From 3d917c996527c69b8cf06461cbe6402976571f29 Mon Sep 17 00:00:00 2001
From: FranklinDM <mrmineshafter17@gmail.com>
Date: Sun, 21 May 2023 15:24:31 +0800
Subject: [PATCH] Issue #2250 - Part 2: Ignore the ancestor filter assertion if
 rule matching is restricted or if the current element is under a shadow host

This only affects debug builds.
---
 layout/style/nsCSSRuleProcessor.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/layout/style/nsCSSRuleProcessor.cpp b/layout/style/nsCSSRuleProcessor.cpp
index 1ecf80bc52..ff3661c73d 100644
--- a/layout/style/nsCSSRuleProcessor.cpp
+++ b/layout/style/nsCSSRuleProcessor.cpp
@@ -680,7 +680,11 @@ void RuleHash::EnumerateAllRules(Element* aElement, ElementDependentRuleProcesso
       aData->mTreeMatchContext.mAncestorFilter.HasFilter() ?
         &aData->mTreeMatchContext.mAncestorFilter : nullptr;
 #ifdef DEBUG
-    if (filter) {
+    bool isRestricted = (aData->mTreeMatchContext.mShadowHosts.Length() > 0 ||
+      aData->mTreeMatchContext.mRestrictToSlottedPseudo ||
+      aData->mTreeMatchContext.mOnlyMatchHostPseudo ||
+      aData->mTreeMatchContext.mForAssignedSlot);
+    if (filter && !isRestricted) {
       filter->AssertHasAllAncestors(aElement);
     }
 #endif