4 files changed, 18 insertions, 1 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 81c6246c5c..f15297f279 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Ensure that autoloaded constants in all-caps nestings are marked as
+    autoloaded.
+
+    *Simon Coffey*
+
 *   Add String#remove(pattern) as a short-hand for the common pattern of String#gsub(pattern, '')
 
     *DHH*
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index 73559bfe0e..db9f5d4baa 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -459,7 +459,7 @@ module ActiveSupport #:nodoc:
         if loaded.include?(expanded)
           raise "Circular dependency detected while autoloading constant #{qualified_name}"
         else
-          require_or_load(expanded)
+          require_or_load(expanded, qualified_name)
           raise LoadError, "Unable to autoload constant #{qualified_name}, expected #{file_path} to define it" unless from_mod.const_defined?(const_name, false)
           return from_mod.const_get(const_name)
         end
diff --git a/activesupport/test/autoloading_fixtures/html/some_class.rb b/activesupport/test/autoloading_fixtures/html/some_class.rb
new file mode 100644
index 0000000000..b43d15d891
--- /dev/null
+++ b/activesupport/test/autoloading_fixtures/html/some_class.rb
@@ -0,0 +1,4 @@
+module HTML
+  class SomeClass
+  end
+end
diff --git a/activesupport/test/dependencies_test.rb b/activesupport/test/dependencies_test.rb
index 68b6cc6e8c..9b84e75902 100644
--- a/activesupport/test/dependencies_test.rb
+++ b/activesupport/test/dependencies_test.rb
@@ -647,6 +647,14 @@ class DependenciesTest < ActiveSupport::TestCase
     Object.class_eval { remove_const :E }
   end
 
+  def test_constants_in_capitalized_nesting_marked_as_autoloaded
+    with_autoloading_fixtures do
+      ActiveSupport::Dependencies.load_missing_constant(HTML, "SomeClass")
+
+      assert ActiveSupport::Dependencies.autoloaded?("HTML::SomeClass")
+    end
+  end
+
   def test_unloadable
     with_autoloading_fixtures do
       Object.const_set :M, Module.new