1 files changed, 44 insertions, 0 deletions
diff --git a/activerecord/lib/arel/nodes/unary.rb b/activerecord/lib/arel/nodes/unary.rb
new file mode 100644
index 0000000000..e458d87ab3
--- /dev/null
+++ b/activerecord/lib/arel/nodes/unary.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+module Arel
+  module Nodes
+    class Unary < Arel::Nodes::NodeExpression
+      attr_accessor :expr
+      alias :value :expr
+
+      def initialize expr
+        super()
+        @expr = expr
+      end
+
+      def hash
+        @expr.hash
+      end
+
+      def eql? other
+        self.class == other.class &&
+          self.expr == other.expr
+      end
+      alias :== :eql?
+    end
+
+    %w{
+      Bin
+      Cube
+      DistinctOn
+      Group
+      GroupingElement
+      GroupingSet
+      Lateral
+      Limit
+      Lock
+      Not
+      Offset
+      On
+      Ordering
+      RollUp
+      Top
+    }.each do |name|
+      const_set(name, Class.new(Unary))
+    end
+  end
+end