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'

7 files changed, 8 insertions, 8 deletions

diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index 888a431e5f..1ad9071cc2 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -369,7 +369,7 @@ module ActiveModel
             "define_method(:'#{name}') do |*args|"
           end
 
-          extra = (extra.map!(&:inspect) << "*args").join(", ".freeze)
+          extra = (extra.map!(&:inspect) << "*args").join(", ")
 
           target = if CALL_COMPILABLE_REGEXP.match?(send)
             "#{"self." unless include_private}#{send}(#{extra})"
diff --git a/activemodel/lib/active_model/attributes.rb b/activemodel/lib/active_model/attributes.rb
index 5bf213d593..41fe5168f3 100644
--- a/activemodel/lib/active_model/attributes.rb
+++ b/activemodel/lib/active_model/attributes.rb
@@ -29,7 +29,7 @@ module ActiveModel
       private
 
         def define_method_attribute=(name)
-          safe_name = name.unpack1("h*".freeze)
+          safe_name = name.unpack1("h*")
           ActiveModel::AttributeMethods::AttrNames.set_name_cache safe_name, name
 
           generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
diff --git a/activemodel/lib/active_model/conversion.rb b/activemodel/lib/active_model/conversion.rb
index cdc1282817..82713ddc81 100644
--- a/activemodel/lib/active_model/conversion.rb
+++ b/activemodel/lib/active_model/conversion.rb
@@ -103,7 +103,7 @@ module ActiveModel
         @_to_partial_path ||= begin
           element = ActiveSupport::Inflector.underscore(ActiveSupport::Inflector.demodulize(name))
           collection = ActiveSupport::Inflector.tableize(name)
-          "#{collection}/#{element}".freeze
+          "#{collection}/#{element}"
         end
       end
     end
diff --git a/activemodel/lib/active_model/naming.rb b/activemodel/lib/active_model/naming.rb
index 983401801f..5f3d674c4e 100644
--- a/activemodel/lib/active_model/naming.rb
+++ b/activemodel/lib/active_model/naming.rb
@@ -209,7 +209,7 @@ module ActiveModel
     private
 
       def _singularize(string)
-        ActiveSupport::Inflector.underscore(string).tr("/".freeze, "_".freeze)
+        ActiveSupport::Inflector.underscore(string).tr("/", "_")
       end
   end
 
diff --git a/activemodel/lib/active_model/type/string.rb b/activemodel/lib/active_model/type/string.rb
index 36f13945b1..a9c9bfadb6 100644
--- a/activemodel/lib/active_model/type/string.rb
+++ b/activemodel/lib/active_model/type/string.rb
@@ -16,8 +16,8 @@ module ActiveModel
         def cast_value(value)
           case value
           when ::String then ::String.new(value)
-          when true then "t".freeze
-          when false then "f".freeze
+          when true then "t"
+          when false then "f"
           else value.to_s
           end
         end
diff --git a/activemodel/lib/active_model/validations/validates.rb b/activemodel/lib/active_model/validations/validates.rb
index 88cca318ef..21c4ce0dfe 100644
--- a/activemodel/lib/active_model/validations/validates.rb
+++ b/activemodel/lib/active_model/validations/validates.rb
@@ -116,7 +116,7 @@ module ActiveModel
           key = "#{key.to_s.camelize}Validator"
 
           begin
-            validator = key.include?("::".freeze) ? key.constantize : const_get(key)
+            validator = key.include?("::") ? key.constantize : const_get(key)
           rescue NameError
             raise ArgumentError, "Unknown validator: '#{key}'"
           end
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
index 5469fdb7af..2d85556d20 100644
--- a/activemodel/test/cases/type/string_test.rb
+++ b/activemodel/test/cases/type/string_test.rb
@@ -19,7 +19,7 @@ module ActiveModel
         assert_equal false, type.cast(s).frozen?
         assert_equal false, s.frozen?
 
-        f = "foo".freeze
+        f = -"foo"
         assert_equal false, type.cast(f).frozen?
         assert_equal true, f.frozen?
       end