Add Sorbet/Refinement

Do not use Ruby Refinements library as it is not supported by Sorbet.

config/default.yml

@@ -1,3 +1,8 @@
+Sorbet/Refinement:
+  Description: Do not use Ruby Refinements library as it is not supported by Sorbet.
+  Enabled: pending
+  VersionAdded: '<<next>>'
+
 inherit_mode:
   merge:
   - Exclude

lib/rubocop/cop/sorbet/refinement.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module Cop
+    module Sorbet
+      # This cop checks for the use of Ruby Refinements library.
+      # Good examples below are examples of unrelated object methods that
+      # incidentally have the same name as the module methods we check for
+      #
+      # @example
+      #   # bad
+      #   module Foo
+      #     refine(Date) do
+      #     end
+      #   end
+
+      #   # bad
+      #   module Foo
+      #     using(Date) do
+      #     end
+      #   end
+      #
+      #   # good
+      #   module Foo
+      #     bar.refine(Date)
+      #   end
+      #
+      #   # good
+      #   module Foo
+      #     bar.using(Date)
+      #   end
+
+      class Refinement < Base
+        MSG = 'Do not use Ruby Refinements library as it is not supported by Sorbet.'
+        RESTRICT_ON_SEND = %i[refine using].freeze
+
+        def on_send(node)
+          add_offense(node) if node.receiver.nil?
+        end
+      end
+    end
+  end
+end

lib/rubocop/cop/sorbet_cops.rb

@@ -16,6 +16,7 @@
 require_relative "sorbet/forbid_t_unsafe"
 require_relative "sorbet/forbid_t_untyped"
 require_relative "sorbet/redundant_extend_t_sig"
+require_relative 'sorbet/refinement'
 require_relative "sorbet/type_alias_name"
 require_relative "sorbet/obsolete_strict_memoization"
 require_relative "sorbet/buggy_obsolete_strict_memoization"

manual/cops.md

@@ -33,6 +33,7 @@ In the following section you find all available cops:
 * [Sorbet/MultipleTEnumValues](cops_sorbet.md#sorbetmultipletenumvalues)
 * [Sorbet/ObsoleteStrictMemoization](cops_sorbet.md#sorbetobsoletestrictmemoization)
 * [Sorbet/RedundantExtendTSig](cops_sorbet.md#sorbetredundantextendtsig)
+* [Sorbet/Refinement](cops_sorbet.md#sorbetrefinement)
 * [Sorbet/SignatureBuildOrder](cops_sorbet.md#sorbetsignaturebuildorder)
 * [Sorbet/SingleLineRbiClassModuleDefinitions](cops_sorbet.md#sorbetsinglelinerbiclassmoduledefinitions)
 * [Sorbet/StrictSigil](cops_sorbet.md#sorbetstrictsigil)

manual/cops_sorbet.md

@@ -759,6 +759,28 @@ class Example
 end
 ```
 
+## Sorbet/Refinement
+
+Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
+--- | --- | --- | --- | ---
+Enabled | Yes | No | <<next>> | -
+
+# bad
+  module Foo
+    using(Date) do
+    end
+  end
+
+  # good
+  module Foo
+    bar.refine(Date)
+  end
+
+  # good
+  module Foo
+    bar.using(Date)
+  end
+
 ## Sorbet/SignatureBuildOrder
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged

spec/rubocop/cop/sorbet/refinement_spec.rb

@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+RSpec.describe RuboCop::Cop::Sorbet::Refinement, :config do
+  it 'registers an offense for using refine' do
+    expect_offense(<<-RUBY)
+      module Foo
+        refine(Date) do
+        ^^^^^^^^^^^^ Do not use Ruby Refinements library as it is not supported by Sorbet.
+        end
+      end
+    RUBY
+  end
+
+  it 'registers an offense for using a refinement' do
+    expect_offense(<<-RUBY)
+      module Foo
+        using(Date)
+        ^^^^^^^^^^^ Do not use Ruby Refinements library as it is not supported by Sorbet.
+      end
+    RUBY
+  end
+
+    it 'registers an offense for using refine in a class' do
+    expect_offense(<<-RUBY)
+      class Foo
+        refine(Date) do
+        ^^^^^^^^^^^^ Do not use Ruby Refinements library as it is not supported by Sorbet.
+        end
+      end
+    RUBY
+  end
+
+  it 'registers an offense for using a refinement in a class' do
+    expect_offense(<<-RUBY)
+      class Foo
+        using(Date)
+        ^^^^^^^^^^^ Do not use Ruby Refinements library as it is not supported by Sorbet.
+      end
+    RUBY
+  end
+
+  it 'registers no offense for using non-refinement method #refine' do
+    expect_no_offenses(<<-RUBY)
+      module Foo
+        bar.refine(Date)
+      end
+    RUBY
+  end
+
+  it 'registers no offense for using non-refinement method #using' do
+    expect_no_offenses(<<-RUBY)
+      module Foo
+        bar.using(Date)
+      end
+    RUBY
+  end
+end