private CodegenExpressionField AddOrGetFieldSharableInternal(CodegenFieldSharable sharable)
        {
            var member = _fieldsShared.Get(sharable);
            if (member != null) {
                return Field(member);
            }

            member = AddFieldUnsharedInternal(true, sharable.Type(), sharable.InitCtorScoped());
            _fieldsShared.Put(sharable, member);
            return Field(member);
        }