diff options
Diffstat (limited to 'library')
25 files changed, 1264 insertions, 226 deletions
diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs index 6955d863c99..67925941c92 100644 --- a/library/alloc/src/boxed.rs +++ b/library/alloc/src/boxed.rs @@ -151,6 +151,8 @@ use core::async_iter::AsyncIterator; use core::borrow; use core::cmp::Ordering; use core::convert::{From, TryFrom}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt; use core::future::Future; use core::hash::{Hash, Hasher}; @@ -174,6 +176,9 @@ use crate::borrow::Cow; use crate::raw_vec::RawVec; #[cfg(not(no_global_oom_handling))] use crate::str::from_boxed_utf8_unchecked; +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +use crate::string::String; #[cfg(not(no_global_oom_handling))] use crate::vec::Vec; @@ -2085,3 +2090,304 @@ impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> { (**self).size_hint() } } + +#[cfg(not(bootstrap))] +impl dyn Error { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error>> { + if self.is::<T>() { + unsafe { + let raw: *mut dyn Error = Box::into_raw(self); + Ok(Box::from_raw(raw as *mut T)) + } + } else { + Err(self) + } + } +} + +#[cfg(not(bootstrap))] +impl dyn Error + Send { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<dyn Error + Send>> { + let err: Box<dyn Error> = self; + <dyn Error>::downcast(err).map_err(|s| unsafe { + // Reapply the `Send` marker. + mem::transmute::<Box<dyn Error>, Box<dyn Error + Send>>(s) + }) + } +} + +#[cfg(not(bootstrap))] +impl dyn Error + Send + Sync { + #[inline] + #[stable(feature = "error_downcast", since = "1.3.0")] + #[rustc_allow_incoherent_impl] + /// Attempts to downcast the box to a concrete type. + pub fn downcast<T: Error + 'static>(self: Box<Self>) -> Result<Box<T>, Box<Self>> { + let err: Box<dyn Error> = self; + <dyn Error>::downcast(err).map_err(|s| unsafe { + // Reapply the `Send + Sync` marker. + mem::transmute::<Box<dyn Error>, Box<dyn Error + Send + Sync>>(s) + }) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a, E: Error + 'a> From<E> for 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)) + /// ``` + fn from(err: E) -> Box<dyn Error + 'a> { + Box::new(err) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a, E: Error + Send + Sync + 'a> From<E> for 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)) + /// ``` + fn from(err: E) -> Box<dyn Error + Send + Sync + 'a> { + Box::new(err) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl From<String> for Box<dyn Error + Send + Sync> { + /// 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)) + /// ``` + #[inline] + fn from(err: String) -> Box<dyn Error + Send + Sync> { + struct StringError(String); + + impl Error for StringError { + #[allow(deprecated)] + fn description(&self) -> &str { + &self.0 + } + } + + impl fmt::Display for StringError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Display::fmt(&self.0, f) + } + } + + // Purposefully skip printing "StringError(..)" + impl fmt::Debug for StringError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&self.0, f) + } + } + + Box::new(StringError(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "string_box_error", since = "1.6.0")] +impl From<String> for Box<dyn Error> { + /// Converts a [`String`] into a box of dyn [`Error`]. + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_string_error = "a string error".to_string(); + /// let a_boxed_error = Box::<dyn Error>::from(a_string_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(str_err: String) -> Box<dyn Error> { + let err1: Box<dyn Error + Send + Sync> = From::from(str_err); + let err2: Box<dyn Error> = err1; + err2 + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "rust1", since = "1.0.0")] +impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> { + /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. + /// + /// [`str`]: prim@str + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_str_error = "a str error"; + /// let a_boxed_error = Box::<dyn Error + Send + Sync>::from(a_str_error); + /// assert!( + /// mem::size_of::<Box<dyn Error + Send + Sync>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + #[inline] + fn from(err: &str) -> Box<dyn Error + Send + Sync + 'a> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "string_box_error", since = "1.6.0")] +impl From<&str> for Box<dyn Error> { + /// Converts a [`str`] into a box of dyn [`Error`]. + /// + /// [`str`]: prim@str + /// + /// # Examples + /// + /// ``` + /// use std::error::Error; + /// use std::mem; + /// + /// let a_str_error = "a str error"; + /// let a_boxed_error = Box::<dyn Error>::from(a_str_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: &str) -> Box<dyn Error> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "cow_box_error", since = "1.22.0")] +impl<'a, 'b> From<Cow<'b, str>> for 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)) + /// ``` + fn from(err: Cow<'b, str>) -> Box<dyn Error + Send + Sync + 'a> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[cfg(not(no_global_oom_handling))] +#[stable(feature = "cow_box_error", since = "1.22.0")] +impl<'a> From<Cow<'a, str>> for Box<dyn Error> { + /// Converts a [`Cow`] into a box of dyn [`Error`]. + /// + /// # 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>::from(a_cow_str_error); + /// assert!(mem::size_of::<Box<dyn Error>>() == mem::size_of_val(&a_boxed_error)) + /// ``` + fn from(err: Cow<'a, str>) -> Box<dyn Error> { + From::from(String::from(err)) + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "box_error", since = "1.8.0")] +impl<T: core::error::Error> core::error::Error for Box<T> { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + core::error::Error::description(&**self) + } + + #[allow(deprecated)] + fn cause(&self) -> Option<&dyn core::error::Error> { + core::error::Error::cause(&**self) + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + core::error::Error::source(&**self) + } +} diff --git a/library/alloc/src/boxed/thin.rs b/library/alloc/src/boxed/thin.rs index 649ccfcaa9e..0a20c74b00f 100644 --- a/library/alloc/src/boxed/thin.rs +++ b/library/alloc/src/boxed/thin.rs @@ -2,6 +2,8 @@ // https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs // by matthieu-m use crate::alloc::{self, Layout, LayoutError}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt::{self, Debug, Display, Formatter}; use core::marker::PhantomData; #[cfg(not(no_global_oom_handling))] @@ -271,3 +273,11 @@ impl<H> WithHeader<H> { Layout::new::<H>().extend(value_layout) } } + +#[cfg(not(bootstrap))] +#[unstable(feature = "thin_box", issue = "92791")] +impl<T: ?Sized + Error> Error for ThinBox<T> { + fn source(&self) -> Option<&(dyn Error + 'static)> { + self.deref().source() + } +} diff --git a/library/alloc/src/collections/btree/map/entry.rs b/library/alloc/src/collections/btree/map/entry.rs index b6eecf9b0e9..cd7cdc19207 100644 --- a/library/alloc/src/collections/btree/map/entry.rs +++ b/library/alloc/src/collections/btree/map/entry.rs @@ -133,6 +133,17 @@ impl<'a, K: Debug + Ord, V: Debug, A: Allocator + Clone> fmt::Display } } +#[cfg(not(bootstrap))] +#[unstable(feature = "map_try_insert", issue = "82766")] +impl<'a, K: core::fmt::Debug + Ord, V: core::fmt::Debug> core::error::Error + for crate::collections::btree_map::OccupiedError<'a, K, V> +{ + #[allow(deprecated)] + fn description(&self) -> &str { + "key already exists" + } +} + impl<'a, K: Ord, V, A: Allocator + Clone> Entry<'a, K, V, A> { /// Ensures a value is in the entry by inserting the default if empty, and returns /// a mutable reference to the value in the entry. diff --git a/library/alloc/src/collections/mod.rs b/library/alloc/src/collections/mod.rs index 628a5b15567..21d0def0866 100644 --- a/library/alloc/src/collections/mod.rs +++ b/library/alloc/src/collections/mod.rs @@ -152,3 +152,7 @@ trait SpecExtend<I: IntoIterator> { /// Extends `self` with the contents of the given iterator. fn spec_extend(&mut self, iter: I); } + +#[cfg(not(bootstrap))] +#[stable(feature = "try_reserve", since = "1.57.0")] +impl core::error::Error for TryReserveError {} diff --git a/library/alloc/src/ffi/c_str.rs b/library/alloc/src/ffi/c_str.rs index be21d8c722d..aede6d54c6c 100644 --- a/library/alloc/src/ffi/c_str.rs +++ b/library/alloc/src/ffi/c_str.rs @@ -1121,3 +1121,29 @@ impl CStr { CString::from(self) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl core::error::Error for NulError { + #[allow(deprecated)] + fn description(&self) -> &str { + "nul byte found in data" + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] +impl core::error::Error for FromVecWithNulError {} + +#[cfg(not(bootstrap))] +#[stable(feature = "cstring_into", since = "1.7.0")] +impl core::error::Error for IntoStringError { + #[allow(deprecated)] + fn description(&self) -> &str { + "C string contained non-utf8 bytes" + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + Some(self.__source()) + } +} diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs index 62fd5955726..ad6d19bbc68 100644 --- a/library/alloc/src/lib.rs +++ b/library/alloc/src/lib.rs @@ -111,6 +111,8 @@ #![feature(const_pin)] #![feature(cstr_from_bytes_until_nul)] #![feature(dispatch_from_dyn)] +#![cfg_attr(not(bootstrap), feature(error_generic_member_access))] +#![cfg_attr(not(bootstrap), feature(error_in_core))] #![feature(exact_size_is_empty)] #![feature(extend_one)] #![feature(fmt_internals)] @@ -127,6 +129,7 @@ #![feature(nonnull_slice_from_raw_parts)] #![feature(pattern)] #![feature(pointer_byte_offsets)] +#![cfg_attr(not(bootstrap), feature(provide_any))] #![feature(ptr_internals)] #![feature(ptr_metadata)] #![feature(ptr_sub_ptr)] @@ -179,6 +182,7 @@ #![feature(unboxed_closures)] #![feature(unsized_fn_params)] #![feature(c_unwind)] +#![feature(with_negative_coherence)] // // Rustdoc features: #![feature(doc_cfg)] diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs index 7bee894d3e4..81922b53886 100644 --- a/library/alloc/src/string.rs +++ b/library/alloc/src/string.rs @@ -44,6 +44,8 @@ #[cfg(not(no_global_oom_handling))] use core::char::{decode_utf16, REPLACEMENT_CHARACTER}; +#[cfg(not(bootstrap))] +use core::error::Error; use core::fmt; use core::hash; use core::iter::FusedIterator; @@ -1938,6 +1940,24 @@ impl fmt::Display for FromUtf16Error { } } +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for FromUtf8Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "invalid utf-8" + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for FromUtf16Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "invalid utf-16" + } +} + #[cfg(not(no_global_oom_handling))] #[stable(feature = "rust1", since = "1.0.0")] impl Clone for String { diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs index 4c03cc3ed15..4377edeee87 100644 --- a/library/alloc/src/sync.rs +++ b/library/alloc/src/sync.rs @@ -2763,3 +2763,25 @@ fn data_offset_align(align: usize) -> usize { let layout = Layout::new::<ArcInner<()>>(); layout.size() + layout.padding_needed_for(align) } + +#[cfg(not(bootstrap))] +#[stable(feature = "arc_error", since = "1.52.0")] +impl<T: core::error::Error + ?Sized> core::error::Error for Arc<T> { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + core::error::Error::description(&**self) + } + + #[allow(deprecated)] + fn cause(&self) -> Option<&dyn core::error::Error> { + core::error::Error::cause(&**self) + } + + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + core::error::Error::source(&**self) + } + + fn provide<'a>(&'a self, req: &mut core::any::Demand<'a>) { + core::error::Error::provide(&**self, req); + } +} diff --git a/library/core/src/alloc/layout.rs b/library/core/src/alloc/layout.rs index 3473ac09e95..f03502429ab 100644 --- a/library/core/src/alloc/layout.rs +++ b/library/core/src/alloc/layout.rs @@ -5,6 +5,8 @@ // Your performance intuition is useless. Run perf. use crate::cmp; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; use crate::mem::{self, ValidAlign}; use crate::ptr::NonNull; @@ -461,6 +463,10 @@ pub type LayoutErr = LayoutError; #[derive(Clone, PartialEq, Eq, Debug)] pub struct LayoutError; +#[cfg(not(bootstrap))] +#[stable(feature = "alloc_layout", since = "1.28.0")] +impl Error for LayoutError {} + // (we need this for downstream impl of trait Error) #[stable(feature = "alloc_layout", since = "1.28.0")] impl fmt::Display for LayoutError { diff --git a/library/core/src/alloc/mod.rs b/library/core/src/alloc/mod.rs index 6cc6e359e65..94efa76664f 100644 --- a/library/core/src/alloc/mod.rs +++ b/library/core/src/alloc/mod.rs @@ -21,6 +21,8 @@ pub use self::layout::LayoutErr; #[stable(feature = "alloc_layout_error", since = "1.50.0")] pub use self::layout::LayoutError; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; use crate::ptr::{self, NonNull}; @@ -32,6 +34,14 @@ use crate::ptr::{self, NonNull}; #[derive(Copy, Clone, PartialEq, Eq, Debug)] pub struct AllocError; +#[cfg(not(bootstrap))] +#[unstable( + feature = "allocator_api", + reason = "the precise API and guarantees it provides may be tweaked.", + issue = "32838" +)] +impl Error for AllocError {} + // (we need this for downstream impl of trait Error) #[unstable(feature = "allocator_api", issue = "32838")] impl fmt::Display for AllocError { diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs index db5bfcab9d2..9effb379016 100644 --- a/library/core/src/array/mod.rs +++ b/library/core/src/array/mod.rs @@ -7,6 +7,8 @@ use crate::borrow::{Borrow, BorrowMut}; use crate::cmp::Ordering; use crate::convert::{Infallible, TryFrom}; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; use crate::hash::{self, Hash}; use crate::iter::TrustedLen; @@ -119,6 +121,15 @@ impl fmt::Display for TryFromSliceError { } } +#[cfg(not(bootstrap))] +#[stable(feature = "try_from", since = "1.34.0")] +impl Error for TryFromSliceError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + impl TryFromSliceError { #[unstable( feature = "array_error_internals", diff --git a/library/core/src/char/decode.rs b/library/core/src/char/decode.rs index 71297acd171..dc8ea66cc6d 100644 --- a/library/core/src/char/decode.rs +++ b/library/core/src/char/decode.rs @@ -1,5 +1,7 @@ //! UTF-8 and UTF-16 decoding iterators +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; use super::from_u32_unchecked; @@ -121,3 +123,12 @@ impl fmt::Display for DecodeUtf16Error { write!(f, "unpaired surrogate found: {:x}", self.code) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "decode_utf16", since = "1.9.0")] +impl Error for DecodeUtf16Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "unpaired surrogate found" + } +} diff --git a/library/core/src/char/mod.rs b/library/core/src/char/mod.rs index a4bdd38f655..72d63ac4b4b 100644 --- a/library/core/src/char/mod.rs +++ b/library/core/src/char/mod.rs @@ -38,6 +38,8 @@ pub use self::methods::encode_utf16_raw; #[unstable(feature = "char_internals", reason = "exposed only for libstd", issue = "none")] pub use self::methods::encode_utf8_raw; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt::{self, Write}; use crate::iter::FusedIterator; @@ -584,3 +586,7 @@ impl fmt::Display for TryFromCharError { "unicode code point out of range".fmt(fmt) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "u8_from_char", since = "1.59.0")] +impl Error for TryFromCharError {} diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs index b30c8a4aeab..5bddfd1a413 100644 --- a/library/core/src/convert/mod.rs +++ b/library/core/src/convert/mod.rs @@ -34,6 +34,8 @@ #![stable(feature = "rust1", since = "1.0.0")] +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; use crate::hash::{Hash, Hasher}; @@ -715,6 +717,14 @@ impl fmt::Display for Infallible { } } +#[cfg(not(bootstrap))] +#[stable(feature = "str_parse_error2", since = "1.8.0")] +impl Error for Infallible { + fn description(&self) -> &str { + match *self {} + } +} + #[stable(feature = "convert_infallible", since = "1.34.0")] impl PartialEq for Infallible { fn eq(&self, _: &Infallible) -> bool { diff --git a/library/core/src/error.md b/library/core/src/error.md new file mode 100644 index 00000000000..891abebbfd3 --- /dev/null +++ b/library/core/src/error.md @@ -0,0 +1,137 @@ +Interfaces for working with Errors. + +# Error Handling In Rust + +The Rust language provides two complementary systems for constructing / +representing, reporting, propagating, reacting to, and discarding errors. +These responsibilities are collectively known as "error handling." The +components of the first system, the panic runtime and interfaces, are most +commonly used to represent bugs that have been detected in your program. The +components of the second system, `Result`, the error traits, and user +defined types, are used to represent anticipated runtime failure modes of +your program. + +## The Panic Interfaces + +The following are the primary interfaces of the panic system and the +responsibilities they cover: + +* [`panic!`] and [`panic_any`] (Constructing, Propagated automatically) +* [`PanicInfo`] (Reporting) +* [`set_hook`], [`take_hook`], and [`#[panic_handler]`][panic-handler] (Reporting) +* [`catch_unwind`] and [`resume_unwind`] (Discarding, Propagating) + +The following are the primary interfaces of the error system and the +responsibilities they cover: + +* [`Result`] (Propagating, Reacting) +* The [`Error`] trait (Reporting) +* User defined types (Constructing / Representing) +* [`match`] and [`downcast`] (Reacting) +* The question mark operator ([`?`]) (Propagating) +* The partially stable [`Try`] traits (Propagating, Constructing) +* [`Termination`] (Reporting) + +## Converting Errors into Panics + +The panic and error systems are not entirely distinct. Often times errors +that are anticipated runtime failures in an API might instead represent bugs +to a caller. For these situations the standard library provides APIs for +constructing panics with an `Error` as it's source. + +* [`Result::unwrap`] +* [`Result::expect`] + +These functions are equivalent, they either return the inner value if the +`Result` is `Ok` or panic if the `Result` is `Err` printing the inner error +as the source. The only difference between them is that with `expect` you +provide a panic error message to be printed alongside the source, whereas +`unwrap` has a default message indicating only that you unwraped an `Err`. + +Of the two, `expect` is generally preferred since its `msg` field allows you +to convey your intent and assumptions which makes tracking down the source +of a panic easier. `unwrap` on the other hand can still be a good fit in +situations where you can trivially show that a piece of code will never +panic, such as `"127.0.0.1".parse::<std::net::IpAddr>().unwrap()` or early +prototyping. + +# Common Message Styles + +There are two common styles for how people word `expect` messages. Using +the message to present information to users encountering a panic +("expect as error message") or using the message to present information +to developers debugging the panic ("expect as precondition"). + +In the former case the expect message is used to describe the error that +has occurred which is considered a bug. Consider the following example: + +```should_panic +// Read environment variable, panic if it is not present +let path = std::env::var("IMPORTANT_PATH").unwrap(); +``` + +In the "expect as error message" style we would use expect to describe +that the environment variable was not set when it should have been: + +```should_panic +let path = std::env::var("IMPORTANT_PATH") + .expect("env variable `IMPORTANT_PATH` is not set"); +``` + +In the "expect as precondition" style, we would instead describe the +reason we _expect_ the `Result` should be `Ok`. With this style we would +prefer to write: + +```should_panic +let path = std::env::var("IMPORTANT_PATH") + .expect("env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`"); +``` + +The "expect as error message" style does not work as well with the +default output of the std panic hooks, and often ends up repeating +information that is already communicated by the source error being +unwrapped: + +```text +thread 'main' panicked at 'env variable `IMPORTANT_PATH` is not set: NotPresent', src/main.rs:4:6 +``` + +In this example we end up mentioning that an env variable is not set, +followed by our source message that says the env is not present, the +only additional information we're communicating is the name of the +environment variable being checked. + +The "expect as precondition" style instead focuses on source code +readability, making it easier to understand what must have gone wrong in +situations where panics are being used to represent bugs exclusively. +Also, by framing our expect in terms of what "SHOULD" have happened to +prevent the source error, we end up introducing new information that is +independent from our source error. + +```text +thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`: NotPresent', src/main.rs:4:6 +``` + +In this example we are communicating not only the name of the +environment variable that should have been set, but also an explanation +for why it should have been set, and we let the source error display as +a clear contradiction to our expectation. + +**Hint**: If you're having trouble remembering how to phrase +expect-as-precondition style error messages remember to focus on the word +"should" as in "env variable should be set by blah" or "the given binary +should be available and executable by the current user". + +[`panic_any`]: ../../std/panic/fn.panic_any.html +[`PanicInfo`]: crate::panic::PanicInfo +[`catch_unwind`]: ../../std/panic/fn.catch_unwind.html +[`resume_unwind`]: ../../std/panic/fn.resume_unwind.html +[`downcast`]: crate::error::Error +[`Termination`]: ../../std/process/trait.Termination.html +[`Try`]: crate::ops::Try +[panic hook]: ../../std/panic/fn.set_hook.html +[`set_hook`]: ../../std/panic/fn.set_hook.html +[`take_hook`]: ../../std/panic/fn.take_hook.html +[panic-handler]: <https://doc.rust-lang.org/nomicon/panic-handler.html> +[`match`]: ../../std/keyword.match.html +[`?`]: ../../std/result/index.html#the-question-mark-operator- diff --git a/library/core/src/error.rs b/library/core/src/error.rs new file mode 100644 index 00000000000..d11debb34ad --- /dev/null +++ b/library/core/src/error.rs @@ -0,0 +1,508 @@ +#![doc = include_str!("error.md")] +#![unstable(feature = "error_in_core", issue = "none")] + +// A note about crates and the facade: +// +// Originally, the `Error` trait was defined in libcore, and the impls +// were scattered about. However, coherence objected to this +// arrangement, because to create the blanket impls for `Box` required +// knowing that `&str: !Error`, and we have no means to deal with that +// sort of conflict just now. Therefore, for the time being, we have +// moved the `Error` trait into libstd. As we evolve a sol'n to the +// coherence challenge (e.g., specialization, neg impls, etc) we can +// reconsider what crate these items belong in. + +#[cfg(test)] +mod tests; + +use crate::any::{Demand, Provider, TypeId}; +use crate::fmt::{Debug, Display}; + +/// `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 chain 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 via `source` chains. +#[stable(feature = "rust1", since = "1.0.0")] +#[cfg_attr(not(test), rustc_diagnostic_item = "Error")] +#[rustc_has_incoherent_inherent_impls] +pub trait Error: Debug + Display { + /// 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"), + /// } + /// } + /// ``` + #[stable(feature = "error_source", since = "1.30.0")] + fn source(&self) -> Option<&(dyn Error + 'static)> { + None + } + + /// Gets the `TypeId` of `self`. + #[doc(hidden)] + #[unstable( + feature = "error_type_id", + reason = "this is memory-unsafe to override in user code", + issue = "60784" + )] + fn type_id(&self, _: private::Internal) -> TypeId + where + Self: 'static, + { + TypeId::of::<Self>() + } + + /// ``` + /// if let Err(e) = "xc".parse::<u32>() { + /// // Print `e` itself, no need for description(). + /// eprintln!("Error: {e}"); + /// } + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[deprecated(since = "1.42.0", note = "use the Display impl or to_string()")] + fn description(&self) -> &str { + "description() is deprecated; use Display" + } + + #[stable(feature = "rust1", since = "1.0.0")] + #[deprecated( + since = "1.33.0", + note = "replaced by Error::source, which can support downcasting" + )] + #[allow(missing_docs)] + fn cause(&self) -> Option<&dyn Error> { + self.source() + } + + /// Provides type based access to context intended for error reports. + /// + /// Used in conjunction with [`Demand::provide_value`] and [`Demand::provide_ref`] to extract + /// references to member variables from `dyn Error` trait objects. + /// + /// # Example + /// + /// ```rust + /// #![feature(provide_any)] + /// #![feature(error_generic_member_access)] + /// use core::fmt; + /// use core::any::Demand; + /// + /// #[derive(Debug)] + /// struct MyBacktrace { + /// // ... + /// } + /// + /// impl MyBacktrace { + /// fn new() -> MyBacktrace { + /// // ... + /// # MyBacktrace {} + /// } + /// } + /// + /// #[derive(Debug)] + /// struct SourceError { + /// // ... + /// } + /// + /// impl fmt::Display for SourceError { + /// fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + /// write!(f, "Example Source Error") + /// } + /// } + /// + /// impl std::error::Error for SourceError {} + /// + /// #[derive(Debug)] + /// struct Error { + /// source: SourceError, + /// 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, req: &mut Demand<'a>) { + /// req + /// .provide_ref::<MyBacktrace>(&self.backtrace) + /// .provide_ref::<dyn std::error::Error + 'static>(&self.source); + /// } + /// } + /// + /// fn main() { + /// let backtrace = MyBacktrace::new(); + /// let source = SourceError {}; + /// let error = Error { source, backtrace }; + /// let dyn_error = &error as &dyn std::error::Error; + /// let backtrace_ref = dyn_error.request_ref::<MyBacktrace>().unwrap(); + /// + /// assert!(core::ptr::eq(&error.backtrace, backtrace_ref)); + /// } + /// ``` + #[unstable(feature = "error_generic_member_access", issue = "99301")] + #[allow(unused_variables)] + fn provide<'a>(&'a self, req: &mut Demand<'a>) {} +} + +#[unstable(feature = "error_generic_member_access", issue = "99301")] +impl<E> Provider for E +where + E: Error + ?Sized, +{ + fn provide<'a>(&'a self, req: &mut Demand<'a>) { + self.provide(req) + } +} + +mod private { + // This is a hack to prevent `type_id` from being overridden by `Error` + // implementations, since that can enable unsound downcasting. + #[unstable(feature = "error_type_id", issue = "60784")] + #[derive(Debug)] + pub struct Internal; +} + +#[unstable(feature = "never_type", issue = "35121")] +impl Error for ! {} + +impl<'a> dyn Error + 'a { + /// Request a reference of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_ref<T: ?Sized + 'static>(&'a self) -> Option<&'a T> { + core::any::request_ref(self) + } + + /// Request a value of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_value<T: 'static>(&'a self) -> Option<T> { + core::any::request_value(self) + } +} + +// Copied from `any.rs`. +impl dyn Error + 'static { + /// Returns `true` if the inner type is the same as `T`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn is<T: Error + 'static>(&self) -> bool { + // Get `TypeId` of the type this function is instantiated with. + let t = TypeId::of::<T>(); + + // Get `TypeId` of the type in the trait object (`self`). + let concrete = self.type_id(private::Internal); + + // Compare both `TypeId`s on equality. + t == concrete + } + + /// Returns some reference to the inner value if it is of type `T`, or + /// `None` if it isn't. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> { + if self.is::<T>() { + // SAFETY: `is` ensures this type cast is correct + unsafe { Some(&*(self as *const dyn Error as *const T)) } + } else { + None + } + } + + /// Returns some mutable reference to the inner value if it is of type `T`, or + /// `None` if it isn't. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> { + if self.is::<T>() { + // SAFETY: `is` ensures this type cast is correct + unsafe { Some(&mut *(self as *mut dyn Error as *mut T)) } + } else { + None + } + } +} + +impl dyn Error + 'static + Send { + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn is<T: Error + 'static>(&self) -> bool { + <dyn Error + 'static>::is::<T>(self) + } + + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> { + <dyn Error + 'static>::downcast_ref::<T>(self) + } + + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> { + <dyn Error + 'static>::downcast_mut::<T>(self) + } + + /// Request a reference of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> { + <dyn Error>::request_ref(self) + } + + /// Request a value of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_value<T: 'static>(&self) -> Option<T> { + <dyn Error>::request_value(self) + } +} + +impl dyn Error + 'static + Send + Sync { + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn is<T: Error + 'static>(&self) -> bool { + <dyn Error + 'static>::is::<T>(self) + } + + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_ref<T: Error + 'static>(&self) -> Option<&T> { + <dyn Error + 'static>::downcast_ref::<T>(self) + } + + /// Forwards to the method defined on the type `dyn Error`. + #[stable(feature = "error_downcast", since = "1.3.0")] + #[inline] + pub fn downcast_mut<T: Error + 'static>(&mut self) -> Option<&mut T> { + <dyn Error + 'static>::downcast_mut::<T>(self) + } + + /// Request a reference of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_ref<T: ?Sized + 'static>(&self) -> Option<&T> { + <dyn Error>::request_ref(self) + } + + /// Request a value of type `T` as context about this error. + #[unstable(feature = "error_generic_member_access", issue = "99301")] + pub fn request_value<T: 'static>(&self) -> Option<T> { + <dyn Error>::request_value(self) + } +} + +impl dyn Error { + /// 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.chain(); + /// + /// 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()); + /// ``` + #[unstable(feature = "error_iter", issue = "58520")] + #[inline] + pub fn chain(&self) -> Chain<'_> { + Chain { current: Some(self) } + } +} + +/// An iterator over an [`Error`] and its sources. +/// +/// If you want to omit the initial error and only process +/// its sources, use `skip(1)`. +#[unstable(feature = "error_iter", issue = "58520")] +#[derive(Clone, Debug)] +pub struct Chain<'a> { + current: Option<&'a (dyn Error + 'static)>, +} + +#[unstable(feature = "error_iter", issue = "58520")] +impl<'a> Iterator for Chain<'a> { + type Item = &'a (dyn Error + 'static); + + fn next(&mut self) -> Option<Self::Item> { + let current = self.current; + self.current = self.current.and_then(Error::source); + current + } +} + +#[stable(feature = "error_by_ref", since = "1.51.0")] +impl<'a, T: Error + ?Sized> Error for &'a T { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + Error::description(&**self) + } + + #[allow(deprecated)] + fn cause(&self) -> Option<&dyn Error> { + Error::cause(&**self) + } + + fn source(&self) -> Option<&(dyn Error + 'static)> { + Error::source(&**self) + } + + fn provide<'b>(&'b self, req: &mut Demand<'b>) { + Error::provide(&**self, req); + } +} + +#[stable(feature = "fmt_error", since = "1.11.0")] +impl Error for crate::fmt::Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "an error occurred when formatting an argument" + } +} + +#[stable(feature = "try_borrow", since = "1.13.0")] +impl Error for crate::cell::BorrowError { + #[allow(deprecated)] + fn description(&self) -> &str { + "already mutably borrowed" + } +} + +#[stable(feature = "try_borrow", since = "1.13.0")] +impl Error for crate::cell::BorrowMutError { + #[allow(deprecated)] + fn description(&self) -> &str { + "already borrowed" + } +} + +#[stable(feature = "try_from", since = "1.34.0")] +impl Error for crate::char::CharTryFromError { + #[allow(deprecated)] + fn description(&self) -> &str { + "converted integer out of range for `char`" + } +} + +#[stable(feature = "char_from_str", since = "1.20.0")] +impl Error for crate::char::ParseCharError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + +#[unstable(feature = "duration_checked_float", issue = "83400")] +impl Error for crate::time::FromFloatSecsError {} + +#[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] +impl Error for crate::ffi::FromBytesWithNulError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + +#[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] +impl Error for crate::ffi::FromBytesUntilNulError {} diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index 24742bb49b9..8d04a213f50 100644 --- a/library/core/src/lib.rs +++ b/library/core/src/lib.rs @@ -302,6 +302,8 @@ pub mod clone; pub mod cmp; pub mod convert; pub mod default; +#[cfg(not(bootstrap))] +pub mod error; pub mod marker; pub mod ops; diff --git a/library/core/src/num/error.rs b/library/core/src/num/error.rs index 1a223016dae..1f6b40e5df5 100644 --- a/library/core/src/num/error.rs +++ b/library/core/src/num/error.rs @@ -1,6 +1,8 @@ //! Error types for conversion to integral types. use crate::convert::Infallible; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; /// The error type returned when a checked integral type conversion fails. @@ -144,3 +146,21 @@ impl fmt::Display for ParseIntError { self.__description().fmt(f) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for ParseIntError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + +#[cfg(not(bootstrap))] +#[stable(feature = "try_from", since = "1.34.0")] +impl Error for TryFromIntError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs index 72b6dc28185..ab17aa0c830 100644 --- a/library/core/src/num/mod.rs +++ b/library/core/src/num/mod.rs @@ -3,6 +3,8 @@ #![stable(feature = "rust1", since = "1.0.0")] use crate::ascii; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::intrinsics; use crate::mem; use crate::ops::{Add, Mul, Sub}; @@ -57,6 +59,16 @@ pub use wrapping::Wrapping; #[cfg(not(no_fp_fmt_parse))] pub use dec2flt::ParseFloatError; +#[cfg(not(bootstrap))] +#[cfg(not(no_fp_fmt_parse))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for ParseFloatError { + #[allow(deprecated)] + fn description(&self) -> &str { + self.__description() + } +} + #[stable(feature = "rust1", since = "1.0.0")] pub use error::ParseIntError; diff --git a/library/core/src/str/error.rs b/library/core/src/str/error.rs index 4e569fcc866..343889b6999 100644 --- a/library/core/src/str/error.rs +++ b/library/core/src/str/error.rs @@ -1,5 +1,7 @@ //! Defines utf8 error type. +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt; /// Errors which can occur when attempting to interpret a sequence of [`u8`] @@ -122,6 +124,15 @@ impl fmt::Display for Utf8Error { } } +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for Utf8Error { + #[allow(deprecated)] + fn description(&self) -> &str { + "invalid utf-8: corrupt contents" + } +} + /// An error returned when parsing a `bool` using [`from_str`] fails /// /// [`from_str`]: super::FromStr::from_str @@ -136,3 +147,12 @@ impl fmt::Display for ParseBoolError { "provided string was not `true` or `false`".fmt(f) } } + +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl Error for ParseBoolError { + #[allow(deprecated)] + fn description(&self) -> &str { + "failed to parse bool" + } +} diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs index e44e025aaf1..2120bf61d75 100644 --- a/library/core/src/str/mod.rs +++ b/library/core/src/str/mod.rs @@ -2638,3 +2638,7 @@ impl_fn_for_zst! { unsafe { from_utf8_unchecked(bytes) } }; } + +#[stable(feature = "rust1", since = "1.0.0")] +#[cfg(not(bootstrap))] +impl !crate::error::Error for &str {} diff --git a/library/std/src/collections/hash/map.rs b/library/std/src/collections/hash/map.rs index db811343fa3..9845d1faf9a 100644 --- a/library/std/src/collections/hash/map.rs +++ b/library/std/src/collections/hash/map.rs @@ -9,6 +9,8 @@ use crate::borrow::Borrow; use crate::cell::Cell; use crate::collections::TryReserveError; use crate::collections::TryReserveErrorKind; +#[cfg(not(bootstrap))] +use crate::error::Error; use crate::fmt::{self, Debug}; #[allow(deprecated)] use crate::hash::{BuildHasher, Hash, Hasher, SipHasher13}; @@ -2158,6 +2160,15 @@ impl<'a, K: Debug, V: Debug> fmt::Display for OccupiedError<'a, K, V> { } } +#[cfg(not(bootstrap))] +#[unstable(feature = "map_try_insert", issue = "82766")] +impl<'a, K: fmt::Debug, V: fmt::Debug> Error for OccupiedError<'a, K, V> { + #[allow(deprecated)] + fn description(&self) -> &str { + "key already exists" + } +} + #[stable(feature = "rust1", since = "1.0.0")] impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S> { type Item = (&'a K, &'a V); diff --git a/library/std/src/error.rs b/library/std/src/error.rs index 4fbcfd85d7c..914f6d6d2e3 100644 --- a/library/std/src/error.rs +++ b/library/std/src/error.rs @@ -1,141 +1,4 @@ -//! The `Error` trait provides common functionality for errors. -//! -//! # Error Handling In Rust -//! -//! The Rust language provides two complementary systems for constructing / -//! representing, reporting, propagating, reacting to, and discarding errors. -//! These responsibilities are collectively known as "error handling." The -//! components of the first system, the panic runtime and interfaces, are most -//! commonly used to represent bugs that have been detected in your program. The -//! components of the second system, `Result`, the error traits, and user -//! defined types, are used to represent anticipated runtime failure modes of -//! your program. -//! -//! ## The Panic Interfaces -//! -//! The following are the primary interfaces of the panic system and the -//! responsibilities they cover: -//! -//! * [`panic!`] and [`panic_any`] (Constructing, Propagated automatically) -//! * [`PanicInfo`] (Reporting) -//! * [`set_hook`], [`take_hook`], and [`#[panic_handler]`][panic-handler] (Reporting) -//! * [`catch_unwind`] and [`resume_unwind`] (Discarding, Propagating) -//! -//! The following are the primary interfaces of the error system and the -//! responsibilities they cover: -//! -//! * [`Result`] (Propagating, Reacting) -//! * The [`Error`] trait (Reporting) -//! * User defined types (Constructing / Representing) -//! * [`match`] and [`downcast`] (Reacting) -//! * The question mark operator ([`?`]) (Propagating) -//! * The partially stable [`Try`] traits (Propagating, Constructing) -//! * [`Termination`] (Reporting) -//! -//! ## Converting Errors into Panics -//! -//! The panic and error systems are not entirely distinct. Often times errors -//! that are anticipated runtime failures in an API might instead represent bugs -//! to a caller. For these situations the standard library provides APIs for -//! constructing panics with an `Error` as it's source. -//! -//! * [`Result::unwrap`] -//! * [`Result::expect`] -//! -//! These functions are equivalent, they either return the inner value if the -//! `Result` is `Ok` or panic if the `Result` is `Err` printing the inner error -//! as the source. The only difference between them is that with `expect` you -//! provide a panic error message to be printed alongside the source, whereas -//! `unwrap` has a default message indicating only that you unwraped an `Err`. -//! -//! Of the two, `expect` is generally preferred since its `msg` field allows you -//! to convey your intent and assumptions which makes tracking down the source -//! of a panic easier. `unwrap` on the other hand can still be a good fit in -//! situations where you can trivially show that a piece of code will never -//! panic, such as `"127.0.0.1".parse::<std::net::IpAddr>().unwrap()` or early -//! prototyping. -//! -//! # Common Message Styles -//! -//! There are two common styles for how people word `expect` messages. Using -//! the message to present information to users encountering a panic -//! ("expect as error message") or using the message to present information -//! to developers debugging the panic ("expect as precondition"). -//! -//! In the former case the expect message is used to describe the error that -//! has occurred which is considered a bug. Consider the following example: -//! -//! ```should_panic -//! // Read environment variable, panic if it is not present -//! let path = std::env::var("IMPORTANT_PATH").unwrap(); -//! ``` -//! -//! In the "expect as error message" style we would use expect to describe -//! that the environment variable was not set when it should have been: -//! -//! ```should_panic -//! let path = std::env::var("IMPORTANT_PATH") -//! .expect("env variable `IMPORTANT_PATH` is not set"); -//! ``` -//! -//! In the "expect as precondition" style, we would instead describe the -//! reason we _expect_ the `Result` should be `Ok`. With this style we would -//! prefer to write: -//! -//! ```should_panic -//! let path = std::env::var("IMPORTANT_PATH") -//! .expect("env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`"); -//! ``` -//! -//! The "expect as error message" style does not work as well with the -//! default output of the std panic hooks, and often ends up repeating -//! information that is already communicated by the source error being -//! unwrapped: -//! -//! ```text -//! thread 'main' panicked at 'env variable `IMPORTANT_PATH` is not set: NotPresent', src/main.rs:4:6 -//! ``` -//! -//! In this example we end up mentioning that an env variable is not set, -//! followed by our source message that says the env is not present, the -//! only additional information we're communicating is the name of the -//! environment variable being checked. -//! -//! The "expect as precondition" style instead focuses on source code -//! readability, making it easier to understand what must have gone wrong in -//! situations where panics are being used to represent bugs exclusively. -//! Also, by framing our expect in terms of what "SHOULD" have happened to -//! prevent the source error, we end up introducing new information that is -//! independent from our source error. -//! -//! ```text -//! thread 'main' panicked at 'env variable `IMPORTANT_PATH` should be set by `wrapper_script.sh`: NotPresent', src/main.rs:4:6 -//! ``` -//! -//! In this example we are communicating not only the name of the -//! environment variable that should have been set, but also an explanation -//! for why it should have been set, and we let the source error display as -//! a clear contradiction to our expectation. -//! -//! **Hint**: If you're having trouble remembering how to phrase -//! expect-as-precondition style error messages remember to focus on the word -//! "should" as in "env variable should be set by blah" or "the given binary -//! should be available and executable by the current user". -//! -//! [`panic_any`]: crate::panic::panic_any -//! [`PanicInfo`]: crate::panic::PanicInfo -//! [`catch_unwind`]: crate::panic::catch_unwind -//! [`resume_unwind`]: crate::panic::resume_unwind -//! [`downcast`]: crate::error::Error -//! [`Termination`]: crate::process::Termination -//! [`Try`]: crate::ops::Try -//! [panic hook]: crate::panic::set_hook -//! [`set_hook`]: crate::panic::set_hook -//! [`take_hook`]: crate::panic::take_hook -//! [panic-handler]: <https://doc.rust-lang.org/nomicon/panic-handler.html> -//! [`match`]: ../../std/keyword.match.html -//! [`?`]: ../../std/result/index.html#the-question-mark-operator- - +#![doc = include_str!("../../core/src/error.md")] #![stable(feature = "rust1", since = "1.0.0")] // A note about crates and the facade: @@ -152,24 +15,48 @@ #[cfg(test)] mod tests; +#[cfg(bootstrap)] use core::array; +#[cfg(bootstrap)] use core::convert::Infallible; +#[cfg(bootstrap)] use crate::alloc::{AllocError, LayoutError}; -use crate::any::{Demand, Provider, TypeId}; +#[cfg(bootstrap)] +use crate::any::Demand; +#[cfg(bootstrap)] +use crate::any::{Provider, TypeId}; use crate::backtrace::Backtrace; +#[cfg(bootstrap)] use crate::borrow::Cow; +#[cfg(bootstrap)] use crate::cell; +#[cfg(bootstrap)] use crate::char; -use crate::fmt::{self, Debug, Display, Write}; +#[cfg(bootstrap)] +use crate::fmt::Debug; +#[cfg(bootstrap)] +use crate::fmt::Display; +use crate::fmt::{self, Write}; +#[cfg(bootstrap)] use crate::io; +#[cfg(bootstrap)] use crate::mem::transmute; +#[cfg(bootstrap)] use crate::num; +#[cfg(bootstrap)] use crate::str; +#[cfg(bootstrap)] use crate::string; +#[cfg(bootstrap)] use crate::sync::Arc; +#[cfg(bootstrap)] use crate::time; +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +pub use core::error::Error; + /// `Error` is a trait representing the basic expectations for error values, /// i.e., values of type `E` in [`Result<T, E>`]. /// @@ -190,6 +77,7 @@ use crate::time; /// implementation for debugging via `source` chains. #[stable(feature = "rust1", since = "1.0.0")] #[cfg_attr(not(test), rustc_diagnostic_item = "Error")] +#[cfg(bootstrap)] pub trait Error: Debug + Display { /// The lower-level source of this error, if any. /// @@ -355,6 +243,7 @@ pub trait Error: Debug + Display { fn provide<'a>(&'a self, req: &mut Demand<'a>) {} } +#[cfg(bootstrap)] #[unstable(feature = "error_generic_member_access", issue = "99301")] impl<'b> Provider for dyn Error + 'b { fn provide<'a>(&'a self, req: &mut Demand<'a>) { @@ -370,6 +259,7 @@ mod private { pub struct Internal; } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> { /// Converts a type of [`Error`] into a box of dyn [`Error`]. @@ -402,6 +292,7 @@ impl<'a, E: Error + 'a> From<E> for Box<dyn Error + 'a> { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + 'a> { /// Converts a type of [`Error`] + [`Send`] + [`Sync`] into a box of @@ -440,6 +331,7 @@ impl<'a, E: Error + Send + Sync + 'a> From<E> for Box<dyn Error + Send + Sync + } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl From<String> for Box<dyn Error + Send + Sync> { /// Converts a [`String`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. @@ -483,6 +375,7 @@ impl From<String> for Box<dyn Error + Send + Sync> { } } +#[cfg(bootstrap)] #[stable(feature = "string_box_error", since = "1.6.0")] impl From<String> for Box<dyn Error> { /// Converts a [`String`] into a box of dyn [`Error`]. @@ -504,6 +397,7 @@ impl From<String> for Box<dyn Error> { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> { /// Converts a [`str`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. @@ -527,6 +421,7 @@ impl<'a> From<&str> for Box<dyn Error + Send + Sync + 'a> { } } +#[cfg(bootstrap)] #[stable(feature = "string_box_error", since = "1.6.0")] impl From<&str> for Box<dyn Error> { /// Converts a [`str`] into a box of dyn [`Error`]. @@ -548,6 +443,7 @@ impl From<&str> for Box<dyn Error> { } } +#[cfg(bootstrap)] #[stable(feature = "cow_box_error", since = "1.22.0")] impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> { /// Converts a [`Cow`] into a box of dyn [`Error`] + [`Send`] + [`Sync`]. @@ -569,6 +465,7 @@ impl<'a, 'b> From<Cow<'b, str>> for Box<dyn Error + Send + Sync + 'a> { } } +#[cfg(bootstrap)] #[stable(feature = "cow_box_error", since = "1.22.0")] impl<'a> From<Cow<'a, str>> for Box<dyn Error> { /// Converts a [`Cow`] into a box of dyn [`Error`]. @@ -589,9 +486,11 @@ impl<'a> From<Cow<'a, str>> for Box<dyn Error> { } } +#[cfg(bootstrap)] #[unstable(feature = "never_type", issue = "35121")] impl Error for ! {} +#[cfg(bootstrap)] #[unstable( feature = "allocator_api", reason = "the precise API and guarantees it provides may be tweaked.", @@ -599,9 +498,11 @@ impl Error for ! {} )] impl Error for AllocError {} +#[cfg(bootstrap)] #[stable(feature = "alloc_layout", since = "1.28.0")] impl Error for LayoutError {} +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for str::ParseBoolError { #[allow(deprecated)] @@ -610,6 +511,7 @@ impl Error for str::ParseBoolError { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for str::Utf8Error { #[allow(deprecated)] @@ -618,6 +520,7 @@ impl Error for str::Utf8Error { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for num::ParseIntError { #[allow(deprecated)] @@ -626,6 +529,7 @@ impl Error for num::ParseIntError { } } +#[cfg(bootstrap)] #[stable(feature = "try_from", since = "1.34.0")] impl Error for num::TryFromIntError { #[allow(deprecated)] @@ -634,6 +538,7 @@ impl Error for num::TryFromIntError { } } +#[cfg(bootstrap)] #[stable(feature = "try_from", since = "1.34.0")] impl Error for array::TryFromSliceError { #[allow(deprecated)] @@ -642,6 +547,7 @@ impl Error for array::TryFromSliceError { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for num::ParseFloatError { #[allow(deprecated)] @@ -650,6 +556,7 @@ impl Error for num::ParseFloatError { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for string::FromUtf8Error { #[allow(deprecated)] @@ -658,6 +565,7 @@ impl Error for string::FromUtf8Error { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for string::FromUtf16Error { #[allow(deprecated)] @@ -666,6 +574,7 @@ impl Error for string::FromUtf16Error { } } +#[cfg(bootstrap)] #[stable(feature = "str_parse_error2", since = "1.8.0")] impl Error for Infallible { fn description(&self) -> &str { @@ -673,6 +582,7 @@ impl Error for Infallible { } } +#[cfg(bootstrap)] #[stable(feature = "decode_utf16", since = "1.9.0")] impl Error for char::DecodeUtf16Error { #[allow(deprecated)] @@ -681,9 +591,11 @@ impl Error for char::DecodeUtf16Error { } } +#[cfg(bootstrap)] #[stable(feature = "u8_from_char", since = "1.59.0")] impl Error for char::TryFromCharError {} +#[cfg(bootstrap)] #[unstable(feature = "map_try_insert", issue = "82766")] impl<'a, K: Debug + Ord, V: Debug> Error for crate::collections::btree_map::OccupiedError<'a, K, V> @@ -694,6 +606,7 @@ impl<'a, K: Debug + Ord, V: Debug> Error } } +#[cfg(bootstrap)] #[unstable(feature = "map_try_insert", issue = "82766")] impl<'a, K: Debug, V: Debug> Error for crate::collections::hash_map::OccupiedError<'a, K, V> { #[allow(deprecated)] @@ -702,6 +615,7 @@ impl<'a, K: Debug, V: Debug> Error for crate::collections::hash_map::OccupiedErr } } +#[cfg(bootstrap)] #[stable(feature = "box_error", since = "1.8.0")] impl<T: Error> Error for Box<T> { #[allow(deprecated, deprecated_in_future)] @@ -719,6 +633,7 @@ impl<T: Error> Error for Box<T> { } } +#[cfg(bootstrap)] #[unstable(feature = "thin_box", issue = "92791")] impl<T: ?Sized + crate::error::Error> crate::error::Error for crate::boxed::ThinBox<T> { fn source(&self) -> Option<&(dyn crate::error::Error + 'static)> { @@ -727,6 +642,7 @@ impl<T: ?Sized + crate::error::Error> crate::error::Error for crate::boxed::Thin } } +#[cfg(bootstrap)] #[stable(feature = "error_by_ref", since = "1.51.0")] impl<'a, T: Error + ?Sized> Error for &'a T { #[allow(deprecated, deprecated_in_future)] @@ -748,6 +664,7 @@ impl<'a, T: Error + ?Sized> Error for &'a T { } } +#[cfg(bootstrap)] #[stable(feature = "arc_error", since = "1.52.0")] impl<T: Error + ?Sized> Error for Arc<T> { #[allow(deprecated, deprecated_in_future)] @@ -769,6 +686,7 @@ impl<T: Error + ?Sized> Error for Arc<T> { } } +#[cfg(bootstrap)] #[stable(feature = "fmt_error", since = "1.11.0")] impl Error for fmt::Error { #[allow(deprecated)] @@ -777,6 +695,7 @@ impl Error for fmt::Error { } } +#[cfg(bootstrap)] #[stable(feature = "try_borrow", since = "1.13.0")] impl Error for cell::BorrowError { #[allow(deprecated)] @@ -785,6 +704,7 @@ impl Error for cell::BorrowError { } } +#[cfg(bootstrap)] #[stable(feature = "try_borrow", since = "1.13.0")] impl Error for cell::BorrowMutError { #[allow(deprecated)] @@ -793,6 +713,7 @@ impl Error for cell::BorrowMutError { } } +#[cfg(bootstrap)] #[stable(feature = "try_from", since = "1.34.0")] impl Error for char::CharTryFromError { #[allow(deprecated)] @@ -801,6 +722,7 @@ impl Error for char::CharTryFromError { } } +#[cfg(bootstrap)] #[stable(feature = "char_from_str", since = "1.20.0")] impl Error for char::ParseCharError { #[allow(deprecated)] @@ -809,12 +731,15 @@ impl Error for char::ParseCharError { } } +#[cfg(bootstrap)] #[stable(feature = "try_reserve", since = "1.57.0")] impl Error for alloc::collections::TryReserveError {} +#[cfg(bootstrap)] #[unstable(feature = "duration_checked_float", issue = "83400")] impl Error for time::FromFloatSecsError {} +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl Error for alloc::ffi::NulError { #[allow(deprecated)] @@ -823,6 +748,7 @@ impl Error for alloc::ffi::NulError { } } +#[cfg(bootstrap)] #[stable(feature = "rust1", since = "1.0.0")] impl From<alloc::ffi::NulError> for io::Error { /// Converts a [`alloc::ffi::NulError`] into a [`io::Error`]. @@ -831,6 +757,7 @@ impl From<alloc::ffi::NulError> for io::Error { } } +#[cfg(bootstrap)] #[stable(feature = "frombyteswithnulerror_impls", since = "1.17.0")] impl Error for core::ffi::FromBytesWithNulError { #[allow(deprecated)] @@ -839,12 +766,15 @@ impl Error for core::ffi::FromBytesWithNulError { } } +#[cfg(bootstrap)] #[unstable(feature = "cstr_from_bytes_until_nul", issue = "95027")] impl Error for core::ffi::FromBytesUntilNulError {} +#[cfg(bootstrap)] #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")] impl Error for alloc::ffi::FromVecWithNulError {} +#[cfg(bootstrap)] #[stable(feature = "cstring_into", since = "1.7.0")] impl Error for alloc::ffi::IntoStringError { #[allow(deprecated)] @@ -857,6 +787,7 @@ impl Error for alloc::ffi::IntoStringError { } } +#[cfg(bootstrap)] impl<'a> dyn Error + 'a { /// Request a reference of type `T` as context about this error. #[unstable(feature = "error_generic_member_access", issue = "99301")] @@ -872,6 +803,7 @@ impl<'a> dyn Error + 'a { } // Copied from `any.rs`. +#[cfg(bootstrap)] impl dyn Error + 'static { /// Returns `true` if the inner type is the same as `T`. #[stable(feature = "error_downcast", since = "1.3.0")] @@ -912,6 +844,7 @@ impl dyn Error + 'static { } } +#[cfg(bootstrap)] impl dyn Error + 'static + Send { /// Forwards to the method defined on the type `dyn Error`. #[stable(feature = "error_downcast", since = "1.3.0")] @@ -947,6 +880,7 @@ impl dyn Error + 'static + Send { } } +#[cfg(bootstrap)] impl dyn Error + 'static + Send + Sync { /// Forwards to the method defined on the type `dyn Error`. #[stable(feature = "error_downcast", since = "1.3.0")] @@ -982,6 +916,7 @@ impl dyn Error + 'static + Send + Sync { } } +#[cfg(bootstrap)] impl dyn Error { #[inline] #[stable(feature = "error_downcast", since = "1.3.0")] @@ -1061,10 +996,12 @@ impl dyn Error { /// its sources, use `skip(1)`. #[unstable(feature = "error_iter", issue = "58520")] #[derive(Clone, Debug)] +#[cfg(bootstrap)] pub struct Chain<'a> { current: Option<&'a (dyn Error + 'static)>, } +#[cfg(bootstrap)] #[unstable(feature = "error_iter", issue = "58520")] impl<'a> Iterator for Chain<'a> { type Item = &'a (dyn Error + 'static); @@ -1076,6 +1013,7 @@ impl<'a> Iterator for Chain<'a> { } } +#[cfg(bootstrap)] impl dyn Error + Send { #[inline] #[stable(feature = "error_downcast", since = "1.3.0")] @@ -1089,6 +1027,7 @@ impl dyn Error + Send { } } +#[cfg(bootstrap)] impl dyn Error + Send + Sync { #[inline] #[stable(feature = "error_downcast", since = "1.3.0")] @@ -1246,7 +1185,7 @@ impl dyn Error + Send + Sync { /// # Err(SuperError { source: SuperErrorSideKick }) /// # } /// -/// fn main() -> Result<(), Report> { +/// fn main() -> Result<(), Report<SuperError>> { /// get_super_error()?; /// Ok(()) /// } @@ -1293,7 +1232,7 @@ impl dyn Error + Send + Sync { /// # Err(SuperError { source: SuperErrorSideKick }) /// # } /// -/// fn main() -> Result<(), Report> { +/// fn main() -> Result<(), Report<SuperError>> { /// get_super_error() /// .map_err(Report::from) /// .map_err(|r| r.pretty(true).show_backtrace(true))?; @@ -1605,72 +1544,6 @@ where } } -impl Report<Box<dyn Error>> { - fn backtrace(&self) -> Option<&Backtrace> { - // have to grab the backtrace on the first error directly since that error may not be - // 'static - let backtrace = self.error.request_ref(); - let backtrace = backtrace.or_else(|| { - self.error - .source() - .map(|source| source.chain().find_map(|source| source.request_ref())) - .flatten() - }); - backtrace - } - - /// Format the report as a single line. - #[unstable(feature = "error_reporter", issue = "90172")] - fn fmt_singleline(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(f, "{}", self.error)?; - - let sources = self.error.source().into_iter().flat_map(<dyn Error>::chain); - - for cause in sources { - write!(f, ": {cause}")?; - } - - Ok(()) - } - - /// Format the report as multiple lines, with each error cause on its own line. - #[unstable(feature = "error_reporter", issue = "90172")] - fn fmt_multiline(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - let error = &self.error; - - write!(f, "{error}")?; - - if let Some(cause) = error.source() { - write!(f, "\n\nCaused by:")?; - - let multiple = cause.source().is_some(); - - for (ind, error) in cause.chain().enumerate() { - writeln!(f)?; - let mut indented = Indented { inner: f }; - if multiple { - write!(indented, "{ind: >4}: {error}")?; - } else { - write!(indented, " {error}")?; - } - } - } - - if self.show_backtrace { - let backtrace = self.backtrace(); - - if let Some(backtrace) = backtrace { - let backtrace = backtrace.to_string(); - - f.write_str("\n\nStack backtrace:\n")?; - f.write_str(backtrace.trim_end())?; - } - } - - Ok(()) - } -} - #[unstable(feature = "error_reporter", issue = "90172")] impl<E> From<E> for Report<E> where @@ -1682,17 +1555,6 @@ where } #[unstable(feature = "error_reporter", issue = "90172")] -impl<'a, E> From<E> for Report<Box<dyn Error + 'a>> -where - E: Error + 'a, -{ - fn from(error: E) -> Self { - let error = box error; - Report { error, show_backtrace: false, pretty: false } - } -} - -#[unstable(feature = "error_reporter", issue = "90172")] impl<E> fmt::Display for Report<E> where E: Error, @@ -1702,13 +1564,6 @@ where } } -#[unstable(feature = "error_reporter", issue = "90172")] -impl fmt::Display for Report<Box<dyn Error>> { - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - if self.pretty { self.fmt_multiline(f) } else { self.fmt_singleline(f) } - } -} - // This type intentionally outputs the same format for `Display` and `Debug`for // situations where you unwrap a `Report` or return it from main. #[unstable(feature = "error_reporter", issue = "90172")] diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs index ff7fdcae16f..885e44f5e18 100644 --- a/library/std/src/io/error.rs +++ b/library/std/src/io/error.rs @@ -76,6 +76,15 @@ impl fmt::Debug for Error { } } +#[cfg(not(bootstrap))] +#[stable(feature = "rust1", since = "1.0.0")] +impl From<alloc::ffi::NulError> for Error { + /// Converts a [`alloc::ffi::NulError`] into a [`Error`]. + fn from(_: alloc::ffi::NulError) -> Error { + const_io_error!(ErrorKind::InvalidInput, "data provided contains a nul byte") + } +} + // Only derive debug in tests, to make sure it // doesn't accidentally get printed. #[cfg_attr(test, derive(Debug))] diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 5029023121f..1f23c98618b 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -281,6 +281,9 @@ #![feature(cstr_internals)] #![feature(duration_checked_float)] #![feature(duration_constants)] +#![cfg_attr(not(bootstrap), feature(error_generic_member_access))] +#![cfg_attr(not(bootstrap), feature(error_in_core))] +#![cfg_attr(not(bootstrap), feature(error_iter))] #![feature(exact_size_is_empty)] #![feature(exclusive_wrapper)] #![feature(extend_one)] |