From 81908207ccf2ade20229e557a8f3dd91be526eaf Mon Sep 17 00:00:00 2001
From: Chris Tate <chris@ctate.dev>
Date: Tue, 20 Oct 2026 14:14:58 -0500
Subject: [PATCH] Read a widening-added member's name with symbolName

---
 packages/compiler/src/frontend/type-mapper.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/compiler/src/frontend/type-mapper.ts b/packages/compiler/src/frontend/type-mapper.ts
index a0dfff906..c9a1cc9df 100644
--- a/packages/compiler/src/frontend/type-mapper.ts
+++ b/packages/compiler/src/frontend/type-mapper.ts
@@ -7228,7 +7228,7 @@ function wideningAddedProperties(
     if ((prop.flags & ts.SymbolFlags.Optional) === 0 || prop.declarations.length === 0) continue;
     if (prop.declarations.some((d) => d.parent === literal)) continue;
     if ((ctx.checker.getTypeOfSymbol(prop).flags & ts.TypeFlags.Undefined) === 0) continue;
-    added.add(prop.name);
+    added.add(ts.symbolName(prop));
   }
   return added;
 }