Fix TimeZoneConverter#== method, so objects will be properly...

compared by their type, scale, limit & precision.

activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb

@@ -32,6 +32,13 @@ def cast(value)
           end
         end
 
+        def ==(other)
+          precision == other.precision &&
+            scale == other.scale &&
+            limit == other.limit &&
+            type == other.type
+        end
+
         private
           def convert_time_to_time_zone(value)
             return if value.nil?

activerecord/lib/active_record/connection_adapters/postgresql/oid/timestamp.rb

@@ -8,13 +8,6 @@ class Timestamp < DateTime # :nodoc:
           def type
             real_type_unless_aliased(:timestamp)
           end
-
-          def ==(other)
-            precision == other.precision &&
-              scale == other.scale &&
-              limit == other.limit &&
-              type == other.type
-          end
         end
       end
     end

activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb

@@ -715,15 +715,6 @@ def test_disable_extension_without_schema
         @connection.execute("DROP EXTENSION IF EXISTS hstore")
       end
 
-      def test_time_zone_converter_equals_to_timestamp
-        subtype = ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Timestamp.new
-        value = ActiveRecord::AttributeMethods::TimeZoneConversion::TimeZoneConverter.new(subtype)
-
-        value_from_cache = Marshal.load(Marshal.dump(value))
-
-        assert_equal value, value_from_cache
-      end
-
       private
         def with_postgresql_apdater_decode_dates
           PostgreSQLAdapter.decode_dates = true

activerecord/test/cases/attribute_methods/time_zone_converter_test.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "active_support/core_ext/enumerable"
+
+module ActiveRecord
+  module AttributeMethods
+    module TimeZoneConversion
+      class TimeZoneConverterTest < ActiveRecord::TestCase
+        def test_with_date_time_type
+          subtype = ActiveRecord::Type::DateTime.new
+          value = ActiveRecord::AttributeMethods::TimeZoneConversion::TimeZoneConverter.new(subtype)
+          value_from_cache = Marshal.load(Marshal.dump(value))
+
+          assert_equal value, value_from_cache
+        end
+      end
+    end
+  end
+end