# E0240

An expression statement whose `Result` value is dropped. Discard one deliberately with `let _ = f()`. Spans the expression.

**Machine-applicable fix:** none.

## Example

This program fails with `E0240`.

```oska
fn main(io: Stdout) -> Result<(), IoError> {
    io.println("hi")
    Ok(())
}
```

## Fixed

The same program, fixed.

```oska
fn main(io: Stdout) -> Result<(), IoError> {
    io.println("hi")?
    Ok(())
}
```

Listed in the [checker notes](/checker.md#e0240). `oskac explain E0240` prints this entry offline.