diff --git a/src/common/generators/plantuml/generator.h b/src/common/generators/plantuml/generator.h
index 9906dbd7..4451e6fd 100644
--- a/src/common/generators/plantuml/generator.h
+++ b/src/common/generators/plantuml/generator.h
@@ -159,7 +159,7 @@ DiagramModel generate(cppast::libclang_compilation_database &db,
     for (auto &file : parser.files())
         ctx(file);
 
-    return d;
+    return std::move(d);
 }
 
 }
diff --git a/src/package_diagram/generators/plantuml/package_diagram_generator.cc b/src/package_diagram/generators/plantuml/package_diagram_generator.cc
index f1a68570..befc0bc4 100644
--- a/src/package_diagram/generators/plantuml/package_diagram_generator.cc
+++ b/src/package_diagram/generators/plantuml/package_diagram_generator.cc
@@ -30,6 +30,8 @@ generator::generator(diagram_config &config, diagram_model &model)
 void generator::generate_relationships(
     const package &p, std::ostream &ostr) const
 {
+    LOG_DBG("Generating relationships for package {}", p.full_name(true));
+
     const auto &uns = m_config.using_namespace();
 
     // Generate this packages relationship
@@ -52,13 +54,15 @@ void generator::generate_relationships(
     }
 
     // Process it's subpackages relationships
-    for (auto subpackage = p.cbegin(); subpackage != p.cend(); subpackage++) {
-        generate_relationships(**subpackage, ostr);
+    for (const std::unique_ptr<package> &subpackage : p) {
+        generate_relationships(*subpackage, ostr);
     }
 }
 
 void generator::generate(const package &p, std::ostream &ostr) const
 {
+    LOG_DBG("Generating package {}", p.name());
+
     const auto &uns = m_config.using_namespace();
 
     ostr << "package [" << p.name() << "] ";
@@ -72,10 +76,8 @@ void generator::generate(const package &p, std::ostream &ostr) const
 
     ostr << " {" << '\n';
 
-    // C++17 cannot figure out to use cbegin/cend in a for-range loop on const
-    // collection...  ¯\_(ツ)_/¯
-    for (auto subpackage = p.cbegin(); subpackage != p.cend(); subpackage++) {
-        generate(**subpackage, ostr);
+    for (const auto &subpackage : p) {
+        generate(*subpackage, ostr);
     }
 
     ostr << "}" << '\n';
@@ -108,5 +110,4 @@ void generator::generate(std::ostream &ostr) const
 
     ostr << "@enduml" << '\n';
 }
-
 }
diff --git a/src/package_diagram/model/diagram.h b/src/package_diagram/model/diagram.h
index 85dd70b0..c4d9ef9a 100644
--- a/src/package_diagram/model/diagram.h
+++ b/src/package_diagram/model/diagram.h
@@ -28,11 +28,16 @@
 namespace clanguml::package_diagram::model {
 
 class diagram : public clanguml::common::model::diagram,
-                public detail::package_trait<package, std::vector> {
+                public detail::package_trait<package> {
 public:
-    std::string to_alias(const std::string &full_name) const;
+    diagram() = default;
 
-private:
-    std::vector<std::unique_ptr<package>> packages_;
+    diagram(const diagram &) = delete;
+    diagram(diagram &&) = default;
+
+    diagram &operator=(const diagram &) = delete;
+    diagram &operator=(diagram &&) = default;
+
+    std::string to_alias(const std::string &full_name) const;
 };
 }
diff --git a/src/package_diagram/model/package.h b/src/package_diagram/model/package.h
index 7f9ac088..83e8646e 100644
--- a/src/package_diagram/model/package.h
+++ b/src/package_diagram/model/package.h
@@ -31,10 +31,18 @@
 namespace clanguml::package_diagram::model {
 
 namespace detail {
-template <typename T, template <typename, typename> class Container,
-    typename Ptr = std::unique_ptr<T>>
-class package_trait {
+template <typename T> class package_trait {
 public:
+    package_trait() = default;
+
+    package_trait(const package_trait &) = delete;
+    package_trait(package_trait &&) = default;
+
+    package_trait &operator=(const package_trait &) = delete;
+    package_trait &operator=(package_trait &&) = default;
+
+    virtual ~package_trait() = default;
+
     void add_package(std::unique_ptr<T> p)
     {
         auto it = std::find_if(packages_.begin(), packages_.end(),
@@ -73,8 +81,11 @@ public:
     {
         LOG_DBG("Getting package at path: {}", fmt::join(path, "::"));
 
-        if (path.empty() || !has_package(path.at(0)))
+        if (path.empty() || !has_package(path.at(0))) {
+            LOG_WARN(
+                "Sub package {} not found in package", fmt::join(path, "::"));
             return {};
+        }
 
         auto p = get_package(path.at(0));
         if (path.size() == 1)
@@ -104,26 +115,31 @@ public:
             packages_.end();
     }
 
-    typedef typename Container<Ptr, std::allocator<Ptr>>::iterator iterator;
-    typedef typename Container<Ptr, std::allocator<Ptr>>::const_iterator
-        const_iterator;
+    auto begin() { return packages_.begin(); }
+    auto end() { return packages_.end(); }
 
-    inline iterator begin() noexcept { return packages_.begin(); }
-    inline const_iterator cbegin() const noexcept { return packages_.cbegin(); }
-    inline iterator end() noexcept { return packages_.end(); }
-    inline const_iterator cend() const noexcept { return packages_.cend(); }
+    auto cbegin() const { return packages_.cbegin(); }
+    auto cend() const { return packages_.cend(); }
 
-protected:
-    Container<Ptr, std::allocator<Ptr>> packages_;
+    auto begin() const { return packages_.begin(); }
+    auto end() const { return packages_.end(); }
+
+private:
+    std::vector<std::unique_ptr<T>> packages_;
 };
 }
 
 class package : public common::model::element,
                 public common::model::stylable_element,
-                public detail::package_trait<package, std::vector> {
+                public detail::package_trait<package> {
 public:
     package(const std::vector<std::string> &using_namespaces);
 
+    package(const package &) = delete;
+    package(package &&) = default;
+
+    package &operator=(const package &) = delete;
+
     std::string full_name(bool relative) const override;
 
     friend bool operator==(const package &l, const package &r);
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index 30190d72..3a9435aa 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -82,11 +82,9 @@ clanguml::package_diagram::model::diagram generate_package_diagram(
     using diagram_visitor =
         clanguml::package_diagram::visitor::translation_unit_visitor;
 
-    auto model = clanguml::common::generators::plantuml::generate<diagram_model,
+    return clanguml::common::generators::plantuml::generate<diagram_model,
         diagram_config, diagram_visitor>(
         db, diagram->name, dynamic_cast<diagram_config &>(*diagram));
-
-    return model;
 }
 
 std::string generate_sequence_puml(