Constraints should be inferred from cast equality constraint

scala> spark.sql("create table t1(c11 int, c12 decimal) ")
res0: org.apache.spark.sql.DataFrame = []

scala> spark.sql("create table t2(c21 bigint, c22 decimal) ")
res1: org.apache.spark.sql.DataFrame = []

scala> spark.sql("select t1.*, t2.* from t1 left join t2 on t1.c11=t2.c21 where t1.c11=1").explain
== Physical Plan ==
SortMergeJoin [cast(c11#0 as bigint)], [c21#2L], LeftOuter
:- *(2) Sort [cast(c11#0 as bigint) ASC NULLS FIRST], false, 0
:  +- Exchange hashpartitioning(cast(c11#0 as bigint), 200), true, [id=#30]
:     +- *(1) Filter (isnotnull(c11#0) AND (c11#0 = 1))
:        +- Scan hive default.t1 [c11#0, c12#1], HiveTableRelation `default`.`t1`, org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe, [c11#0, c12#1], Statistics(sizeInBytes=8.0 EiB)
+- *(4) Sort [c21#2L ASC NULLS FIRST], false, 0
   +- Exchange hashpartitioning(c21#2L, 200), true, [id=#37]
      +- *(3) Filter isnotnull(c21#2L)
         +- Scan hive default.t2 [c21#2L, c22#3], HiveTableRelation `default`.`t2`, org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe, [c21#2L, c22#3], Statistics(sizeInBytes=8.0 EiB)

postgres=# create table t1(c11 int4, c12 decimal);
CREATE TABLE
postgres=# create table t2(c21 int8, c22 decimal);
CREATE TABLE
postgres=# explain select t1.*, t2.* from t1 left join t2 on t1.c11=t2.c21 where t1.c11=1;
                           QUERY PLAN
----------------------------------------------------------------
 Nested Loop Left Join  (cost=0.00..51.43 rows=36 width=76)
   Join Filter: (t1.c11 = t2.c21)
   ->  Seq Scan on t1  (cost=0.00..25.88 rows=6 width=36)
         Filter: (c11 = 1)
   ->  Materialize  (cost=0.00..25.03 rows=6 width=40)
         ->  Seq Scan on t2  (cost=0.00..25.00 rows=6 width=40)
               Filter: (c21 = 1)
(7 rows)