**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.
constraints.cend(),
                [this](const ASTPtr & constraint_ast)
                {
                    return constraint_ast->as<ASTConstraintDeclaration &>().name == constraint_name;
                }))
        {
            if (if_not_exists)
                return;
            throw Exception("Cannot add constraint " + constraint_name + ": constraint with this name already exists",
                        ErrorCodes::ILLEGAL_COLUMN);
        }
        auto insert_it = constraints.end();
        constraints.emplace(insert_it, constraint_decl);
        metadata.constraints = ConstraintsDescription(constraints);
    }
    else if (type == DROP_CONSTRAINT)
    {
        auto constraints = metadata.constraints.getConstraints();
        auto erase_it = std::find_if(
                constraints.begin(),
                constraints.end(),
                [this](const ASTPtr & constraint_ast)
                {
                    return constraint_ast->as<ASTConstraintDeclaration &>().name == constraint_name;
                });
        if (erase_it == constraints.end())
        {
            if (if_exists)
                return;
            throw Exception("Wrong constraint name. Cannot find constraint `" + constraint_name + "` to drop.",