diff --git a/src/catch2/reporters/catch_reporter_cumulative_base.cpp b/src/catch2/reporters/catch_reporter_cumulative_base.cpp
index 85e9c156..9dd1eb78 100644
--- a/src/catch2/reporters/catch_reporter_cumulative_base.cpp
+++ b/src/catch2/reporters/catch_reporter_cumulative_base.cpp
@@ -146,18 +146,18 @@ namespace Catch {
     }
 
     void CumulativeReporterBase::listReporters(std::vector<ReporterDescription> const& descriptions) {
-        defaultListReporters(stream, descriptions, m_config->verbosity());
+        defaultListReporters(m_stream, descriptions, m_config->verbosity());
     }
 
     void CumulativeReporterBase::listTests(std::vector<TestCaseHandle> const& tests) {
-        defaultListTests(stream,
+        defaultListTests(m_stream,
                          tests,
                          m_config->hasTestFilters(),
                          m_config->verbosity());
     }
 
     void CumulativeReporterBase::listTags(std::vector<TagInfo> const& tags) {
-        defaultListTags( stream, tags, m_config->hasTestFilters() );
+        defaultListTags( m_stream, tags, m_config->hasTestFilters() );
     }
 
     bool CumulativeReporterBase::SectionNode::hasAnyAssertions() const {
diff --git a/src/catch2/reporters/catch_reporter_cumulative_base.hpp b/src/catch2/reporters/catch_reporter_cumulative_base.hpp
index 55abd1e1..732a9469 100644
--- a/src/catch2/reporters/catch_reporter_cumulative_base.hpp
+++ b/src/catch2/reporters/catch_reporter_cumulative_base.hpp
@@ -59,7 +59,8 @@ namespace Catch {
      * performance. **Accessing the assertion expansions if it wasn't stored is
      * UB.**
      */
-    struct CumulativeReporterBase : IStreamingReporter {
+    class CumulativeReporterBase : public IStreamingReporter {
+    public:
         template<typename T, typename ChildNodeT>
         struct Node {
             explicit Node( T const& _value ) : value( _value ) {}
@@ -90,7 +91,7 @@ namespace Catch {
 
         CumulativeReporterBase( ReporterConfig const& _config ):
             IStreamingReporter( _config.fullConfig() ),
-            stream( _config.stream() ) {}
+            m_stream( _config.stream() ) {}
         ~CumulativeReporterBase() override;
 
         void benchmarkPreparing( StringRef ) override {}
@@ -131,17 +132,22 @@ namespace Catch {
         bool m_shouldStoreFailedAssertions = true;
 
         //! Stream to write the output to
-        std::ostream& stream;
+        std::ostream& m_stream;
 
+        // We need lazy construction here. We should probably refactor it
+        // later, after the events are redone.
+        //! The root node of the test run tree.
+        Detail::unique_ptr<TestRunNode> m_testRun;
+
+    private:
         // Note: We rely on pointer identity being stable, which is why
         //       we store pointers to the nodes rather than the values.
         std::vector<Detail::unique_ptr<TestCaseNode>> m_testCases;
-        // We need lazy construction here. We should probably refactor it
-        // later, after the events are redone.
-        Detail::unique_ptr<TestRunNode> m_testRun;
-
+        // Root section of the _current_ test case
         Detail::unique_ptr<SectionNode> m_rootSection;
+        // Deepest section of the _current_ test case
         SectionNode* m_deepestSection = nullptr;
+        // Stack of _active_ sections in the _current_ test case
         std::vector<SectionNode*> m_sectionStack;
     };