**Describe the bug**
Under certain conditions the equals comparison between String and Date yields the wrong result. Range Comparisons with greather-than-equals returns the correct result set.

**How to reproduce**
* Which ClickHouse server version to use: 21.2.5.5 (latest at the time of this issue)
* Which interface to use, if matters: HTTP (but should not matter)

```sql
CREATE TABLE default.myTable (
	myDay Date,
	myOrder Int32,
	someData String
) 
ENGINE = ReplacingMergeTree
PARTITION BY floor(toYYYYMMDD(myDay), -1)
ORDER BY (myOrder)
;

INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-01', 1);
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-02', 2); // This row should be returned
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-03', 3);

SELECT * FROM default.myTable mt
WHERE myDay = '2021-01-02';
```

**Expected behavior**
The last query in the example should yield the marked row. Instead it returns a empty result set.

There must be a connection to the used `PARTITION KEY`. The issue fails to reproduce as soon as I do any changes to the `PARTITION KEY` setting.

if (cur_node->type == ActionsDAG::ActionType::FUNCTION && cur_node->children.size() <= 2)
                {
                    if (!cur_node->function_base->isDeterministic())
                        is_valid_chain = false;
                    const ActionsDAG::Node * next_node = nullptr;
                    for (const auto * arg : cur_node->children)
                    {
                        if (arg->column && isColumnConst(*arg->column))
                            continue;
                        if (next_node)
                            is_valid_chain = false;
                        next_node = arg;
                    }
                    if (!next_node)
                        is_valid_chain = false;
                    cur_node = next_node;
                }
                else if (cur_node->type == ActionsDAG::ActionType::ALIAS)
                    cur_node = cur_node->children.front();
                else
                    is_valid_chain = false;
            }
            if (is_valid_chain)
            {
                {
                    auto input_column = sample_block.getByName(expr_name);
                    auto const_column = out_type->createColumnConst(1, out_value);
                    out_value = (*castColumn({const_column, out_type, "c"}, input_column.type))[0];
                    out_type = input_column.type;
                }