diff --git a/src/common/generators/generators.cc b/src/common/generators/generators.cc
index 30eca388..657a3c98 100644
--- a/src/common/generators/generators.cc
+++ b/src/common/generators/generators.cc
@@ -58,7 +58,6 @@ void find_translation_units_for_diagrams(
 }
 
 void render_diagram(const clanguml::common::generator_type_t generator_type,
-    const std::string &output_directory,
     std::shared_ptr<config::diagram> diagram_config)
 {
     std::string cmd;
@@ -162,8 +161,7 @@ void generate_diagram_impl(const std::string &name,
         }
 
         if (runtime_config.render_diagrams) {
-            render_diagram(
-                generator_type, runtime_config.output_directory, diagram);
+            render_diagram(generator_type, diagram);
         }
     }
 }
diff --git a/src/common/generators/plantuml/generator.h b/src/common/generators/plantuml/generator.h
index 0b670164..4cfd2cc4 100644
--- a/src/common/generators/plantuml/generator.h
+++ b/src/common/generators/plantuml/generator.h
@@ -234,7 +234,7 @@ inja::json generator<C, D>::element_context(const E &e) const
         ctx["element"]["source"]["line"] = e.line();
     }
 
-    const auto maybe_comment = e.comment();
+    const auto &maybe_comment = e.comment();
     if (maybe_comment) {
         ctx["element"]["comment"] = maybe_comment.value();
     }
diff --git a/src/common/model/diagram_filter.cc b/src/common/model/diagram_filter.cc
index b7fedc06..179b3291 100644
--- a/src/common/model/diagram_filter.cc
+++ b/src/common/model/diagram_filter.cc
@@ -670,7 +670,7 @@ void context_filter::initialize(const diagram &d) const
 
     // Prepare effective_contexts_
     for (auto i = 0U; i < context_.size(); i++) {
-        effective_contexts_.push_back({});
+        effective_contexts_.push_back({}); // NOLINT
         initialize_effective_context(d, i);
     }
 }
diff --git a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
index a1b44af0..059fa526 100644
--- a/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
+++ b/src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc
@@ -80,7 +80,7 @@ void generator::generate_message_comment(
     if (comment_generated_from_note_decorators)
         return;
 
-    if (auto &cmt = m.comment();
+    if (const auto &cmt = m.comment();
         config().generate_message_comments() && cmt.has_value()) {
 
         ostr << indent(1) << "note over " << generate_alias(from.value())