1 files changed, 25 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
new file mode 100644
index 0000000000..db9853fbcc
--- /dev/null
+++ b/activerecord/lib/active_record/type/hash_lookup_type_map.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ActiveRecord
+  module Type
+    class HashLookupTypeMap < TypeMap # :nodoc:
+      def alias_type(type, alias_type)
+        register_type(type) { |_, *args| lookup(alias_type, *args) }
+      end
+
+      def key?(key)
+        @mapping.key?(key)
+      end
+
+      def keys
+        @mapping.keys
+      end
+
+      private
+
+        def perform_fetch(type, *args, &block)
+          @mapping.fetch(type, block).call(type, *args)
+        end
+    end
+  end
+end