diff --git a/src/libs/cplusplus/CppDocument.cpp b/src/libs/cplusplus/CppDocument.cpp
index 58301011b95..034e2f55854 100644
--- a/src/libs/cplusplus/CppDocument.cpp
+++ b/src/libs/cplusplus/CppDocument.cpp
@@ -825,6 +825,11 @@ void Snapshot::updateDependencyTable() const
         m_deps.build(*this);
 }
 
+bool Snapshot::operator==(const Snapshot &other) const
+{
+    return _documents == other._documents;
+}
+
 void Snapshot::allIncludesForDocument_helper(const QString &fileName, QSet<QString> &result) const
 {
     if (Document::Ptr doc = document(fileName)) {
diff --git a/src/libs/cplusplus/CppDocument.h b/src/libs/cplusplus/CppDocument.h
index dba6291351e..f9d4dba3c4a 100644
--- a/src/libs/cplusplus/CppDocument.h
+++ b/src/libs/cplusplus/CppDocument.h
@@ -431,6 +431,8 @@ public:
     QStringList filesDependingOn(const QString &fileName) const;
     void updateDependencyTable() const;
 
+    bool operator==(const Snapshot &other) const;
+
 private:
     void allIncludesForDocument_helper(const QString &fileName, QSet<QString> &result) const;
 
diff --git a/src/plugins/cpptools/cppsemanticinfoupdater.cpp b/src/plugins/cpptools/cppsemanticinfoupdater.cpp
index 6c1cda731ed..f05f0d5d828 100644
--- a/src/plugins/cpptools/cppsemanticinfoupdater.cpp
+++ b/src/plugins/cpptools/cppsemanticinfoupdater.cpp
@@ -148,7 +148,8 @@ bool SemanticInfoUpdaterPrivate::reuseCurrentSemanticInfo(const SemanticInfo::So
             && currentSemanticInfo.doc
             && currentSemanticInfo.doc->translationUnit()->ast()
             && currentSemanticInfo.doc->fileName() == source.fileName
-            && !currentSemanticInfo.snapshot.isEmpty()) {
+            && !currentSemanticInfo.snapshot.isEmpty()
+            && currentSemanticInfo.snapshot == source.snapshot) {
         SemanticInfo newSemanticInfo;
         newSemanticInfo.revision = source.revision;
         newSemanticInfo.snapshot = source.snapshot;