diff --git a/Cargo.lock b/Cargo.lock
index 8e4ddfc4..9a219c57 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1160,7 +1160,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_builtins"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "chrono",
  "fast-float",
@@ -1185,7 +1185,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_bytecode"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "num-bigint",
  "oxide_log",
@@ -1193,7 +1193,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cfg"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_emit",
@@ -1204,7 +1204,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_cli"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "ansi_term",
  "bumpalo",
@@ -1226,7 +1226,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_code_cache"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "lru",
  "oxide_bytecode",
@@ -1235,7 +1235,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_compiler"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1255,7 +1255,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_dce"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1269,7 +1269,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_emit"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "num-bigint",
  "oxc_allocator",
@@ -1284,7 +1284,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_engine"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1296,7 +1296,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_ir"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_log",
@@ -1305,7 +1305,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_kernel"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1319,7 +1319,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_liveness"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1331,7 +1331,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_log"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "tracing",
  "tracing-appender",
@@ -1340,7 +1340,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_parser"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxc_allocator",
  "oxc_ast",
@@ -1355,7 +1355,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_regalloc"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_cfg",
@@ -1371,7 +1371,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_runtime_api"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "num-bigint",
  "num-traits",
@@ -1384,7 +1384,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_test262"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "oxide_bytecode",
  "oxide_compiler",
@@ -1402,7 +1402,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_types"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "bumpalo",
  "dashmap",
@@ -1415,7 +1415,7 @@ dependencies = [
 
 [[package]]
 name = "oxide_vm"
-version = "0.13.9"
+version = "0.13.10"
 dependencies = [
  "bumpalo",
  "chrono",
diff --git a/Cargo.toml b/Cargo.toml
index da15246f..ff878789 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.13.9"
+version = "0.13.10"
 edition = "2021"
 license = "MIT"
 rust-version = "1.80"
diff --git a/crates/oxide_vm/src/async_from_sync.rs b/crates/oxide_vm/src/async_from_sync.rs
index 3fbc96e8..0129cb24 100644
--- a/crates/oxide_vm/src/async_from_sync.rs
+++ b/crates/oxide_vm/src/async_from_sync.rs
@@ -19,16 +19,19 @@ const INNER_PROP: &str = "__inner__";
 /// `@@asyncIterator` 的 well-known symbol 键序号。
 const ASYNC_ITERATOR_SYMBOL_ID: u32 = 8;
 
-/// GetAsyncIterator（ECMA-262）：取 `value[@@asyncIterator]`，不可调用时回退同步
-/// 迭代器并包 AsyncFromSyncIterator。
+/// GetAsyncIterator（ECMA-262）：取 `value[@@asyncIterator]`，可调用则调用；
+/// undefined/null 时回退同步迭代器并包 AsyncFromSyncIterator；
+/// 已定义但不可调用时抛 TypeError。
 ///
 /// # 步骤
 /// 1. ToObject 后读取 `@@asyncIterator`，可调用则调用并校验结果为对象。
-/// 2. 否则经同步迭代协议取迭代器包装器，包成 AsyncFromSyncIterator。
+/// 2. 已定义但不可调用时抛 TypeError（GetMethod 步 4）。
+/// 3. undefined/null 时经同步迭代协议取迭代器包装器，包成 AsyncFromSyncIterator。
 ///
 /// # 返回值
 /// - `Ok(iterator)`：异步迭代器对象；
-/// - `Err`：`@@asyncIterator` getter/调用抛错或 ToObject 失败，透传原异常值。
+/// - `Err`：`@@asyncIterator` getter/调用抛错或 ToObject 失败（透传原异常值），
+///   或已定义但不可调用（构造 TypeError）。
 pub(crate) fn make_async_iterator(vm: &mut Vm, value: JsValue) -> Result<JsValue, JsValue> {
     let obj_value = if value.is_object() {
         value
@@ -69,6 +72,10 @@ pub(crate) fn make_async_iterator(vm: &mut Vm, value: JsValue) -> Result<JsValue
         }
         return Ok(iterator);
     }
+    if !method.is_null() && !method.is_undefined() {
+        // GetMethod 步 4：已定义非可调用方法 → TypeError，不落入同步回退。
+        return Err(oxide_builtins::error::create_type_error(vm, "value is not async iterable"));
+    }
     let sync = oxide_builtins::iterator::make_iterator_for_value(vm, value)?;
     Ok(vm.create_async_from_sync_iterator(sync))
 }
diff --git a/crates/oxide_vm/tests/async_gen_delegation_tests.rs b/crates/oxide_vm/tests/async_gen_delegation_tests.rs
index a214df18..441211a2 100644
--- a/crates/oxide_vm/tests/async_gen_delegation_tests.rs
+++ b/crates/oxide_vm/tests/async_gen_delegation_tests.rs
@@ -409,3 +409,80 @@ fn t21_async_gen_multi_layer_escape_no_signal_leak_into_async_func() {
         .to_string();
     assert_eq!(eval(&source), "\"body,c2,c1,f-body,f-finally|f-done|g:true:42\"");
 }
+
+// T22：`@@asyncIterator` 已定义但不可调用（对象形）——GetMethod 步 4 抛 TypeError
+// 入委托 body，可捕获；同步 `@@iterator` getter 不得被触发（若触发，拒绝原因会是
+// getter 抛值而非 TypeError）。
+#[test]
+fn t22_async_iterator_not_callable_object_typeerror() {
+    assert_eq!(
+        eval(
+            "async function* g() { try { yield* { \
+             get [Symbol.iterator]() { throw 'no-sync-iter'; }, \
+             [Symbol.asyncIterator]: {} }; } \
+             catch (e) { return 'caught:' + e.name; } } \
+             (async function run() { const it = g(); const r = await it.next(); \
+             return r.value + ':' + r.done; })()"
+        ),
+        "\"caught:TypeError:true\""
+    );
+}
+
+// T23：`@@asyncIterator` 为 null——null/undefined 形保持同步回退，元素正常让出。
+#[test]
+fn t23_async_iterator_null_sync_fallback() {
+    assert_eq!(
+        eval(
+            "async function* g() { yield* { [Symbol.asyncIterator]: null, \
+             [Symbol.iterator]: function* () { yield 1; yield 2; } }; } \
+             (async function run() { const it = g(); \
+             const a = (await it.next()).value; const b = (await it.next()).value; \
+             const c = (await it.next()).done; return a + ',' + b + ',' + c; })()"
+        ),
+        "\"1,2,true\""
+    );
+}
+
+// T24：`@@asyncIterator` 为 undefined——undefined/null 形保持同步回退，元素正常让出。
+#[test]
+fn t24_async_iterator_undefined_sync_fallback() {
+    assert_eq!(
+        eval(
+            "async function* g() { yield* { [Symbol.asyncIterator]: undefined, \
+             [Symbol.iterator]: function* () { yield 3; } }; } \
+             (async function run() { const it = g(); \
+             const a = (await it.next()).value; const b = (await it.next()).done; \
+             return a + ':' + b; })()"
+        ),
+        "\"3:true\""
+    );
+}
+
+// T25：for-await-of 臂——`@@asyncIterator` 已定义但不可调用，TypeError 被外围
+// try/catch 捕获（验证 Err 臂经 unwind 透传原异常值）。
+#[test]
+fn t25_for_await_of_not_callable_typeerror_caught() {
+    assert_eq!(
+        eval(
+            "async function f() { try { for await (const x of { [Symbol.asyncIterator]: {} }) { } } \
+             catch (e) { return 'caught:' + e.name; } } \
+             (async function run() { return await f(); })()"
+        ),
+        "\"caught:TypeError\""
+    );
+}
+
+// T26：`@@asyncIterator` 在原型上不可调用（boolean 形）——ToObject 装箱后读原型，
+// GetMethod 步 4 抛 TypeError，可捕获（覆盖原始值走原型链的形态）。
+#[test]
+fn t26_async_iterator_not_callable_boolean_primitive() {
+    assert_eq!(
+        eval(
+            "Boolean.prototype[Symbol.asyncIterator] = {}; \
+             async function* g() { try { yield* true; } catch (e) { return 'caught:' + e.name; } } \
+             (async function run() { const it = g(); const r = await it.next(); \
+             return r.value + ':' + r.done; })()"
+        ),
+        "\"caught:TypeError:true\""
+    );
+}