From 3cbda905e52b3bbfe2c051bc8e0150d4b66cf104 Mon Sep 17 00:00:00 2001
From: ringabout <43030857+ringabout@users.noreply.github.com>
Date: Tue, 7 Apr 2026 16:00:04 +0800
Subject: [PATCH] The fix adds a guard: when d.k == locExpr and the destination
 type differs from the constructor type (inheritance/subtyping), a temporary
 is still used so that genAssignment can perform the proper type-tag and
 slicing checks.

---
 compiler/ccgexprs.nim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/compiler/ccgexprs.nim b/compiler/ccgexprs.nim
index 414a05a70a..3009223925 100644
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
@@ -1893,6 +1893,7 @@ proc genObjConstr(p: BProc, e: PNode, d: var TLoc) =
   var useTemp =
         isRef or
         (d.k notin {locTemp,locLocalVar,locGlobalVar,locParam,locField,locExpr}) or
+        (d.k == locExpr and d.lode.typ != nil and not sameType(d.lode.typ.skipTypes(abstractInst), t)) or
         (isPartOf(d.lode, e) != arNo)
 
   var tmp: TLoc = default(TLoc)