Update Rails/Pluck to be aware of numblocks.

Author: sammiya

changelog/change_update_railspluck_to_be_aware_of.md

@@ -0,0 +1 @@
+* [#631](https://github.com/rubocop/rubocop-rails/pull/631): Update `Rails/Pluck` to be aware of numblocks. ([@sammiya][])

lib/rubocop/cop/rails/pluck.rb

@@ -21,34 +21,42 @@ class Pluck < Base
         extend AutoCorrector
         extend TargetRailsVersion
 
-        MSG = 'Prefer `pluck(:%<value>s)` over `%<method>s { |%<argument>s| %<element>s[:%<value>s] }`.'
+        MSG = 'Prefer `pluck(:%<value>s)` over `%<current>s`.'
 
         minimum_target_rails_version 5.0
 
         def_node_matcher :pluck_candidate?, <<~PATTERN
-          (block (send _ ${:map :collect}) (args (arg $_argument)) (send (lvar $_element) :[] (sym $_value)))
+          ({block numblock} (send _ {:map :collect}) $_argument (send (lvar $_element) :[] (sym $_value)))
         PATTERN
 
         def on_block(node)
-          pluck_candidate?(node) do |method, argument, element, value|
-            next unless argument == element
+          pluck_candidate?(node) do |argument, element, value|
+            match = if node.block_type?
+                      argument.children.first.source.to_sym == element
+                    else # numblock
+                      argument == 1 && element == :_1
+                    end
+            next unless match
 
-            message = message(method, argument, element, value)
+            message = message(value, node)
 
             add_offense(offense_range(node), message: message) do |corrector|
               corrector.replace(offense_range(node), "pluck(:#{value})")
             end
           end
         end
+        alias on_numblock on_block
 
         private
 
         def offense_range(node)
           node.send_node.loc.selector.join(node.loc.end)
         end
 
-        def message(method, argument, element, value)
-          format(MSG, method: method, argument: argument, element: element, value: value)
+        def message(value, node)
+          current = offense_range(node).source
+
+          format(MSG, value: value, current: current)
         end
       end
     end

spec/rubocop/cop/rails/pluck_spec.rb

@@ -31,6 +31,23 @@
           RUBY
         end
       end
+
+      context 'when using Ruby 2.7 or newer', :ruby27 do
+        context 'when using numbered parameter' do
+          context "when `#{method}` can be replaced with `pluck`" do
+            it 'registers an offense' do
+              expect_offense(<<~RUBY, method: method)
+                x.%{method} { _1[:foo] }
+                  ^{method}^^^^^^^^^^^^^ Prefer `pluck(:foo)` over `%{method} { _1[:foo] }`.
+              RUBY
+
+              expect_correction(<<~RUBY)
+                x.pluck(:foo)
+              RUBY
+            end
+          end
+        end
+      end
     end
 
     context 'when using Rails 4.2 or older', :rails42 do