# E0281

A `requires` or `ensures` condition whose type is not `Bool`. Spans the condition.

**Machine-applicable fix:** none.

## Example

This program fails with `E0281`.

```oska
fn run(n: Int) -> Int
    requires n
{
    n
}
```

## Fixed

The same program, fixed.

```oska
fn run(n: Int) -> Int
    requires n > 0
{
    n
}
```

Listed in the [checker notes](/checker.md#e0281). `oskac explain E0281` prints this entry offline.