diff --git a/src/engine/document.cpp b/src/engine/document.cpp
--- a/src/engine/document.cpp
+++ b/src/engine/document.cpp
@@ -47,15 +47,15 @@
     Q_ASSERT(!term.isEmpty());
     TermData& td = m_terms[term];
     td.wdf += wdfInc;
-    td.positions += position;
+    td.positions.append(position);
 }
 
 void Document::addXattrPositionTerm(const QByteArray& term, int position, int wdfInc)
 {
     Q_ASSERT(!term.isEmpty());
     TermData& td = m_xattrTerms[term];
     td.wdf += wdfInc;
-    td.positions += position;
+    td.positions.append(position);
 }
 
 void Document::addXattrTerm(const QByteArray& term, int wdfInc)
@@ -75,7 +75,7 @@
     Q_ASSERT(!term.isEmpty());
     TermData& td = m_fileNameTerms[term];
     td.wdf += wdfInc;
-    td.positions += position;
+    td.positions.append(position);
 }
 
 void Document::addFileNameTerm(const QByteArray& term, int wdfInc)