Let querySelector(All) match (nth-)last with unclosed parent.

third_party/WebKit/Source/core/css/SelectorChecker.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc.
  * All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
@@ skipping 727 matching lines @@
           parent->setChildrenAffectedByForwardPositionalRules();
         return isFirstOfType(element, element.tagQName());
       }
       break;
     case CSSSelector::PseudoLastChild:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle) {
           parent->setChildrenAffectedByLastChildRules();
           element.setAffectedByLastChildRules();
         }
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return isLastChild(element);
       }
       break;
     case CSSSelector::PseudoLastOfType:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle)
           parent->setChildrenAffectedByBackwardPositionalRules();
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return isLastOfType(element, element.tagQName());
       }
       break;
     case CSSSelector::PseudoOnlyChild:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle) {
           parent->setChildrenAffectedByFirstChildRules();
           parent->setChildrenAffectedByLastChildRules();
           element.setAffectedByFirstChildRules();
           element.setAffectedByLastChildRules();
         }
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return isFirstChild(element) && isLastChild(element);
       }
       break;
     case CSSSelector::PseudoOnlyOfType:
       // FIXME: This selector is very slow.
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle) {
           parent->setChildrenAffectedByForwardPositionalRules();
           parent->setChildrenAffectedByBackwardPositionalRules();
         }
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return isFirstOfType(element, element.tagQName()) &&
                isLastOfType(element, element.tagQName());
       }
       break;
     case CSSSelector::PseudoPlaceholderShown:
       if (isHTMLTextFormControlElement(element))
         return toHTMLTextFormControlElement(element).isPlaceholderVisible();
       break;
     case CSSSelector::PseudoNthChild:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle)
           parent->setChildrenAffectedByForwardPositionalRules();
         return selector.matchNth(NthIndexCache::nthChildIndex(element));
       }
       break;
     case CSSSelector::PseudoNthOfType:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle)
           parent->setChildrenAffectedByForwardPositionalRules();
         return selector.matchNth(NthIndexCache::nthOfTypeIndex(element));
       }
       break;
     case CSSSelector::PseudoNthLastChild:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle)
           parent->setChildrenAffectedByBackwardPositionalRules();
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return selector.matchNth(NthIndexCache::nthLastChildIndex(element));
       }
       break;
     case CSSSelector::PseudoNthLastOfType:
       if (ContainerNode* parent = element.parentElementOrDocumentFragment()) {
         if (m_mode == ResolvingStyle)
           parent->setChildrenAffectedByBackwardPositionalRules();
-        if (!parent->isFinishedParsingChildren())
+        if (!m_isQuerySelector && !parent->isFinishedParsingChildren())
           return false;
         return selector.matchNth(NthIndexCache::nthLastOfTypeIndex(element));
       }
       break;
     case CSSSelector::PseudoTarget:
       return element == element.document().cssTarget();
     case CSSSelector::PseudoAny: {
       SelectorCheckingContext subContext(context);
       subContext.isSubSelector = true;
       DCHECK(selector.selectorList());
@@ skipping 438 matching lines @@
 }
 
 bool SelectorChecker::matchesFocusPseudoClass(const Element& element) {
   if (InspectorInstrumentation::forcePseudoState(const_cast<Element*>(&element),
                                                  CSSSelector::PseudoFocus))
     return true;
   return element.isFocused() && isFrameFocused(element);
 }
 
 }  // namespace blink