diff --git a/python/core/expression/qgsexpressionfunction.sip b/python/core/expression/qgsexpressionfunction.sip
index f7c429e7a7a..6b6636d039b 100644
--- a/python/core/expression/qgsexpressionfunction.sip
+++ b/python/core/expression/qgsexpressionfunction.sip
@@ -10,6 +10,7 @@
 
 
 
+
 class QgsExpressionFunction
 {
 %Docstring
diff --git a/src/core/expression/qgsexpressionfunction.h b/src/core/expression/qgsexpressionfunction.h
index 992cdbf9a6b..80084a2df26 100644
--- a/src/core/expression/qgsexpressionfunction.h
+++ b/src/core/expression/qgsexpressionfunction.h
@@ -16,6 +16,8 @@
 #ifndef QGSEXPRESSIONFUNCTION_H
 #define QGSEXPRESSIONFUNCTION_H
 
+#include <functional>
+
 #include <QString>
 #include <QVariant>
 #include <QSet>