Add new InternalAffairs/RedundantLetRuboCopConfigNew cop

Follow #9421.

This PR adds new `InternalAffairs/RedundantLetRuboCopConfigNew` cop.
It checks that `let` is `RuboCop::Config.new` with no arguments.

```ruby
# bad
RSpec.describe RuboCop::Cop::Department::Foo, :config do
  let(:config) { RuboCop::Config.new }
end

# good
RSpec.describe RuboCop::Cop::Department::Foo, :config do
end

RSpec.describe RuboCop::Cop::Department::Foo, :config do
  let(:config) { RuboCop::Config.new('Department/Bar' => configuration) }
end
```

No changelog entry has been added to the changelog due to this cop is
for use inside development.

.rubocop.yml

@@ -109,6 +109,7 @@ Metrics/ModuleLength:
 
 RSpec/FilePath:
   Exclude:
+    - spec/rubocop/cop/internal_affairs/redundant_let_rubocop_config_new_spec.rb
     - spec/rubocop/formatter/junit_formatter_spec.rb
 
 RSpec/PredicateMatcher:

lib/rubocop/cop/internal_affairs.rb

@@ -7,7 +7,8 @@
 require_relative 'internal_affairs/node_type_predicate'
 require_relative 'internal_affairs/offense_location_keyword'
 require_relative 'internal_affairs/redundant_described_class_as_subject'
-require_relative 'internal_affairs/redundant_message_argument'
+require_relative 'internal_affairs/redundant_let_rubocop_config_new'
 require_relative 'internal_affairs/redundant_location_argument'
+require_relative 'internal_affairs/redundant_message_argument'
 require_relative 'internal_affairs/style_detected_api_use'
 require_relative 'internal_affairs/useless_message_assertion'

lib/rubocop/cop/internal_affairs/redundant_let_rubocop_config_new.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module InternalAffairs
+      # This cop checks that `let` is `RuboCop::Config.new` with no arguments.
+      #
+      # @example
+      #   # bad
+      #   RSpec.describe RuboCop::Cop::Department::Foo, :config do
+      #     let(:config) { RuboCop::Config.new }
+      #   end
+      #
+      #   # good
+      #   RSpec.describe RuboCop::Cop::Department::Foo, :config do
+      #   end
+      #
+      #   RSpec.describe RuboCop::Cop::Department::Foo, :config do
+      #     let(:config) { RuboCop::Config.new(argument) }
+      #   end
+      #
+      class RedundantLetRuboCopConfigNew < Base
+        include RangeHelp
+        extend AutoCorrector
+
+        MSG = 'Remove `let` that is `RuboCop::Config.new` with no arguments%<additional_message>s.'
+
+        def_node_matcher :let_rubocop_config_new?, <<~PATTERN
+          (block
+            (send nil? :let
+              (sym :config))
+            (args)
+            (send
+              (const
+                (const nil? :RuboCop) :Config) :new))
+        PATTERN
+
+        def on_block(node)
+          return unless let_rubocop_config_new?(node)
+
+          describe = find_describe_method_node(node)
+
+          unless (exist_config = describe.last_argument.source == ':config')
+            additional_message = ' and specify `:config` in `describe`'
+          end
+
+          message = format(MSG, additional_message: additional_message)
+
+          add_offense(node, message: message) do |corrector|
+            corrector.remove(range_by_whole_lines(node.source_range, include_final_newline: true))
+
+            corrector.insert_after(describe.last_argument, ', :config') unless exist_config
+          end
+        end
+
+        private
+
+        def find_describe_method_node(block_node)
+          block_node.ancestors.find { |node| node.block_type? && node.method?(:describe) }.send_node
+        end
+      end
+    end
+  end
+end

spec/rubocop/cop/internal_affairs/method_name_equal_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::InternalAffairs::MethodNameEqual, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when using `#method == :do_something`' do
     expect_offense(<<~RUBY)
       node.method_name == :do_something

spec/rubocop/cop/internal_affairs/redundant_let_rubocop_config_new_spec.rb

@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::InternalAffairs::RedundantLetRuboCopConfigNew, :config do
+  it 'registers an offense when using `let(:config)` and `:config` is not specified in `describe`' do
+    expect_offense(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma do
+        subject(:cop) { described_class.new(config) }
+
+        let(:config) { RuboCop::Config.new }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove `let` that is `RuboCop::Config.new` with no arguments and specify `:config` in `describe`.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma, :config do
+        subject(:cop) { described_class.new(config) }
+
+      end
+    RUBY
+  end
+
+  it 'registers an offense when using `let(:config)` and `:config` is already specified in `describe`' do
+    expect_offense(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma, :config do
+        subject(:cop) { described_class.new(config) }
+
+        let(:config) { RuboCop::Config.new }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove `let` that is `RuboCop::Config.new` with no arguments.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma, :config do
+        subject(:cop) { described_class.new(config) }
+
+      end
+    RUBY
+  end
+
+  it 'registers an offense when using `let(:config)` with no argument `RuboCop::Config.new` and `:config` is specified' do
+    expect_offense(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma, :config do
+        subject(:cop) { described_class.new }
+
+        let(:config) { RuboCop::Config.new }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Remove `let` that is `RuboCop::Config.new` with no arguments.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma, :config do
+        subject(:cop) { described_class.new }
+
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when using `let(:config)` with arguments to `RuboCop::Config.new`' do
+    expect_no_offenses(<<~RUBY)
+      RSpec.describe RuboCop::Cop::Layout::SpaceAfterComma do
+        let(:config) { RuboCop::Config.new('Layout/SpaceInsideHashLiteralBraces' => brace_config) }
+      end
+    RUBY
+  end
+end

spec/rubocop/cop/internal_affairs/style_detected_api_use_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::InternalAffairs::StyleDetectedApiUse, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when correct_style_detected is used without a negative *_style_detected follow up' do
     expect_offense(<<~RUBY)
       def on_send(node)

spec/rubocop/cop/layout/empty_line_after_magic_comment_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Layout::EmptyLineAfterMagicComment, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense for code that immediately follows comment' do
     expect_offense(<<~RUBY)
       # frozen_string_literal: true

spec/rubocop/cop/layout/empty_lines_around_begin_body_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Layout::EmptyLinesAroundBeginBody, :config do
-  let(:config) { RuboCop::Config.new }
-
   shared_examples 'accepts' do |name, code|
     it "accepts #{name}" do
       expect_no_offenses(code)

spec/rubocop/cop/layout/empty_lines_around_exception_handling_keywords_spec.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Layout::EmptyLinesAroundExceptionHandlingKeywords, :config do
-  let(:config) { RuboCop::Config.new }
   let(:message) { '^{} Extra empty line detected' }
 
   shared_examples 'accepts' do |name, code|

spec/rubocop/cop/layout/space_around_method_call_operator_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Layout::SpaceAroundMethodCallOperator, :config do
-  let(:config) { RuboCop::Config.new }
-
   # FIXME: Remove unused vars
   shared_examples 'offense' do |name, _code, offense, correction|
     it "registers an offense and corrects when #{name}" do

spec/rubocop/cop/lint/big_decimal_new_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::BigDecimalNew, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense and corrects using `BigDecimal.new()`' do
     expect_offense(<<~RUBY)
       BigDecimal.new(123.456, 3)

spec/rubocop/cop/lint/deprecated_open_ssl_constant_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::DeprecatedOpenSSLConstant, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense with cipher constant and two arguments and corrects' do
     expect_offense(<<~RUBY)
       OpenSSL::Cipher::AES.new(128, :GCM)

spec/rubocop/cop/lint/duplicate_methods_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::DuplicateMethods, :config do
-  let(:config) { RuboCop::Config.new }
-
   shared_examples 'in scope' do |type, opening_line|
     it "registers an offense for duplicate method in #{type}" do
       expect_offense(<<~RUBY)

spec/rubocop/cop/lint/mixed_regexp_capture_types_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::MixedRegexpCaptureTypes, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when both of named and numbered captures are used' do
     expect_offense(<<~RUBY)
       /(?<foo>bar)(baz)/

spec/rubocop/cop/lint/multiple_comparison_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::MultipleComparison, :config do
-  let(:config) { RuboCop::Config.new }
-
   shared_examples 'Check to use two comparison operator' do |operator1, operator2|
     it "registers an offense for x #{operator1} y #{operator2} z" do
       expect_offense(<<~RUBY, operator1: operator1, operator2: operator2)

spec/rubocop/cop/lint/no_return_in_begin_end_blocks_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::NoReturnInBeginEndBlocks, :config do
-  let(:config) { RuboCop::Config.new }
-
   shared_examples 'rejects return inside a block' do |operator|
     it "rejects a return statement inside a block when using #{operator}" do
       expect_offense(<<-RUBY)

spec/rubocop/cop/lint/out_of_range_regexp_ref_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::OutOfRangeRegexpRef, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when references are used before any regexp' do
     expect_offense(<<~RUBY)
       puts $3

spec/rubocop/cop/lint/redundant_with_index_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::RedundantWithIndex, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense for `ary.each_with_index { |v| v }` ' \
     'and corrects to `ary.each`' do
     expect_offense(<<~RUBY)

spec/rubocop/cop/lint/redundant_with_object_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::RedundantWithObject, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense and corrects when using ' \
     '`ary.each_with_object { |v| v }`' do
     expect_offense(<<~RUBY)

spec/rubocop/cop/lint/regexp_as_condition_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::RegexpAsCondition, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense and corrects for a regexp literal in `if` condition' do
     expect_offense(<<~RUBY)
       if /foo/

spec/rubocop/cop/lint/rescue_type_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::RescueType, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'accepts rescue modifier' do
     expect_no_offenses('foo rescue nil')
   end

spec/rubocop/cop/lint/script_permission_spec.rb

@@ -1,10 +1,9 @@
 # frozen_string_literal: true
 
 # rubocop:disable Style/NumericLiteralPrefix
-RSpec.describe RuboCop::Cop::Lint::ScriptPermission do
+RSpec.describe RuboCop::Cop::Lint::ScriptPermission, :config do
   subject(:cop) { described_class.new(config, options) }
 
-  let(:config) { RuboCop::Config.new }
   let(:options) { nil }
 
   let(:file) { Tempfile.new('') }

spec/rubocop/cop/lint/send_with_mixin_argument_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::SendWithMixinArgument, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when using `send` with `include`' do
     expect_offense(<<~RUBY)
       Foo.send(:include, Bar)

spec/rubocop/cop/lint/struct_new_override_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::StructNewOverride, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense using `Struct.new(symbol)`' do
     expect_offense(<<~RUBY)
       Bad = Struct.new(:members)

spec/rubocop/cop/lint/to_json_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::ToJSON, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense and corrects using `#to_json` without arguments' do
     expect_offense(<<~RUBY)
       def to_json

spec/rubocop/cop/lint/trailing_comma_in_attribute_declaration_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::TrailingCommaInAttributeDeclaration, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense when using trailing comma' do
     expect_offense(<<~RUBY)
       class Foo

spec/rubocop/cop/lint/uri_escape_unescape_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::UriEscapeUnescape, :config do
-  let(:config) { RuboCop::Config.new }
-
   it "registers an offense when using `URI.escape('http://example.com')`" do
     expect_offense(<<~RUBY)
       URI.escape('http://example.com')

spec/rubocop/cop/lint/uri_regexp_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::UriRegexp, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'does not register an offense when using `regexp` without receiver' do
     expect_no_offenses(<<~RUBY)
       regexp('http://example.com')

spec/rubocop/cop/lint/useless_access_modifier_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::UselessAccessModifier, :config do
-  let(:config) { RuboCop::Config.new }
-
   context 'when an access modifier has no effect' do
     it 'registers an offense and corrects' do
       expect_offense(<<~RUBY)

spec/rubocop/cop/lint/void_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Lint::Void, :config do
-  let(:config) { RuboCop::Config.new }
-
   described_class::BINARY_OPERATORS.each do |op|
     it "registers an offense for void op #{op} if not on last line" do
       expect_offense(<<~RUBY, op: op)

spec/rubocop/cop/style/commented_keyword_spec.rb

@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 RSpec.describe RuboCop::Cop::Style::CommentedKeyword, :config do
-  let(:config) { RuboCop::Config.new }
-
   it 'registers an offense and corrects when commenting on the same line as `end`' do
     expect_offense(<<~RUBY)
       if x