# E0271

Construction of a prelude struct with private fields, such as a built-in capability (`Stdout(handle: 1)`) or `Args`. Capabilities cannot be forged; they come from `main`.

**Machine-applicable fix:** none.

## Example

This program fails with `E0271`.

```oska
fn main() {
    let out = Stdout(handle: 1)
}
```

## Fixed

The same program, fixed.

```oska
fn main(out: Stdout) {}
```

Listed in the [checker notes](/checker.md#e0271). `oskac explain E0271` prints this entry offline.