From 908548ef9017e654345266c68a3a0164117eb0a4 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 2 Sep 2022 06:53:56 -0700
Subject: [PATCH] 'in' operator shouldn't narrow {} originating in unknown

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 1ac041a3653c2..280b3dc51ef1a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -25150,7 +25150,7 @@ namespace ts {
 
             function narrowByInKeyword(type: Type, name: __String, assumeTrue: boolean) {
                 if (type.flags & TypeFlags.Union
-                    || type.flags & TypeFlags.Object && declaredType !== type
+                    || type.flags & TypeFlags.Object && declaredType !== type && !(declaredType === unknownType && isEmptyAnonymousObjectType(type))
                     || isThisTypeParameter(type)
                     || type.flags & TypeFlags.Intersection && every((type as IntersectionType).types, t => t.symbol !== globalThisSymbol)) {
                     return filterType(type, t => isTypePresencePossible(t, name, assumeTrue));