pub trait StdError: Debug + Display {
// Provided methods
fn source(&self) -> Option<&(dyn Error + 'static)> { ... }
fn description(&self) -> &str { ... }
fn cause(&self) -> Option<&dyn Error> { ... }
fn provide<'a>(&'a self, request: &mut Request<'a>) { ... }
}
Expand description
Error
is a trait representing the basic expectations for error values,
i.e., values of type E
in Result<T, E>
.
Errors must describe themselves through the Display
and Debug
traits. Error messages are typically concise lowercase sentences without
trailing punctuation:
let err = "NaN".parse::<u32>().unwrap_err();
assert_eq!(err.to_string(), "invalid digit found in string");
Errors may provide cause information. Error::source()
is generally
used when errors cross “abstraction boundaries”. If one module must report
an error that is caused by an error from a lower-level module, it can allow
accessing that error via Error::source()
. This makes it possible for the
high-level module to provide its own errors while also revealing some of the
implementation for debugging.
Provided Methods§
1.30.0 · sourcefn source(&self) -> Option<&(dyn Error + 'static)>
fn source(&self) -> Option<&(dyn Error + 'static)>
The lower-level source of this error, if any.
§Examples
use std::error::Error;
use std::fmt;
#[derive(Debug)]
struct SuperError {
source: SuperErrorSideKick,
}
impl fmt::Display for SuperError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "SuperError is here!")
}
}
impl Error for SuperError {
fn source(&self) -> Option<&(dyn Error + 'static)> {
Some(&self.source)
}
}
#[derive(Debug)]
struct SuperErrorSideKick;
impl fmt::Display for SuperErrorSideKick {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "SuperErrorSideKick is here!")
}
}
impl Error for SuperErrorSideKick {}
fn get_super_error() -> Result<(), SuperError> {
Err(SuperError { source: SuperErrorSideKick })
}
fn main() {
match get_super_error() {
Err(e) => {
println!("Error: {e}");
println!("Caused by: {}", e.source().unwrap());
}
_ => println!("No error"),
}
}
1.0.0 · sourcefn description(&self) -> &str
👎Deprecated since 1.42.0: use the Display impl or to_string()
fn description(&self) -> &str
if let Err(e) = "xc".parse::<u32>() {
// Print `e` itself, no need for description().
eprintln!("Error: {e}");
}
fn cause(&self) -> Option<&dyn Error>
sourcefn provide<'a>(&'a self, request: &mut Request<'a>)
🔬This is a nightly-only experimental API. (error_generic_member_access
)
fn provide<'a>(&'a self, request: &mut Request<'a>)
error_generic_member_access
)Provides type based access to context intended for error reports.
Used in conjunction with Request::provide_value
and Request::provide_ref
to extract
references to member variables from dyn Error
trait objects.
§Example
#![feature(error_generic_member_access)]
use core::fmt;
use core::error::{request_ref, Request};
#[derive(Debug)]
enum MyLittleTeaPot {
Empty,
}
#[derive(Debug)]
struct MyBacktrace {
// ...
}
impl MyBacktrace {
fn new() -> MyBacktrace {
// ...
}
}
#[derive(Debug)]
struct Error {
backtrace: MyBacktrace,
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "Example Error")
}
}
impl std::error::Error for Error {
fn provide<'a>(&'a self, request: &mut Request<'a>) {
request
.provide_ref::<MyBacktrace>(&self.backtrace);
}
}
fn main() {
let backtrace = MyBacktrace::new();
let error = Error { backtrace };
let dyn_error = &error as &dyn std::error::Error;
let backtrace_ref = request_ref::<MyBacktrace>(dyn_error).unwrap();
assert!(core::ptr::eq(&error.backtrace, backtrace_ref));
assert!(request_ref::<MyLittleTeaPot>(dyn_error).is_none());
}
Implementations§
source§impl dyn Error
impl dyn Error
1.3.0 · sourcepub fn is<T>(&self) -> boolwhere
T: Error + 'static,
pub fn is<T>(&self) -> boolwhere
T: Error + 'static,
Returns true
if the inner type is the same as T
.
1.3.0 · sourcepub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
pub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
Returns some reference to the inner value if it is of type T
, or
None
if it isn’t.
1.3.0 · sourcepub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
pub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
Returns some mutable reference to the inner value if it is of type T
, or
None
if it isn’t.
source§impl dyn Error + Send
impl dyn Error + Send
1.3.0 · sourcepub fn is<T>(&self) -> boolwhere
T: Error + 'static,
pub fn is<T>(&self) -> boolwhere
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
1.3.0 · sourcepub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
pub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
1.3.0 · sourcepub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
pub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
source§impl dyn Error + Send + Sync
impl dyn Error + Send + Sync
1.3.0 · sourcepub fn is<T>(&self) -> boolwhere
T: Error + 'static,
pub fn is<T>(&self) -> boolwhere
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
1.3.0 · sourcepub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
pub fn downcast_ref<T>(&self) -> Option<&T>where
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
1.3.0 · sourcepub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
pub fn downcast_mut<T>(&mut self) -> Option<&mut T>where
T: Error + 'static,
Forwards to the method defined on the type dyn Error
.
source§impl dyn Error
impl dyn Error
sourcepub fn sources(&self) -> Source<'_> ⓘ
🔬This is a nightly-only experimental API. (error_iter
)
pub fn sources(&self) -> Source<'_> ⓘ
error_iter
)Returns an iterator starting with the current error and continuing with
recursively calling Error::source
.
If you want to omit the current error and only use its sources,
use skip(1)
.
§Examples
#![feature(error_iter)]
use std::error::Error;
use std::fmt;
#[derive(Debug)]
struct A;
#[derive(Debug)]
struct B(Option<Box<dyn Error + 'static>>);
impl fmt::Display for A {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "A")
}
}
impl fmt::Display for B {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "B")
}
}
impl Error for A {}
impl Error for B {
fn source(&self) -> Option<&(dyn Error + 'static)> {
self.0.as_ref().map(|e| e.as_ref())
}
}
let b = B(Some(Box::new(A)));
// let err : Box<Error> = b.into(); // or
let err = &b as &(dyn Error);
let mut iter = err.sources();
assert_eq!("B".to_string(), iter.next().unwrap().to_string());
assert_eq!("A".to_string(), iter.next().unwrap().to_string());
assert!(iter.next().is_none());
assert!(iter.next().is_none());
Trait Implementations§
1.6.0 · source§impl<'a> From<&str> for Box<dyn Error + 'a>
impl<'a> From<&str> for Box<dyn Error + 'a>
1.0.0 · source§impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a>
impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a>
1.22.0 · source§impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a>
impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + 'a>
1.22.0 · source§impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>
impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a>
source§fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>
fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a>
Converts a Cow
into a box of dyn Error
+ Send
+ Sync
.
§Examples
use std::error::Error;
use std::mem;
use std::borrow::Cow;
let a_cow_str_error = Cow::from("a str error");
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_cow_str_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
1.0.0 · source§impl<'a, E> From<E> for Box<dyn Error + 'a>where
E: Error + 'a,
impl<'a, E> From<E> for Box<dyn Error + 'a>where
E: Error + 'a,
source§fn from(err: E) -> Box<dyn Error + 'a>
fn from(err: E) -> Box<dyn Error + 'a>
Converts a type of Error
into a box of dyn Error
.
§Examples
use std::error::Error;
use std::fmt;
use std::mem;
#[derive(Debug)]
struct AnError;
impl fmt::Display for AnError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "An error")
}
}
impl Error for AnError {}
let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error>::from(an_error);
assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error))
1.0.0 · source§impl<'a, E> From<E> for Box<dyn Error + Send + Sync + 'a>
impl<'a, E> From<E> for Box<dyn Error + Send + Sync + 'a>
source§fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>
fn from(err: E) -> Box<dyn Error + Send + Sync + 'a>
Converts a type of Error
+ Send
+ Sync
into a box of
dyn Error
+ Send
+ Sync
.
§Examples
use std::error::Error;
use std::fmt;
use std::mem;
#[derive(Debug)]
struct AnError;
impl fmt::Display for AnError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "An error")
}
}
impl Error for AnError {}
unsafe impl Send for AnError {}
unsafe impl Sync for AnError {}
let an_error = AnError;
assert!(0 == mem::size_of_val(&an_error));
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(an_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
1.6.0 · source§impl<'a> From<String> for Box<dyn Error + 'a>
impl<'a> From<String> for Box<dyn Error + 'a>
1.0.0 · source§impl<'a> From<String> for Box<dyn Error + Send + Sync + 'a>
impl<'a> From<String> for Box<dyn Error + Send + Sync + 'a>
source§fn from(err: String) -> Box<dyn Error + Send + Sync + 'a>
fn from(err: String) -> Box<dyn Error + Send + Sync + 'a>
Converts a String
into a box of dyn Error
+ Send
+ Sync
.
§Examples
use std::error::Error;
use std::mem;
let a_string_error = "a string error".to_string();
let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_string_error);
assert!(
mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error))
Implementors§
impl !Error for &str
impl Error for LnUrlAuthError
impl Error for LnUrlError
impl Error for LnUrlPayError
impl Error for LnUrlWithdrawError
impl Error for ConnectError
impl Error for ReceiveOnchainError
impl Error for ReceivePaymentError
impl Error for RedeemOnchainError
impl Error for SdkError
impl Error for SendOnchainError
impl Error for SendPaymentError
impl Error for InvoiceError
impl Error for Bolt11ParseError
impl Error for Bolt11SemanticError
impl Error for CreationError
impl Error for ParseOrSemanticError
impl Error for breez_sdk_core::bitcoin::bech32::Error
impl Error for breez_sdk_core::bitcoin::bitcoinconsensus::Error
impl Error for Bip34Error
impl Error for breez_sdk_core::bitcoin::blockdata::locktime::Error
impl Error for OperationError
impl Error for breez_sdk_core::bitcoin::blockdata::script::Error
impl Error for ParseOutPointError
impl Error for RelativeLockTimeError
impl Error for breez_sdk_core::bitcoin::consensus::encode::Error
impl Error for EcdsaSigError
impl Error for breez_sdk_core::bitcoin::Error
impl Error for SchnorrSigError
impl Error for breez_sdk_core::bitcoin::util::address::Error
impl Error for ParseAmountError
impl Error for breez_sdk_core::bitcoin::util::base58::Error
impl Error for breez_sdk_core::bitcoin::util::bip32::Error
impl Error for breez_sdk_core::bitcoin::util::bip152::Error
impl Error for breez_sdk_core::bitcoin::util::bip158::Error
impl Error for MessageSignatureError
impl Error for breez_sdk_core::bitcoin::util::psbt::Error
impl Error for IncompleteTapTree
impl Error for breez_sdk_core::bitcoin::util::sighash::Error
impl Error for TaprootBuilderError
impl Error for TaprootError
impl Error for breez_sdk_core::bitcoin::util::key::Error
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::Error
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::hashes::Error
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::hashes::hex::Error
impl Error for BernoulliError
impl Error for WeightedError
impl Error for Infallible
impl Error for VarError
impl Error for RecvTimeoutError
impl Error for std::sync::mpsc::TryRecvError
impl Error for RoundingError
impl Error for FromHexError
impl Error for url::parser::ParseError
impl Error for !
impl Error for breez_sdk_core::lightning::io::Error
impl Error for WriterPanicked
impl Error for PeerHandleError
impl Error for ServiceConnectivityError
impl Error for ConversionError
impl Error for NonStandardSighashType
impl Error for breez_sdk_core::bitcoin::error::ParseIntError
impl Error for CommandStringError
impl Error for TxIndexOutOfRangeError
impl Error for SighashTypeParseError
impl Error for ParseLengthError
impl Error for ReadError
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::rand::Error
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::scalar::OutOfRangeError
impl Error for InvalidParityValue
impl Error for UnorderedKeyError
impl Error for alloc::collections::TryReserveError
impl Error for FromVecWithNulError
impl Error for IntoStringError
impl Error for NulError
impl Error for FromUtf8Error
impl Error for FromUtf16Error
impl Error for LayoutError
impl Error for AllocError
impl Error for TryFromSliceError
impl Error for BorrowError
impl Error for BorrowMutError
impl Error for CharTryFromError
impl Error for ParseCharError
impl Error for DecodeUtf16Error
impl Error for TryFromCharError
impl Error for FromBytesUntilNulError
impl Error for FromBytesWithNulError
impl Error for core::fmt::Error
impl Error for core::net::parser::AddrParseError
impl Error for ParseFloatError
impl Error for core::num::error::ParseIntError
impl Error for core::num::error::TryFromIntError
impl Error for ParseBoolError
impl Error for Utf8Error
impl Error for TryFromFloatSecsError
impl Error for JoinPathsError
impl Error for StripPrefixError
impl Error for ExitStatusError
impl Error for std::sync::mpsc::RecvError
impl Error for AccessError
impl Error for SystemTimeError
impl Error for chrono::duration::OutOfRangeError
impl Error for chrono::format::ParseError
impl Error for ParseMonthError
impl Error for OutOfRange
impl Error for ParseWeekdayError
impl Error for getrandom::error::Error
impl Error for http_body::limited::LengthLimitError
impl Error for http::error::Error
impl Error for InvalidHeaderName
impl Error for InvalidHeaderValue
impl Error for http::header::value::ToStrError
impl Error for InvalidMethod
impl Error for InvalidStatusCode
impl Error for InvalidUri
impl Error for InvalidUriParts
impl Error for indexmap::TryReserveError
impl Error for IntoArrayError
impl Error for NotEqualError
impl Error for OutIsTooSmallError
impl Error for PadError
impl Error for PrefixLenError
impl Error for ipnet::parser::AddrParseError
impl Error for log::ParseLevelError
impl Error for SetLoggerError
impl Error for FromStrError
impl Error for num_bigint_dig::ParseBigIntError
impl Error for num_bigint::ParseBigIntError
impl Error for openssl::error::Error
impl Error for ErrorStack
impl Error for openssl::ssl::error::Error
impl Error for X509VerifyResult
impl Error for prost::error::DecodeError
impl Error for EncodeError
impl Error for reqwest::error::Error
impl Error for serde_json::error::Error
impl Error for PathPersistError
impl Error for InvalidMetadataValue
impl Error for InvalidMetadataValueBytes
impl Error for InvalidMetadataKey
impl Error for tonic::metadata::value::ToStrError
impl Error for Status
impl Error for tonic::transport::error::Error
impl Error for TimeoutExpired
impl Error for uuid::error::Error
impl Error for breez_sdk_core::bitcoin::util::key::secp256k1::serde::de::value::Error
impl Error for ASN1DecodeErr
impl Error for ASN1EncodeErr
impl Error for ASN1Error
impl Error for Aborted
impl Error for AcquireError
impl Error for AddrParseError
impl Error for AnyDelimiterCodecError
impl Error for Asn1DerError
impl Error for Asn1DerError
impl Error for BuildError
impl Error for BuildError
impl Error for BuildError
impl Error for BuildError
impl Error for BuildError
impl Error for BytesRejection
impl Error for CaChainError
impl Error for CacheError
impl Error for Canceled
impl Error for CaseFoldError
impl Error for CertError
impl Error for CharSetError
impl Error for CharSetError
impl Error for Closed
impl Error for ColorChoiceParseError
impl Error for ComponentRange
impl Error for ConversionRange
impl Error for CsrError
impl Error for DecodeError
impl Error for DecodeError
impl Error for DecodeError
impl Error for DecodeError
impl Error for DecodeSliceError
impl Error for DecodeSliceError
impl Error for DerConstraint
impl Error for DeserializeError
impl Error for DifferentVariant
impl Error for Discover
impl Error for Elapsed
impl Error for Elapsed
impl Error for Elapsed
impl Error for EncodeSliceError
impl Error for EncodeSliceError
impl Error for EnterError
impl Error for Errno
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
Requires the std
feature.
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for Error
impl Error for ErrorKind
impl Error for Errors
impl Error for ExtensionRejection
impl Error for FailedToBufferBody
impl Error for FailedToDeserializeForm
impl Error for FailedToDeserializeFormBody
impl Error for FailedToDeserializePathParams
impl Error for FailedToDeserializeQueryString
impl Error for FailedToResolveHost
impl Error for FormRejection
impl Error for Format
impl Error for FromSqlError
impl Error for GetTimezoneError
impl Error for GroupInfoError
impl Error for HostRejection
impl Error for HttpRequestError
impl Error for HttpSignatureError
impl Error for InsertError
impl Error for InvalidBufferSize
impl Error for InvalidDnsNameError
impl Error for InvalidDnsNameError
Requires the std
feature.
impl Error for InvalidDnsNameError
impl Error for InvalidDnsNameError
impl Error for InvalidFormContentType
impl Error for InvalidFormatDescription
impl Error for InvalidInteger
impl Error for InvalidLength
impl Error for InvalidNameError
impl Error for InvalidOutputSize
impl Error for InvalidOutputSize
impl Error for InvalidThreadAccess
impl Error for InvalidUtf8
impl Error for InvalidUtf8InPathParam
impl Error for InvalidVariant
impl Error for JoinError
impl Error for JweError
impl Error for JwkError
impl Error for JwsError
impl Error for JwtError
impl Error for KeyError
impl Error for KeyIdGenError
impl Error for LengthDelimitedCodecError
impl Error for LengthLimitError
impl Error for LinesCodecError
impl Error for LspsError
impl Error for MacError
impl Error for MatchError
impl Error for MatchError
impl Error for MatchError
impl Error for MigrationDefinitionError
impl Error for MissingExtension
impl Error for MissingPathParams
impl Error for None
impl Error for OverflowError
impl Error for OverflowError
impl Error for PEMError
impl Error for Parse
impl Error for ParseAlphabetError
impl Error for ParseAlphabetError
impl Error for ParseColorError
impl Error for ParseError
impl Error for ParseError
impl Error for ParseFromDescription
impl Error for ParseIntError
impl Error for ParseLevelError
impl Error for ParseLevelFilterError
impl Error for ParseOidError
impl Error for PathRejection
impl Error for PatternIDError
impl Error for PatternIDError
impl Error for PatternSetInsertError
impl Error for PemError
impl Error for PemError
impl Error for PemError
impl Error for PemError
impl Error for QueryRejection
impl Error for RawFormRejection
impl Error for RawPathParamsRejection
impl Error for RcgenError
impl Error for RecvError
impl Error for RecvError
impl Error for RecvError
impl Error for ReuniteError
impl Error for ReuniteError
impl Error for RuneError
impl Error for SchemaVersionError
impl Error for SendError
impl Error for SerializeError
impl Error for SerializeError
impl Error for ServiceError
impl Error for SetGlobalDefaultError
impl Error for SignError
impl Error for SignError
impl Error for SignatureError
impl Error for SmallIndexError
impl Error for SpawnError
impl Error for SpecificationError
impl Error for StartError
impl Error for StateIDError
impl Error for StateIDError
impl Error for StreamCipherError
impl Error for StringRejection
impl Error for TryAcquireError
impl Error for TryCurrentError
impl Error for TryFromIntError
impl Error for TryFromParsed
impl Error for TryLockError
impl Error for TryRecvError
impl Error for TryRecvError
impl Error for TryRecvError
impl Error for TryRecvError
impl Error for TypeMismatch
impl Error for UnicodeWordBoundaryError
impl Error for UnicodeWordError
impl Error for UnknownBodyError
impl Error for UnpadError
impl Error for UnsupportedAlgorithmError
impl Error for UnsupportedAlgorithmError
impl Error for UnsupportedHashAlgorithmError
impl Error for X509CertificateError
impl Error for X509Error
impl<'a, K, V> Error for alloc::collections::btree::map::entry::OccupiedError<'a, K, V>
impl<'a, K, V> Error for std::collections::hash::map::OccupiedError<'a, K, V>
impl<'a, T> Error for &'a T
impl<E> Error for Err<E>where
E: Debug,
impl<F> Error for PersistError<F>
impl<I> Error for ExactlyOneError<I>
impl<I> Error for Error<I>
impl<I> Error for VerboseError<I>
impl<K> Error for Failed<K>where
K: Debug,
impl<K, V> Error for TryIntoHeaderError<K, V>
impl<L, R> Error for Either<L, R>
Either
implements Error
if both L
and R
implement it.