diff --git a/library/core/Cargo.toml b/library/core/Cargo.toml
index 3dc8c84e0bfde..a02fcf504168a 100644
--- a/library/core/Cargo.toml
+++ b/library/core/Cargo.toml
@@ -7,7 +7,8 @@ description = "The Rust Core Library"
autotests = false
autobenches = false
# If you update this, be sure to update it in a bunch of other places too!
-# As of 2022, it was the ci/pgo.sh script and the core-no-fp-fmt-parse test.
+# As of 2024, it was src/tools/opt-dist, the core-no-fp-fmt-parse test and
+# the version of the prelude imported in core/lib.rs.
edition = "2021"
[lib]
diff --git a/library/core/src/array/equality.rs b/library/core/src/array/equality.rs
index bdb6599abf549..bb668d2a67309 100644
--- a/library/core/src/array/equality.rs
+++ b/library/core/src/array/equality.rs
@@ -1,5 +1,4 @@
use crate::cmp::BytewiseEq;
-use crate::convert::TryInto;
#[stable(feature = "rust1", since = "1.0.0")]
impl<T, U, const N: usize> PartialEq<[U; N]> for [T; N]
diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 8b5b48c59c29b..2a447aafe72d3 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -6,7 +6,7 @@
use crate::borrow::{Borrow, BorrowMut};
use crate::cmp::Ordering;
-use crate::convert::{Infallible, TryFrom};
+use crate::convert::Infallible;
use crate::error::Error;
use crate::fmt;
use crate::hash::{self, Hash};
diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs
index 8f61292911030..f0c2636307fcf 100644
--- a/library/core/src/char/convert.rs
+++ b/library/core/src/char/convert.rs
@@ -1,7 +1,6 @@
//! Character conversions.
use crate::char::TryFromCharError;
-use crate::convert::TryFrom;
use crate::error::Error;
use crate::fmt;
use crate::mem::transmute;
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index 46a9006c14665..0167d04c413fe 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -1,4 +1,3 @@
-use super::TryFrom;
use crate::num::TryFromIntError;
mod private {
@@ -323,7 +322,6 @@ impl_try_from_lower_bounded!(isize => usize);
#[cfg(target_pointer_width = "16")]
mod ptr_try_from_impls {
use super::TryFromIntError;
- use crate::convert::TryFrom;
impl_try_from_upper_bounded!(usize => u8);
impl_try_from_unbounded!(usize => u16, u32, u64, u128);
@@ -346,7 +344,6 @@ mod ptr_try_from_impls {
#[cfg(target_pointer_width = "32")]
mod ptr_try_from_impls {
use super::TryFromIntError;
- use crate::convert::TryFrom;
impl_try_from_upper_bounded!(usize => u8, u16);
impl_try_from_unbounded!(usize => u32, u64, u128);
@@ -372,7 +369,6 @@ mod ptr_try_from_impls {
#[cfg(target_pointer_width = "64")]
mod ptr_try_from_impls {
use super::TryFromIntError;
- use crate::convert::TryFrom;
impl_try_from_upper_bounded!(usize => u8, u16, u32);
impl_try_from_unbounded!(usize => u64, u128);
diff --git a/library/core/src/iter/adapters/step_by.rs b/library/core/src/iter/adapters/step_by.rs
index 54ed4c952fb8b..b8b96417d134e 100644
--- a/library/core/src/iter/adapters/step_by.rs
+++ b/library/core/src/iter/adapters/step_by.rs
@@ -1,4 +1,3 @@
-use crate::convert::TryFrom;
use crate::{
intrinsics,
iter::{from_fn, TrustedLen, TrustedRandomAccess},
diff --git a/library/core/src/iter/range.rs b/library/core/src/iter/range.rs
index 055ead117ea24..5eea764b28adc 100644
--- a/library/core/src/iter/range.rs
+++ b/library/core/src/iter/range.rs
@@ -1,5 +1,4 @@
use crate::ascii::Char as AsciiChar;
-use crate::convert::TryFrom;
use crate::mem;
use crate::net::{Ipv4Addr, Ipv6Addr};
use crate::num::NonZero;
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index e1904ed220cb4..d2c9e1554b4f8 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -8,11 +8,11 @@ use super::super::ByRefSized;
use super::super::TrustedRandomAccessNoCoerce;
use super::super::{ArrayChunks, Chain, Cloned, Copied, Cycle, Enumerate, Filter, FilterMap, Fuse};
use super::super::{FlatMap, Flatten};
-use super::super::{FromIterator, Intersperse, IntersperseWith, Product, Sum, Zip};
use super::super::{
Inspect, Map, MapWhile, MapWindows, Peekable, Rev, Scan, Skip, SkipWhile, StepBy, Take,
TakeWhile,
};
+use super::super::{Intersperse, IntersperseWith, Product, Sum, Zip};
fn _assert_is_object_safe(_: &dyn Iterator<Item = ()>) {}
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index f0448a98981fb..d6f4b33c24025 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -285,7 +285,7 @@ extern crate self as core;
#[prelude_import]
#[allow(unused)]
-use prelude::v1::*;
+use prelude::rust_2021::*;
#[cfg(not(test))] // See #65860
#[macro_use]
diff --git a/library/core/src/net/parser.rs b/library/core/src/net/parser.rs
index 835ab9d73af57..deea821244859 100644
--- a/library/core/src/net/parser.rs
+++ b/library/core/src/net/parser.rs
@@ -3,7 +3,6 @@
//! This module is "publicly exported" through the `FromStr` implementations
//! below.
-use crate::convert::{TryFrom, TryInto};
use crate::error::Error;
use crate::fmt;
use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 0083d15efaefb..631e1654ce075 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -553,7 +553,7 @@
#![stable(feature = "rust1", since = "1.0.0")]
-use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
+use crate::iter::{self, FusedIterator, TrustedLen};
use crate::panicking::{panic, panic_str};
use crate::pin::Pin;
use crate::{
diff --git a/library/core/src/ptr/alignment.rs b/library/core/src/ptr/alignment.rs
index bc84fb5ccb0d7..68fce3960c78c 100644
--- a/library/core/src/ptr/alignment.rs
+++ b/library/core/src/ptr/alignment.rs
@@ -1,4 +1,3 @@
-use crate::convert::{TryFrom, TryInto};
use crate::num::NonZero;
#[cfg(debug_assertions)]
use crate::ub_checks::assert_unsafe_precondition;
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 6879ac03f70bc..b2b627fe6a9cc 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -488,7 +488,7 @@
#![stable(feature = "rust1", since = "1.0.0")]
-use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
+use crate::iter::{self, FusedIterator, TrustedLen};
use crate::ops::{self, ControlFlow, Deref, DerefMut};
use crate::{convert, fmt, hint};
diff --git a/library/core/src/unit.rs b/library/core/src/unit.rs
index 6656dd5c40beb..d656005f3d42d 100644
--- a/library/core/src/unit.rs
+++ b/library/core/src/unit.rs
@@ -1,5 +1,3 @@
-use crate::iter::FromIterator;
-
/// Collapses all unit items from an iterator into one.
///
/// This is more useful when combined with higher-level abstractions, like
diff --git a/library/portable-simd/crates/core_simd/src/lib.rs b/library/portable-simd/crates/core_simd/src/lib.rs
index 7a161b7e01d25..48514e52587f0 100644
--- a/library/portable-simd/crates/core_simd/src/lib.rs
+++ b/library/portable-simd/crates/core_simd/src/lib.rs
@@ -45,10 +45,6 @@
#![unstable(feature = "portable_simd", issue = "86656")]
//! Portable SIMD module.
-#[prelude_import]
-#[allow(unused_imports)]
-use core::prelude::v1::*;
-
#[path = "mod.rs"]
mod core_simd;
pub use self::core_simd::simd;
diff --git a/library/portable-simd/crates/core_simd/src/vector.rs b/library/portable-simd/crates/core_simd/src/vector.rs
index 6c8205b112c31..8dbdfc0e1fe03 100644
--- a/library/portable-simd/crates/core_simd/src/vector.rs
+++ b/library/portable-simd/crates/core_simd/src/vector.rs
@@ -4,7 +4,6 @@ use crate::simd::{
ptr::{SimdConstPtr, SimdMutPtr},
LaneCount, Mask, MaskElement, SupportedLaneCount, Swizzle,
};
-use core::convert::{TryFrom, TryInto};
/// A SIMD vector with the shape of `[T; N]` but the operations of `T`.
///