Auto merge of #99917 - yaahc:error-in-core-move, r=thomcc

Move Error trait into core

This PR moves the error trait from the standard library into a new unstable `error` module within the core library. The goal of this PR is to help unify error reporting across the std and no_std ecosystems, as well as open the door to integrating the error trait into the panic reporting system when reporting panics whose source is an errors (such as via `expect`).

This PR is a rewrite of https://github.com/rust-lang/rust/pull/90328 using new compiler features that have been added to support error in core.

1 files changed, 11 insertions, 0 deletions

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",