diff --git a/poincare/include/poincare/layout_node.h b/poincare/include/poincare/layout_node.h
index f9aa51d50..40a2afe41 100644
--- a/poincare/include/poincare/layout_node.h
+++ b/poincare/include/poincare/layout_node.h
@@ -37,6 +37,7 @@ public:
   KDCoordinate baseline();
   //TODO: invalid cache when tempering with hierarchy
   virtual void invalidAllSizesPositionsAndBaselines();
+  int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode = Preferences::PrintFloatMode::Decimal, int numberOfSignificantDigits = 0) const override { assert(false); return 0; }
 
   // Tree
   LayoutNode * parent() const override { return static_cast<LayoutNode *>(TreeNode::parent()); }
diff --git a/poincare/include/poincare/tree_node.h b/poincare/include/poincare/tree_node.h
index f21c2efa6..4a5393b4f 100644
--- a/poincare/include/poincare/tree_node.h
+++ b/poincare/include/poincare/tree_node.h
@@ -83,7 +83,7 @@ public:
   virtual void didAddChildAtIndex(int newNumberOfChildren) {}
 
   // Serialization
-  virtual int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode = Preferences::PrintFloatMode::Decimal, int numberOfSignificantDigits = 0) const { assert(false); return 0; }
+  virtual int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const { assert(false); return 0; }
   virtual bool childNeedsParenthesis(const TreeNode * child) const { return false; };
 
   template <typename T>