# XO0801: child or group task error does not convert to the enclosing error type

If a task fails with an error that no `await` consumes, the scope cancels everything else and the error propagates out of the scope as if by `?`, so it must convert to the enclosing function's error type. The same holds for tasks on a task group. When the group or scope handle came from outside the function, a task started on it must not fail unless its handle is bound and awaited. Bind the handle and handle `t.await`, handle the error inside the task, or declare a compatible error type. See core 7.1.

## Example

```xo
enum E { Boom }

fn work() -> Int ! E { 1 }

fn f() {
  scope s {
    s.spawn(fn() { work() })
  }
}
```

## Fix

```xo
enum E { Boom }

fn work() -> Int ! E { 1 }

fn f() -> Int {
  scope s {
    let t = s.spawn(fn() { work() })
    t.await.ok() ?? 0
  }
}
```

Run `xo explain XO0801` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).