qdoc: Search for QML type before creating it

Because we have QML types that represent C++ classes,
it is possible for qdoc to process a \qmlproperty command
before it has processed the \qmltype for the QML type
where the QML property belongs. This is because the
\qmlproperty command can appear in a different .cpp file
from the one containing the \qmltype command. If the .cpp
file is parsed first, the QML type node won't exist when
the \qmlproperty is processed, resulting in a qdoc error.

This update forces qdoc to always check for the exist of
the QML type before creating it and before creating any
QML properties for it, and if the QML type does not exist,
create it. If it does exist, use it.

Change-Id: I78705aa95ee5bf3abc2e17fb2b6cd52191d54b68
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Paul Wicking <paul.wicking@qt.io>

13 files changed, 101 insertions, 145 deletions

diff --git a/src/qdoc/clangcodeparser.cpp b/src/qdoc/clangcodeparser.cpp
index 298669764..b8774b4a7 100644
--- a/src/qdoc/clangcodeparser.cpp
+++ b/src/qdoc/clangcodeparser.cpp
@@ -224,7 +224,7 @@ static Node *findNodeForCursor(QDocDatabase* qdb, CXCursor cur) {
         return qdb->primaryTreeRoot();
 
     Node *p = findNodeForCursor(qdb, clang_getCursorSemanticParent(cur));
-    if (!p)
+    if (p == nullptr)
         return nullptr;
     if (!p->isAggregate())
         return nullptr;
@@ -313,7 +313,7 @@ static Node *findFunctionNodeForCursor(QDocDatabase* qdb, CXCursor cur) {
         return qdb->primaryTreeRoot();
 
     Node *p = findNodeForCursor(qdb, clang_getCursorSemanticParent(cur));
-    if (!p || !p->isAggregate())
+    if (p == nullptr || !p->isAggregate())
         return nullptr;
     auto parent = static_cast<Aggregate *>(p);
 
@@ -617,7 +617,7 @@ CXChildVisitResult ClangVisitor::visitHeader(CXCursor cursor, CXSourceLocation l
         auto baseCursor = clang_getTypeDeclaration(type);
         auto baseNode = findNodeForCursor(qdb_, baseCursor);
         auto classe = static_cast<ClassNode*>(parent_);
-        if (!baseNode || !baseNode->isClassNode()) {
+        if (baseNode == nullptr || !baseNode->isClassNode()) {
             QString bcName = fromCXString(clang_getCursorSpelling(baseCursor));
             classe->addUnresolvedBaseClass(access, QStringList(bcName), bcName);
             return CXChildVisit_Continue;
diff --git a/src/qdoc/cppcodeparser.cpp b/src/qdoc/cppcodeparser.cpp
index cd0c9e952..0a1ee6461 100644
--- a/src/qdoc/cppcodeparser.cpp
+++ b/src/qdoc/cppcodeparser.cpp
@@ -336,11 +336,21 @@ Node* CppCodeParser::processTopicCommand(const Doc& doc,
         pn->setLocation(doc.startLocation());
         return pn;
     } else if (command == COMMAND_QMLTYPE) {
-        QmlTypeNode* qcn = new QmlTypeNode(qdb_->primaryTreeRoot(), arg.first);
+        QmlTypeNode *qcn = nullptr;
+        Node *candidate = qdb_->primaryTreeRoot()->findChildNode(arg.first, Node::QML);
+        if (candidate != nullptr)
+            qcn = static_cast<QmlTypeNode*>(candidate);
+        else
+            qcn = new QmlTypeNode(qdb_->primaryTreeRoot(), arg.first);
         qcn->setLocation(doc.startLocation());
         return qcn;
     } else if (command == COMMAND_JSTYPE) {
-        QmlTypeNode* qcn = new QmlTypeNode(qdb_->primaryTreeRoot(), arg.first, Node::JsType);
+        QmlTypeNode *qcn = nullptr;
+        Node *candidate = qdb_->primaryTreeRoot()->findChildNode(arg.first, Node::JS);
+        if (candidate != nullptr)
+            qcn = static_cast<QmlTypeNode*>(candidate);
+        else
+            qcn = new QmlTypeNode(qdb_->primaryTreeRoot(), arg.first, Node::JsType);
         qcn->setLocation(doc.startLocation());
         return qcn;
     } else if (command == COMMAND_QMLBASICTYPE) {
@@ -442,15 +452,8 @@ void CppCodeParser::processQmlProperties(const Doc &doc, NodeList &nodes, DocLis
     }
 
     QmlTypeNode* qmlType = qdb_->findQmlType(module, qmlTypeName);
-    if (qmlType == nullptr) {
-        QString msg;
-        if (topics.size() > 1 && !group.isEmpty())
-            msg = tr("QML/JS type '%1' not found for property group '%2'").arg(qmlTypeName).arg(group);
-        else
-            msg = tr("QML/JS type '%1' not found for property '%2'").arg(qmlTypeName).arg(property);
-        doc.startLocation().warning(msg);
-        return;
-    }
+    if (qmlType == nullptr)
+        qmlType = new QmlTypeNode(qdb_->primaryTreeRoot(), qmlTypeName);
 
     SharedCommentNode* scn = nullptr;
     if (topics.size() > 1) {
@@ -565,7 +568,7 @@ void CppCodeParser::processMetaCommand(const Doc &doc,
     else if (command == COMMAND_RELATES) {
         QStringList path = arg.split("::");
         Aggregate *aggregate = qdb_->findRelatesNode(path);
-        if (!aggregate)
+        if (aggregate == nullptr)
             aggregate = new ProxyNode(node->root(), arg);
 
         if (node->parent() == aggregate) { // node is already a child of aggregate
@@ -751,9 +754,9 @@ FunctionNode *CppCodeParser::parseOtherFuncArg(const QString &topic, const Locat
     funcName = colonSplit.last();
 
     Aggregate *aggregate = qdb_->findQmlType(moduleName, elementName);
-    if (!aggregate)
+    if (aggregate == nullptr)
         aggregate = qdb_->findQmlBasicType(moduleName, elementName);
-    if (!aggregate)
+    if (aggregate == nullptr)
         return nullptr;
 
     QString params;
diff --git a/src/qdoc/doc.cpp b/src/qdoc/doc.cpp
index 979bf9f2a..e460b2865 100644
--- a/src/qdoc/doc.cpp
+++ b/src/qdoc/doc.cpp
@@ -2577,7 +2577,7 @@ QString DocParser::getCode(int cmd, CodeMarker *marker, const QString &argStr)
 
     int indent = indentLevel(code);
     code = unindent(indent, code);
-    if (!marker)
+    if (marker == nullptr)
         marker = CodeMarker::markerForCode(code);
     return marker->markedUpCode(code, nullptr, location());
 }
@@ -3389,7 +3389,7 @@ QString Doc::canonicalTitle(const QString &title)
 
 void Doc::detach()
 {
-    if (!priv) {
+    if (priv == nullptr) {
         priv = new DocPrivate;
         return;
     }
diff --git a/src/qdoc/generator.cpp b/src/qdoc/generator.cpp
index 144f20704..e5720d5fb 100644
--- a/src/qdoc/generator.cpp
+++ b/src/qdoc/generator.cpp
@@ -423,7 +423,7 @@ QString Generator::fileBase(const Node *node) const
         forever {
             const Node *pp = p->parent();
             base.prepend(p->name());
-            if (!pp || pp->name().isEmpty() || pp->isTextPageNode())
+            if (pp == nullptr || pp->name().isEmpty() || pp->isTextPageNode())
                 break;
             base.prepend(QLatin1Char('-'));
             p = pp;
@@ -546,7 +546,7 @@ QMap<QString, QString>& Generator::formattingRightMap()
  */
 QString Generator::fullDocumentLocation(const Node *node, bool useSubdir)
 {
-    if (!node)
+    if (node == nullptr)
         return QString();
     if (!node->url().isEmpty())
         return node->url();
@@ -721,7 +721,7 @@ const Atom *Generator::generateAtomList(const Atom *atom,
                                         bool generate,
                                         int &numAtoms)
 {
-    while (atom) {
+    while (atom != nullptr) {
         if (atom->type() == Atom::FormatIf) {
             int numAtoms0 = numAtoms;
             bool rightFormat = canHandleFormat(atom->string());
@@ -730,7 +730,7 @@ const Atom *Generator::generateAtomList(const Atom *atom,
                                     marker,
                                     generate && rightFormat,
                                     numAtoms);
-            if (!atom)
+            if (atom == nullptr)
                 return nullptr;
 
             if (atom->type() == Atom::FormatElse) {
@@ -740,7 +740,7 @@ const Atom *Generator::generateAtomList(const Atom *atom,
                                         marker,
                                         generate && !rightFormat,
                                         numAtoms);
-                if (!atom)
+                if (atom == nullptr)
                     return nullptr;
             }
 
diff --git a/src/qdoc/helpprojectwriter.cpp b/src/qdoc/helpprojectwriter.cpp
index 06e19af7f..500052eb6 100644
--- a/src/qdoc/helpprojectwriter.cpp
+++ b/src/qdoc/helpprojectwriter.cpp
@@ -650,7 +650,7 @@ void HelpProjectWriter::generateProject(HelpProject &project)
     else
         rootNode = qdb_->primaryTreeRoot();
 
-    if (!rootNode)
+    if (rootNode == nullptr)
         return;
 
     project.files.clear();
diff --git a/src/qdoc/htmlgenerator.cpp b/src/qdoc/htmlgenerator.cpp
index 0b4c0758c..ec96d3dd4 100644
--- a/src/qdoc/htmlgenerator.cpp
+++ b/src/qdoc/htmlgenerator.cpp
@@ -2181,9 +2181,9 @@ void HtmlGenerator::generateHeader(const QString& title,
         if (node->links().contains(Node::PreviousLink)) {
             linkPair = node->links()[Node::PreviousLink];
             linkNode = qdb_->findNodeForTarget(linkPair.first, node);
-            if (!linkNode)
+            if (linkNode == nullptr)
                 node->doc().location().warning(tr("Cannot link to '%1'").arg(linkPair.first));
-            if (!linkNode || linkNode == node)
+            if (linkNode == nullptr || linkNode == node)
                 anchorPair = linkPair;
             else
                 anchorPair = anchorForNode(linkNode);
@@ -2202,9 +2202,9 @@ void HtmlGenerator::generateHeader(const QString& title,
         if (node->links().contains(Node::NextLink)) {
             linkPair = node->links()[Node::NextLink];
             linkNode = qdb_->findNodeForTarget(linkPair.first, node);
-            if (!linkNode)
+            if (linkNode == nullptr)
                 node->doc().location().warning(tr("Cannot link to '%1'").arg(linkPair.first));
-            if (!linkNode || linkNode == node)
+            if (linkNode == nullptr || linkNode == node)
                 anchorPair = linkPair;
             else
                 anchorPair = anchorForNode(linkNode);
@@ -2225,9 +2225,9 @@ void HtmlGenerator::generateHeader(const QString& title,
         if (node->links().contains(Node::StartLink)) {
             linkPair = node->links()[Node::StartLink];
             linkNode = qdb_->findNodeForTarget(linkPair.first, node);
-            if (!linkNode)
+            if (linkNode == nullptr)
                 node->doc().location().warning(tr("Cannot link to '%1'").arg(linkPair.first));
-            if (!linkNode || linkNode == node)
+            if (linkNode == nullptr || linkNode == node)
                 anchorPair = linkPair;
             else
                 anchorPair = anchorForNode(linkNode);
@@ -2412,7 +2412,7 @@ The number of rows is known.
 */
 void HtmlGenerator::generateQmlRequisites(QmlTypeNode *qcn, CodeMarker *marker)
 {
-    if (!qcn)
+    if (qcn == nullptr)
         return;
     QMap<QString, Text> requisites;
     Text text;
@@ -2434,7 +2434,7 @@ void HtmlGenerator::generateQmlRequisites(QmlTypeNode *qcn, CodeMarker *marker)
     //add the module name and version to the map
     QString logicalModuleVersion;
     const CollectionNode* collection = qdb_->getCollectionNode(qcn->logicalModuleName(), qcn->nodeType());
-    if (collection)
+    if (collection != nullptr)
         logicalModuleVersion = collection->logicalModuleVersion();
     else
         logicalModuleVersion = qcn->logicalModuleVersion();
diff --git a/src/qdoc/node.cpp b/src/qdoc/node.cpp
index 5f6f6925a..630991db3 100644
--- a/src/qdoc/node.cpp
+++ b/src/qdoc/node.cpp
@@ -1709,9 +1709,9 @@ void ClassNode::fixBaseClasses()
     // Remove private and duplicate base classes.
     while (i < bases_.size()) {
         ClassNode* bc = bases_.at(i).node_;
-        if (!bc)
+        if (bc == nullptr)
             bc = QDocDatabase::qdocDB()->findClassNode(bases_.at(i).path_);
-        if (bc && (bc->access() == Node::Private || found.contains(bc))) {
+        if (bc != nullptr && (bc->access() == Node::Private || found.contains(bc))) {
             RelatedClass rc = bases_.at(i);
             bases_.removeAt(i);
             ignoredBases_.append(rc);
@@ -1728,7 +1728,7 @@ void ClassNode::fixBaseClasses()
     i = 0;
     while (i < derived_.size()) {
         ClassNode* dc = derived_.at(i).node_;
-        if (dc && dc->access() == Node::Private) {
+        if (dc != nullptr && dc->access() == Node::Private) {
             derived_.removeAt(i);
             const QList<RelatedClass> &dd = dc->derivedClasses();
             for (int j = dd.size() - 1; j >= 0; --j)
@@ -1847,16 +1847,16 @@ FunctionNode* ClassNode::findOverriddenFunction(const FunctionNode* fn)
     QList<RelatedClass>::Iterator bc = bases_.begin();
     while (bc != bases_.end()) {
         ClassNode *cn = bc->node_;
-        if (!cn) {
+        if (cn == nullptr) {
             cn = QDocDatabase::qdocDB()->findClassNode(bc->path_);
             bc->node_ = cn;
         }
-        if (cn) {
+        if (cn != nullptr) {
             FunctionNode *result = cn->findFunctionChild(fn);
-            if (result && !result->isNonvirtual())
+            if (result != nullptr && !result->isNonvirtual())
                 return result;
             result = cn->findOverriddenFunction(fn);
-            if (result && !result->isNonvirtual())
+            if (result != nullptr && !result->isNonvirtual())
                 return result;
         }
         ++bc;
@@ -2528,7 +2528,7 @@ void FunctionNode::debug() const
  */
 bool FunctionNode::compare(const FunctionNode *fn) const
 {
-    if (!fn)
+    if (fn == nullptr)
         return false;
     if (metaness() != fn->metaness())
         return false;
@@ -3362,12 +3362,12 @@ void Aggregate::resolveQmlInheritance()
                     base = QDocDatabase::qdocDB()->findQmlType(imports[i], type->qmlBaseName());
                     if (base && (base != type)) {
                         if (base->logicalModuleVersion()[0] != imports[i].version_[0])
-                            base = 0; // Safeguard for QTBUG-53529
+                            base = nullptr; // Safeguard for QTBUG-53529
                         break;
                     }
                 }
             }
-            if (base == 0) {
+            if (base == nullptr) {
                 base = QDocDatabase::qdocDB()->findQmlType(QString(), type->qmlBaseName());
             }
             if (base && (base != type)) {
diff --git a/src/qdoc/qdocdatabase.cpp b/src/qdoc/qdocdatabase.cpp
index ab1d44f46..d7bf16ea1 100644
--- a/src/qdoc/qdocdatabase.cpp
+++ b/src/qdoc/qdocdatabase.cpp
@@ -159,7 +159,7 @@ void QDocForest::setPrimaryTree(const QString& t)
     QString T = t.toLower();
     primaryTree_ = findTree(T);
     forest_.remove(T);
-    if (!primaryTree_)
+    if (primaryTree_ == nullptr)
         qDebug() << "ERROR: Could not set primary tree to:" << t;
 }
 
@@ -477,7 +477,7 @@ QDocDatabase::~QDocDatabase()
 */
 QDocDatabase* QDocDatabase::qdocDB()
 {
-    if (!qdocDB_) {
+    if (qdocDB_ == nullptr) {
       qdocDB_ = new QDocDatabase;
       initializeDB();
     }
@@ -489,7 +489,7 @@ QDocDatabase* QDocDatabase::qdocDB()
  */
 void QDocDatabase::destroyQdocDB()
 {
-    if (qdocDB_) {
+    if (qdocDB_ != nullptr) {
         delete qdocDB_;
         qdocDB_ = nullptr;
     }
@@ -1555,7 +1555,7 @@ const Node* QDocDatabase::findNodeForAtom(const Atom* a, const Node* relative, Q
             QStringList path = function.split("::");
             node = domain->findFunctionNode(path, Parameters(signature), nullptr, genus);
         }
-        if (!node) {
+        if (node == nullptr) {
             int flags = SearchBaseClasses | SearchEnumValues;
             QStringList nodePath = first.split("::");
             QString target;
@@ -1572,11 +1572,11 @@ const Node* QDocDatabase::findNodeForAtom(const Atom* a, const Node* relative, Q
             node = findNodeByNameAndType(QStringList(first), &Node::isPageNode);
         else if (first.endsWith(QChar(')')))
             node = findFunctionNode(first, relative, genus);
-        if (!node)
+        if (node == nullptr)
             return findNodeForTarget(targetPath, relative, genus, ref);
     }
 
-    if (node && ref.isEmpty()) {
+    if (node != nullptr && ref.isEmpty()) {
         if (!node->url().isEmpty())
             return node;
         targetPath.removeFirst();
diff --git a/src/qdoc/qdocindexfiles.cpp b/src/qdoc/qdocindexfiles.cpp
index 7302149a3..617c132f2 100644
--- a/src/qdoc/qdocindexfiles.cpp
+++ b/src/qdoc/qdocindexfiles.cpp
@@ -85,7 +85,7 @@ QDocIndexFiles::~QDocIndexFiles()
  */
 QDocIndexFiles* QDocIndexFiles::qdocIndexFiles()
 {
-   if (!qdocIndexFiles_)
+   if (qdocIndexFiles_ == nullptr)
       qdocIndexFiles_ = new QDocIndexFiles;
    return qdocIndexFiles_;
 }
@@ -95,7 +95,7 @@ QDocIndexFiles* QDocIndexFiles::qdocIndexFiles()
  */
 void QDocIndexFiles::destroyQDocIndexFiles()
 {
-    if (qdocIndexFiles_) {
+    if (qdocIndexFiles_ != nullptr) {
         delete qdocIndexFiles_;
         qdocIndexFiles_ = nullptr;
     }
@@ -762,7 +762,7 @@ static const QString getThreadSafenessString(Node::ThreadSafeness t)
  */
 bool QDocIndexFiles::generateIndexSection(QXmlStreamWriter &writer, Node *node, IndexSectionWriter *post)
 {
-    if (!gen_)
+    if (gen_ == nullptr)
         gen_ = Generator::currentGenerator();
 
     Q_ASSERT(gen_);
diff --git a/src/qdoc/qdoctagfiles.cpp b/src/qdoc/qdoctagfiles.cpp
index 2c934193b..e04f684a3 100644
--- a/src/qdoc/qdoctagfiles.cpp
+++ b/src/qdoc/qdoctagfiles.cpp
@@ -73,7 +73,7 @@ QDocTagFiles::~QDocTagFiles()
  */
 QDocTagFiles* QDocTagFiles::qdocTagFiles()
 {
-   if (!qdocTagFiles_)
+   if (qdocTagFiles_ == nullptr)
       qdocTagFiles_ = new QDocTagFiles;
    return qdocTagFiles_;
 }
@@ -83,7 +83,7 @@ QDocTagFiles* QDocTagFiles::qdocTagFiles()
  */
 void QDocTagFiles::destroyQDocTagFiles()
 {
-    if (qdocTagFiles_) {
+    if (qdocTagFiles_ != nullptr) {
         delete qdocTagFiles_;
         qdocTagFiles_ = nullptr;
     }
diff --git a/src/qdoc/qmlvisitor.cpp b/src/qdoc/qmlvisitor.cpp
index c52081847..e41a544f2 100644
--- a/src/qdoc/qmlvisitor.cpp
+++ b/src/qdoc/qmlvisitor.cpp
@@ -550,7 +550,12 @@ bool QmlDocVisitor::visit(QQmlJS::AST::UiObjectDefinition *definition)
     nestingLevel++;
 
     if (current->isNamespace()) {
-        QmlTypeNode *component = new QmlTypeNode(current, name);
+        QmlTypeNode *component = nullptr;
+        Node *candidate = current ->findChildNode(name, Node::QML);
+        if (candidate != nullptr)
+            component = static_cast<QmlTypeNode*>(candidate);
+        else
+            component = new QmlTypeNode(current, name);
         component->setTitle(name);
         component->setImportList(importList);
         importList.clear();
diff --git a/src/qdoc/sections.cpp b/src/qdoc/sections.cpp
index 5ba7ea09f..14bf96191 100644
--- a/src/qdoc/sections.cpp
+++ b/src/qdoc/sections.cpp
@@ -35,7 +35,7 @@
 
 QT_BEGIN_NAMESPACE
 
-//Aggregate *Sections::aggregate_ = 0;
+//Aggregate *Sections::aggregate_ = nullptr;
 
 static bool sectionsInitialized = false;
 QVector<Section> Sections::stdSummarySections_(7, Section(Section::Summary, Section::Active));
diff --git a/src/qdoc/tree.cpp b/src/qdoc/tree.cpp
index b63bec4cf..dff42d095 100644
--- a/src/qdoc/tree.cpp
+++ b/src/qdoc/tree.cpp
@@ -129,7 +129,7 @@ Tree::~Tree()
 Node* Tree::findNodeForInclude(const QStringList& path) const
 {
     Node* n = findClassNode(path);
-    if (!n)
+    if (n == nullptr)
         n = findNamespaceNode(path);
     return n;
 }
@@ -157,7 +157,7 @@ Aggregate *Tree::findAggregate(const QString &name)
  */
 ClassNode* Tree::findClassNode(const QStringList& path, const Node* start) const
 {
-    if (!start)
+    if (start == nullptr)
         start = const_cast<NamespaceNode*>(root());
     return static_cast<ClassNode*>(findNodeRecursive(path, 0, start, &Node::isClassNode));
 }
@@ -191,7 +191,7 @@ QmlTypeNode* Tree::findQmlTypeNode(const QStringList& path)
     */
     if (path.size() >= 2 && !path[0].isEmpty()) {
         QmlTypeNode* qcn = qdb_->findQmlType(path[0], path[1]);
-        if (qcn)
+        if (qcn != nullptr)
             return qcn;
     }
     return static_cast<QmlTypeNode*>(findNodeRecursive(path, 0, root(), &Node::isQmlType));
@@ -212,7 +212,7 @@ QmlTypeNode* Tree::findQmlTypeNode(const QStringList& path)
 Aggregate *Tree::findRelatesNode(const QStringList &path)
 {
     Node* n = findNodeRecursive(path, 0, root(), &Node::isRelatableType);
-    return ((n && n->isAggregate()) ? static_cast<Aggregate*>(n) : nullptr);
+    return (((n != nullptr) && n->isAggregate()) ? static_cast<Aggregate*>(n) : nullptr);
 }
 
 /*!
@@ -272,7 +272,7 @@ void Tree::resolveInheritanceHelper(int pass, ClassNode* cn)
         QList<RelatedClass>& bases = cn->baseClasses();
         QList<RelatedClass>::iterator b = bases.begin();
         while (b != bases.end()) {
-            if (!(*b).node_) {
+            if ((*b).node_ == nullptr) {
                 Node* n = qdb_->findClassNode((*b).path_);
                 /*
                   If the node for the base class was not found,
@@ -284,14 +284,14 @@ void Tree::resolveInheritanceHelper(int pass, ClassNode* cn)
                   at the parent of the subclass node (the namespace
                   node) using the unqualified base class name.
                  */
-                if (!n) {
+                if (n == nullptr) {
                     Aggregate* parent = cn->parent();
-                    if (parent)
+                    if (parent != nullptr)
                         // Exclude the root namespace
                         if (parent->isNamespace() && !parent->name().isEmpty())
                             n = findClassNode((*b).path_, parent);
                 }
-                if (n) {
+                if (n != nullptr) {
                     ClassNode* bcn = static_cast<ClassNode*>(n);
                     (*b).node_ = bcn;
                     bcn->addDerivedClass((*b).access_, cn);
@@ -395,9 +395,9 @@ void Tree::resolveUsingClauses()
             QList<UsingClause>& usingClauses = cn->usingClauses();
             QList<UsingClause>::iterator uc = usingClauses.begin();
             while (uc != usingClauses.end()) {
-                if (!(*uc).node()) {
+                if ((*uc).node() == nullptr) {
                     const Node* n = qdb_->findFunctionNode((*uc).signature(), cn, Node::CPP);
-                    if (n)
+                    if (n != nullptr)
                         (*uc).setNode(n);
                 }
                 ++uc;
@@ -410,7 +410,7 @@ void Tree::resolveUsingClauses()
  */
 void Tree::fixInheritance(NamespaceNode* rootNode)
 {
-    if (!rootNode)
+    if (rootNode == nullptr)
         rootNode = root();
 
     NodeList::ConstIterator c = rootNode->constBegin();
@@ -429,7 +429,7 @@ ClassList Tree::allBaseClasses(const ClassNode *classNode) const
 {
     ClassList result;
     foreach (const RelatedClass& r, classNode->baseClasses()) {
-        if (r.node_) {
+        if (r.node_ != nullptr) {
             result += r.node_;
             result += allBaseClasses(r.node_);
         }
@@ -483,7 +483,7 @@ Node* Tree::findNodeRecursive(const QStringList& path,
     const NodeList& children = current->childNodes();
     const QString& name = path.at(pathIndex);
     foreach (Node *n, children) {
-        if (!n)
+        if (n == nullptr)
             continue;
         if (n->name() == name) {
             if (pathIndex+1 >= path.size()) {
@@ -493,66 +493,14 @@ Node* Tree::findNodeRecursive(const QStringList& path,
             }
             else { // Search the children of n for the next name in the path.
                 n = findNodeRecursive(path, pathIndex+1, n, isMatch);
-                if (n)
+                if (n != nullptr)
                     return n;
             }
         }
     }
     return nullptr;
 }
-#if 0
-/*!
-  Recursive search for a node identified by \a path. Each
-  path element is a name. \a pathIndex specifies the index
-  of the name in \a path to try to match. \a start is the
-  node whose children shoulod be searched for one that has
-  that name. Each time a match is found, increment the
-  \a pathIndex and call this function recursively.
-
-  If the end of the path is reached (i.e. if a matching
-  node is found for each name in the \a path), the \a type
-  must match the type of the last matching node, and if the
-  type is \e{Page}, the \a subtype must match as well.
-
-  If the algorithm is successful, the pointer to the final
-  node is returned. Otherwise 0 is returned.
- */
-Node* Tree::findNodeRecursive(const QStringList& path,
-                              int pathIndex,
-                              const Node* start,
-                              Node::NodeType type) const
-{
-    if (!start || path.isEmpty())
-        return 0; // no place to start, or nothing to search for.
-    Node* node = const_cast<Node*>(start);
-    if (!start->isAggregate()) {
-        if (pathIndex >= path.size())
-            return node; // found a match.
-        return 0; // premature leaf
-    }
 
-    Aggregate* current = static_cast<Aggregate*>(node);
-    const NodeList& children = current->childNodes();
-    const QString& name = path.at(pathIndex);
-    foreach (Node *n, children) {
-        if (!n)
-            continue;
-        if (n->name() == name) {
-            if (pathIndex+1 >= path.size()) {
-                if ((n->nodeType() == type) || (type == Node::NoType))
-                    return n;
-                continue;
-            }
-            else { // Search the children of n for the next name in the path.
-                n = findNodeRecursive(path, pathIndex+1, n, type);
-                if (n)
-                    return n;
-            }
-        }
-    }
-    return nullptr;
-}
-#endif
 /*!
   Searches the tree for a node that matches the \a path plus
   the \a target. The search begins at \a start and moves up
@@ -599,7 +547,7 @@ const Node* Tree::findNodeForTarget(const QStringList& path,
     }
 
     const Node* current = start;
-    if (!current)
+    if (current == nullptr)
         current = root();
 
     /*
@@ -630,7 +578,7 @@ const Node* Tree::findNodeForTarget(const QStringList& path,
         }
     }
 
-    while (current) {
+    while (current != nullptr) {
         if (current->isAggregate()) { // Should this be isPageNode() ???
             const Node* node = matchPathAndTarget(path, path_idx, target, current, flags, genus, ref);
             if (node)
@@ -736,7 +684,7 @@ const Node* Tree::findNode(const QStringList& path,
                            Node::Genus genus) const
 {
     const Node* current = start;
-    if (!current)
+    if (current == nullptr)
         current = root();
 
     do {
@@ -755,7 +703,7 @@ const Node* Tree::findNode(const QStringList& path,
         if (((genus == Node::QML) || (genus == Node::DontCare)) &&
             (path.size() >= 2) && !path[0].isEmpty()) {
             QmlTypeNode* qcn = lookupQmlType(QString(path[0] + "::" + path[1]));
-            if (qcn) {
+            if (qcn != nullptr) {
                 node = qcn;
                 if (path.size() == 2)
                     return node;
@@ -772,26 +720,26 @@ const Node* Tree::findNode(const QStringList& path,
             int tmpFlags = (i < path.size() - 1) ? (flags & ~TypesOnly) | IgnoreModules : flags;
 
             const Node* next = static_cast<const Aggregate*>(node)->findChildNode(path.at(i), genus, tmpFlags);
-            if (!next && (flags & SearchEnumValues) && i == path.size()-1) {
+            if ((next == nullptr) && (flags & SearchEnumValues) && i == path.size()-1) {
                 next = static_cast<const Aggregate*>(node)->findEnumNodeForValue(path.at(i));
             }
-            if (!next && ((genus == Node::CPP) || (genus == Node::DontCare)) &&
+            if ((next == nullptr) && ((genus == Node::CPP) || (genus == Node::DontCare)) &&
                 node->isClassNode() && (flags & SearchBaseClasses)) {
                 ClassList bases = allBaseClasses(static_cast<const ClassNode*>(node));
                 foreach (const ClassNode *base, bases) {
                     next = base->findChildNode(path.at(i), genus, tmpFlags);
-                    if (!next && (flags & SearchEnumValues) && i == path.size() - 1)
+                    if ((next == nullptr) && (flags & SearchEnumValues) && i == path.size() - 1)
                         next = base->findEnumNodeForValue(path.at(i));
-                    if (next)
+                    if (next != nullptr)
                         break;
                 }
             }
             node = next;
         }
-        if (node && i == path.size())
+        if ((node != nullptr) && i == path.size())
             return node;
         current = current->parent();
-    } while (current);
+    } while (current != nullptr);
 
     return nullptr;
 }
@@ -1308,13 +1256,13 @@ const FunctionNode *Tree::findFunctionNode(const QStringList &path,
     if (path.size() == 3 && !path[0].isEmpty() &&
         ((genus == Node::QML) || (genus == Node::DontCare))) {
         QmlTypeNode *qcn = lookupQmlType(QString(path[0] + "::" + path[1]));
-        if (!qcn) {
+        if (qcn == nullptr) {
             QStringList p(path[1]);
             Node* n = findNodeByNameAndType(p, &Node::isQmlType);
-            if (n && (n->isQmlType() || n->isJsType()))
+            if ((n != nullptr) && (n->isQmlType() || n->isJsType()))
                 qcn = static_cast<QmlTypeNode*>(n);
         }
-        if (qcn)
+        if (qcn != nullptr)
             return static_cast<const FunctionNode*>(qcn->findFunctionChild(path[2], parameters));
     }
 
@@ -1340,7 +1288,7 @@ const FunctionNode *Tree::findFunctionNode(const QStringList &path,
             else
                 next = aggregate->findChildNode(path.at(i), genus);
 
-            if (!next && aggregate->isClassNode()) {
+            if ((next == nullptr) && aggregate->isClassNode()) {
                 ClassList bases = allBaseClasses(static_cast<const ClassNode*>(aggregate));
                 foreach (ClassNode *base, bases) {
                     if (i == path.size() - 1)
@@ -1396,7 +1344,7 @@ QString Tree::getNewLinkTarget(const Node* locNode,
                                bool broken)
 {
     QString physicalModuleName;
-    if (t && !broken) {
+    if (t != nullptr && !broken) {
         Tree* tree = t->tree();
         if (tree != this)
             tree->incrementLinkCount();
@@ -1435,17 +1383,17 @@ TargetList* Tree::getTargetList(const QString& module)
  */
 FunctionNode *Tree::findFunctionNodeForTag(const QString &tag, Aggregate *parent)
 {
-    if (!parent)
+    if (parent == nullptr)
         parent = root();
     const NodeList& children = parent->childNodes();
     for (Node *n : children) {
-        if (n && n->isFunction() && n->hasTag(tag))
+        if (n != nullptr && n->isFunction() && n->hasTag(tag))
             return static_cast<FunctionNode*>(n);
     }
     for (Node *n : children) {
-        if (n && n->isAggregate()) {
+        if (n != nullptr && n->isAggregate()) {
             n = findFunctionNodeForTag(tag, static_cast<Aggregate*>(n));
-            if (n)
+            if (n != nullptr)
                 return static_cast<FunctionNode*>(n);
         }
     }
@@ -1458,17 +1406,17 @@ FunctionNode *Tree::findFunctionNodeForTag(const QString &tag, Aggregate *parent
  */
 FunctionNode *Tree::findMacroNode(const QString &t, const Aggregate *parent)
 {
-    if (!parent)
+    if (parent == nullptr)
         parent = root();
     const NodeList &children = parent->childNodes();
     for (Node *n : children) {
-        if (n && (n->isMacro() || n->isFunction()) && n->name() == t)
+        if (n != nullptr && (n->isMacro() || n->isFunction()) && n->name() == t)
             return static_cast<FunctionNode*>(n);
     }
     for (Node *n : children) {
-        if (n && n->isAggregate()) {
+        if (n != nullptr && n->isAggregate()) {
             FunctionNode *fn = findMacroNode(t, static_cast<Aggregate*>(n));
-            if (fn)
+            if (fn != nullptr)
                 return fn;
         }
     }