordinary_get(proto, prop_name_si, val).map(Some);
+        }
         Ok(None)
     }
 

crates/oxide_vm/tests/builtins_symbol_tests.rs

@@ -283,3 +283,69 @@ fn symbol_key_read_via_get_own_property_symbols_index() {
     .unwrap();
     assert!(result.as_bool());
 }
+
+// --- Symbol 原始值成员访问走 Symbol.prototype 链 ---
+
+#[test]
+fn symbol_primitive_to_string_via_symbol_proto() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Symbol('66').toString()").unwrap();
+    assert_eq!(to_str(&vm, result), "Symbol(66)");
+}
+
+#[test]
+fn symbol_primitive_value_of_via_symbol_proto() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "var s = Symbol('x'); s.valueOf() === s").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn symbol_primitive_chain_reaches_object_proto_method() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Symbol('x').hasOwnProperty('description')").unwrap();
+    assert!(!result.as_bool());
+}
+
+#[test]
+fn symbol_primitive_description_getter() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Symbol('desc').description").unwrap();
+    assert_eq!(to_str(&vm, result), "desc");
+}
+
+#[test]
+fn symbol_without_description_returns_undefined() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Symbol().description").unwrap();
+    assert!(result.is_undefined());
+}
+
+#[test]
+fn symbol_wrapper_object_description_unboxes() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Object(Symbol('w')).description").unwrap();
+    assert_eq!(to_str(&vm, result), "w");
+}
+
+#[test]
+fn symbol_description_non_symbol_receiver_throws_type_error() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "try { Object.getOwnPropertyDescriptor(Symbol.prototype, 'description').get.call(42); false } catch (e) { e instanceof TypeError }",
+    )
+    .unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn symbol_proto_direct_description_access_throws_type_error() {
+    let mut vm = Vm::new();
+    let result = eval(
+        &mut vm,
+        "try { Symbol.prototype.description; false } catch (e) { e instanceof TypeError }",
+    )
+    .unwrap();
+    assert!(result.as_bool());
+}

crates/oxide_vm/tests/ic_polymorphic_tests.rs

@@ -181,3 +181,18 @@ fn primitive_receiver_skips_ic_ext_words() {
     );
     assert_eq!(r, "303", "字符串 length 经 primitive 分支返回 3，扩展字跳越无错位");
 }
+
+/// 非对象 receiver（symbol）经 IC primitive 分支走 Symbol.prototype 链：
+/// toString/description 均经原型解析，扩展字跳越无错位。
+#[test]
+fn symbol_primitive_receiver_walks_symbol_proto() {
+    let (r, _hits, _misses) = run_once(
+        r#"var s = Symbol('x');
+           var ok = 0;
+           for (var i = 0; i < 100; i++) {
+             ok += (s.toString() === 'Symbol(x)') ? 1 : 0;
+           }
+           ok + ((s.description === 'x') ? 1 : 0)"#,
+    );
+    assert_eq!(r, "101", "symbol 原始值 toString/description 经 Symbol.prototype 解析");
+}