Struct snafu::Whatever

source ·
pub struct Whatever { /* private fields */ }
Expand description

A basic error type that you can use as a first step to better error handling.

You can use this type in your own application as a quick way to create errors or add basic context to another error. This can also be used in a library, but consider wrapping it in an opaque error to avoid putting the SNAFU crate in your public API.

Examples

use snafu::prelude::*;

type Result<T, E = snafu::Whatever> = std::result::Result<T, E>;

fn subtract_numbers(a: u32, b: u32) -> Result<u32> {
    if a > b {
        Ok(a - b)
    } else {
        whatever!("Can't subtract {} - {}", a, b)
    }
}

fn complicated_math(a: u32, b: u32) -> Result<u32> {
    let val = subtract_numbers(a, b).whatever_context("Can't do the math")?;
    Ok(val * 2)
}

See whatever! for detailed usage instructions.

Limitations

When wrapping errors, only the backtrace from the shallowest function is guaranteed to be available. If you need the deepest possible trace, consider creating a custom error type and using #[snafu(backtrace)] on the source field. If a best-effort attempt is sufficient, see the backtrace method.

When the standard library stabilizes backtrace support, this behavior may change.

Implementations§

Gets the backtrace from the deepest Whatever error. If none of the underlying errors are Whatever, returns the backtrace from when this instance was created.

Trait Implementations§

Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
👎Deprecated since 1.42.0: use the Display impl or to_string()
👎Deprecated since 1.33.0: replaced by Error::source, which can support downcasting
The lower-level source of this error, if any. Read more
🔬This is a nightly-only experimental API. (error_generic_member_access)
Provides type based access to context intended for error reports. Read more
Returns a Backtrace that may be printed.
Returns an iterator for traversing the chain of errors, starting with the current error and continuing with recursive calls to Error::source. Read more
The underlying error
Create a brand new error from the given string
Wrap an existing error with the given string

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
For maximum effectiveness, this needs to be called as a method to benefit from Rust’s automatic dereferencing of method receivers. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

🔬This is a nightly-only experimental API. (provide_any)
Data providers should implement this method to provide all values they are able to provide by using demand. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.