You have to provide the following information whenever possible.

**Describe the bug**
This query fails with the latest stable version 21.5.5.12. It worked with the last stable version 21.4.7.3.

**Does it reproduce on recent release?**
yes

**How to reproduce**
21.5.5.12

```
SELECT
    label,
    number
FROM
(
    SELECT
        'a' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
    UNION ALL
    SELECT
        'b' AS label,
        number
    FROM
    (
        SELECT number
        FROM numbers(10)
    )
)
WHERE number IN
(
    SELECT number
    FROM numbers(5)
)
```

**Expected behavior**
Query should run without errors

**Error message and/or stacktrace**
```
Received exception from server (version 21.5.5):
Code: 49. DB::Exception: Received from localhost:9000. DB::Exception: Block structure mismatch in Pipe::unitePipes stream: different names of columns:
label String String(size = 0), number UInt64 UInt64(size = 0), 'b' String Const(size = 0, String(size = 1))
label String String(size = 0), number UInt64 UInt64(size = 0), 'a' String Const(size = 0, String(size = 1)).
```

}
            }
        }
    }
    for (const auto * node : index)
        second_index.push_back(data[node].to_second);
    NodeRawConstPtrs second_inputs;
    NodeRawConstPtrs first_inputs;
    for (const auto * input : inputs)
    {
        const auto & cur = data[input];
        first_inputs.push_back(cur.to_first);
    }
    for (const auto * input : new_inputs)
    {
        const auto & cur = data[input];
        second_inputs.push_back(cur.to_second);
        first_index.push_back(cur.to_first);
    }
    auto first_actions = std::make_shared<ActionsDAG>();
    first_actions->nodes.swap(first_nodes);
    first_actions->index.swap(first_index);
    first_actions->inputs.swap(first_inputs);
    auto second_actions = std::make_shared<ActionsDAG>();
    second_actions->nodes.swap(second_nodes);
    second_actions->index.swap(second_index);
    second_actions->inputs.swap(second_inputs);
    return {std::move(first_actions), std::move(second_actions)};
}
ActionsDAG::SplitResult ActionsDAG::splitActionsBeforeArrayJoin(const NameSet & array_joined_columns) const