Where conditions are eliminated wrongly caused by HashCode collision

[time-and-fate]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create table t(a varchar(10));
explain select * from t where cast(a as float) and cast(a as char);
explain select * from t where a = 0xe59388e59388e59388 and a = 0xe598bfe598bfe598bf;

UPDATE: the second SQL can't trigger the bug anymore. Please switch to use the following SQL:

explain select * from t30094 t1 where  concat(t1.a,'1') = _binary 0xe59388e59388e59388 collate binary and concat(t1.a,'1') = _binary 0xe598bfe598bfe598bf collate binary;

2. What did you expect to see? (Required)

The selection operator has two conditions.

3. What did you see instead (Required)

> explain select * from t where cast(a as float) and cast(a as char);
+-------------------------+----------+-----------+---------------+--------------------------------+
| id                      | estRows  | task      | access object | operator info                  |
+-------------------------+----------+-----------+---------------+--------------------------------+
| TableReader_7           | 8000.00  | root      |               | data:Selection_6               |
| └─Selection_6           | 8000.00  | cop[tikv] |               | cast(test2.t.a, float BINARY)  |
|   └─TableFullScan_5     | 10000.00 | cop[tikv] | table:t       | keep order:false, stats:pseudo |
+-------------------------+----------+-----------+---------------+--------------------------------+

> explain select * from t where a = 0xe59388e59388e59388 and a = 0xe598bfe598bfe598bf;
+-------------------------+----------+-----------+---------------+---------------------------------------+
| id                      | estRows  | task      | access object | operator info                         |
+-------------------------+----------+-----------+---------------+---------------------------------------+
| TableReader_7           | 10.00    | root      |               | data:Selection_6                      |
| └─Selection_6           | 10.00    | cop[tikv] |               | eq(test2.t.a, "0xe59388e59388e59388") |
|   └─TableFullScan_5     | 10000.00 | cop[tikv] | table:t       | keep order:false, stats:pseudo        |
+-------------------------+----------+-----------+---------------+---------------------------------------+

4. What is your TiDB version? (Required)

master

[time-and-fate]

/assign

[github-actions]

Please check whether the issue should be labeled with 'affects-x.y' or 'fixes-x.y.z', and then remove 'needs-more-info' label.