**Use case**

```
Received exception from server (version 21.11.1):
Code: 36. DB::Exception: Received from localhost:9000. DB::Exception: Wrong index name. Cannot find index `test_pentagram` to drop.. (BAD_ARGUMENTS)

github-explorer.ru-central1.internal :) ALTER TABLE hackernews DROP INDEX text_pentagram
```

It did not show me the typo.
command.type = AlterCommand::DROP_INDEX;
        command.index_name = command_ast->index->as<ASTIdentifier &>().name();
        command.if_exists = command_ast->if_exists;
        if (command_ast->clear_index)
            command.clear = true;
        if (command_ast->partition)
            command.partition = command_ast->partition;
        return command;
    }
    else if (command_ast->type == ASTAlterCommand::DROP_PROJECTION)
    {
        AlterCommand command;
        command.ast = command_ast->clone();
        command.type = AlterCommand::DROP_PROJECTION;
        command.projection_name = command_ast->projection->as<ASTIdentifier &>().name();
        command.if_exists = command_ast->if_exists;
        if (command_ast->clear_projection)
            command.clear = true;
        if (command_ast->partition)
            command.partition = command_ast->partition;
        return command;
    }
    else if (command_ast->type == ASTAlterCommand::MODIFY_TTL)
    {
        AlterCommand command;
        command.ast = command_ast->clone();
        command.type = AlterCommand::MODIFY_TTL;
        command.ttl = command_ast->ttl;
        return command;
    }