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)).
```

{
    auto actions = std::make_shared<ActionsDAG>();
    actions->project_input = project_input;
    actions->projected_output = projected_output;
    std::unordered_map<const Node *, Node *> copy_map;
    for (const auto & node : nodes)
    {
        auto & copy_node = actions->nodes.emplace_back(node);
        copy_map[&node] = &copy_node;
    }
    for (auto & node : actions->nodes)
        for (auto & child : node.children)
            child = copy_map[child];
    for (const auto & node : index)
        actions->index.push_back(copy_map[node]);
    for (const auto & node : inputs)
        actions->inputs.push_back(copy_map[node]);
    return actions;
}
#if USE_EMBEDDED_COMPILER
void ActionsDAG::compileExpressions(size_t min_count_to_compile_expression)