Try Clazy fix-its

clazy is a compiler plugin which allows clang to understand Qt
semantics. You get more than 50 Qt related compiler warnings, ranging
from unneeded memory allocations to misusage of API, including fix-its
for automatic refactoring.

https://invent.kde.org/sdk/clazy

sources/properties/xrefproperties.cpp

@@ -89,7 +89,8 @@ void XRefProperties::fromSettings(const QSettings &settings,
 	QMetaEnum var = QMetaEnum::fromType<Qt::Alignment>();
 	m_xref_pos = Qt::AlignmentFlag(var.keyToValue((settings.value(prefix + "xrefpos").toString()).toStdString().data()));
 
-	for (QString key : m_prefix_keys) {
+	for (const QString& key : std::as_const(m_prefix_keys))
+	{
 		m_prefix.insert(key, settings.value(prefix + key + "prefix").toString());
 	}
 }