diff --git a/src/catch2/matchers/catch_matchers.hpp b/src/catch2/matchers/catch_matchers.hpp
index 7a77a62c..373e2a67 100644
--- a/src/catch2/matchers/catch_matchers.hpp
+++ b/src/catch2/matchers/catch_matchers.hpp
@@ -37,14 +37,18 @@ namespace Matchers {
 
 
     template<typename T>
-    struct MatcherBase : MatcherUntypedBase {
+    class MatcherBase : public MatcherUntypedBase {
+    public:
         virtual bool match( T const& arg ) const = 0;
     };
 
     namespace Detail {
 
         template<typename ArgT>
-        struct MatchAllOf final : MatcherBase<ArgT> {
+        class MatchAllOf final : public MatcherBase<ArgT> {
+            std::vector<MatcherBase<ArgT> const*> m_matchers;
+
+        public:
             MatchAllOf() = default;
             MatchAllOf(MatchAllOf const&) = delete;
             MatchAllOf& operator=(MatchAllOf const&) = delete;
@@ -83,9 +87,6 @@ namespace Matchers {
                 rhs.m_matchers.insert(rhs.m_matchers.begin(), &lhs);
                 return CATCH_MOVE(rhs);
             }
-
-        private:
-            std::vector<MatcherBase<ArgT> const*> m_matchers;
         };
 
         //! lvalue overload is intentionally deleted, users should
@@ -98,7 +99,9 @@ namespace Matchers {
         MatchAllOf<ArgT> operator&& (MatcherBase<ArgT> const& lhs, MatchAllOf<ArgT> const& rhs) = delete;
 
         template<typename ArgT>
-        struct MatchAnyOf final : MatcherBase<ArgT> {
+        class MatchAnyOf final : public MatcherBase<ArgT> {
+            std::vector<MatcherBase<ArgT> const*> m_matchers;
+        public:
             MatchAnyOf() = default;
             MatchAnyOf(MatchAnyOf const&) = delete;
             MatchAnyOf& operator=(MatchAnyOf const&) = delete;
@@ -136,9 +139,6 @@ namespace Matchers {
                 rhs.m_matchers.insert(rhs.m_matchers.begin(), &lhs);
                 return CATCH_MOVE(rhs);
             }
-
-        private:
-            std::vector<MatcherBase<ArgT> const*> m_matchers;
         };
 
         //! lvalue overload is intentionally deleted, users should
@@ -151,8 +151,10 @@ namespace Matchers {
         MatchAnyOf<ArgT> operator|| (MatcherBase<ArgT> const& lhs, MatchAnyOf<ArgT> const& rhs) = delete;
 
         template<typename ArgT>
-        struct MatchNotOf final : MatcherBase<ArgT> {
+        class MatchNotOf final : public MatcherBase<ArgT> {
+            MatcherBase<ArgT> const& m_underlyingMatcher;
 
+        public:
             explicit MatchNotOf( MatcherBase<ArgT> const& underlyingMatcher ):
                 m_underlyingMatcher( underlyingMatcher )
             {}
@@ -164,9 +166,6 @@ namespace Matchers {
             std::string describe() const override {
                 return "not " + m_underlyingMatcher.toString();
             }
-
-        private:
-            MatcherBase<ArgT> const& m_underlyingMatcher;
         };
 
     } // namespace Detail
diff --git a/src/catch2/matchers/catch_matchers_floating_point.hpp b/src/catch2/matchers/catch_matchers_floating_point.hpp
index dc0fa8f7..99572e43 100644
--- a/src/catch2/matchers/catch_matchers_floating_point.hpp
+++ b/src/catch2/matchers/catch_matchers_floating_point.hpp
@@ -17,7 +17,8 @@ namespace Matchers {
         enum class FloatingPointKind : uint8_t;
     }
 
-    struct WithinAbsMatcher final : MatcherBase<double> {
+    class  WithinAbsMatcher final : public MatcherBase<double> {
+    public:
         WithinAbsMatcher(double target, double margin);
         bool match(double const& matchee) const override;
         std::string describe() const override;
@@ -26,8 +27,11 @@ namespace Matchers {
         double m_margin;
     };
 
-    struct WithinUlpsMatcher final : MatcherBase<double> {
-        WithinUlpsMatcher(double target, uint64_t ulps, Detail::FloatingPointKind baseType);
+    class WithinUlpsMatcher final : public MatcherBase<double> {
+    public:
+        WithinUlpsMatcher( double target,
+                           uint64_t ulps,
+                           Detail::FloatingPointKind baseType );
         bool match(double const& matchee) const override;
         std::string describe() const override;
     private:
@@ -42,8 +46,9 @@ namespace Matchers {
     // |lhs - rhs| <= epsilon * max(fabs(lhs), fabs(rhs)), then we get
     // the same result if we do this for floats, as if we do this for
     // doubles that were promoted from floats.
-    struct WithinRelMatcher final : MatcherBase<double> {
-        WithinRelMatcher(double target, double epsilon);
+    class WithinRelMatcher final : public MatcherBase<double> {
+    public:
+        WithinRelMatcher( double target, double epsilon );
         bool match(double const& matchee) const override;
         std::string describe() const override;
     private:
diff --git a/src/catch2/matchers/catch_matchers_string.hpp b/src/catch2/matchers/catch_matchers_string.hpp
index 549e2d85..7f961c45 100644
--- a/src/catch2/matchers/catch_matchers_string.hpp
+++ b/src/catch2/matchers/catch_matchers_string.hpp
@@ -26,39 +26,46 @@ namespace Matchers {
         std::string m_str;
     };
 
-    struct StringMatcherBase : MatcherBase<std::string> {
-        StringMatcherBase( StringRef operation, CasedString const& comparator );
-        std::string describe() const override;
-
+    class StringMatcherBase : public MatcherBase<std::string> {
+    protected:
         CasedString m_comparator;
         StringRef m_operation;
+
+    public:
+        StringMatcherBase( StringRef operation,
+                           CasedString const& comparator );
+        std::string describe() const override;
     };
 
-    struct StringEqualsMatcher final : StringMatcherBase {
+    class StringEqualsMatcher final : public StringMatcherBase {
+    public:
         StringEqualsMatcher( CasedString const& comparator );
         bool match( std::string const& source ) const override;
     };
-    struct StringContainsMatcher final : StringMatcherBase {
+    class StringContainsMatcher final : public StringMatcherBase {
+    public:
         StringContainsMatcher( CasedString const& comparator );
         bool match( std::string const& source ) const override;
     };
-    struct StartsWithMatcher final : StringMatcherBase {
+    class StartsWithMatcher final : public StringMatcherBase {
+    public:
         StartsWithMatcher( CasedString const& comparator );
         bool match( std::string const& source ) const override;
     };
-    struct EndsWithMatcher final : StringMatcherBase {
+    class EndsWithMatcher final : public StringMatcherBase {
+    public:
         EndsWithMatcher( CasedString const& comparator );
         bool match( std::string const& source ) const override;
     };
 
-    struct RegexMatcher final : MatcherBase<std::string> {
+    class RegexMatcher final : public MatcherBase<std::string> {
+        std::string m_regex;
+        CaseSensitive m_caseSensitivity;
+
+    public:
         RegexMatcher( std::string regex, CaseSensitive caseSensitivity );
         bool match( std::string const& matchee ) const override;
         std::string describe() const override;
-
-    private:
-        std::string m_regex;
-        CaseSensitive m_caseSensitivity;
     };
 
     //! Creates matcher that accepts strings that are exactly equal to `str`
diff --git a/src/catch2/matchers/catch_matchers_templated.hpp b/src/catch2/matchers/catch_matchers_templated.hpp
index 200ca74b..2673a3af 100644
--- a/src/catch2/matchers/catch_matchers_templated.hpp
+++ b/src/catch2/matchers/catch_matchers_templated.hpp
@@ -19,7 +19,8 @@
 
 namespace Catch {
 namespace Matchers {
-    struct MatcherGenericBase : MatcherUntypedBase {
+    class MatcherGenericBase : public MatcherUntypedBase {
+    public:
         MatcherGenericBase() = default;
         virtual ~MatcherGenericBase(); // = default;
 
@@ -119,7 +120,8 @@ namespace Matchers {
 
 
         template<typename... MatcherTs>
-        struct MatchAllOfGeneric final : MatcherGenericBase {
+        class MatchAllOfGeneric final : public MatcherGenericBase {
+        public:
             MatchAllOfGeneric(MatchAllOfGeneric const&) = delete;
             MatchAllOfGeneric& operator=(MatchAllOfGeneric const&) = delete;
             MatchAllOfGeneric(MatchAllOfGeneric&&) = default;
@@ -137,7 +139,11 @@ namespace Matchers {
                 return describe_multi_matcher<MatcherTs...>(" and "_sr, m_matchers, std::index_sequence_for<MatcherTs...>{});
             }
 
-            std::array<void const*, sizeof...(MatcherTs)> m_matchers;
+            // Has to be public to enable the concatenating operators
+            // below, because they are not friend of the RHS, only LHS,
+            // and thus cannot access private fields of RHS
+            std::array<void const*, sizeof...( MatcherTs )> m_matchers;
+
 
             //! Avoids type nesting for `GenericAllOf && GenericAllOf` case
             template<typename... MatchersRHS>
@@ -169,7 +175,8 @@ namespace Matchers {
 
 
         template<typename... MatcherTs>
-        struct MatchAnyOfGeneric final : MatcherGenericBase {
+        class MatchAnyOfGeneric final : public MatcherGenericBase {
+        public:
             MatchAnyOfGeneric(MatchAnyOfGeneric const&) = delete;
             MatchAnyOfGeneric& operator=(MatchAnyOfGeneric const&) = delete;
             MatchAnyOfGeneric(MatchAnyOfGeneric&&) = default;
@@ -187,7 +194,11 @@ namespace Matchers {
                 return describe_multi_matcher<MatcherTs...>(" or "_sr, m_matchers, std::index_sequence_for<MatcherTs...>{});
             }
 
-            std::array<void const*, sizeof...(MatcherTs)> m_matchers;
+
+            // Has to be public to enable the concatenating operators
+            // below, because they are not friend of the RHS, only LHS,
+            // and thus cannot access private fields of RHS
+            std::array<void const*, sizeof...( MatcherTs )> m_matchers;
 
             //! Avoids type nesting for `GenericAnyOf || GenericAnyOf` case
             template<typename... MatchersRHS>
@@ -218,7 +229,10 @@ namespace Matchers {
 
 
         template<typename MatcherT>
-        struct MatchNotOfGeneric final : MatcherGenericBase {
+        class MatchNotOfGeneric final : public MatcherGenericBase {
+            MatcherT const& m_matcher;
+
+        public:
             MatchNotOfGeneric(MatchNotOfGeneric const&) = delete;
             MatchNotOfGeneric& operator=(MatchNotOfGeneric const&) = delete;
             MatchNotOfGeneric(MatchNotOfGeneric&&) = default;
@@ -239,8 +253,6 @@ namespace Matchers {
             friend MatcherT const& operator ! (MatchNotOfGeneric<MatcherT> const& matcher) {
                 return matcher.m_matcher;
             }
-        private:
-            MatcherT const& m_matcher;
         };
     } // namespace Detail
 
diff --git a/src/catch2/matchers/catch_matchers_vector.hpp b/src/catch2/matchers/catch_matchers_vector.hpp
index 00ecbc33..b9a02f57 100644
--- a/src/catch2/matchers/catch_matchers_vector.hpp
+++ b/src/catch2/matchers/catch_matchers_vector.hpp
@@ -17,8 +17,10 @@ namespace Catch {
 namespace Matchers {
 
     template<typename T, typename Alloc>
-    struct VectorContainsElementMatcher final : MatcherBase<std::vector<T, Alloc>> {
+    class VectorContainsElementMatcher final : public MatcherBase<std::vector<T, Alloc>> {
+        T const& m_comparator;
 
+    public:
         VectorContainsElementMatcher(T const& comparator):
             m_comparator(comparator)
         {}
@@ -35,13 +37,13 @@ namespace Matchers {
         std::string describe() const override {
             return "Contains: " + ::Catch::Detail::stringify( m_comparator );
         }
-
-        T const& m_comparator;
     };
 
     template<typename T, typename AllocComp, typename AllocMatch>
-    struct ContainsMatcher final : MatcherBase<std::vector<T, AllocMatch>> {
+    class ContainsMatcher final : public MatcherBase<std::vector<T, AllocMatch>> {
+        std::vector<T, AllocComp> const& m_comparator;
 
+    public:
         ContainsMatcher(std::vector<T, AllocComp> const& comparator):
             m_comparator( comparator )
         {}
@@ -67,13 +69,13 @@ namespace Matchers {
         std::string describe() const override {
             return "Contains: " + ::Catch::Detail::stringify( m_comparator );
         }
-
-        std::vector<T, AllocComp> const& m_comparator;
     };
 
     template<typename T, typename AllocComp, typename AllocMatch>
-    struct EqualsMatcher final : MatcherBase<std::vector<T, AllocMatch>> {
+    class EqualsMatcher final : public MatcherBase<std::vector<T, AllocMatch>> {
+        std::vector<T, AllocComp> const& m_comparator;
 
+    public:
         EqualsMatcher(std::vector<T, AllocComp> const& comparator):
             m_comparator( comparator )
         {}
@@ -93,12 +95,14 @@ namespace Matchers {
         std::string describe() const override {
             return "Equals: " + ::Catch::Detail::stringify( m_comparator );
         }
-        std::vector<T, AllocComp> const& m_comparator;
     };
 
     template<typename T, typename AllocComp, typename AllocMatch>
-    struct ApproxMatcher final : MatcherBase<std::vector<T, AllocMatch>> {
+    class ApproxMatcher final : public MatcherBase<std::vector<T, AllocMatch>> {
+        std::vector<T, AllocComp> const& m_comparator;
+        mutable Catch::Approx approx = Catch::Approx::custom();
 
+    public:
         ApproxMatcher(std::vector<T, AllocComp> const& comparator):
             m_comparator( comparator )
         {}
@@ -129,13 +133,13 @@ namespace Matchers {
             approx.scale(static_cast<double>(newScale));
             return *this;
         }
-
-        std::vector<T, AllocComp> const& m_comparator;
-        mutable Catch::Approx approx = Catch::Approx::custom();
     };
 
     template<typename T, typename AllocComp, typename AllocMatch>
-    struct UnorderedEqualsMatcher final : MatcherBase<std::vector<T, AllocMatch>> {
+    class UnorderedEqualsMatcher final : public MatcherBase<std::vector<T, AllocMatch>> {
+        std::vector<T, AllocComp> const& m_target;
+
+    public:
         UnorderedEqualsMatcher(std::vector<T, AllocComp> const& target):
             m_target(target)
         {}
@@ -149,15 +153,12 @@ namespace Matchers {
         std::string describe() const override {
             return "UnorderedEquals: " + ::Catch::Detail::stringify(m_target);
         }
-    private:
-        std::vector<T, AllocComp> const& m_target;
     };
 
 
     // The following functions create the actual matcher objects.
     // This allows the types to be inferred
 
-
     //! Creates a matcher that matches vectors that contain all elements in `comparator`
     template<typename T, typename AllocComp = std::allocator<T>, typename AllocMatch = AllocComp>
     ContainsMatcher<T, AllocComp, AllocMatch> Contains( std::vector<T, AllocComp> const& comparator ) {
diff --git a/src/catch2/matchers/internal/catch_matchers_impl.hpp b/src/catch2/matchers/internal/catch_matchers_impl.hpp
index 2acbec1f..5d00ad7d 100644
--- a/src/catch2/matchers/internal/catch_matchers_impl.hpp
+++ b/src/catch2/matchers/internal/catch_matchers_impl.hpp
@@ -36,7 +36,7 @@ namespace Catch {
 
     namespace Matchers {
         template <typename ArgT>
-        struct MatcherBase;
+        class MatcherBase;
     }
 
     using StringMatcher = Matchers::MatcherBase<std::string>;