3.0.3隐式转换逻辑异常

如下SQL，t1有2行结果。
t2取自varchar字段，但关联后会发散
实际代码t1取自表，还会出现，关联后取不到结果的情况
查看执行计划发现，隐匿转换 bigint as double，应该是有效位不够导致t2中接近的数字同化了
这个隐式转换逻辑不对，不能单纯看左侧？

select t1.*   ,
       t2.code
  from (
       select cast(1037773994249297944 as bigint) as id  ,
              1                                   as flag
    union all
       select cast(1037773994249297944 as bigint) as id  ,
              2                                   as flag
       ) as t1
 inner join (
       select '1037773994249297944' as code
    union all
       select '1037773994249297941' as code
       ) t2
    on t1.id = t2.code