diff --git a/src/uml/class_diagram_model.cc b/src/uml/class_diagram_model.cc
index 8c0b6ec3..d957d917 100644
--- a/src/uml/class_diagram_model.cc
+++ b/src/uml/class_diagram_model.cc
@@ -316,6 +316,20 @@ bool operator==(const class_template &l, const class_template &r)
     return (l.name == r.name) && (l.type == r.type);
 }
 
+//
+// type_alias
+//
+void type_alias::set_alias(const std::string &alias) { alias_ = alias; }
+
+std::string type_alias::alias() const { return alias_; }
+
+void type_alias::set_underlying_type(const std::string &type)
+{
+    underlying_type_ = type;
+}
+
+std::string type_alias::underlying_type() const { return underlying_type_; }
+
 //
 // class_
 //
@@ -387,8 +401,8 @@ bool operator==(const class_ &l, const class_ &r)
 
 void class_::add_type_alias(type_alias &&ta)
 {
-    LOG_DBG("Adding class alias: {} -> {}", ta.alias, ta.underlying_type);
-    type_aliases_[ta.alias] = std::move(ta);
+    LOG_DBG("Adding class alias: {} -> {}", ta.alias(), ta.underlying_type());
+    type_aliases_[ta.alias()] = std::move(ta);
 }
 
 std::string class_::full_name(bool relative) const
@@ -480,9 +494,9 @@ bool diagram::has_class(const class_ &c) const
 
 void diagram::add_type_alias(type_alias &&ta)
 {
-    LOG_DBG("Adding global alias: {} -> {}", ta.alias, ta.underlying_type);
+    LOG_DBG("Adding global alias: {} -> {}", ta.alias(), ta.underlying_type());
 
-    type_aliases_[ta.alias] = std::move(ta);
+    type_aliases_[ta.alias()] = std::move(ta);
 }
 
 void diagram::add_class(class_ &&c)
diff --git a/src/uml/class_diagram_model.h b/src/uml/class_diagram_model.h
index 978a4834..6387c479 100644
--- a/src/uml/class_diagram_model.h
+++ b/src/uml/class_diagram_model.h
@@ -244,9 +244,17 @@ private:
     static std::atomic_uint64_t m_nextId;
 };
 
-struct type_alias {
-    std::string alias;
-    std::string underlying_type;
+class type_alias {
+public:
+    void set_alias(const std::string &alias);
+    std::string alias() const;
+
+    void set_underlying_type(const std::string &type);
+    std::string underlying_type() const;
+
+private:
+    std::string alias_;
+    std::string underlying_type_;
 };
 
 class class_ : public element, public stylable_element {
diff --git a/src/uml/class_diagram_visitor.cc b/src/uml/class_diagram_visitor.cc
index f23c7564..e9b1380c 100644
--- a/src/uml/class_diagram_visitor.cc
+++ b/src/uml/class_diagram_visitor.cc
@@ -246,9 +246,9 @@ void tu_visitor::operator()(const cppast::cpp_entity &file)
 
                 auto &ta = static_cast<const cppast::cpp_type_alias &>(e);
                 type_alias t;
-                t.alias = cx::util::full_name(ctx.namespace_, ta);
-                t.underlying_type = cx::util::full_name(ta.underlying_type(),
-                    ctx.entity_index, cx::util::is_inside_class(e));
+                t.set_alias(cx::util::full_name(ctx.namespace_, ta));
+                t.set_underlying_type(cx::util::full_name(ta.underlying_type(),
+                    ctx.entity_index, cx::util::is_inside_class(e)));
 
                 ctx.add_type_alias(cx::util::full_name(ctx.namespace_, ta),
                     type_safe::ref(ta.underlying_type()));