diff --git a/alib2data/src/label/NextLabel.h b/alib2data/src/label/NextLabel.h
index 831d8911b7dddf52f2dd5a1094f12781b11416d7..d72a33f8c7299ebe10d7c709faecb0022c5117c0 100644
--- a/alib2data/src/label/NextLabel.h
+++ b/alib2data/src/label/NextLabel.h
@@ -36,6 +36,8 @@ class NextLabel : public VisitableLabelBase::const_visitor_type, public Visitabl
 	void Visit(void*, UniqueLabel& label) const;
 
 public:
+	NextLabel() {}
+
 	/**
 	 * Prints XML representation of String to the output stream.
 	 * @param string String to print
diff --git a/alib2data/src/primitive/NextPrimitive.h b/alib2data/src/primitive/NextPrimitive.h
index 5ad68ddc38c44e7ea2a2ac44a2a1421145b4ab91..aa92bda252bef6a694f213732f550f2a7dbafc88 100644
--- a/alib2data/src/primitive/NextPrimitive.h
+++ b/alib2data/src/primitive/NextPrimitive.h
@@ -35,6 +35,8 @@ class NextPrimitive : public VisitablePrimitiveBase::const_visitor_type, public
 	void Visit(void*, Bool& primitive) const;
 
 public:
+	NextPrimitive() {}
+
 	/**
 	 * Prints XML representation of String to the output stream.
 	 * @param string String to print