diff --git a/src/class_diagram/model/diagram.h b/src/class_diagram/model/diagram.h
index 7f230b02..5ceecfb9 100644
--- a/src/class_diagram/model/diagram.h
+++ b/src/class_diagram/model/diagram.h
@@ -29,6 +29,13 @@ namespace clanguml::class_diagram::model {
 
 class diagram : public clanguml::common::model::diagram {
 public:
+    diagram() = default;
+
+    diagram(const diagram &) = delete;
+    diagram(diagram &&) = default;
+    diagram &operator=(const diagram &) = delete;
+    diagram &operator=(diagram &&) = default;
+
     const std::vector<class_> classes() const;
 
     const std::vector<enum_> enums() const;
diff --git a/src/package_diagram/model/diagram.h b/src/package_diagram/model/diagram.h
index 2a1d8ab6..fd6778ce 100644
--- a/src/package_diagram/model/diagram.h
+++ b/src/package_diagram/model/diagram.h
@@ -34,7 +34,6 @@ public:
 
     diagram(const diagram &) = delete;
     diagram(diagram &&) = default;
-
     diagram &operator=(const diagram &) = delete;
     diagram &operator=(diagram &&) = default;
 
diff --git a/src/package_diagram/model/package.h b/src/package_diagram/model/package.h
index 6f7ed77f..dc96518d 100644
--- a/src/package_diagram/model/package.h
+++ b/src/package_diagram/model/package.h
@@ -39,8 +39,8 @@ public:
 
     package(const package &) = delete;
     package(package &&) = default;
-
     package &operator=(const package &) = delete;
+    package &operator=(package &&) = default;
 
     std::string full_name(bool relative) const override;
 
diff --git a/src/sequence_diagram/model/diagram.h b/src/sequence_diagram/model/diagram.h
index 8cbc70eb..50b4eede 100644
--- a/src/sequence_diagram/model/diagram.h
+++ b/src/sequence_diagram/model/diagram.h
@@ -27,6 +27,13 @@ namespace clanguml::sequence_diagram::model {
 
 class diagram : public clanguml::common::model::diagram {
 public:
+    diagram() = default;
+
+    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;
 
     bool started{false};