Enable `Style/DefWithParentheses` rubocop rule

The def with blank `()` was newly added in #31176, but we have not used
the blank `()` style in most part of our code base.
So I've enabled `Style/DefWithParentheses` to prevent to newly added the
code.

5 files changed, 7 insertions, 4 deletions

diff --git a/.rubocop.yml b/.rubocop.yml
index 399fc66730..f6259fe432 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -76,6 +76,9 @@ Layout/SpaceAroundOperators:
 Layout/SpaceBeforeFirstArg:
     Enabled: true
 
+Style/DefWithParentheses:
+  Enabled: true
+
 # Defining a method with parameters needs parentheses.
 Style/MethodDefParentheses:
   Enabled: true
diff --git a/actionview/test/template/form_helper/form_with_test.rb b/actionview/test/template/form_helper/form_with_test.rb
index ad23d31d41..4e268eaa16 100644
--- a/actionview/test/template/form_helper/form_with_test.rb
+++ b/actionview/test/template/form_helper/form_with_test.rb
@@ -218,7 +218,7 @@ class FormWithActsLikeFormForTest < FormWithTest
 
     @post = Post.new
     @comment = Comment.new
-    def @post.errors()
+    def @post.errors
       Class.new {
         def [](field); field == "author_name" ? ["can't be empty"] : [] end
         def empty?() false end
diff --git a/actionview/test/template/form_helper_test.rb b/actionview/test/template/form_helper_test.rb
index 4442465047..e7b249cc9c 100644
--- a/actionview/test/template/form_helper_test.rb
+++ b/actionview/test/template/form_helper_test.rb
@@ -105,7 +105,7 @@ class FormHelperTest < ActionView::TestCase
 
     @post = Post.new
     @comment = Comment.new
-    def @post.errors()
+    def @post.errors
       Class.new {
         def [](field); field == "author_name" ? ["can't be empty"] : [] end
         def empty?() false end
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index 07e37f5dd2..4d81ac939e 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -256,7 +256,7 @@ module ActiveSupport
         @country_zones[code] ||= load_country_zones(code)
       end
 
-      def clear() #:nodoc:
+      def clear #:nodoc:
         @lazy_zones_map = Concurrent::Map.new
         @country_zones  = Concurrent::Map.new
         @zones = nil
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
index 96ad8dfbdb..d904f79ccf 100644
--- a/activesupport/test/json/encoding_test.rb
+++ b/activesupport/test/json/encoding_test.rb
@@ -210,7 +210,7 @@ class TestJSONEncoding < ActiveSupport::TestCase
 
   People = Class.new(BasicObject) do
     include Enumerable
-    def initialize()
+    def initialize
       @people = [
         { name: "John", address: { city: "London", country: "UK" } },
         { name: "Jean", address: { city: "Paris" , country: "France" } }