clean up some old const trait impl syntax

20 files changed, 55 insertions, 106 deletions

diff --git a/library/core/src/borrow.rs b/library/core/src/borrow.rs
index 6ce7e4656b9..78ba69fec14 100644
--- a/library/core/src/borrow.rs
+++ b/library/core/src/borrow.rs
@@ -154,9 +154,8 @@
 /// [`String`]: ../../std/string/struct.String.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Borrow"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait Borrow<Borrowed: ?Sized> {
+pub const trait Borrow<Borrowed: ?Sized> {
     /// Immutably borrows from an owned value.
     ///
     /// # Examples
@@ -187,9 +186,8 @@ pub trait Borrow<Borrowed: ?Sized> {
 /// for more information on borrowing as another type.
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "BorrowMut"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait BorrowMut<Borrowed: ?Sized>: Borrow<Borrowed> {
+pub const trait BorrowMut<Borrowed: ?Sized>: Borrow<Borrowed> {
     /// Mutably borrows from an owned value.
     ///
     /// # Examples
diff --git a/library/core/src/clone.rs b/library/core/src/clone.rs
index 0add77b2bc8..7f2a40f753f 100644
--- a/library/core/src/clone.rs
+++ b/library/core/src/clone.rs
@@ -191,8 +191,7 @@ mod uninit;
 #[rustc_diagnostic_item = "Clone"]
 #[rustc_trivial_field_reads]
 #[rustc_const_unstable(feature = "const_clone", issue = "142757")]
-#[const_trait]
-pub trait Clone: Sized {
+pub const trait Clone: Sized {
     /// Returns a duplicate of the value.
     ///
     /// Note that what "duplicate" means varies by type:
diff --git a/library/core/src/cmp.rs b/library/core/src/cmp.rs
index ab018fa2675..0812322f3fb 100644
--- a/library/core/src/cmp.rs
+++ b/library/core/src/cmp.rs
@@ -247,9 +247,8 @@ use crate::ops::ControlFlow;
     append_const_msg
 )]
 #[rustc_diagnostic_item = "PartialEq"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-pub trait PartialEq<Rhs: PointeeSized = Self>: PointeeSized {
+pub const trait PartialEq<Rhs: PointeeSized = Self>: PointeeSized {
     /// Tests for `self` and `other` values to be equal, and is used by `==`.
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/cmp/bytewise.rs b/library/core/src/cmp/bytewise.rs
index a06a6e8b69a..2265fa7a353 100644
--- a/library/core/src/cmp/bytewise.rs
+++ b/library/core/src/cmp/bytewise.rs
@@ -17,7 +17,7 @@ use crate::num::NonZero;
 /// - Neither `Self` nor `Rhs` have provenance, so integer comparisons are correct.
 /// - `<Self as PartialEq<Rhs>>::{eq,ne}` are equivalent to comparing the bytes.
 #[rustc_specialization_trait]
-#[const_trait]
+#[const_trait] // FIXME(const_trait_impl): Migrate to `const unsafe trait` once #146122 is fixed.
 pub(crate) unsafe trait BytewiseEq<Rhs = Self>:
     [const] PartialEq<Rhs> + Sized
 {
diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index add21b491ad..a3cfd85974a 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -216,9 +216,8 @@ pub const fn identity<T>(x: T) -> T {
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "AsRef"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait AsRef<T: PointeeSized>: PointeeSized {
+pub const trait AsRef<T: PointeeSized>: PointeeSized {
     /// Converts this type into a shared reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn as_ref(&self) -> &T;
@@ -369,9 +368,8 @@ pub trait AsRef<T: PointeeSized>: PointeeSized {
 /// `&mut Vec<u8>`, for example, is the better choice (callers need to pass the correct type then).
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "AsMut"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait AsMut<T: PointeeSized>: PointeeSized {
+pub const trait AsMut<T: PointeeSized>: PointeeSized {
     /// Converts this type into a mutable reference of the (usually inferred) input type.
     #[stable(feature = "rust1", since = "1.0.0")]
     fn as_mut(&mut self) -> &mut T;
@@ -450,8 +448,7 @@ pub trait AsMut<T: PointeeSized>: PointeeSized {
 #[stable(feature = "rust1", since = "1.0.0")]
 #[doc(search_unbox)]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-#[const_trait]
-pub trait Into<T>: Sized {
+pub const trait Into<T>: Sized {
     /// Converts this type into the (usually inferred) input type.
     #[must_use]
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -587,8 +584,7 @@ pub trait Into<T>: Sized {
 ))]
 #[doc(search_unbox)]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-#[const_trait]
-pub trait From<T>: Sized {
+pub const trait From<T>: Sized {
     /// Converts to this type from the input type.
     #[rustc_diagnostic_item = "from_fn"]
     #[must_use]
@@ -616,8 +612,7 @@ pub trait From<T>: Sized {
 #[rustc_diagnostic_item = "TryInto"]
 #[stable(feature = "try_from", since = "1.34.0")]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-#[const_trait]
-pub trait TryInto<T>: Sized {
+pub const trait TryInto<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]
     type Error;
@@ -696,8 +691,7 @@ pub trait TryInto<T>: Sized {
 #[rustc_diagnostic_item = "TryFrom"]
 #[stable(feature = "try_from", since = "1.34.0")]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-#[const_trait]
-pub trait TryFrom<T>: Sized {
+pub const trait TryFrom<T>: Sized {
     /// The type returned in the event of a conversion error.
     #[stable(feature = "try_from", since = "1.34.0")]
     type Error;
diff --git a/library/core/src/default.rs b/library/core/src/default.rs
index 897267968aa..cc9289307c1 100644
--- a/library/core/src/default.rs
+++ b/library/core/src/default.rs
@@ -103,9 +103,8 @@ use crate::ascii::Char as AsciiChar;
 /// ```
 #[rustc_diagnostic_item = "Default"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_default", issue = "143894")]
-pub trait Default: Sized {
+pub const trait Default: Sized {
     /// Returns the "default value" for a type.
     ///
     /// Default values are often some kind of initial value, identity value, or anything else that
diff --git a/library/core/src/intrinsics/fallback.rs b/library/core/src/intrinsics/fallback.rs
index 96928325328..932537f2581 100644
--- a/library/core/src/intrinsics/fallback.rs
+++ b/library/core/src/intrinsics/fallback.rs
@@ -7,9 +7,8 @@
 )]
 #![allow(missing_docs)]
 
-#[const_trait]
 #[rustc_const_unstable(feature = "core_intrinsics_fallbacks", issue = "none")]
-pub trait CarryingMulAdd: Copy + 'static {
+pub const trait CarryingMulAdd: Copy + 'static {
     type Unsigned: Copy + 'static;
     fn carrying_mul_add(
         self,
@@ -111,9 +110,8 @@ impl const CarryingMulAdd for i128 {
     }
 }
 
-#[const_trait]
 #[rustc_const_unstable(feature = "core_intrinsics_fallbacks", issue = "none")]
-pub trait DisjointBitOr: Copy + 'static {
+pub const trait DisjointBitOr: Copy + 'static {
     /// See [`super::disjoint_bitor`]; we just need the trait indirection to handle
     /// different types since calling intrinsics with generics doesn't work.
     unsafe fn disjoint_bitor(self, other: Self) -> Self;
@@ -149,9 +147,8 @@ impl_disjoint_bitor! {
     i8, i16, i32, i64, i128, isize,
 }
 
-#[const_trait]
 #[rustc_const_unstable(feature = "core_intrinsics_fallbacks", issue = "none")]
-pub trait FunnelShift: Copy + 'static {
+pub const trait FunnelShift: Copy + 'static {
     /// See [`super::unchecked_funnel_shl`]; we just need the trait indirection to handle
     /// different types since calling intrinsics with generics doesn't work.
     unsafe fn unchecked_funnel_shl(self, rhs: Self, shift: u32) -> Self;
diff --git a/library/core/src/marker.rs b/library/core/src/marker.rs
index 73aad27afef..d03d7a43469 100644
--- a/library/core/src/marker.rs
+++ b/library/core/src/marker.rs
@@ -1057,8 +1057,7 @@ marker_impls! {
 #[rustc_on_unimplemented(message = "can't drop `{Self}`", append_const_msg)]
 #[rustc_deny_explicit_impl]
 #[rustc_do_not_implement_via_object]
-#[const_trait]
-pub trait Destruct {}
+pub const trait Destruct {}
 
 /// A marker for tuple types.
 ///
diff --git a/library/core/src/ops/arith.rs b/library/core/src/ops/arith.rs
index 16c719b0c39..6c6479c9984 100644
--- a/library/core/src/ops/arith.rs
+++ b/library/core/src/ops/arith.rs
@@ -74,8 +74,7 @@
     append_const_msg
 )]
 #[doc(alias = "+")]
-#[const_trait]
-pub trait Add<Rhs = Self> {
+pub const trait Add<Rhs = Self> {
     /// The resulting type after applying the `+` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -188,8 +187,7 @@ add_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f64 f128
     append_const_msg
 )]
 #[doc(alias = "-")]
-#[const_trait]
-pub trait Sub<Rhs = Self> {
+pub const trait Sub<Rhs = Self> {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -323,8 +321,7 @@ sub_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f64 f128
     label = "no implementation for `{Self} * {Rhs}`"
 )]
 #[doc(alias = "*")]
-#[const_trait]
-pub trait Mul<Rhs = Self> {
+pub const trait Mul<Rhs = Self> {
     /// The resulting type after applying the `*` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -462,8 +459,7 @@ mul_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f64 f128
     label = "no implementation for `{Self} / {Rhs}`"
 )]
 #[doc(alias = "/")]
-#[const_trait]
-pub trait Div<Rhs = Self> {
+pub const trait Div<Rhs = Self> {
     /// The resulting type after applying the `/` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -572,8 +568,7 @@ div_impl_float! { f16 f32 f64 f128 }
     label = "no implementation for `{Self} % {Rhs}`"
 )]
 #[doc(alias = "%")]
-#[const_trait]
-pub trait Rem<Rhs = Self> {
+pub const trait Rem<Rhs = Self> {
     /// The resulting type after applying the `%` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -694,8 +689,7 @@ rem_impl_float! { f16 f32 f64 f128 }
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
 #[doc(alias = "-")]
-#[const_trait]
-pub trait Neg {
+pub const trait Neg {
     /// The resulting type after applying the `-` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -772,8 +766,7 @@ neg_impl! { isize i8 i16 i32 i64 i128 f16 f32 f64 f128 }
 )]
 #[doc(alias = "+")]
 #[doc(alias = "+=")]
-#[const_trait]
-pub trait AddAssign<Rhs = Self> {
+pub const trait AddAssign<Rhs = Self> {
     /// Performs the `+=` operation.
     ///
     /// # Example
@@ -844,8 +837,7 @@ add_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f
 )]
 #[doc(alias = "-")]
 #[doc(alias = "-=")]
-#[const_trait]
-pub trait SubAssign<Rhs = Self> {
+pub const trait SubAssign<Rhs = Self> {
     /// Performs the `-=` operation.
     ///
     /// # Example
@@ -907,8 +899,7 @@ sub_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f
 )]
 #[doc(alias = "*")]
 #[doc(alias = "*=")]
-#[const_trait]
-pub trait MulAssign<Rhs = Self> {
+pub const trait MulAssign<Rhs = Self> {
     /// Performs the `*=` operation.
     ///
     /// # Example
@@ -970,8 +961,7 @@ mul_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f
 )]
 #[doc(alias = "/")]
 #[doc(alias = "/=")]
-#[const_trait]
-pub trait DivAssign<Rhs = Self> {
+pub const trait DivAssign<Rhs = Self> {
     /// Performs the `/=` operation.
     ///
     /// # Example
@@ -1036,8 +1026,7 @@ div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f16 f32 f
 )]
 #[doc(alias = "%")]
 #[doc(alias = "%=")]
-#[const_trait]
-pub trait RemAssign<Rhs = Self> {
+pub const trait RemAssign<Rhs = Self> {
     /// Performs the `%=` operation.
     ///
     /// # Example
diff --git a/library/core/src/ops/bit.rs b/library/core/src/ops/bit.rs
index 00196728219..0cd61b07373 100644
--- a/library/core/src/ops/bit.rs
+++ b/library/core/src/ops/bit.rs
@@ -32,8 +32,7 @@
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
 #[doc(alias = "!")]
-#[const_trait]
-pub trait Not {
+pub const trait Not {
     /// The resulting type after applying the `!` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -148,8 +147,7 @@ impl const Not for ! {
     message = "no implementation for `{Self} & {Rhs}`",
     label = "no implementation for `{Self} & {Rhs}`"
 )]
-#[const_trait]
-pub trait BitAnd<Rhs = Self> {
+pub const trait BitAnd<Rhs = Self> {
     /// The resulting type after applying the `&` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -253,8 +251,7 @@ bitand_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} | {Rhs}`",
     label = "no implementation for `{Self} | {Rhs}`"
 )]
-#[const_trait]
-pub trait BitOr<Rhs = Self> {
+pub const trait BitOr<Rhs = Self> {
     /// The resulting type after applying the `|` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -358,8 +355,7 @@ bitor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^ {Rhs}`",
     label = "no implementation for `{Self} ^ {Rhs}`"
 )]
-#[const_trait]
-pub trait BitXor<Rhs = Self> {
+pub const trait BitXor<Rhs = Self> {
     /// The resulting type after applying the `^` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -462,8 +458,7 @@ bitxor_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} << {Rhs}`",
     label = "no implementation for `{Self} << {Rhs}`"
 )]
-#[const_trait]
-pub trait Shl<Rhs = Self> {
+pub const trait Shl<Rhs = Self> {
     /// The resulting type after applying the `<<` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -585,8 +580,7 @@ shl_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} >> {Rhs}`",
     label = "no implementation for `{Self} >> {Rhs}`"
 )]
-#[const_trait]
-pub trait Shr<Rhs = Self> {
+pub const trait Shr<Rhs = Self> {
     /// The resulting type after applying the `>>` operator.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Output;
@@ -717,8 +711,7 @@ shr_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} &= {Rhs}`",
     label = "no implementation for `{Self} &= {Rhs}`"
 )]
-#[const_trait]
-pub trait BitAndAssign<Rhs = Self> {
+pub const trait BitAndAssign<Rhs = Self> {
     /// Performs the `&=` operation.
     ///
     /// # Examples
@@ -793,8 +786,7 @@ bitand_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} |= {Rhs}`",
     label = "no implementation for `{Self} |= {Rhs}`"
 )]
-#[const_trait]
-pub trait BitOrAssign<Rhs = Self> {
+pub const trait BitOrAssign<Rhs = Self> {
     /// Performs the `|=` operation.
     ///
     /// # Examples
@@ -869,8 +861,7 @@ bitor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} ^= {Rhs}`",
     label = "no implementation for `{Self} ^= {Rhs}`"
 )]
-#[const_trait]
-pub trait BitXorAssign<Rhs = Self> {
+pub const trait BitXorAssign<Rhs = Self> {
     /// Performs the `^=` operation.
     ///
     /// # Examples
@@ -943,8 +934,7 @@ bitxor_assign_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
     message = "no implementation for `{Self} <<= {Rhs}`",
     label = "no implementation for `{Self} <<= {Rhs}`"
 )]
-#[const_trait]
-pub trait ShlAssign<Rhs = Self> {
+pub const trait ShlAssign<Rhs = Self> {
     /// Performs the `<<=` operation.
     ///
     /// # Examples
@@ -1030,8 +1020,7 @@ shl_assign_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
     message = "no implementation for `{Self} >>= {Rhs}`",
     label = "no implementation for `{Self} >>= {Rhs}`"
 )]
-#[const_trait]
-pub trait ShrAssign<Rhs = Self> {
+pub const trait ShrAssign<Rhs = Self> {
     /// Performs the `>>=` operation.
     ///
     /// # Examples
diff --git a/library/core/src/ops/deref.rs b/library/core/src/ops/deref.rs
index 877b83d3a61..305861ea7b6 100644
--- a/library/core/src/ops/deref.rs
+++ b/library/core/src/ops/deref.rs
@@ -135,9 +135,8 @@ use crate::marker::PointeeSized;
 #[doc(alias = "&*")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_diagnostic_item = "Deref"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait Deref: PointeeSized {
+pub const trait Deref: PointeeSized {
     /// The resulting type after dereferencing.
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_diagnostic_item = "deref_target"]
@@ -267,9 +266,8 @@ impl<T: ?Sized> const Deref for &mut T {
 #[lang = "deref_mut"]
 #[doc(alias = "*")]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait DerefMut: [const] Deref + PointeeSized {
+pub const trait DerefMut: [const] Deref + PointeeSized {
     /// Mutably dereferences the value.
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_diagnostic_item = "deref_mut_method"]
diff --git a/library/core/src/ops/drop.rs b/library/core/src/ops/drop.rs
index bbef7023207..7125bf54701 100644
--- a/library/core/src/ops/drop.rs
+++ b/library/core/src/ops/drop.rs
@@ -203,9 +203,8 @@
 /// [nomicon]: ../../nomicon/phantom-data.html#an-exception-the-special-case-of-the-standard-library-and-its-unstable-may_dangle
 #[lang = "drop"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_destruct", issue = "133214")]
-pub trait Drop {
+pub const trait Drop {
     /// Executes the destructor for this type.
     ///
     /// This method is called implicitly when the value goes out of scope,
diff --git a/library/core/src/ops/function.rs b/library/core/src/ops/function.rs
index ad46e52a475..479368ba8f8 100644
--- a/library/core/src/ops/function.rs
+++ b/library/core/src/ops/function.rs
@@ -72,9 +72,8 @@ use crate::marker::Tuple;
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_trait_impl", issue = "143874")]
-pub trait Fn<Args: Tuple>: FnMut<Args> {
+pub const trait Fn<Args: Tuple>: FnMut<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
     extern "rust-call" fn call(&self, args: Args) -> Self::Output;
@@ -160,9 +159,8 @@ pub trait Fn<Args: Tuple>: FnMut<Args> {
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_trait_impl", issue = "143874")]
-pub trait FnMut<Args: Tuple>: FnOnce<Args> {
+pub const trait FnMut<Args: Tuple>: FnOnce<Args> {
     /// Performs the call operation.
     #[unstable(feature = "fn_traits", issue = "29625")]
     extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output;
@@ -240,9 +238,8 @@ pub trait FnMut<Args: Tuple>: FnOnce<Args> {
 )]
 #[fundamental] // so that regex can rely that `&str: !FnMut`
 #[must_use = "closures are lazy and do nothing unless called"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_trait_impl", issue = "143874")]
-pub trait FnOnce<Args: Tuple> {
+pub const trait FnOnce<Args: Tuple> {
     /// The returned type after the call operator is used.
     #[lang = "fn_once_output"]
     #[stable(feature = "fn_once_output", since = "1.12.0")]
diff --git a/library/core/src/ops/index.rs b/library/core/src/ops/index.rs
index 1aed2fb4742..2c62a3930c2 100644
--- a/library/core/src/ops/index.rs
+++ b/library/core/src/ops/index.rs
@@ -55,9 +55,8 @@
 #[doc(alias = "]")]
 #[doc(alias = "[")]
 #[doc(alias = "[]")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_index", issue = "143775")]
-pub trait Index<Idx: ?Sized> {
+pub const trait Index<Idx: ?Sized> {
     /// The returned type after indexing.
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_diagnostic_item = "IndexOutput"]
@@ -168,8 +167,7 @@ see chapter in The Book <https://doc.rust-lang.org/book/ch08-02-strings.html#ind
 #[doc(alias = "]")]
 #[doc(alias = "[]")]
 #[rustc_const_unstable(feature = "const_index", issue = "143775")]
-#[const_trait]
-pub trait IndexMut<Idx: ?Sized>: [const] Index<Idx> {
+pub const trait IndexMut<Idx: ?Sized>: [const] Index<Idx> {
     /// Performs the mutable indexing (`container[index]`) operation.
     ///
     /// # Panics
diff --git a/library/core/src/ops/try_trait.rs b/library/core/src/ops/try_trait.rs
index 76bf438878f..e1f2ebcf4c2 100644
--- a/library/core/src/ops/try_trait.rs
+++ b/library/core/src/ops/try_trait.rs
@@ -128,9 +128,8 @@ use crate::ops::ControlFlow;
 )]
 #[doc(alias = "?")]
 #[lang = "Try"]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_try", issue = "74935")]
-pub trait Try: [const] FromResidual {
+pub const trait Try: [const] FromResidual {
     /// The type of the value produced by `?` when *not* short-circuiting.
     #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
     type Output;
@@ -306,9 +305,8 @@ pub trait Try: [const] FromResidual {
 )]
 #[rustc_diagnostic_item = "FromResidual"]
 #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_try", issue = "74935")]
-pub trait FromResidual<R = <Self as Try>::Residual> {
+pub const trait FromResidual<R = <Self as Try>::Residual> {
     /// Constructs the type from a compatible `Residual` type.
     ///
     /// This should be implemented consistently with the `branch` method such
@@ -361,9 +359,8 @@ where
 /// and in the other direction,
 /// `<Result<Infallible, E> as Residual<T>>::TryType = Result<T, E>`.
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_try", issue = "74935")]
-pub trait Residual<O> {
+pub const trait Residual<O> {
     /// The "return" type of this meta-function.
     #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
     type TryType: Try<Output = O, Residual = Self>;
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 2a57536500a..198636c67d0 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -1640,7 +1640,7 @@ impl<T> Option<T> {
     pub const fn or_else<F>(self, f: F) -> Option<T>
     where
         F: [const] FnOnce() -> Option<T> + [const] Destruct,
-        //FIXME(const_hack): this `T: ~const Destruct` is unnecessary, but even precise live drops can't tell
+        //FIXME(const_hack): this `T: [const] Destruct` is unnecessary, but even precise live drops can't tell
         // no value of type `T` gets dropped here
         T: [const] Destruct,
     {
@@ -2185,7 +2185,7 @@ const fn expect_failed(msg: &str) -> ! {
 #[rustc_const_unstable(feature = "const_clone", issue = "142757")]
 impl<T> const Clone for Option<T>
 where
-    // FIXME(const_hack): the T: ~const Destruct should be inferred from the Self: ~const Destruct in clone_from.
+    // FIXME(const_hack): the T: [const] Destruct should be inferred from the Self: [const] Destruct in clone_from.
     // See https://github.com/rust-lang/rust/issues/144207
     T: [const] Clone + [const] Destruct,
 {
diff --git a/library/core/src/pat.rs b/library/core/src/pat.rs
index 91d015b1bc5..a13eea3fb58 100644
--- a/library/core/src/pat.rs
+++ b/library/core/src/pat.rs
@@ -18,12 +18,11 @@ macro_rules! pattern_type {
 /// used right now to simplify ast lowering of pattern type ranges.
 #[unstable(feature = "pattern_type_range_trait", issue = "123646")]
 #[rustc_const_unstable(feature = "pattern_type_range_trait", issue = "123646")]
-#[const_trait]
 #[diagnostic::on_unimplemented(
     message = "`{Self}` is not a valid base type for range patterns",
     label = "only integer types and `char` are supported"
 )]
-pub trait RangePattern {
+pub const trait RangePattern {
     /// Trait version of the inherent `MIN` assoc const.
     #[lang = "RangeMin"]
     const MIN: Self;
diff --git a/library/core/src/slice/cmp.rs b/library/core/src/slice/cmp.rs
index 68bd12aa7bf..0d801306984 100644
--- a/library/core/src/slice/cmp.rs
+++ b/library/core/src/slice/cmp.rs
@@ -95,9 +95,8 @@ impl<T: PartialOrd> PartialOrd for [T] {
 
 #[doc(hidden)]
 // intermediate trait for specialization of slice's PartialEq
-#[const_trait]
 #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
-trait SlicePartialEq<B> {
+const trait SlicePartialEq<B> {
     fn equal(&self, other: &[B]) -> bool;
 
     fn not_equal(&self, other: &[B]) -> bool {
diff --git a/library/core/src/slice/index.rs b/library/core/src/slice/index.rs
index 98091e9fe83..8e1bc0bae70 100644
--- a/library/core/src/slice/index.rs
+++ b/library/core/src/slice/index.rs
@@ -151,7 +151,7 @@ mod private_slice_index {
     message = "the type `{T}` cannot be indexed by `{Self}`",
     label = "slice indices are of type `usize` or ranges of `usize`"
 )]
-#[const_trait]
+#[const_trait] // FIXME(const_trait_impl): Migrate to `const unsafe trait` once #146122 is fixed.
 #[rustc_const_unstable(feature = "const_index", issue = "143775")]
 pub unsafe trait SliceIndex<T: ?Sized>: private_slice_index::Sealed {
     /// The output type returned by methods.
diff --git a/library/core/src/str/traits.rs b/library/core/src/str/traits.rs
index 971c8e829c6..4f228edf78e 100644
--- a/library/core/src/str/traits.rs
+++ b/library/core/src/str/traits.rs
@@ -825,9 +825,8 @@ unsafe impl const SliceIndex<str> for ops::RangeToInclusive<usize> {
 /// assert!(Point::from_str("(1 2)").is_err());
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
-#[const_trait]
 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
-pub trait FromStr: Sized {
+pub const trait FromStr: Sized {
     /// The associated error which can be returned from parsing.
     #[stable(feature = "rust1", since = "1.0.0")]
     type Err;