diff --git a/python/core/auto_generated/expression/qgsexpressionnode.sip.in b/python/core/auto_generated/expression/qgsexpressionnode.sip.in
index ef74ec3036f..fcf88d85463 100644
--- a/python/core/auto_generated/expression/qgsexpressionnode.sip.in
+++ b/python/core/auto_generated/expression/qgsexpressionnode.sip.in
@@ -297,6 +297,9 @@ Returns a reference to the current object if no optimizations were applied.
   protected:
 
     QgsExpressionNode();
+%Docstring
+Constructor.
+%End
 
     QgsExpressionNode( const QgsExpressionNode &other );
 %Docstring
diff --git a/src/core/expression/qgsexpressionnode.h b/src/core/expression/qgsexpressionnode.h
index 58c0b177867..4e5bfb5c5df 100644
--- a/src/core/expression/qgsexpressionnode.h
+++ b/src/core/expression/qgsexpressionnode.h
@@ -345,6 +345,9 @@ class CORE_EXPORT QgsExpressionNode SIP_ABSTRACT
 
   protected:
 
+    /**
+     * Constructor.
+     */
     QgsExpressionNode() = default;
 
     //! Copy constructor