diff --git a/App/lib/core/Gen/AssignGenMixin.vp b/App/lib/core/Gen/AssignGenMixin.vp
index 007844e..7591632 100644
--- a/App/lib/core/Gen/AssignGenMixin.vp
+++ b/App/lib/core/Gen/AssignGenMixin.vp
@@ -844,6 +844,55 @@ novirtual class AssignGenMixin:
             leak_l = self.Gen.StructGen.escape_leak_line(leak_func, leak_param)
             if leak_l > 0: leak_f = self.Gen.TypeGenResolve.get_current_file()
         self.Gen.TypeGenErr.fatal_error(node, f"stack address escapes: `{nm_pre}{nm_txt}` is frame-local; using it at {where} hands out a dangling pointer once this frame returns. Copy the value, or allocate on the heap (`new heap hlife ...`).", "LifetimeError", 0, 0, leak_f, leak_l)
+        return 0
+
+    # check_return_frame_decl - **定义端** `return <本帧存储>` 的**声明感知**检查（A2 / §14.3 第 6 条）。
+    # A2 移除了"一律拦"的旧判据：定义端分不清"交出本帧"与"借出调用方的存储"（后者是
+    # `return <借用形参>`，一律拦会误报）。但也不能一律放 —— 无声明的函数返回本帧存储会让调用点
+    # 永远只拿到"未知"（悬垂指针一路静默）。判据收敛到被调者自己的 `@life(ret(...))`：
+    #   · `ret(frame)`              → 放行（去向由调用点负责）；
+    #   · `ret(borrows=<该形参>)`   → 放行（借出的正是那个形参）；
+    #   · 无声明 / `ret(heap|static|borrows=none)` → `LifetimeError`（提示补声明 / 改声明）。
+    # 拿不到当前函数定义（非三条函数体翻译路径）时**不判**：宁可少报，也不误报。
+    def check_return_frame_decl(self, trans: HT.Translator*, value: ast.AST*) -> int:
+        """返回值是本帧存储且当前函数的 ret 声明不允许 → LifetimeError；0=放行"""
+        if trans is None or value is None: return 0
+        fd: ast.AST* = self.Gen.StructGen.NllCurFunc
+        if fd is None: return 0
+        rv_ty: mlirlite.LLVMType* = None
+        if trans._cur_func is not None: rv_ty = mlirlite.function_get_ret_ty(trans._cur_func)
+        # target_ty 必须传返回类型：裸本帧数组名在**指针**返回类型下是数组退让（交出栈地址），
+        # 在同型聚合返回类型下是按值拷贝（LIFE_VALUE，不在此列）。
+        if self.life_of_expr(trans, value, rv_ty) != GenTypes.LIFE_FRAME: return 0
+        rk: int = GenApi.get_ret_kind_by_func(fd)
+        if rk == GenApi.RET_KIND_FRAME: return 0
+        is_borrow_kind: int = 0
+        pi: int = -1
+        if rk >= GenApi.RET_KIND_BORROW_BASE:
+            is_borrow_kind = 1
+            pi = rk - GenApi.RET_KIND_BORROW_BASE
+            # 只有"返回的正是被声明的那个形参"才算借出；返回别的本帧存储仍是悬垂
+            if self.Gen.StructGen._ParamIndex(ast.FunctionDef*(fd), value) == pi: return 0
+        # 报文里给出名字（&x / x），便于定位
+        nm_txt: str = "expression"
+        nm_pre: str = ""
+        if value.kind() == ast.ASTKind.Name:
+            n2: ast.Name* = ast.Name*(value)
+            if n2.id is not None: nm_txt = n2.id
+        elif value.kind() == ast.ASTKind.UnaryOp:
+            u2: ast.UnaryOp* = ast.UnaryOp*(value)
+            if u2.operand is not None and u2.operand.kind() == ast.ASTKind.Name:
+                n3: ast.Name* = ast.Name*(u2.operand)
+                if n3.id is not None:
+                    nm_txt = n3.id
+                    nm_pre = "&"
+        if rk == 0:
+            self.Gen.TypeGenErr.fatal_error(value, f"stack address escapes: `{nm_pre}{nm_txt}` is frame-local and this function has no `@life(ret(...))` declaration, so callers cannot know the result's lifetime. Declare `@life(ret(frame))` (the result may point into this frame; callers must keep it in-frame) or `@life(ret(borrows=<param>))` (the result borrows a parameter), or return a value copy / a heap allocation (`new heap hlife ...`).", "LifetimeError")
+            return 0
+        if is_borrow_kind != 0:
+            self.Gen.TypeGenErr.fatal_error(value, f"stack address escapes: `{nm_pre}{nm_txt}` is frame-local but this function declares `@life(ret(borrows=<param>))` (parameter #{pi}), which only permits returning that parameter. Return that parameter, or declare `@life(ret(frame))`.", "LifetimeError")
+            return 0
+        self.Gen.TypeGenErr.fatal_error(value, f"stack address escapes: `{nm_pre}{nm_txt}` is frame-local but this function is declared as non-frame (`@life(ret(heap))` / `ret(static)` / `ret(borrows=none)`); the declaration contradicts the returned value. Fix the declaration, or return a non-frame value.", "LifetimeError")
         return 0
 
     # _SlifeDropOwned - 该槽已被登记为 slife 绑定时交还所有权：释放它当前拥有的对象、影子清 0。
diff --git a/App/lib/core/Gen/GenApi.vp b/App/lib/core/Gen/GenApi.vp
index f83bf8b..dddd7be 100644
--- a/App/lib/core/Gen/GenApi.vp
+++ b/App/lib/core/Gen/GenApi.vp
@@ -574,6 +574,12 @@ def get_ret_kind_method(pool: memhub.MemBuddy*, class_name: str, method_name: st
     return 0
 
 
+def get_ret_kind_by_func(fd: ast.AST*) -> int:
+    """**定义端**按 FunctionDef* 取本函数的 `@life(ret(...))` 契约（顶层/方法/嵌套都覆盖）；0 = 无声明"""
+    if _g_gen is not None: return _g_gen.StructGen.get_ret_kind_by_func(fd)
+    return 0
+
+
 def lookup_ret_kind_via_vpi(cls_sha1: str, class_name: str, func_name: str) -> int:
     """跨模块给被调者的 `@life(ret(...))` 契约；0 = 无声明（含该模块未加载）"""
     if _g_gen is not None: return _g_gen.CallGenBase.lookup_ret_kind_via_vpi(cls_sha1, class_name, func_name)
diff --git a/App/lib/core/Gen/Stmt/StmtGenCifMixin.vp b/App/lib/core/Gen/Stmt/StmtGenCifMixin.vp
index bfa0a7a..a7b909a 100644
--- a/App/lib/core/Gen/Stmt/StmtGenCifMixin.vp
+++ b/App/lib/core/Gen/Stmt/StmtGenCifMixin.vp
@@ -434,11 +434,12 @@ novirtual class StmtGenCifMixin:
             # f-string escape (return f"..."): its buffer lives on this frame's stack and dies on
             # return; copy it out explicitly (GenApi.escape_fstring_copy) before returning it.
             GenApi.fail_if_fstring_escape(rt.value, "function return value")
-            # A2（§14.3 第 6 条）：此处**不再**对 `return &local` / `return arr`（指针位置的数组退让）
-            # 直接 fail-fast。返回值去向改由**调用点**按被调者的 `@life(ret(...))` 契约判定（见
-            # AssignGenMixin.life_of_expr 的 ret_kind 分支）：定义端无法区分"交出本帧"与"借出调用方的
-            # 存储"，一律拦会误报 `return <借用形参>`。必须在 `ret_kind` 契约（同批）落地后移除，
-            # 否则未声明的函数会静默漏检。
+            # A2（§14.3 第 6 条，方案 A）：定义端对 `return <本帧存储>` 的**声明感知** fail-fast。
+            # A2 移除了"一律拦"的旧判据（定义端分不清"交出本帧"与"借出调用方的存储"），
+            # 但也不能一律放：判据收敛到被调者自己的 `@life(ret(...))` —— `ret(frame)` 或
+            # `ret(borrows=<该形参>)` 放行；无声明 / 声明为非帧 → LifetimeError。
+            # 实现见 AssignGenMixin.check_return_frame_decl。
+            self.Gen.AssignGen.check_return_frame_decl(trans, rt.value)
             # return a, b → pack an anonymous struct value (multi-return, return type tuple[T1,T2])
             if rt.value.kind() == ast.ASTKind.Tuple:
                 rtp: ast.Tuple* = ast.Tuple*(rt.value)
diff --git a/App/lib/core/Gen/StructGenMixin.vp b/App/lib/core/Gen/StructGenMixin.vp
index 0d99be0..2a2a9df 100644
--- a/App/lib/core/Gen/StructGenMixin.vp
+++ b/App/lib/core/Gen/StructGenMixin.vp
@@ -573,6 +573,25 @@ novirtual class StructGenMixin:
         if idx < 0: return 0
         return int(self.EscDirTable[idx * 4 + 3])
 
+    # get_ret_kind_by_func - **定义端**（`return` 处）用：按 FunctionDef* 反查本函数的 ret_kind。
+    # 不靠"类名拼接"：EscFuncTable 里已有"名哈希 → FunctionDef*"，反查拿到哈希后再去
+    # EscDirTable 取 ret_kind 列 —— 顶层函数 / 方法 / 嵌套 def 三种键形式一次性覆盖，
+    # 无需在翻译期猜测 Class 名。0 = 无声明（或该函数未被登记）。
+    def get_ret_kind_by_func(self, fd: ast.AST*) -> int:
+        """当前函数体的 `@life(ret(...))` 编码；0 = 无声明"""
+        if fd is None or self.EscFuncTable is None: return 0
+        i: int = 0
+        while i < self.EscFuncCount:
+            if sizet(self.EscFuncTable[i * 2 + 1]) == sizet(fd):
+                h: sizet = self.EscFuncTable[i * 2]
+                j: int = 0
+                while j < self.EscDirCount:
+                    if self.EscDirTable[j * 4] == h: return int(self.EscDirTable[j * 4 + 3])
+                    j += 1
+                return 0
+            i += 1
+        return 0
+
     # get_ret_kind_method - 方法版 `@life(ret(...))`：查 "Class.method" 并沿 MRO 回退。
     def get_ret_kind_method(self, pool: memhub.MemBuddy*, class_name: str, method_name: str) -> int:
         if method_name is None or class_name is None: return 0