Add `Style/RedundantFreeze` to remove redudant `.freeze`

Since Rails 6.0 will support Ruby 2.4.1 or higher
`# frozen_string_literal: true` magic comment is enough to make string object frozen.
This magic comment is enabled by `Style/FrozenStringLiteralComment` cop.

* Exclude these files not to auto correct false positive `Regexp#freeze`
 - 'actionpack/lib/action_dispatch/journey/router/utils.rb'
 - 'activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb'

It has been fixed by https://github.com/rubocop-hq/rubocop/pull/6333
Once the newer version of RuboCop released and available at Code Climate these exclude entries should be removed.

* Replace `String#freeze` with `String#-@` manually if explicit frozen string objects are required

 - 'actionpack/test/controller/test_case_test.rb'
 - 'activemodel/test/cases/type/string_test.rb'
 - 'activesupport/lib/active_support/core_ext/string/strip.rb'
 - 'activesupport/test/core_ext/string_ext_test.rb'
 - 'railties/test/generators/actions_test.rb'

1 files changed, 3 insertions, 3 deletions

diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index 238a9f0ee6..063d8d1587 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -144,7 +144,7 @@ module ActiveSupport #:nodoc:
 
           # Normalize the list of new constants, and add them to the list we will return
           new_constants.each do |suffix|
-            constants << ([namespace, suffix] - ["Object"]).join("::".freeze)
+            constants << ([namespace, suffix] - ["Object"]).join("::")
           end
         end
         constants
@@ -410,7 +410,7 @@ module ActiveSupport #:nodoc:
         next unless expanded_path.start_with?(expanded_root)
 
         root_size = expanded_root.size
-        next if expanded_path[root_size] != ?/.freeze
+        next if expanded_path[root_size] != ?/
 
         nesting = expanded_path[(root_size + 1)..-1]
         paths << nesting.camelize unless nesting.blank?
@@ -505,7 +505,7 @@ module ActiveSupport #:nodoc:
 
       if file_path
         expanded = File.expand_path(file_path)
-        expanded.sub!(/\.rb\z/, "".freeze)
+        expanded.sub!(/\.rb\z/, "")
 
         if loading.include?(expanded)
           raise "Circular dependency detected while autoloading constant #{qualified_name}"