diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index c1ceeb0deb837..346df21383650 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 649ccfcaa9ed8..0a20c74b00fdc 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 b6eecf9b0e952..cd7cdc1920719 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 628a5b155673c..21d0def0866ed 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 ae61b1f1e8ed5..b3c3941be5afb 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 8b6f4054851dd..93f40d902ef24 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)]
@@ -178,6 +181,7 @@
 #![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 a5118e5333b82..2c72dcdf1570d 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 4c03cc3ed158a..4377edeee8710 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 3473ac09e956f..f03502429ab21 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 6cc6e359e65b6..94efa76664f6a 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 c9823a136bc42..7cbd47175123f 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 71297acd17145..dc8ea66cc6d0e 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 0df23e7bbe695..d3a9feeaec79b 100644
--- a/library/core/src/char/mod.rs
+++ b/library/core/src/char/mod.rs
@@ -36,6 +36,8 @@ 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;
 
@@ -582,3 +584,7 @@ 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 b30c8a4aeabdd..5bddfd1a413e7 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 0000000000000..891abebbfd39b
--- /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 0000000000000..d11debb34adca
--- /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 24742bb49b9a5..8d04a213f503d 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 1a223016dae0f..1f6b40e5df554 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 f481399fdcf92..8f5e39dc29522 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 4e569fcc866b6..343889b6999fa 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 ee66895a7ed2a..4682e9a85b0be 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 db811343fa322..9845d1faf9aa1 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 df7a49d258282..914f6d6d2e3e9 100644
--- a/library/std/src/error.rs
+++ b/library/std/src/error.rs
@@ -1,141 +1,4 @@
-//! 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`]: 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
@@ -1681,17 +1554,6 @@ 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
@@ -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 ff7fdcae16f53..885e44f5e18bd 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 a8d6645794ae5..b6bf70ea377ae 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -269,6 +269,9 @@
 #![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)]