diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index 48ecc96e4b..0cb7d6a99b 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -117,8 +117,6 @@ module ActiveSupport
   def self.utc_to_local_returns_utc_offset_times=(value)
     DateAndTime::Compatibility.utc_to_local_returns_utc_offset_times = value
   end
-
-  @has_native_class_descendants = Class.method_defined?(:descendants) # RUBY_VERSION >= "3.1"
 end
 
 autoload :I18n, "active_support/i18n"
diff --git a/activesupport/lib/active_support/core_ext/class/subclasses.rb b/activesupport/lib/active_support/core_ext/class/subclasses.rb
index 56f3312036..b2df3af457 100644
--- a/activesupport/lib/active_support/core_ext/class/subclasses.rb
+++ b/activesupport/lib/active_support/core_ext/class/subclasses.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "active_support/ruby_features"
+
 class Class
   # Returns an array with all classes that are < than its receiver.
   #
@@ -18,7 +20,7 @@ class Class
     ObjectSpace.each_object(singleton_class).reject do |k|
       k.singleton_class? || k == self
     end
-  end unless ActiveSupport.instance_variable_get(:@has_native_class_descendants) # RUBY_VERSION >= "3.1"
+  end unless ActiveSupport::RubyFeatures::CLASS_DESCENDANTS
 
   # Returns an array with the direct children of +self+.
   #
@@ -29,5 +31,5 @@ class Class
   #   Foo.subclasses # => [Bar]
   def subclasses
     descendants.select { |descendant| descendant.superclass == self }
-  end
+  end unless ActiveSupport::RubyFeatures::CLASS_SUBCLASSES
 end
diff --git a/activesupport/lib/active_support/descendants_tracker.rb b/activesupport/lib/active_support/descendants_tracker.rb
index 2764ec0262..42e611ef7d 100644
--- a/activesupport/lib/active_support/descendants_tracker.rb
+++ b/activesupport/lib/active_support/descendants_tracker.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "weakref"
+require "active_support/ruby_features"
 
 module ActiveSupport
   # This module provides an internal implementation to track descendants
@@ -16,7 +17,7 @@ module ActiveSupport
       end
     end
 
-    if ActiveSupport.instance_variable_get(:@has_native_class_descendants) # RUBY_VERSION >= "3.1"
+    if RubyFeatures::CLASS_DESCENDANTS
       class << self
         def subclasses(klass)
           klass.subclasses
@@ -35,8 +36,10 @@ module ActiveSupport
         end
       end
 
-      def subclasses
-        descendants.select { |descendant| descendant.superclass == self }
+      unless RubyFeatures::CLASS_SUBCLASSES
+        def subclasses
+          descendants.select { |descendant| descendant.superclass == self }
+        end
       end
 
       def direct_descendants
diff --git a/activesupport/lib/active_support/ruby_features.rb b/activesupport/lib/active_support/ruby_features.rb
new file mode 100644
index 0000000000..6c4b489c1e
--- /dev/null
+++ b/activesupport/lib/active_support/ruby_features.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module ActiveSupport
+  module RubyFeatures # :nodoc:
+    CLASS_DESCENDANTS = Class.method_defined?(:descendants) # RUBY_VERSION >= "3.1"
+    CLASS_SUBCLASSES = Class.method_defined?(:subclasses) # RUBY_VERSION >= "3.1"
+  end
+end