diff --git a/App/lib/core/Gen/GenApi.vp b/App/lib/core/Gen/GenApi.vp
index 990be0f..b60f47e 100644
--- a/App/lib/core/Gen/GenApi.vp
+++ b/App/lib/core/Gen/GenApi.vp
@@ -555,18 +555,24 @@ def _RetKindFromTag(fn: ast.FunctionDef*, tcl: ast.Call*) -> int:
         if val is None:
             fatal_error(tcl, "@life(ret(borrows=...)) requires a parameter name or `none`", "LifetimeError")
             return -1
+        # `borrows=none`：返回值不借用任何形参（非本帧）。
+        # 其余一律交给 _WillFreeArgIndex：它同时认**形参名**与**0 起序号**（与 willFree(...) 同口径，
+        # 见 includes/stdlib.vp 的注释："写法二选一：形参名 willFree(p) 或形参位置序号 willFree(0)"），
+        # 非法实参（非名非整数/越界/不是形参名）在那边 fail-fast。
         if val.kind() == ast.ASTKind.Name:
             vn: ast.Name* = ast.Name*(val)
             if vn.id is None: return -1
             if string.strcmp(vn.id, "none") == 0: return RET_KIND_NONFRAME
-            idx: int = _WillFreeArgIndex(fn, val)
-            if idx < 0: return -1     # 已 fail-fast
-            return RET_KIND_BORROW_BASE + idx
-        if val.kind() == ast.ASTKind.Constant:
+        elif val.kind() == ast.ASTKind.Constant:
             vc: ast.Constant* = ast.Constant*(val)
             if vc is not None and vc.const_kind == ast.CONST_NONE: return RET_KIND_NONFRAME
-        fatal_error(tcl, "@life(ret(borrows=...)) accepts only a parameter name or `none`", "LifetimeError")
-        return -1
+        else:
+            fatal_error(tcl, "@life(ret(borrows=...)) accepts only a parameter name (or its 0-based position) or `none`", "LifetimeError")
+            return -1
+        idx: int = _WillFreeArgIndex(fn, val)
+        if idx < 0: return -1     # 已 fail-fast
+        return RET_KIND_BORROW_BASE + idx
+
     # 形式二：ret(frame) / ret(heap) / ret(static)
     if tcl.args is None or len(tcl.args) != 1:
         fatal_error(tcl, "@life(ret(...)) expects exactly one of `frame` / `heap` / `static`, or `borrows=<param>` / `borrows=none`", "LifetimeError")