diff --git a/src/class_diagram/model/diagram.cc b/src/class_diagram/model/diagram.cc
index e964244c..a240f8eb 100644
--- a/src/class_diagram/model/diagram.cc
+++ b/src/class_diagram/model/diagram.cc
@@ -99,15 +99,16 @@ void diagram::add_type_alias(std::unique_ptr<type_alias> &&ta)
     type_aliases_[ta->alias()] = std::move(ta);
 }
 
-void diagram::add_package(std::unique_ptr<common::model::package> &&p)
+bool diagram::add_package(std::unique_ptr<common::model::package> &&p)
 {
     LOG_DBG("Adding namespace package: {}, {}", p->name(), p->full_name(true));
 
     auto ns = p->get_relative_namespace();
-    add_element(ns, std::move(p));
+
+    return add_element(ns, std::move(p));
 }
 
-void diagram::add_class(std::unique_ptr<class_> &&c)
+bool diagram::add_class(std::unique_ptr<class_> &&c)
 {
     const auto base_name = c->name();
     const auto full_name = c->full_name(false);
@@ -128,33 +129,48 @@ void diagram::add_class(std::unique_ptr<class_> &&c)
     auto name = base_name;
     auto name_with_ns = c->name_and_ns();
     auto name_and_ns = ns | name;
+    const auto &cc = *c;
 
-    if (!has_class(*c)) {
-        classes_.push_back(type_safe::ref(*c));
+    auto cc_ref = type_safe::ref(cc);
 
-        add_element(ns, std::move(c));
+    if (!has_class(cc)) {
+        if (add_element(ns, std::move(c)))
+            classes_.push_back(std::move(cc_ref));
 
         const auto &el = get_element<class_>(name_and_ns).value();
+
         assert(el.name() == name);
         assert(el.get_relative_namespace() == ns);
+
+        return true;
     }
-    else
-        LOG_DBG("Class {} ({}) already in the model", base_name, full_name);
+
+    LOG_DBG("Class {} ({}) already in the model", base_name, full_name);
+
+    return false;
 }
 
-void diagram::add_enum(std::unique_ptr<enum_> &&e)
+bool diagram::add_enum(std::unique_ptr<enum_> &&e)
 {
-    LOG_DBG("Adding enum: {}", e->name());
+    const auto full_name = e->name();
+
+    LOG_DBG("Adding enum: {}", full_name);
 
     assert(!util::contains(e->name(), "::"));
 
+    auto e_ref = type_safe::ref(*e);
+    auto ns = e->get_relative_namespace();
+
     if (!has_enum(*e)) {
-        enums_.emplace_back(*e);
-        auto ns = e->get_relative_namespace();
-        add_element(ns, std::move(e));
+        if (add_element(ns, std::move(e))) {
+            enums_.emplace_back(std::move(e_ref));
+            return true;
+        }
     }
-    else
-        LOG_DBG("Enum {} already in the model", e->name());
+
+    LOG_DBG("Enum {} already in the model", full_name);
+
+    return false;
 }
 
 void diagram::get_parents(
diff --git a/src/class_diagram/model/diagram.h b/src/class_diagram/model/diagram.h
index ccfc546d..48d3887b 100644
--- a/src/class_diagram/model/diagram.h
+++ b/src/class_diagram/model/diagram.h
@@ -63,11 +63,11 @@ public:
 
     void add_type_alias(std::unique_ptr<type_alias> &&ta);
 
-    void add_class(std::unique_ptr<class_> &&c);
+    bool add_class(std::unique_ptr<class_> &&c);
 
-    void add_enum(std::unique_ptr<enum_> &&e);
+    bool add_enum(std::unique_ptr<enum_> &&e);
 
-    void add_package(std::unique_ptr<common::model::package> &&p);
+    bool add_package(std::unique_ptr<common::model::package> &&p);
 
     std::string to_alias(const std::string &full_name) const;
 
diff --git a/src/class_diagram/visitor/translation_unit_visitor.cc b/src/class_diagram/visitor/translation_unit_visitor.cc
index 83ca6db7..acbe6349 100644
--- a/src/class_diagram/visitor/translation_unit_visitor.cc
+++ b/src/class_diagram/visitor/translation_unit_visitor.cc
@@ -765,9 +765,12 @@ bool translation_unit_visitor::process_field_with_template_instantiation(
         }
     }
 
+    const auto tinst_namespace = tinst.get_namespace();
+    const auto tinst_name = tinst.name();
+
     // Add instantiation relationship from the generated template instantiation
     // of the field type to its primary template
-    if (ctx.diagram().should_include(tinst.get_namespace(), tinst.name())) {
+    if (ctx.diagram().should_include(tinst_namespace, tinst_name)) {
         LOG_DBG("Adding field instantiation relationship {} {} {} : {}",
             rr.destination(), clanguml::common::model::to_string(rr.type()),
             c.full_name(), rr.label());
@@ -787,7 +790,7 @@ bool translation_unit_visitor::process_field_with_template_instantiation(
     // Only add nested template relationships to this class if the top level
     // template is not in the diagram (e.g. it is a std::shared_ptr<>)
     //
-    if (!ctx.diagram().should_include(tinst.get_namespace(), tinst.name())) {
+    if (!ctx.diagram().should_include(tinst_namespace, tinst_name)) {
         res = add_nested_template_relationships(mv, c, member, as, tinst,
             relationship_type, decorator_rtype, decorator_rmult);
     }
@@ -1660,16 +1663,21 @@ std::unique_ptr<class_> translation_unit_visitor::build_template_instantiation(
 
     tinst.set_namespace(ctx.get_namespace());
 
-    auto tinst_full_name = cppast::to_string(t);
+    std::string tinst_full_name;
 
     //
     // Typically, every template instantiation should have a
-    // primary_template() which should also be generated here if it doesn't
+    // primary_template(), which should also be generated here if it doesn't
     // exist yet in the model
     //
-    if (t.primary_template().get(ctx.entity_index()).size()) {
-        auto size = t.primary_template().get(ctx.entity_index()).size();
-        (void)size;
+    if (t_is_alias &&
+        unaliased.primary_template().get(ctx.entity_index()).size()) {
+        tinst_full_name = cppast::to_string(unaliased);
+        build_template_instantiation_primary_template(
+            unaliased, tinst, template_base_params, parent, full_template_name);
+    }
+    else if (t.primary_template().get(ctx.entity_index()).size()) {
+        tinst_full_name = cppast::to_string(t);
         build_template_instantiation_primary_template(
             t, tinst, template_base_params, parent, full_template_name);
     }
@@ -1677,6 +1685,7 @@ std::unique_ptr<class_> translation_unit_visitor::build_template_instantiation(
         LOG_DBG("Template instantiation {} has no primary template?",
             cppast::to_string(t));
 
+        tinst_full_name = cppast::to_string(t);
         full_template_name = cppast::to_string(t);
     }
 
diff --git a/src/common/model/nested_trait.h b/src/common/model/nested_trait.h
index b4e79cfe..bd134a7f 100644
--- a/src/common/model/nested_trait.h
+++ b/src/common/model/nested_trait.h
@@ -38,21 +38,24 @@ public:
 
     virtual ~nested_trait() = default;
 
-    template <typename V = T> void add_element(std::unique_ptr<V> p)
+    template <typename V = T>
+    [[nodiscard]] bool add_element(std::unique_ptr<V> p)
     {
         auto it = std::find_if(elements_.begin(), elements_.end(),
             [&p](const auto &e) { return *e == *p; });
 
         if (it != elements_.end()) {
-            (*it)->append(*p);
-        }
-        else {
-            elements_.emplace_back(std::move(p));
+            // Element already in element tree
+            return false;
         }
+
+        elements_.emplace_back(std::move(p));
+
+        return true;
     }
 
     template <typename V = T>
-    void add_element(const Path &path, std::unique_ptr<V> p)
+    bool add_element(const Path &path, std::unique_ptr<V> p)
     {
         assert(p);
 
@@ -60,14 +63,13 @@ public:
             path.to_string());
 
         if (path.is_empty()) {
-            add_element(std::move(p));
-            return;
+            return add_element(std::move(p));
         }
 
         auto parent = get_element(path);
 
         if (parent && dynamic_cast<nested_trait<T, Path> *>(&parent.value()))
-            dynamic_cast<nested_trait<T, Path> &>(parent.value())
+            return dynamic_cast<nested_trait<T, Path> &>(parent.value())
                 .template add_element<V>(std::move(p));
         else {
             spdlog::error("No parent element found at: {}", path.to_string());
diff --git a/src/include_diagram/visitor/translation_unit_visitor.cc b/src/include_diagram/visitor/translation_unit_visitor.cc
index 29daf43e..da1189b2 100644
--- a/src/include_diagram/visitor/translation_unit_visitor.cc
+++ b/src/include_diagram/visitor/translation_unit_visitor.cc
@@ -132,7 +132,8 @@ void translation_unit_visitor::process_external_system_header(
     f->set_name(include_directive.name());
     f->set_type(common::model::source_file_t::kHeader);
 
-    ctx.diagram().add_element(std::move(f));
+    if (!ctx.diagram().add_element(std::move(f)))
+        LOG_DBG("Include {} already in the model", include_directive.name());
 
     auto dependency_relationship = common::model::relationship{
         common::model::relationship_t::kDependency,
diff --git a/tests/t00014/t00014.cc b/tests/t00014/t00014.cc
index 880f7d0b..c065b3f7 100644
--- a/tests/t00014/t00014.cc
+++ b/tests/t00014/t00014.cc
@@ -48,11 +48,13 @@ using BVector2 = BVector;
 
 using AIntString = AString<int>;
 using ACharString = AString<char>;
-using AWCharString = AString<wchar_t>;
+
 using AStringString = AString<std::string>;
 using BStringString = AStringString;
 
 class R {
+    using AWCharString = AString<wchar_t>;
+
     PairPairBA<bool> bapair;
 
     APtr<bool> abool;
diff --git a/tests/t00014/test_case.h b/tests/t00014/test_case.h
index 7b5c0299..cac37dce 100644
--- a/tests/t00014/test_case.h
+++ b/tests/t00014/test_case.h
@@ -61,7 +61,8 @@ TEST_CASE("t00014", "[test-case][class]")
     REQUIRE_THAT(puml, IsField<Protected>("bs", "BVector"));
 
     REQUIRE_THAT(puml, IsField<Public>("cb", "SimpleCallback<ACharString>"));
-    REQUIRE_THAT(puml, IsField<Public>("gcb", "GenericCallback<AWCharString>"));
+    REQUIRE_THAT(
+        puml, IsField<Public>("gcb", "GenericCallback<R::AWCharString>"));
     REQUIRE_THAT(puml, IsField<Public>("vcb", "VoidCallback"));
 
     REQUIRE_THAT(
diff --git a/tests/t00044/.clang-uml b/tests/t00044/.clang-uml
new file mode 100644
index 00000000..69dab8ac
--- /dev/null
+++ b/tests/t00044/.clang-uml
@@ -0,0 +1,13 @@
+compilation_database_dir: ..
+output_directory: puml
+diagrams:
+  t00044_class:
+    type: class
+    generate_packages: true
+    glob:
+      - ../../tests/t00044/t00044.cc
+    using_namespace:
+      - clanguml::t00044
+    include:
+      namespaces:
+        - clanguml::t00044
\ No newline at end of file
diff --git a/tests/t00044/t00044.cc b/tests/t00044/t00044.cc
new file mode 100644
index 00000000..67ff645b
--- /dev/null
+++ b/tests/t00044/t00044.cc
@@ -0,0 +1,35 @@
+// Inspired by skypjack/entt signal handlers
+// This test case checks that at least clang-uml does not crash on this code
+namespace clanguml::t00044 {
+
+template <typename T> class sink;
+
+template <typename T, typename A> class signal_handler;
+
+template <typename Ret, typename... Args, typename A>
+class sink<signal_handler<Ret(Args...), A>> {
+    using signal_t = signal_handler<Ret(Args...), A>;
+
+public:
+    sink(signal_t &sh)
+        : signal{&sh}
+    {
+    }
+
+private:
+    signal_t *signal;
+};
+
+template <typename Ret, typename... Args, typename A>
+class signal_handler<Ret(Args...), A> {
+};
+
+template <typename Ret, typename... Args, typename A>
+sink(signal_handler<Ret(Args...), A> &)
+    -> sink<signal_handler<Ret(Args...), A>>;
+
+signal_handler<void(int), bool> int_handler;
+
+sink sink1{int_handler};
+
+} // namespace clanguml::t00044
diff --git a/tests/t00044/test_case.h b/tests/t00044/test_case.h
new file mode 100644
index 00000000..26b4fa16
--- /dev/null
+++ b/tests/t00044/test_case.h
@@ -0,0 +1,43 @@
+/**
+ * tests/t00044/test_case.cc
+ *
+ * Copyright (c) 2021-2022 Bartek Kryza <bkryza@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+TEST_CASE("t00044", "[test-case][class]")
+{
+    auto [config, db] = load_config("t00044");
+
+    auto diagram = config.diagrams["t00044_class"];
+
+    REQUIRE(diagram->name == "t00044_class");
+    REQUIRE(diagram->generate_packages() == true);
+
+    auto model = generate_class_diagram(db, diagram);
+
+    REQUIRE(model->name() == "t00044_class");
+
+    auto puml = generate_class_puml(diagram, *model);
+    AliasMatcher _A(puml);
+
+    REQUIRE_THAT(puml, StartsWith("@startuml"));
+    REQUIRE_THAT(puml, EndsWith("@enduml\n"));
+
+    // Check dependants filter<void(int), bool>
+    REQUIRE_THAT(puml, IsClassTemplate("signal_handler", "Ret,Args...,A"));
+
+    save_puml(
+        "./" + config.output_directory() + "/" + diagram->name + ".puml", puml);
+}
diff --git a/tests/test_cases.cc b/tests/test_cases.cc
index 7e78b34f..02683907 100644
--- a/tests/test_cases.cc
+++ b/tests/test_cases.cc
@@ -225,6 +225,7 @@ using namespace clanguml::test::matchers;
 #include "t00041/test_case.h"
 #include "t00042/test_case.h"
 #include "t00043/test_case.h"
+#include "t00044/test_case.h"
 
 //
 // Sequence diagram tests