diff --git a/src/libs/cplusplus/TypeOfExpression.cpp b/src/libs/cplusplus/TypeOfExpression.cpp
index 8be7be2572de0ca8aaffc2817c27b7e689c4ac3c..bb773b200026cc685adfb539d7a4b41c1f572cc7 100644
--- a/src/libs/cplusplus/TypeOfExpression.cpp
+++ b/src/libs/cplusplus/TypeOfExpression.cpp
@@ -133,6 +133,9 @@ QString TypeOfExpression::preprocessedExpression(const QString &expression,
                                                  Snapshot documents,
                                                  Document::Ptr thisDocument) const
 {
+    if (expression.trimmed().isEmpty())
+        return expression;
+
     Environment env;
     QSet<QString> processed;
     processEnvironment(documents, thisDocument,