diff --git a/src/libs/cplusplus/Dumpers.cpp b/src/libs/cplusplus/Dumpers.cpp
index 52daefb1016317399e3d776172bf48a82e2ed34b..3d48bcf01ee38dbdbb26170b8d8b9b2908bb7be1 100644
--- a/src/libs/cplusplus/Dumpers.cpp
+++ b/src/libs/cplusplus/Dumpers.cpp
@@ -82,7 +82,7 @@ QString CPlusPlus::toString(const Symbol *s, QString id)
                 indent(toString(s->type())));
 }
 
-QString CPlusPlus::toString(LookupItem it, QString id)
+QString CPlusPlus::toString(const LookupItem &it, const QString &id)
 {
     QString result = QString::fromLatin1("%1:").arg(id);
     if (it.declaration())
@@ -114,7 +114,7 @@ void CPlusPlus::dump(const Name *name)
     qDebug() << qPrintable(toString(name));
 }
 
-void CPlusPlus::dump(FullySpecifiedType ty)
+void CPlusPlus::dump(const FullySpecifiedType &ty)
 {
     qDebug() << qPrintable(toString(ty));
 }
@@ -124,7 +124,7 @@ void CPlusPlus::dump(const Symbol *s)
     qDebug() << qPrintable(toString(s));
 }
 
-void CPlusPlus::dump(LookupItem it)
+void CPlusPlus::dump(const LookupItem &it)
 {
     qDebug() << qPrintable(toString(it));
 }
diff --git a/src/libs/cplusplus/Dumpers.h b/src/libs/cplusplus/Dumpers.h
index 19684fb285398086a2bf2cc2eeecce038b9eed2d..ceb33b100cc08becb34f8deec52a4f7895f6a74c 100644
--- a/src/libs/cplusplus/Dumpers.h
+++ b/src/libs/cplusplus/Dumpers.h
@@ -43,13 +43,13 @@ namespace CPlusPlus {
 QString CPLUSPLUS_EXPORT toString(const Name *name, QString id = QLatin1String("Name"));
 QString CPLUSPLUS_EXPORT toString(FullySpecifiedType ty, QString id = QLatin1String("Type"));
 QString CPLUSPLUS_EXPORT toString(const Symbol *s, QString id = QLatin1String("Symbol"));
-QString CPLUSPLUS_EXPORT toString(LookupItem it, QString id = QLatin1String("LookupItem"));
+QString CPLUSPLUS_EXPORT toString(const LookupItem &it, const QString &id = QLatin1String("LookupItem"));
 QString CPLUSPLUS_EXPORT toString(const ClassOrNamespace *binding, QString id = QLatin1String("ClassOrNamespace"));
 
 void CPLUSPLUS_EXPORT dump(const Name *name);
-void CPLUSPLUS_EXPORT dump(FullySpecifiedType ty);
+void CPLUSPLUS_EXPORT dump(const FullySpecifiedType &ty);
 void CPLUSPLUS_EXPORT dump(const Symbol *s);
-void CPLUSPLUS_EXPORT dump(LookupItem it);
+void CPLUSPLUS_EXPORT dump(const LookupItem &it);
 void CPLUSPLUS_EXPORT dump(const ClassOrNamespace *binding);
 
 } // namespace CPlusPlus