1 files changed, 6 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb
index 828ada00a7..8503d3ea1b 100644
--- a/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb
+++ b/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb
@@ -2,10 +2,16 @@ module ActiveRecord
   module ConnectionAdapters
     module Type
       class HashLookupTypeMap < TypeMap # :nodoc:
+        delegate :key?, to: :@mapping
+
         def lookup(type)
           @mapping.fetch(type, proc { default_value }).call(type)
         end
 
+        def fetch(type, &block)
+          @mapping.fetch(type, block).call(type)
+        end
+
         def alias_type(type, alias_type)
           register_type(type) { lookup(alias_type) }
         end