diff --git a/CMakeLists.txt b/CMakeLists.txt
index 912da58a..0fbb5ff0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -46,7 +46,8 @@ set(LLVM_PREFERRED_VERSION 12.0.0)
 # to use custom LLVM version
 find_package(LibClang REQUIRED)
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 ${LIBCLANG_CXXFLAGS}")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -Wall -Wextra -std=c++17 ${LIBCLANG_CXXFLAGS}")
+
 message(STATUS "Using CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
 
 # Thirdparty sources
diff --git a/src/class_diagram/generators/plantuml/class_diagram_generator.cc b/src/class_diagram/generators/plantuml/class_diagram_generator.cc
index 18d7aa3b..a955ccdd 100644
--- a/src/class_diagram/generators/plantuml/class_diagram_generator.cc
+++ b/src/class_diagram/generators/plantuml/class_diagram_generator.cc
@@ -450,8 +450,6 @@ void generator::generate(const package &p, std::ostream &ostr) const
 void generator::generate_relationships(
     const package &p, std::ostream &ostr) const
 {
-    const auto &uns = m_config.using_namespace();
-
     for (const auto &subpackage : p) {
         if (dynamic_cast<package *>(subpackage.get())) {
             // TODO: add option - generate_empty_packages
diff --git a/src/class_diagram/model/class.cc b/src/class_diagram/model/class.cc
index c623359f..be5ab786 100644
--- a/src/class_diagram/model/class.cc
+++ b/src/class_diagram/model/class.cc
@@ -174,7 +174,7 @@ int class_::calculate_template_specialization_match(
     }
 
     // Iterate over all template arguments
-    for (int i = 0; i < other.templates().size(); i++) {
+    for (auto i = 0U; i < other.templates().size(); i++) {
         const auto &template_arg = templates().at(i);
         const auto &other_template_arg = other.templates().at(i);
 
diff --git a/src/class_diagram/visitor/translation_unit_visitor.cc b/src/class_diagram/visitor/translation_unit_visitor.cc
index acbe6349..1bdb06f3 100644
--- a/src/class_diagram/visitor/translation_unit_visitor.cc
+++ b/src/class_diagram/visitor/translation_unit_visitor.cc
@@ -901,10 +901,10 @@ void translation_unit_visitor::process_field(
         !template_instantiation_added_as_aggregation &&
         (tr.kind() != cppast::cpp_type_kind::builtin_t) &&
         (tr.kind() != cppast::cpp_type_kind::template_parameter_t)) {
-        const auto &ttt = resolve_alias(mv.type());
-
         found_relationships_t relationships;
-        auto found = find_relationships(ttt, relationships);
+
+        const auto &unaliased_type = resolve_alias(mv.type());
+        find_relationships(unaliased_type, relationships);
 
         for (const auto &[type, relationship_type] : relationships) {
             if (relationship_type != relationship_t::kNone) {
@@ -1350,9 +1350,9 @@ void translation_unit_visitor::process_friend(const cppast::cpp_friend &f,
 {
     // Only process friends to other classes or class templates
     if (!f.entity() ||
-        (f.entity().value().kind() != cppast::cpp_entity_kind::class_t) &&
+        ((f.entity().value().kind() != cppast::cpp_entity_kind::class_t) &&
             (f.entity().value().kind() !=
-                cppast::cpp_entity_kind::class_template_t))
+                cppast::cpp_entity_kind::class_template_t)))
         return;
 
     relationship r{relationship_t::kFriendship, "",
@@ -1384,11 +1384,11 @@ void translation_unit_visitor::process_friend(const cppast::cpp_friend &f,
                 f.entity().value());
             const auto &class_ = ft.class_();
             auto scope = cppast::cpp_scope_name(type_safe::ref(ft));
-            if (ft.class_().user_data() == nullptr) {
+            if (class_.user_data() == nullptr) {
                 spdlog::warn(
                     "Empty user data in friend class template: {}, {}, {}",
                     ft.name(),
-                    fmt::ptr(reinterpret_cast<const void *>(&ft.class_())),
+                    fmt::ptr(reinterpret_cast<const void *>(&class_)),
                     scope.name());
                 return;
             }
@@ -1940,8 +1940,6 @@ void translation_unit_visitor::
         const auto &function_argument =
             static_cast<const cppast::cpp_function_type &>(targ_type);
 
-        const auto &rt = function_argument.return_type();
-
         // Search for relationships in argument return type
         // TODO...
 
diff --git a/src/common/generators/plantuml/generator.h b/src/common/generators/plantuml/generator.h
index e5c28b57..957dbe60 100644
--- a/src/common/generators/plantuml/generator.h
+++ b/src/common/generators/plantuml/generator.h
@@ -261,7 +261,7 @@ std::unique_ptr<DiagramModel> generate(
 
     diagram->set_complete(true);
 
-    return std::move(diagram);
+    return diagram;
 }
 
 template <typename C, typename D> void generator<C, D>::init_context()
diff --git a/src/common/model/diagram_element.h b/src/common/model/diagram_element.h
index 023cd90c..5fa49a70 100644
--- a/src/common/model/diagram_element.h
+++ b/src/common/model/diagram_element.h
@@ -42,7 +42,7 @@ public:
 
     std::string name() const { return name_; }
 
-    virtual std::string full_name(bool relative) const { return name(); }
+    virtual std::string full_name(bool /*relative*/) const { return name(); }
 
     std::vector<relationship> &relationships();
 
diff --git a/src/common/model/diagram_filter.cc b/src/common/model/diagram_filter.cc
index 8969abd4..4389ba1b 100644
--- a/src/common/model/diagram_filter.cc
+++ b/src/common/model/diagram_filter.cc
@@ -90,31 +90,31 @@ filter_visitor::filter_visitor(filter_t type)
 }
 
 tvl::value_t filter_visitor::match(
-    const diagram &d, const common::model::element &e) const
+    const diagram & /*d*/, const common::model::element & /*e*/) const
 {
     return {};
 }
 
 tvl::value_t filter_visitor::match(
-    const diagram &d, const common::model::relationship_t &r) const
+    const diagram & /*d*/, const common::model::relationship_t & /*r*/) const
 {
     return {};
 }
 
 tvl::value_t filter_visitor::match(
-    const diagram &d, const common::model::access_t &a) const
+    const diagram & /*d*/, const common::model::access_t & /*a*/) const
 {
     return {};
 }
 
 tvl::value_t filter_visitor::match(
-    const diagram &d, const common::model::namespace_ &ns) const
+    const diagram & /*d*/, const common::model::namespace_ & /*ns*/) const
 {
     return {};
 }
 
 tvl::value_t filter_visitor::match(
-    const diagram &d, const common::model::source_file &f) const
+    const diagram & /*d*/, const common::model::source_file & /*f*/) const
 {
     return {};
 }
@@ -160,7 +160,7 @@ namespace_filter::namespace_filter(
 }
 
 tvl::value_t namespace_filter::match(
-    const diagram &d, const namespace_ &ns) const
+    const diagram & /*d*/, const namespace_ &ns) const
 {
     if (ns.is_empty())
         return {};
@@ -169,7 +169,8 @@ tvl::value_t namespace_filter::match(
         [&ns](const auto &nsit) { return ns.starts_with(nsit) || ns == nsit; });
 }
 
-tvl::value_t namespace_filter::match(const diagram &d, const element &e) const
+tvl::value_t namespace_filter::match(
+    const diagram & /*d*/, const element &e) const
 {
     if (dynamic_cast<const package *>(&e) != nullptr) {
         return tvl::any_of(
@@ -193,7 +194,8 @@ element_filter::element_filter(filter_t type, std::vector<std::string> elements)
 {
 }
 
-tvl::value_t element_filter::match(const diagram &d, const element &e) const
+tvl::value_t element_filter::match(
+    const diagram & /*d*/, const element &e) const
 {
     return tvl::any_of(elements_.begin(), elements_.end(),
         [&e](const auto &el) { return e.full_name(false) == el; });
@@ -253,7 +255,7 @@ relationship_filter::relationship_filter(
 }
 
 tvl::value_t relationship_filter::match(
-    const diagram &d, const relationship_t &r) const
+    const diagram & /*d*/, const relationship_t &r) const
 {
     return tvl::any_of(relationships_.begin(), relationships_.end(),
         [&r](const auto &rel) { return r == rel; });
@@ -265,7 +267,8 @@ access_filter::access_filter(filter_t type, std::vector<access_t> access)
 {
 }
 
-tvl::value_t access_filter::match(const diagram &d, const access_t &a) const
+tvl::value_t access_filter::match(
+    const diagram & /*d*/, const access_t &a) const
 {
     return tvl::any_of(access_.begin(), access_.end(),
         [&a](const auto &access) { return a == access; });
@@ -349,7 +352,7 @@ paths_filter::paths_filter(filter_t type, const std::filesystem::path &root,
 }
 
 tvl::value_t paths_filter::match(
-    const diagram &d, const common::model::source_file &p) const
+    const diagram & /*d*/, const common::model::source_file &p) const
 {
     if (paths_.empty()) {
         return {};
diff --git a/src/common/model/diagram_filter.h b/src/common/model/diagram_filter.h
index a6beaf7d..9fa73c42 100644
--- a/src/common/model/diagram_filter.h
+++ b/src/common/model/diagram_filter.h
@@ -131,8 +131,8 @@ struct edge_traversal_filter : public filter_visitor {
     edge_traversal_filter(filter_t type, relationship_t relationship,
         std::vector<std::string> roots, bool forward = false)
         : filter_visitor{type}
-        , relationship_{relationship}
         , roots_{roots}
+        , relationship_{relationship}
         , forward_{forward}
     {
     }
diff --git a/src/common/model/element.h b/src/common/model/element.h
index 4fda5918..e4655b43 100644
--- a/src/common/model/element.h
+++ b/src/common/model/element.h
@@ -55,7 +55,7 @@ public:
 
     const namespace_ &path() const { return ns_; }
 
-    std::string full_name(bool relative) const override
+    std::string full_name(bool /*relative*/) const override
     {
         return name_and_ns();
     }
diff --git a/src/common/model/relationship.cc b/src/common/model/relationship.cc
index 2dfef55b..9ead05e9 100644
--- a/src/common/model/relationship.cc
+++ b/src/common/model/relationship.cc
@@ -26,10 +26,10 @@ relationship::relationship(relationship_t type, const std::string &destination,
     const std::string &multiplicity_destination)
     : type_{type}
     , destination_{destination}
-    , access_{access}
-    , label_{label}
     , multiplicity_source_{multiplicity_source}
     , multiplicity_destination_{multiplicity_destination}
+    , label_{label}
+    , access_{access}
 {
 }
 
diff --git a/src/common/model/relationship.h b/src/common/model/relationship.h
index 6a695528..3b154223 100644
--- a/src/common/model/relationship.h
+++ b/src/common/model/relationship.h
@@ -56,11 +56,11 @@ public:
     friend bool operator==(const relationship &l, const relationship &r);
 
 private:
-    relationship_t type_{relationship_t::kAssociation};
+    relationship_t type_;
     std::string destination_;
     std::string multiplicity_source_;
     std::string multiplicity_destination_;
     std::string label_;
-    access_t access_{access_t::kPublic};
+    access_t access_;
 };
 }
diff --git a/src/common/model/source_file.h b/src/common/model/source_file.h
index 0ba8af1d..af34ff55 100644
--- a/src/common/model/source_file.h
+++ b/src/common/model/source_file.h
@@ -72,7 +72,7 @@ public:
 
     const filesystem_path &path() const { return path_; }
 
-    std::string full_name(bool relative) const override
+    std::string full_name(bool /*relative*/) const override
     {
         return (path_ | name()).to_string();
     }
diff --git a/src/cx/util.cc b/src/cx/util.cc
index 4de3512e..8cb0f785 100644
--- a/src/cx/util.cc
+++ b/src/cx/util.cc
@@ -262,7 +262,6 @@ parse_unexposed_template_params(const std::string &params,
 
     std::vector<template_parameter> res;
 
-    int nested_template_level{0};
     auto it = params.begin();
 
     std::string type{};
diff --git a/src/decorators/decorators.cc b/src/decorators/decorators.cc
index a83d862d..4bebf67f 100644
--- a/src/decorators/decorators.cc
+++ b/src/decorators/decorators.cc
@@ -119,12 +119,13 @@ std::shared_ptr<decorator> note::from_string(std::string_view c)
     return res;
 }
 
-std::shared_ptr<decorator> skip::from_string(std::string_view c)
+std::shared_ptr<decorator> skip::from_string(std::string_view /*c*/)
 {
     return std::make_shared<skip>();
 }
 
-std::shared_ptr<decorator> skip_relationship::from_string(std::string_view c)
+std::shared_ptr<decorator> skip_relationship::from_string(
+    std::string_view /*c*/)
 {
     return std::make_shared<skip_relationship>();
 }
diff --git a/src/include_diagram/visitor/translation_unit_visitor.cc b/src/include_diagram/visitor/translation_unit_visitor.cc
index da1189b2..4a6b981b 100644
--- a/src/include_diagram/visitor/translation_unit_visitor.cc
+++ b/src/include_diagram/visitor/translation_unit_visitor.cc
@@ -40,7 +40,7 @@ void translation_unit_visitor::operator()(const cppast::cpp_entity &file)
     process_source_file(static_cast<const cppast::cpp_file &>(file));
 
     cppast::visit(file,
-        [&, this](const cppast::cpp_entity &e, cppast::visitor_info info) {
+        [&, this](const cppast::cpp_entity &e, cppast::visitor_info /*info*/) {
             if (e.kind() == cppast::cpp_entity_kind::include_directive_t) {
                 const auto &inc =
                     static_cast<const cppast::cpp_include_directive &>(e);
diff --git a/src/package_diagram/visitor/translation_unit_visitor.cc b/src/package_diagram/visitor/translation_unit_visitor.cc
index 110ba147..e5f558f1 100644
--- a/src/package_diagram/visitor/translation_unit_visitor.cc
+++ b/src/package_diagram/visitor/translation_unit_visitor.cc
@@ -215,34 +215,26 @@ void translation_unit_visitor::operator()(const cppast::cpp_entity &file)
                 LOG_DBG("========== Visiting '{}' - {}",
                     cx::util::full_name(ctx.get_namespace(), e),
                     cppast::to_string(e.kind()));
-
-                auto &at = static_cast<const cppast::cpp_alias_template &>(e);
             }
         });
 }
 
 void translation_unit_visitor::process_class_declaration(
     const cppast::cpp_class &cls,
-    type_safe::optional_ref<const cppast::cpp_template_specialization> tspec)
+    type_safe::optional_ref<
+        const cppast::cpp_template_specialization> /*tspec*/)
 {
     auto current_package = ctx.get_current_package();
 
     if (!current_package)
         return;
 
-    cppast::cpp_access_specifier_kind last_access_specifier =
-        cppast::cpp_access_specifier_kind::cpp_private;
-
     std::vector<std::pair<std::string, relationship_t>> relationships;
 
     // Process class elements
     for (auto &child : cls) {
         auto name = child.name();
-        if (child.kind() == cppast::cpp_entity_kind::access_specifier_t) {
-            auto &as = static_cast<const cppast::cpp_access_specifier &>(child);
-            last_access_specifier = as.access_specifier();
-        }
-        else if (child.kind() == cppast::cpp_entity_kind::member_variable_t) {
+        if (child.kind() == cppast::cpp_entity_kind::member_variable_t) {
             auto &mv = static_cast<const cppast::cpp_member_variable &>(child);
             find_relationships(
                 mv.type(), relationships, relationship_t::kDependency);
diff --git a/src/sequence_diagram/model/diagram.cc b/src/sequence_diagram/model/diagram.cc
index 460ce2ea..39140f29 100644
--- a/src/sequence_diagram/model/diagram.cc
+++ b/src/sequence_diagram/model/diagram.cc
@@ -29,7 +29,7 @@ common::model::diagram_t diagram::type() const
 }
 
 type_safe::optional_ref<const common::model::diagram_element> diagram::get(
-    const std::string &full_name) const
+    const std::string & /*full_name*/) const
 {
     return {};
 }
diff --git a/src/sequence_diagram/visitor/translation_unit_visitor.cc b/src/sequence_diagram/visitor/translation_unit_visitor.cc
index 8923b844..fe478d00 100644
--- a/src/sequence_diagram/visitor/translation_unit_visitor.cc
+++ b/src/sequence_diagram/visitor/translation_unit_visitor.cc
@@ -138,7 +138,7 @@ void translation_unit_visitor::operator()(const cppast::cpp_entity &file)
     using cppast::cpp_member_function_call;
     using cppast::visitor_info;
 
-    cppast::visit(file, [&, this](const cpp_entity &e, visitor_info info) {
+    cppast::visit(file, [&, this](const cpp_entity &e, visitor_info /*info*/) {
         if (e.kind() == cpp_entity_kind::function_t) {
             const auto &function = static_cast<const cpp_function &>(e);
             process_activities(function);
diff --git a/src/util/util.cc b/src/util/util.cc
index 25a90c0e..7a4c2165 100644
--- a/src/util/util.cc
+++ b/src/util/util.cc
@@ -109,7 +109,7 @@ std::vector<std::string> split(std::string str, std::string_view delimiter)
         result.push_back(str);
     else
         while (str.size()) {
-            int index = str.find(delimiter);
+            auto index = str.find(delimiter);
             if (index != std::string::npos) {
                 result.push_back(str.substr(0, index));
                 str = str.substr(index + delimiter.size());
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index f3113c7c..f3705823 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -4,6 +4,8 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 set(CMAKE_CXX_STANDARD 17)
 
+set(CMAKE_CXX_FLAGS "-std=c++17 ${LIBCLANG_CXXFLAGS}")
+
 file(GLOB_RECURSE TEST_CASE_SOURCES t*/*.cc)
 file(GLOB_RECURSE TEST_CASE_CONFIGS t*/.clang-uml)
 file(GLOB_RECURSE TEST_CONFIG_YMLS test_config_data/*.yml)