1 files changed, 29 insertions, 0 deletions
diff --git a/rubocop/cop/migration/remove_concurrent_index.rb b/rubocop/cop/migration/remove_concurrent_index.rb
new file mode 100644
index 00000000000..268c49865cb
--- /dev/null
+++ b/rubocop/cop/migration/remove_concurrent_index.rb
@@ -0,0 +1,29 @@
+require_relative '../../migration_helpers'
+
+module RuboCop
+  module Cop
+    module Migration
+      # Cop that checks if `remove_concurrent_index` is used with `up`/`down` methods
+      # and not `change`.
+      class RemoveConcurrentIndex < RuboCop::Cop::Cop
+        include MigrationHelpers
+
+        MSG = '`remove_concurrent_index` is not reversible so you must manually define ' \
+          'the `up` and `down` methods in your migration class, using `add_concurrent_index` in `down`'.freeze
+
+        def on_send(node)
+          return unless in_migration?(node)
+          return unless node.children[1] == :remove_concurrent_index
+
+          node.each_ancestor(:def) do |def_node|
+            add_offense(def_node, :name) if method_name(def_node) == :change
+          end
+        end
+
+        def method_name(node)
+          node.children[0]
+        end
+      end
+    end
+  end
+end