Struct DriverError 

pub struct DriverError { /* private fields */ }

The error that stops a compilation run.

A Stage returns a DriverError from Stage::run when it cannot produce its output: a phase that hit an unrecoverable condition, or a call to Session::abort_if_errors that found the session already holds errors. It is the control-flow failure that ends the pipeline, as distinct from a Diagnostic, which is a record a stage emits and may keep going after.

The error carries the message describing what went wrong and the stage it came from. A stage does not name itself: it returns DriverError::new(reason) with an empty stage, and the Pipeline stamps in the name of the stage that failed as it propagates the error. Stamping only fills an empty name, so in a chain the innermost stage — the one that actually failed — keeps the attribution.

The reason is stored as a Cow<'static, str>, so a static message costs no allocation and a computed one is owned only when built.

Examples

A stage failing with a static reason:

use driver_lang::DriverError;

let err = DriverError::new("unresolved import");
assert_eq!(err.message(), "unresolved import");
assert_eq!(err.stage(), ""); // not stamped until it flows through a Pipeline

A computed reason:

use driver_lang::DriverError;

let path = "src/main";
let err = DriverError::new(format!("cannot read `{path}.rs`"));
assert_eq!(err.message(), "cannot read `src/main.rs`");

Implementations

impl DriverError

pub fn new(message: impl Into<Cow<'static, str>>) -> Self

Create an error describing why a stage could not complete.

Call this from inside Stage::run. The message accepts a string literal (no allocation) or an owned String (a computed reason). The failing stage’s name is filled in by the Pipeline — you do not repeat it here.

Examples

use driver_lang::DriverError;

let from_literal = DriverError::new("boom");
let from_owned = DriverError::new(String::from("boom"));
assert_eq!(from_literal, from_owned);

pub fn stage(&self) -> &str

The name of the stage that failed, or "" if the error has not yet propagated through a Pipeline.

Examples

use driver_lang::DriverError;

assert_eq!(DriverError::new("boom").stage(), "");

pub fn message(&self) -> &str

The reason the stage could not complete.

Examples

use driver_lang::DriverError;

assert_eq!(DriverError::new("type error").message(), "type error");

Trait Implementations

impl Clone for DriverError

fn clone(&self) -> DriverError

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DriverError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DriverError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for DriverError

impl Error for DriverError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for DriverError

fn eq(&self, other: &DriverError) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for DriverError