---
title: bail
summary: Return early with an error.
url: https://www.fastly.com/documentation/reference/compute/sdks/rust/fastly/error/macro.bail/
---

**Kind:** Macro  
**Module:** [error](https://www.fastly.com/documentation/reference/compute/sdks/rust/fastly/error/)  
**Package:** fastly 0.13.1

```rust
macro_rules! bail {
    ($msg:literal $(,)?) => { ... };
    ($err:expr $(,)?) => { ... };
    ($fmt:expr, $($arg:tt)*) => { ... };
}
```

Return early with an error.

This macro is equivalent to
<code>return Err(anyhow!($args\...))</code>.

The surrounding function's or closure's return value is required to be
<code>Result&lt;_, [anyhow::Error][crate::Error]&gt;</code>.

## Example

```rust
if !has_permission(user, resource) {
    bail!("permission denied for accessing {}", resource);
}
```

```rust
#[derive(Error, Debug)]
enum ScienceError {
    #[error("recursion limit exceeded")]
    RecursionLimitExceeded,
    ...
}

if depth > MAX_DEPTH {
    bail!(ScienceError::RecursionLimitExceeded);
}
```