diff --git a/src/libs/cplusplus/CheckUndefinedSymbols.cpp b/src/libs/cplusplus/CheckUndefinedSymbols.cpp
index 98cf2226c25c0b52297b409e136721b181e7a9d2..c972e89abb6cd087e3e5eb274019d7141c2fc2bb 100644
--- a/src/libs/cplusplus/CheckUndefinedSymbols.cpp
+++ b/src/libs/cplusplus/CheckUndefinedSymbols.cpp
@@ -196,6 +196,8 @@ void CheckUndefinedSymbols::buildTypeMap(NamespaceBinding *binding, QSet<Namespa
                     addType(e->name());
                 } else if (ForwardClassDeclaration *fwd = member->asForwardClassDeclaration()) {
                     addType(fwd->name());
+                } else if (NamespaceAlias *alias = member->asNamespaceAlias()) {
+                    addType(alias->name());
                 } else if (Declaration *decl = member->asDeclaration()) {
                     if (decl->isTypedef())
                         addType(decl->name());