diff --git a/poincare/src/global_context.cpp b/poincare/src/global_context.cpp
index 43c76c323..c83f7129d 100644
--- a/poincare/src/global_context.cpp
+++ b/poincare/src/global_context.cpp
@@ -55,7 +55,7 @@ const char * GlobalContext::ExtensionForExpression(const Expression & exp) {
 
 const Expression GlobalContext::ExpressionForRecord(const Ion::Storage::Record & record) {
   if (record.isNull()) {
-    return Undefined();
+    return Expression();
   }
   // Build the Expression in the Tree Pool
   return Expression(static_cast<ExpressionNode *>(TreePool::sharedPool()->copyTreeFromAddress(record.value().buffer, record.value().size)));
diff --git a/poincare/src/symbol.cpp b/poincare/src/symbol.cpp
index f4c2c4540..094ee332f 100644
--- a/poincare/src/symbol.cpp
+++ b/poincare/src/symbol.cpp
@@ -190,7 +190,7 @@ bool Symbol::isRegressionSymbol(const char * c) {
 
 bool Symbol::matches(ExpressionTest test, Context & context) const {
   Expression e = context.expressionForSymbol(*this);
-  return test(e, context);
+  return !e.isUninitialized() && test(e, context);
 }
 
 Expression Symbol::shallowReduce(Context & context, Preferences::AngleUnit angleUnit) {