Make Arel nodes more invertable

It makes node detection for `unscope` and `merge` more easier.

activerecord/lib/arel/nodes/binary.rb

@@ -40,12 +40,54 @@ module Arel # :nodoc: all
     end
 
     class Between < Binary; include FetchAttribute; end
-    class NotIn < Binary; include FetchAttribute; end
-    class GreaterThan < Binary; include FetchAttribute; end
-    class GreaterThanOrEqual < Binary; include FetchAttribute; end
-    class NotEqual < Binary; include FetchAttribute; end
-    class LessThan < Binary; include FetchAttribute; end
-    class LessThanOrEqual < Binary; include FetchAttribute; end
+
+    class GreaterThan < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::LessThanOrEqual.new(left, right)
+      end
+    end
+
+    class GreaterThanOrEqual < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::LessThan.new(left, right)
+      end
+    end
+
+    class LessThan < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::GreaterThanOrEqual.new(left, right)
+      end
+    end
+
+    class LessThanOrEqual < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::GreaterThan.new(left, right)
+      end
+    end
+
+    class NotEqual < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::Equality.new(left, right)
+      end
+    end
+
+    class NotIn < Binary
+      include FetchAttribute
+
+      def invert
+        Arel::Nodes::In.new(left, right)
+      end
+    end
 
     class Or < Binary
       def fetch_attribute(&block)

activerecord/test/cases/relation/merging_test.rb

@@ -175,6 +175,24 @@ class RelationMergingTest < ActiveRecord::TestCase
     assert_equal [david], Author.where(id: mary).merge(non_mary_and_bob, rewhere: true)
   end
 
+  def test_merge_not_range_clause
+    david, mary, bob = authors(:david, :mary, :bob)
+
+    less_than_bob = Author.where.not(id: bob.id..Float::INFINITY).order(:id)
+
+    assert_equal [david, mary], less_than_bob
+
+    assert_deprecated do
+      assert_equal [david], Author.where(id: david).merge(less_than_bob)
+    end
+    assert_equal [david, mary], Author.where(id: david).merge(less_than_bob, rewhere: true)
+
+    assert_deprecated do
+      assert_equal [mary], Author.where(id: mary).merge(less_than_bob)
+    end
+    assert_equal [david, mary], Author.where(id: mary).merge(less_than_bob, rewhere: true)
+  end
+
   def test_merge_doesnt_duplicate_same_clauses
     david, mary, bob = authors(:david, :mary, :bob)
 

activerecord/test/cases/relation/where_clause_test.rb

@@ -90,14 +90,26 @@ class ActiveRecord::Relation
     test "invert replaces each part of the predicate with its inverse" do
       original = WhereClause.new([
         table["id"].in([1, 2, 3]),
+        table["id"].not_in([1, 2, 3]),
         table["id"].eq(1),
+        table["id"].not_eq(2),
+        table["id"].gt(1),
+        table["id"].gteq(2),
+        table["id"].lt(1),
+        table["id"].lteq(2),
         table["id"].is_not_distinct_from(1),
         table["id"].is_distinct_from(2),
         "sql literal"
       ])
       expected = WhereClause.new([
         table["id"].not_in([1, 2, 3]),
+        table["id"].in([1, 2, 3]),
         table["id"].not_eq(1),
+        table["id"].eq(2),
+        table["id"].lteq(1),
+        table["id"].lt(2),
+        table["id"].gteq(1),
+        table["id"].gt(2),
         table["id"].is_distinct_from(1),
         table["id"].is_not_distinct_from(2),
         Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new("sql literal"))