ClangCodeModel: Classify Q_PROPERTY functions as Qt-invokable

Fixes: QTCREATORBUG-28971
Change-Id: Ia60a82aa83ad89fbf6b5d1332d413de029510b34
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangdast.cpp

@@ -172,6 +172,20 @@ bool ClangdAstNode::hasChildWithRole(const QString &role) const
                            [&role](const ClangdAstNode &c) { return c.role() == role; });
 }
 
+bool ClangdAstNode::hasChild(const std::function<bool(const ClangdAstNode &)> &predicate,
+                             bool recursive) const
+{
+    std::function<bool(const ClangdAstNode &)> fullPredicate = predicate;
+    if (recursive) {
+        fullPredicate = [&predicate](const ClangdAstNode &n) {
+            if (predicate(n))
+                return true;
+            return n.hasChild(predicate, true);
+        };
+    }
+    return Utils::contains(children().value_or(QList<ClangdAstNode>()), fullPredicate);
+}
+
 QString ClangdAstNode::operatorString() const
 {
     if (kind() == "BinaryOperator")

src/plugins/clangcodemodel/clangdast.h

@@ -77,6 +77,7 @@ public:
 
     bool childContainsRange(int index, const LanguageServerProtocol::Range &range) const;
     bool hasChildWithRole(const QString &role) const;
+    bool hasChild(const std::function<bool(const ClangdAstNode &child)> &predicate, bool recursive) const;
     QString operatorString() const;
 
     enum class FileStatus { Ours, Foreign, Mixed, Unknown };

src/plugins/clangcodemodel/clangdfindreferences.cpp

@@ -595,6 +595,19 @@ static Usage::Tags getUsageType(const ClangdAstPath &path, const QString &search
                     tags |= Usage::Tag::Operator;
                 }
             }
+            if (pathIt->kind() == "CXXMethod") {
+                const ClangdAstNode &classNode = *std::next(pathIt);
+                if (classNode.hasChild([&](const ClangdAstNode &n) {
+                    if (n.kind() != "StaticAssert")
+                        return false;
+                    return n.hasChild([&](const ClangdAstNode &n) {
+                        return n.arcanaContains("Q_PROPERTY"); }, true)
+                           && n.hasChild([&](const ClangdAstNode &n) {
+                                  return n.arcanaContains(" " + searchTerm); }, true);
+                    }, false)) {
+                    tags |= Usage::Tag::MocInvokable;
+                }
+            }
             return tags;
         }
         if (pathIt->kind() == "MemberInitializer")