diff --git a/apps/shared/expression_model.cpp b/apps/shared/expression_model.cpp
index 2734b3d12..e84795250 100644
--- a/apps/shared/expression_model.cpp
+++ b/apps/shared/expression_model.cpp
@@ -77,7 +77,7 @@ Ion::Storage::Record::ErrorStatus ExpressionModel::setContent(Ion::Storage::Reco
   return setExpressionContent(record, e);
 }
 
-Ion::Storage::Record::ErrorStatus ExpressionModel::setExpressionContent(Ion::Storage::Record * record, Expression & newExpression) {
+Ion::Storage::Record::ErrorStatus ExpressionModel::setExpressionContent(Ion::Storage::Record * record, const Expression & newExpression) {
   assert(record->fullName() != nullptr);
   // Prepare the new data to be stored
   Ion::Storage::Record::Data newData = record->value();
diff --git a/apps/shared/expression_model.h b/apps/shared/expression_model.h
index e6a4f08bb..8e1a24d7f 100644
--- a/apps/shared/expression_model.h
+++ b/apps/shared/expression_model.h
@@ -19,7 +19,7 @@ public:
 
   // Setters
   Ion::Storage::Record::ErrorStatus setContent(Ion::Storage::Record * record, const char * c, CodePoint symbol = 0);
-  Ion::Storage::Record::ErrorStatus setExpressionContent(Ion::Storage::Record * record, Poincare::Expression & e);
+  Ion::Storage::Record::ErrorStatus setExpressionContent(Ion::Storage::Record * record, const Poincare::Expression & newExpression);
 
   // Property
   bool isCircularlyDefined(const Ion::Storage::Record * record, Poincare::Context * context) const;
diff --git a/apps/shared/expression_model_handle.h b/apps/shared/expression_model_handle.h
index 4284b0be3..b2493fa79 100644
--- a/apps/shared/expression_model_handle.h
+++ b/apps/shared/expression_model_handle.h
@@ -31,7 +31,7 @@ public:
    * Sequence). */
   virtual void tidy() { model()->tidy(); }
   Ion::Storage::Record::ErrorStatus setContent(const char * c) { return editableModel()->setContent(this, c, symbol()); }
-  Ion::Storage::Record::ErrorStatus setExpressionContent(Poincare::Expression & e) { return editableModel()->setExpressionContent(this, e); }
+  Ion::Storage::Record::ErrorStatus setExpressionContent(const Poincare::Expression & e) { return editableModel()->setExpressionContent(this, e); }
 protected:
   bool isCircularlyDefined(Poincare::Context * context) const { return model()->isCircularlyDefined(this, context); }
   ExpressionModel * editableModel() { return const_cast<ExpressionModel *>(model()); }