diff --git a/App/lib/core/Gen/Call/CallGenCtor.vp b/App/lib/core/Gen/Call/CallGenCtor.vp
index cd08561..ab45293 100644
--- a/App/lib/core/Gen/Call/CallGenCtor.vp
+++ b/App/lib/core/Gen/Call/CallGenCtor.vp
@@ -322,6 +322,10 @@ novirtual class CallGenCtor(CallGenBase.CallGenBase):
         if pool is None or builder is None or new_node is None or trans is None: return None
         src: int = new_node.Source
         life: int = new_node.Life
+        # 缺省规则（§3.2 / D3）：来源缺省 = heap；生命期缺省由来源决定
+        #   stack            → slife（帧生命期；故 `new stack T(...)` 不写 slife 也等效）
+        #   heap / memgr     → hlife（自由生命期）
+        # 生命期在 life_of_expr 里按同一张表落地（LIFE_FRAME / LIFE_HEAP），此处只管存储。
         # §2.4-3：stack 不可能超帧
         if src == ast.NEW_SRC_STACK and life == ast.NEW_LIFE_HLIFE:
             self.Gen.TypeGenErr.fatal_error(new_node, "`new stack hlife` is contradictory: a stack allocation can never outlive its frame; use `new stack slife` (the default for stack), or `heap`/`memgr(x)` for a longer lifetime", "LifetimeError")