Constify Try, From, TryFrom

32 files changed, 204 insertions, 299 deletions

diff --git a/library/core/src/array/mod.rs b/library/core/src/array/mod.rs
index 62203e132b7..1c23218552a 100644
--- a/library/core/src/array/mod.rs
+++ b/library/core/src/array/mod.rs
@@ -198,7 +198,8 @@ impl Error for TryFromSliceError {
 }
 
 #[stable(feature = "try_from_slice_error", since = "1.36.0")]
-impl From<Infallible> for TryFromSliceError {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Infallible> for TryFromSliceError {
     fn from(x: Infallible) -> TryFromSliceError {
         match x {}
     }
diff --git a/library/core/src/ascii/ascii_char.rs b/library/core/src/ascii/ascii_char.rs
index 0b72b4780f1..054ddf84470 100644
--- a/library/core/src/ascii/ascii_char.rs
+++ b/library/core/src/ascii/ascii_char.rs
@@ -546,7 +546,8 @@ macro_rules! into_int_impl {
     ($($ty:ty)*) => {
         $(
             #[unstable(feature = "ascii_char", issue = "110998")]
-            impl From<AsciiChar> for $ty {
+            #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+            impl const From<AsciiChar> for $ty {
                 #[inline]
                 fn from(chr: AsciiChar) -> $ty {
                     chr as u8 as $ty
diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs
index 78cd89fefae..23061cb663b 100644
--- a/library/core/src/char/convert.rs
+++ b/library/core/src/char/convert.rs
@@ -36,7 +36,8 @@ pub(super) const unsafe fn from_u32_unchecked(i: u32) -> char {
 }
 
 #[stable(feature = "char_convert", since = "1.13.0")]
-impl From<char> for u32 {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<char> for u32 {
     /// Converts a [`char`] into a [`u32`].
     ///
     /// # Examples
@@ -53,7 +54,8 @@ impl From<char> for u32 {
 }
 
 #[stable(feature = "more_char_conversions", since = "1.51.0")]
-impl From<char> for u64 {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<char> for u64 {
     /// Converts a [`char`] into a [`u64`].
     ///
     /// # Examples
@@ -72,7 +74,8 @@ impl From<char> for u64 {
 }
 
 #[stable(feature = "more_char_conversions", since = "1.51.0")]
-impl From<char> for u128 {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<char> for u128 {
     /// Converts a [`char`] into a [`u128`].
     ///
     /// # Examples
@@ -157,7 +160,8 @@ impl TryFrom<char> for u16 {
 /// for a superset of Windows-1252 that fills the remaining blanks with corresponding
 /// C0 and C1 control codes.
 #[stable(feature = "char_convert", since = "1.13.0")]
-impl From<u8> for char {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<u8> for char {
     /// Converts a [`u8`] into a [`char`].
     ///
     /// # Examples
@@ -247,7 +251,8 @@ const fn char_try_from_u32(i: u32) -> Result<char, CharTryFromError> {
 }
 
 #[stable(feature = "try_from", since = "1.34.0")]
-impl TryFrom<u32> for char {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const TryFrom<u32> for char {
     type Error = CharTryFromError;
 
     #[inline]
diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index 38381dbdf23..220a24caf09 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -216,6 +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_try", issue = "74935")]
 pub 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")]
@@ -367,6 +369,8 @@ 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_try", issue = "74935")]
 pub 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")]
@@ -710,9 +714,10 @@ pub trait TryFrom<T>: Sized {
 
 // As lifts over &
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: PointeeSized, U: PointeeSized> AsRef<U> for &T
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T: PointeeSized, U: PointeeSized> const AsRef<U> for &T
 where
-    T: AsRef<U>,
+    T: ~const AsRef<U>,
 {
     #[inline]
     fn as_ref(&self) -> &U {
@@ -722,9 +727,10 @@ where
 
 // As lifts over &mut
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: PointeeSized, U: PointeeSized> AsRef<U> for &mut T
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T: PointeeSized, U: PointeeSized> const AsRef<U> for &mut T
 where
-    T: AsRef<U>,
+    T: ~const AsRef<U>,
 {
     #[inline]
     fn as_ref(&self) -> &U {
@@ -742,9 +748,10 @@ where
 
 // AsMut lifts over &mut
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T: PointeeSized, U: PointeeSized> AsMut<U> for &mut T
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T: PointeeSized, U: PointeeSized> const AsMut<U> for &mut T
 where
-    T: AsMut<U>,
+    T: ~const AsMut<U>,
 {
     #[inline]
     fn as_mut(&mut self) -> &mut U {
@@ -840,7 +847,8 @@ where
 ////////////////////////////////////////////////////////////////////////////////
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> AsRef<[T]> for [T] {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const AsRef<[T]> for [T] {
     #[inline(always)]
     fn as_ref(&self) -> &[T] {
         self
@@ -848,7 +856,8 @@ impl<T> AsRef<[T]> for [T] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> AsMut<[T]> for [T] {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const AsMut<[T]> for [T] {
     #[inline(always)]
     fn as_mut(&mut self) -> &mut [T] {
         self
@@ -856,7 +865,8 @@ impl<T> AsMut<[T]> for [T] {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl AsRef<str> for str {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const AsRef<str> for str {
     #[inline(always)]
     fn as_ref(&self) -> &str {
         self
@@ -864,7 +874,8 @@ impl AsRef<str> for str {
 }
 
 #[stable(feature = "as_mut_str_for_str", since = "1.51.0")]
-impl AsMut<str> for str {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const AsMut<str> for str {
     #[inline(always)]
     fn as_mut(&mut self) -> &mut str {
         self
@@ -925,7 +936,8 @@ impl AsMut<str> for str {
 pub enum Infallible {}
 
 #[stable(feature = "convert_infallible", since = "1.34.0")]
-impl Clone for Infallible {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const Clone for Infallible {
     fn clone(&self) -> Infallible {
         match *self {}
     }
@@ -953,7 +965,8 @@ impl Error for Infallible {
 }
 
 #[stable(feature = "convert_infallible", since = "1.34.0")]
-impl PartialEq for Infallible {
+#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
+impl const PartialEq for Infallible {
     fn eq(&self, _: &Infallible) -> bool {
         match *self {}
     }
@@ -977,7 +990,8 @@ impl Ord for Infallible {
 }
 
 #[stable(feature = "convert_infallible", since = "1.34.0")]
-impl From<!> for Infallible {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<!> for Infallible {
     #[inline]
     fn from(x: !) -> Self {
         x
diff --git a/library/core/src/convert/num.rs b/library/core/src/convert/num.rs
index 50616732b77..affb4eb64d3 100644
--- a/library/core/src/convert/num.rs
+++ b/library/core/src/convert/num.rs
@@ -69,7 +69,8 @@ macro_rules! impl_from {
     };
     ($Small:ty => $Large:ty, #[$attr:meta], $doc:expr $(,)?) => {
         #[$attr]
-        impl From<$Small> for $Large {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const From<$Small> for $Large {
             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
             // Rustdocs on functions do not.
             #[doc = $doc]
@@ -200,7 +201,8 @@ macro_rules! impl_float_from_bool {
         )?
     ) => {
         #[stable(feature = "float_from_bool", since = "1.68.0")]
-        impl From<bool> for $float {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+            impl const From<bool> for $float {
             #[doc = concat!("Converts a [`bool`] to [`", stringify!($float),"`] losslessly.")]
             /// The resulting value is positive `0.0` for `false` and `1.0` for `true` values.
             ///
@@ -250,7 +252,8 @@ impl_float_from_bool!(
 macro_rules! impl_try_from_unbounded {
     ($source:ty => $($target:ty),+) => {$(
         #[stable(feature = "try_from", since = "1.34.0")]
-        impl TryFrom<$source> for $target {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
             /// Tries to create the target number type from a source
@@ -268,7 +271,8 @@ macro_rules! impl_try_from_unbounded {
 macro_rules! impl_try_from_lower_bounded {
     ($source:ty => $($target:ty),+) => {$(
         #[stable(feature = "try_from", since = "1.34.0")]
-        impl TryFrom<$source> for $target {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
             /// Tries to create the target number type from a source
@@ -290,7 +294,8 @@ macro_rules! impl_try_from_lower_bounded {
 macro_rules! impl_try_from_upper_bounded {
     ($source:ty => $($target:ty),+) => {$(
         #[stable(feature = "try_from", since = "1.34.0")]
-        impl TryFrom<$source> for $target {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
             /// Tries to create the target number type from a source
@@ -312,7 +317,8 @@ macro_rules! impl_try_from_upper_bounded {
 macro_rules! impl_try_from_both_bounded {
     ($source:ty => $($target:ty),+) => {$(
         #[stable(feature = "try_from", since = "1.34.0")]
-        impl TryFrom<$source> for $target {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const TryFrom<$source> for $target {
             type Error = TryFromIntError;
 
             /// Tries to create the target number type from a source
@@ -450,7 +456,8 @@ use crate::num::NonZero;
 macro_rules! impl_nonzero_int_from_nonzero_int {
     ($Small:ty => $Large:ty) => {
         #[stable(feature = "nz_int_conv", since = "1.41.0")]
-        impl From<NonZero<$Small>> for NonZero<$Large> {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const From<NonZero<$Small>> for NonZero<$Large> {
             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
             // Rustdocs on functions do not.
             #[doc = concat!("Converts <code>[NonZero]\\<[", stringify!($Small), "]></code> ")]
@@ -540,7 +547,8 @@ impl_nonzero_int_try_from_int!(isize);
 macro_rules! impl_nonzero_int_try_from_nonzero_int {
     ($source:ty => $($target:ty),+) => {$(
         #[stable(feature = "nzint_try_from_nzint_conv", since = "1.49.0")]
-        impl TryFrom<NonZero<$source>> for NonZero<$target> {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const TryFrom<NonZero<$source>> for NonZero<$target> {
             type Error = TryFromIntError;
 
             // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
diff --git a/library/core/src/net/ip_addr.rs b/library/core/src/net/ip_addr.rs
index aaa68e8d7d1..fef987153cb 100644
--- a/library/core/src/net/ip_addr.rs
+++ b/library/core/src/net/ip_addr.rs
@@ -1089,7 +1089,8 @@ impl fmt::Debug for IpAddr {
 }
 
 #[stable(feature = "ip_from_ip", since = "1.16.0")]
-impl From<Ipv4Addr> for IpAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Ipv4Addr> for IpAddr {
     /// Copies this address to a new `IpAddr::V4`.
     ///
     /// # Examples
@@ -1111,7 +1112,8 @@ impl From<Ipv4Addr> for IpAddr {
 }
 
 #[stable(feature = "ip_from_ip", since = "1.16.0")]
-impl From<Ipv6Addr> for IpAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Ipv6Addr> for IpAddr {
     /// Copies this address to a new `IpAddr::V6`.
     ///
     /// # Examples
@@ -1221,7 +1223,8 @@ impl Ord for Ipv4Addr {
 }
 
 #[stable(feature = "ip_u32", since = "1.1.0")]
-impl From<Ipv4Addr> for u32 {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Ipv4Addr> for u32 {
     /// Uses [`Ipv4Addr::to_bits`] to convert an IPv4 address to a host byte order `u32`.
     #[inline]
     fn from(ip: Ipv4Addr) -> u32 {
@@ -1230,7 +1233,8 @@ impl From<Ipv4Addr> for u32 {
 }
 
 #[stable(feature = "ip_u32", since = "1.1.0")]
-impl From<u32> for Ipv4Addr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<u32> for Ipv4Addr {
     /// Uses [`Ipv4Addr::from_bits`] to convert a host byte order `u32` into an IPv4 address.
     #[inline]
     fn from(ip: u32) -> Ipv4Addr {
@@ -1239,7 +1243,8 @@ impl From<u32> for Ipv4Addr {
 }
 
 #[stable(feature = "from_slice_v4", since = "1.9.0")]
-impl From<[u8; 4]> for Ipv4Addr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u8; 4]> for Ipv4Addr {
     /// Creates an `Ipv4Addr` from a four element byte array.
     ///
     /// # Examples
@@ -1257,7 +1262,8 @@ impl From<[u8; 4]> for Ipv4Addr {
 }
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
-impl From<[u8; 4]> for IpAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u8; 4]> for IpAddr {
     /// Creates an `IpAddr::V4` from a four element byte array.
     ///
     /// # Examples
@@ -2211,7 +2217,8 @@ impl Ord for Ipv6Addr {
 }
 
 #[stable(feature = "i128", since = "1.26.0")]
-impl From<Ipv6Addr> for u128 {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Ipv6Addr> for u128 {
     /// Uses [`Ipv6Addr::to_bits`] to convert an IPv6 address to a host byte order `u128`.
     #[inline]
     fn from(ip: Ipv6Addr) -> u128 {
@@ -2219,7 +2226,8 @@ impl From<Ipv6Addr> for u128 {
     }
 }
 #[stable(feature = "i128", since = "1.26.0")]
-impl From<u128> for Ipv6Addr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<u128> for Ipv6Addr {
     /// Uses [`Ipv6Addr::from_bits`] to convert a host byte order `u128` to an IPv6 address.
     #[inline]
     fn from(ip: u128) -> Ipv6Addr {
@@ -2228,7 +2236,8 @@ impl From<u128> for Ipv6Addr {
 }
 
 #[stable(feature = "ipv6_from_octets", since = "1.9.0")]
-impl From<[u8; 16]> for Ipv6Addr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u8; 16]> for Ipv6Addr {
     /// Creates an `Ipv6Addr` from a sixteen element byte array.
     ///
     /// # Examples
@@ -2255,7 +2264,8 @@ impl From<[u8; 16]> for Ipv6Addr {
 }
 
 #[stable(feature = "ipv6_from_segments", since = "1.16.0")]
-impl From<[u16; 8]> for Ipv6Addr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u16; 8]> for Ipv6Addr {
     /// Creates an `Ipv6Addr` from an eight element 16-bit array.
     ///
     /// # Examples
@@ -2283,7 +2293,8 @@ impl From<[u16; 8]> for Ipv6Addr {
 }
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
-impl From<[u8; 16]> for IpAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u8; 16]> for IpAddr {
     /// Creates an `IpAddr::V6` from a sixteen element byte array.
     ///
     /// # Examples
@@ -2310,7 +2321,8 @@ impl From<[u8; 16]> for IpAddr {
 }
 
 #[stable(feature = "ip_from_slice", since = "1.17.0")]
-impl From<[u16; 8]> for IpAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<[u16; 8]> for IpAddr {
     /// Creates an `IpAddr::V6` from an eight element 16-bit array.
     ///
     /// # Examples
diff --git a/library/core/src/net/socket_addr.rs b/library/core/src/net/socket_addr.rs
index 936f9f64930..69924199f99 100644
--- a/library/core/src/net/socket_addr.rs
+++ b/library/core/src/net/socket_addr.rs
@@ -592,7 +592,8 @@ impl SocketAddrV6 {
 }
 
 #[stable(feature = "ip_from_ip", since = "1.16.0")]
-impl From<SocketAddrV4> for SocketAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<SocketAddrV4> for SocketAddr {
     /// Converts a [`SocketAddrV4`] into a [`SocketAddr::V4`].
     #[inline]
     fn from(sock4: SocketAddrV4) -> SocketAddr {
@@ -601,7 +602,8 @@ impl From<SocketAddrV4> for SocketAddr {
 }
 
 #[stable(feature = "ip_from_ip", since = "1.16.0")]
-impl From<SocketAddrV6> for SocketAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<SocketAddrV6> for SocketAddr {
     /// Converts a [`SocketAddrV6`] into a [`SocketAddr::V6`].
     #[inline]
     fn from(sock6: SocketAddrV6) -> SocketAddr {
@@ -610,7 +612,8 @@ impl From<SocketAddrV6> for SocketAddr {
 }
 
 #[stable(feature = "addr_from_into_ip", since = "1.17.0")]
-impl<I: Into<IpAddr>> From<(I, u16)> for SocketAddr {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<I: ~const Into<IpAddr>> const From<(I, u16)> for SocketAddr {
     /// Converts a tuple struct (Into<[`IpAddr`]>, `u16`) into a [`SocketAddr`].
     ///
     /// This conversion creates a [`SocketAddr::V4`] for an [`IpAddr::V4`]
diff --git a/library/core/src/num/error.rs b/library/core/src/num/error.rs
index f9c4cdd0ebe..cfedd465cab 100644
--- a/library/core/src/num/error.rs
+++ b/library/core/src/num/error.rs
@@ -26,14 +26,16 @@ impl Error for TryFromIntError {
 }
 
 #[stable(feature = "try_from", since = "1.34.0")]
-impl From<Infallible> for TryFromIntError {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Infallible> for TryFromIntError {
     fn from(x: Infallible) -> TryFromIntError {
         match x {}
     }
 }
 
 #[unstable(feature = "never_type", issue = "35121")]
-impl From<!> for TryFromIntError {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<!> for TryFromIntError {
     #[inline]
     fn from(never: !) -> TryFromIntError {
         // Match rather than coerce to make sure that code like
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
index faa41ddf13c..acfe38b7a37 100644
--- a/library/core/src/num/mod.rs
+++ b/library/core/src/num/mod.rs
@@ -1378,7 +1378,8 @@ const fn from_ascii_radix_panic(radix: u32) -> ! {
 macro_rules! from_str_int_impl {
     ($signedness:ident $($int_ty:ty)+) => {$(
         #[stable(feature = "rust1", since = "1.0.0")]
-        impl FromStr for $int_ty {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const FromStr for $int_ty {
             type Err = ParseIntError;
 
             /// Parses an integer from a string slice with decimal digits.
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index b8900c4113a..f793602de50 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -297,7 +297,8 @@ where
 }
 
 #[stable(feature = "from_nonzero", since = "1.31.0")]
-impl<T> From<NonZero<T>> for T
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const From<NonZero<T>> for T
 where
     T: ZeroablePrimitive,
 {
diff --git a/library/core/src/ops/try_trait.rs b/library/core/src/ops/try_trait.rs
index aebbddb4f1c..a889c824be5 100644
--- a/library/core/src/ops/try_trait.rs
+++ b/library/core/src/ops/try_trait.rs
@@ -128,7 +128,9 @@ use crate::ops::ControlFlow;
 )]
 #[doc(alias = "?")]
 #[lang = "Try"]
-pub trait Try: FromResidual {
+#[const_trait]
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+pub 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;
@@ -304,6 +306,8 @@ pub trait Try: 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> {
     /// Constructs the type from a compatible `Residual` type.
     ///
@@ -357,6 +361,8 @@ 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> {
     /// The "return" type of this meta-function.
     #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 8036c59e893..7f8c30b95b2 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -2144,9 +2144,12 @@ const fn expect_failed(msg: &str) -> ! {
 /////////////////////////////////////////////////////////////////////////////
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Clone for Option<T>
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const Clone for Option<T>
 where
-    T: Clone,
+    // 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,
 {
     #[inline]
     fn clone(&self) -> Self {
@@ -2230,7 +2233,8 @@ impl<'a, T> IntoIterator for &'a mut Option<T> {
 }
 
 #[stable(since = "1.12.0", feature = "option_from")]
-impl<T> From<T> for Option<T> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const From<T> for Option<T> {
     /// Moves `val` into a new [`Some`].
     ///
     /// # Examples
@@ -2246,7 +2250,8 @@ impl<T> From<T> for Option<T> {
 }
 
 #[stable(feature = "option_ref_from_ref_option", since = "1.30.0")]
-impl<'a, T> From<&'a Option<T>> for Option<&'a T> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<'a, T> const From<&'a Option<T>> for Option<&'a T> {
     /// Converts from `&Option<T>` to `Option<&T>`.
     ///
     /// # Examples
@@ -2273,7 +2278,8 @@ impl<'a, T> From<&'a Option<T>> for Option<&'a T> {
 }
 
 #[stable(feature = "option_ref_from_ref_option", since = "1.30.0")]
-impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<'a, T> const From<&'a mut Option<T>> for Option<&'a mut T> {
     /// Converts from `&mut Option<T>` to `Option<&mut T>`
     ///
     /// # Examples
@@ -2593,7 +2599,8 @@ impl<A, V: FromIterator<A>> FromIterator<Option<A>> for Option<V> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
-impl<T> ops::Try for Option<T> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const ops::Try for Option<T> {
     type Output = T;
     type Residual = Option<convert::Infallible>;
 
@@ -2612,9 +2619,10 @@ impl<T> ops::Try for Option<T> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
 // Note: manually specifying the residual type instead of using the default to work around
 // https://github.com/rust-lang/rust/issues/99940
-impl<T> ops::FromResidual<Option<convert::Infallible>> for Option<T> {
+impl<T> const ops::FromResidual<Option<convert::Infallible>> for Option<T> {
     #[inline]
     fn from_residual(residual: Option<convert::Infallible>) -> Self {
         match residual {
@@ -2625,7 +2633,8 @@ impl<T> ops::FromResidual<Option<convert::Infallible>> for Option<T> {
 
 #[diagnostic::do_not_recommend]
 #[unstable(feature = "try_trait_v2_yeet", issue = "96374")]
-impl<T> ops::FromResidual<ops::Yeet<()>> for Option<T> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const ops::FromResidual<ops::Yeet<()>> for Option<T> {
     #[inline]
     fn from_residual(ops::Yeet(()): ops::Yeet<()>) -> Self {
         None
@@ -2633,7 +2642,8 @@ impl<T> ops::FromResidual<ops::Yeet<()>> for Option<T> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T> ops::Residual<T> for Option<convert::Infallible> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T> const ops::Residual<T> for Option<convert::Infallible> {
     type TryType = Option<T>;
 }
 
diff --git a/library/core/src/ptr/alignment.rs b/library/core/src/ptr/alignment.rs
index 6d473a4bd56..bd5b4e21baa 100644
--- a/library/core/src/ptr/alignment.rs
+++ b/library/core/src/ptr/alignment.rs
@@ -189,7 +189,8 @@ impl TryFrom<usize> for Alignment {
 }
 
 #[unstable(feature = "ptr_alignment_type", issue = "102070")]
-impl From<Alignment> for NonZero<usize> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Alignment> for NonZero<usize> {
     #[inline]
     fn from(align: Alignment) -> NonZero<usize> {
         align.as_nonzero()
@@ -197,7 +198,8 @@ impl From<Alignment> for NonZero<usize> {
 }
 
 #[unstable(feature = "ptr_alignment_type", issue = "102070")]
-impl From<Alignment> for usize {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<Alignment> for usize {
     #[inline]
     fn from(align: Alignment) -> usize {
         align.as_usize()
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 7f3f2964985..f65257ff59b 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -1288,9 +1288,11 @@ impl<T, E> Result<T, E> {
     /// ```
     #[unstable(feature = "unwrap_infallible", reason = "newly added", issue = "61695")]
     #[inline]
-    pub fn into_ok(self) -> T
+    #[rustc_allow_const_fn_unstable(const_precise_live_drops)]
+    #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+    pub const fn into_ok(self) -> T
     where
-        E: Into<!>,
+        E: ~const Into<!>,
     {
         match self {
             Ok(x) => x,
@@ -1323,9 +1325,11 @@ impl<T, E> Result<T, E> {
     /// ```
     #[unstable(feature = "unwrap_infallible", reason = "newly added", issue = "61695")]
     #[inline]
-    pub fn into_err(self) -> E
+    #[rustc_allow_const_fn_unstable(const_precise_live_drops)]
+    #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+    pub const fn into_err(self) -> E
     where
-        T: Into<!>,
+        T: ~const Into<!>,
     {
         match self {
             Ok(x) => x.into(),
@@ -2052,7 +2056,8 @@ impl<A, E, V: FromIterator<A>> FromIterator<Result<A, E>> for Result<V, E> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
-impl<T, E> ops::Try for Result<T, E> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E> const ops::Try for Result<T, E> {
     type Output = T;
     type Residual = Result<convert::Infallible, E>;
 
@@ -2071,7 +2076,10 @@ impl<T, E> ops::Try for Result<T, E> {
 }
 
 #[unstable(feature = "try_trait_v2", issue = "84277", old_name = "try_trait")]
-impl<T, E, F: From<E>> ops::FromResidual<Result<convert::Infallible, E>> for Result<T, F> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E, F: ~const From<E>> const ops::FromResidual<Result<convert::Infallible, E>>
+    for Result<T, F>
+{
     #[inline]
     #[track_caller]
     fn from_residual(residual: Result<convert::Infallible, E>) -> Self {
@@ -2082,7 +2090,8 @@ impl<T, E, F: From<E>> ops::FromResidual<Result<convert::Infallible, E>> for Res
 }
 #[diagnostic::do_not_recommend]
 #[unstable(feature = "try_trait_v2_yeet", issue = "96374")]
-impl<T, E, F: From<E>> ops::FromResidual<ops::Yeet<E>> for Result<T, F> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E, F: ~const From<E>> const ops::FromResidual<ops::Yeet<E>> for Result<T, F> {
     #[inline]
     fn from_residual(ops::Yeet(e): ops::Yeet<E>) -> Self {
         Err(From::from(e))
@@ -2090,6 +2099,7 @@ impl<T, E, F: From<E>> ops::FromResidual<ops::Yeet<E>> for Result<T, F> {
 }
 
 #[unstable(feature = "try_trait_v2_residual", issue = "91285")]
-impl<T, E> ops::Residual<T> for Result<convert::Infallible, E> {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl<T, E> const ops::Residual<T> for Result<convert::Infallible, E> {
     type TryType = Result<T, E>;
 }
diff --git a/library/core/src/str/traits.rs b/library/core/src/str/traits.rs
index d0f2b9226bf..1597d1c1fa8 100644
--- a/library/core/src/str/traits.rs
+++ b/library/core/src/str/traits.rs
@@ -825,6 +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_try", issue = "74935")]
 pub trait FromStr: Sized {
     /// The associated error which can be returned from parsing.
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/src/sync/atomic.rs b/library/core/src/sync/atomic.rs
index 04c8d1473b0..546f3d91a80 100644
--- a/library/core/src/sync/atomic.rs
+++ b/library/core/src/sync/atomic.rs
@@ -2518,7 +2518,8 @@ impl<T> AtomicPtr<T> {
 
 #[cfg(target_has_atomic_load_store = "8")]
 #[stable(feature = "atomic_bool_from", since = "1.24.0")]
-impl From<bool> for AtomicBool {
+#[rustc_const_unstable(feature = "const_try", issue = "74935")]
+impl const From<bool> for AtomicBool {
     /// Converts a `bool` into an `AtomicBool`.
     ///
     /// # Examples
@@ -2615,7 +2616,8 @@ macro_rules! atomic_int {
         }
 
         #[$stable_from]
-        impl From<$int_type> for $atomic_type {
+        #[rustc_const_unstable(feature = "const_try", issue = "74935")]
+        impl const From<$int_type> for $atomic_type {
             #[doc = concat!("Converts an `", stringify!($int_type), "` into an `", stringify!($atomic_type), "`.")]
             #[inline]
             fn from(v: $int_type) -> Self { Self::new(v) }
diff --git a/tests/ui/consts/const-try-feature-gate.rs b/tests/ui/consts/const-try-feature-gate.rs
index 09985079e8e..4a98185a18a 100644
--- a/tests/ui/consts/const-try-feature-gate.rs
+++ b/tests/ui/consts/const-try-feature-gate.rs
@@ -4,6 +4,8 @@ const fn t() -> Option<()> {
     Some(())?;
     //~^ ERROR `?` is not allowed
     //~| ERROR `?` is not allowed
+    //~| ERROR `Try` is not yet stable as a const trait
+    //~| ERROR `FromResidual` is not yet stable as a const trait
     None
 }
 
diff --git a/tests/ui/consts/const-try-feature-gate.stderr b/tests/ui/consts/const-try-feature-gate.stderr
index 0ad19d05b38..62a4a5fba4f 100644
--- a/tests/ui/consts/const-try-feature-gate.stderr
+++ b/tests/ui/consts/const-try-feature-gate.stderr
@@ -1,19 +1,47 @@
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
+error[E0658]: `?` is not allowed on `Option<()>` in constant functions
   --> $DIR/const-try-feature-gate.rs:4:5
    |
 LL |     Some(())?;
    |     ^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = note: see issue #143874 <https://github.com/rust-lang/rust/issues/143874> for more information
+   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
+error: `Try` is not yet stable as a const trait
+  --> $DIR/const-try-feature-gate.rs:4:5
+   |
+LL |     Some(())?;
+   |     ^^^^^^^^^
+   |
+help: add `#![feature(const_try)]` to the crate attributes to enable
+   |
+LL + #![feature(const_try)]
+   |
+
+error[E0658]: `?` is not allowed on `Option<()>` in constant functions
   --> $DIR/const-try-feature-gate.rs:4:5
    |
 LL |     Some(())?;
    |     ^^^^^^^^^
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+   = note: see issue #143874 <https://github.com/rust-lang/rust/issues/143874> for more information
+   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: `FromResidual` is not yet stable as a const trait
+  --> $DIR/const-try-feature-gate.rs:4:5
+   |
+LL |     Some(())?;
+   |     ^^^^^^^^^
+   |
+help: add `#![feature(const_try)]` to the crate attributes to enable
+   |
+LL + #![feature(const_try)]
+   |
 
-error: aborting due to 2 previous errors
+error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/consts/const-try.rs b/tests/ui/consts/const-try.rs
index e13fad78441..152400d702e 100644
--- a/tests/ui/consts/const-try.rs
+++ b/tests/ui/consts/const-try.rs
@@ -1,4 +1,6 @@
-//@ compile-flags: -Znext-solver
+//@ check-pass
+//@ revisions: current next
+//@[next] compile-flags: -Znext-solver
 
 // Demonstrates what's needed to make use of `?` in const contexts.
 
@@ -13,14 +15,12 @@ struct TryMe;
 struct Error;
 
 impl const FromResidual<Error> for TryMe {
-    //~^ ERROR const `impl` for trait `FromResidual` which is not `const`
     fn from_residual(residual: Error) -> Self {
         TryMe
     }
 }
 
 impl const Try for TryMe {
-    //~^ ERROR const `impl` for trait `Try` which is not `const`
     type Output = ();
     type Residual = Error;
     fn from_output(output: Self::Output) -> Self {
@@ -33,8 +33,6 @@ impl const Try for TryMe {
 
 const fn t() -> TryMe {
     TryMe?;
-    //~^ ERROR `?` is not allowed on
-    //~| ERROR `?` is not allowed on
     TryMe
 }
 
diff --git a/tests/ui/consts/const-try.stderr b/tests/ui/consts/const-try.stderr
deleted file mode 100644
index 7004ea3e6db..00000000000
--- a/tests/ui/consts/const-try.stderr
+++ /dev/null
@@ -1,37 +0,0 @@
-error: const `impl` for trait `FromResidual` which is not `const`
-  --> $DIR/const-try.rs:15:12
-   |
-LL | impl const FromResidual<Error> for TryMe {
-   |            ^^^^^^^^^^^^^^^^^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
-error: const `impl` for trait `Try` which is not `const`
-  --> $DIR/const-try.rs:22:12
-   |
-LL | impl const Try for TryMe {
-   |            ^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
-error[E0015]: `?` is not allowed on `TryMe` in constant functions
-  --> $DIR/const-try.rs:35:5
-   |
-LL |     TryMe?;
-   |     ^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `TryMe` in constant functions
-  --> $DIR/const-try.rs:35:5
-   |
-LL |     TryMe?;
-   |     ^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0015`.
diff --git a/tests/ui/consts/control-flow/try.rs b/tests/ui/consts/control-flow/try.rs
index 67083e1a39b..6d762f9194e 100644
--- a/tests/ui/consts/control-flow/try.rs
+++ b/tests/ui/consts/control-flow/try.rs
@@ -1,11 +1,12 @@
-// The `?` operator is still not const-evaluatable because it calls `From::from` on the error
-// variant.
+//@ check-pass
+
+#![allow(dead_code)]
+#![feature(const_trait_impl)]
+#![feature(const_try)]
 
 const fn opt() -> Option<i32> {
     let x = Some(2);
     x?;
-    //~^ ERROR: `?` is not allowed
-    //~| ERROR: `?` is not allowed
     None
 }
 
diff --git a/tests/ui/consts/control-flow/try.stderr b/tests/ui/consts/control-flow/try.stderr
deleted file mode 100644
index 62a3e3ce6bc..00000000000
--- a/tests/ui/consts/control-flow/try.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0015]: `?` is not allowed on `Option<i32>` in constant functions
-  --> $DIR/try.rs:6:5
-   |
-LL |     x?;
-   |     ^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `Option<i32>` in constant functions
-  --> $DIR/try.rs:6:5
-   |
-LL |     x?;
-   |     ^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0015`.
diff --git a/tests/ui/consts/try-operator.rs b/tests/ui/consts/try-operator.rs
index 352dbeefa8a..59d9fcb1cbd 100644
--- a/tests/ui/consts/try-operator.rs
+++ b/tests/ui/consts/try-operator.rs
@@ -1,9 +1,8 @@
-//@ known-bug: #110395
+//@ run-pass
 
 #![feature(try_trait_v2)]
 #![feature(const_trait_impl)]
 #![feature(const_try)]
-#![feature(const_convert)]
 
 fn main() {
     const fn result() -> Result<bool, ()> {
diff --git a/tests/ui/consts/try-operator.stderr b/tests/ui/consts/try-operator.stderr
deleted file mode 100644
index fc37039d260..00000000000
--- a/tests/ui/consts/try-operator.stderr
+++ /dev/null
@@ -1,42 +0,0 @@
-error[E0635]: unknown feature `const_convert`
-  --> $DIR/try-operator.rs:6:12
-   |
-LL | #![feature(const_convert)]
-   |            ^^^^^^^^^^^^^
-
-error[E0015]: `?` is not allowed on `Result<(), ()>` in constant functions
-  --> $DIR/try-operator.rs:10:9
-   |
-LL |         Err(())?;
-   |         ^^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `Result<bool, ()>` in constant functions
-  --> $DIR/try-operator.rs:10:9
-   |
-LL |         Err(())?;
-   |         ^^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
-  --> $DIR/try-operator.rs:18:9
-   |
-LL |         None?;
-   |         ^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
-  --> $DIR/try-operator.rs:18:9
-   |
-LL |         None?;
-   |         ^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 5 previous errors
-
-Some errors have detailed explanations: E0015, E0635.
-For more information about an error, try `rustc --explain E0015`.
diff --git a/tests/ui/traits/const-traits/hir-const-check.rs b/tests/ui/traits/const-traits/hir-const-check.rs
index c485fb12184..1b6fa1afab9 100644
--- a/tests/ui/traits/const-traits/hir-const-check.rs
+++ b/tests/ui/traits/const-traits/hir-const-check.rs
@@ -1,8 +1,10 @@
+//@ check-pass
 //@ compile-flags: -Znext-solver
 
 // Regression test for #69615.
 
 #![feature(const_trait_impl)]
+#![feature(const_try)]
 
 #[const_trait]
 pub trait MyTrait {
@@ -12,8 +14,6 @@ pub trait MyTrait {
 impl const MyTrait for () {
     fn method(&self) -> Option<()> {
         Some(())?;
-        //~^ ERROR `?` is not allowed on
-        //~| ERROR `?` is not allowed on
         None
     }
 }
diff --git a/tests/ui/traits/const-traits/hir-const-check.stderr b/tests/ui/traits/const-traits/hir-const-check.stderr
deleted file mode 100644
index d66a7ea3144..00000000000
--- a/tests/ui/traits/const-traits/hir-const-check.stderr
+++ /dev/null
@@ -1,19 +0,0 @@
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
-  --> $DIR/hir-const-check.rs:14:9
-   |
-LL |         Some(())?;
-   |         ^^^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `Option<()>` in constant functions
-  --> $DIR/hir-const-check.rs:14:9
-   |
-LL |         Some(())?;
-   |         ^^^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0015`.
diff --git a/tests/ui/traits/const-traits/ice-119717-constant-lifetime.rs b/tests/ui/traits/const-traits/ice-119717-constant-lifetime.rs
index 47c85980aca..af552ac0c5e 100644
--- a/tests/ui/traits/const-traits/ice-119717-constant-lifetime.rs
+++ b/tests/ui/traits/const-traits/ice-119717-constant-lifetime.rs
@@ -1,11 +1,10 @@
 #![allow(incomplete_features)]
-#![feature(const_trait_impl, try_trait_v2)]
+#![feature(const_trait_impl, const_try, try_trait_v2)]
 
 use std::ops::FromResidual;
 
 impl<T> const FromResidual for T {
-    //~^ ERROR const `impl` for trait `FromResidual` which is not `const`
-    //~| ERROR type parameter `T` must be used as the type parameter for some local type
+    //~^ ERROR type parameter `T` must be used as the type parameter for some local type
     fn from_residual(t: T) -> _ {
         //~^ ERROR the placeholder `_` is not allowed
         t
diff --git a/tests/ui/traits/const-traits/ice-119717-constant-lifetime.stderr b/tests/ui/traits/const-traits/ice-119717-constant-lifetime.stderr
index 5c5fba95f02..08fc73fe77b 100644
--- a/tests/ui/traits/const-traits/ice-119717-constant-lifetime.stderr
+++ b/tests/ui/traits/const-traits/ice-119717-constant-lifetime.stderr
@@ -1,12 +1,3 @@
-error: const `impl` for trait `FromResidual` which is not `const`
-  --> $DIR/ice-119717-constant-lifetime.rs:6:15
-   |
-LL | impl<T> const FromResidual for T {
-   |               ^^^^^^^^^^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
 error[E0210]: type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
   --> $DIR/ice-119717-constant-lifetime.rs:6:6
    |
@@ -17,7 +8,7 @@ LL | impl<T> const FromResidual for T {
    = note: only traits defined in the current crate can be implemented for a type parameter
 
 error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated functions
-  --> $DIR/ice-119717-constant-lifetime.rs:9:31
+  --> $DIR/ice-119717-constant-lifetime.rs:8:31
    |
 LL |     fn from_residual(t: T) -> _ {
    |                               ^ not allowed in type signatures
@@ -28,7 +19,7 @@ LL -     fn from_residual(t: T) -> _ {
 LL +     fn from_residual(t: T) -> T {
    |
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
 Some errors have detailed explanations: E0121, E0210.
 For more information about an error, try `rustc --explain E0121`.
diff --git a/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.rs b/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.rs
index 5e368b9e6a9..bfce9dc9c73 100644
--- a/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.rs
+++ b/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.rs
@@ -6,20 +6,16 @@ struct TryMe;
 struct Error;
 
 impl const FromResidual<Error> for TryMe {}
-//~^ ERROR const `impl` for trait `FromResidual` which is not `const`
-//~| ERROR not all trait items implemented
+//~^ ERROR not all trait items implemented
 
 impl const Try for TryMe {
-    //~^ ERROR const `impl` for trait `Try` which is not `const`
-    //~| ERROR not all trait items implemented
+    //~^ ERROR not all trait items implemented
     type Output = ();
     type Residual = Error;
 }
 
 const fn t() -> TryMe {
     TryMe?;
-    //~^ ERROR `?` is not allowed on
-    //~| ERROR `?` is not allowed on
     TryMe
 }
 
diff --git a/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.stderr b/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.stderr
index 849d6522cd6..183203aa8ba 100644
--- a/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.stderr
+++ b/tests/ui/traits/const-traits/ice-126148-failed-to-normalize.stderr
@@ -1,12 +1,3 @@
-error: const `impl` for trait `FromResidual` which is not `const`
-  --> $DIR/ice-126148-failed-to-normalize.rs:8:12
-   |
-LL | impl const FromResidual<Error> for TryMe {}
-   |            ^^^^^^^^^^^^^^^^^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
 error[E0046]: not all trait items implemented, missing: `from_residual`
   --> $DIR/ice-126148-failed-to-normalize.rs:8:1
    |
@@ -15,17 +6,8 @@ LL | impl const FromResidual<Error> for TryMe {}
    |
    = help: implement the missing item: `fn from_residual(_: Error) -> Self { todo!() }`
 
-error: const `impl` for trait `Try` which is not `const`
-  --> $DIR/ice-126148-failed-to-normalize.rs:12:12
-   |
-LL | impl const Try for TryMe {
-   |            ^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
 error[E0046]: not all trait items implemented, missing: `from_output`, `branch`
-  --> $DIR/ice-126148-failed-to-normalize.rs:12:1
+  --> $DIR/ice-126148-failed-to-normalize.rs:11:1
    |
 LL | impl const Try for TryMe {
    | ^^^^^^^^^^^^^^^^^^^^^^^^ missing `from_output`, `branch` in implementation
@@ -33,23 +15,6 @@ LL | impl const Try for TryMe {
    = help: implement the missing item: `fn from_output(_: <Self as Try>::Output) -> Self { todo!() }`
    = help: implement the missing item: `fn branch(self) -> ControlFlow<<Self as Try>::Residual, <Self as Try>::Output> { todo!() }`
 
-error[E0015]: `?` is not allowed on `TryMe` in constant functions
-  --> $DIR/ice-126148-failed-to-normalize.rs:20:5
-   |
-LL |     TryMe?;
-   |     ^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `TryMe` in constant functions
-  --> $DIR/ice-126148-failed-to-normalize.rs:20:5
-   |
-LL |     TryMe?;
-   |     ^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 6 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0015, E0046.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0046`.
diff --git a/tests/ui/traits/const-traits/trait-default-body-stability.rs b/tests/ui/traits/const-traits/trait-default-body-stability.rs
index 567f1b3c284..a8157d37ce3 100644
--- a/tests/ui/traits/const-traits/trait-default-body-stability.rs
+++ b/tests/ui/traits/const-traits/trait-default-body-stability.rs
@@ -1,4 +1,4 @@
-//@ known-bug: #110395
+//@ check-pass
 //@ compile-flags: -Znext-solver
 #![allow(incomplete_features)]
 #![feature(staged_api)]
diff --git a/tests/ui/traits/const-traits/trait-default-body-stability.stderr b/tests/ui/traits/const-traits/trait-default-body-stability.stderr
deleted file mode 100644
index b995d6f4f3d..00000000000
--- a/tests/ui/traits/const-traits/trait-default-body-stability.stderr
+++ /dev/null
@@ -1,37 +0,0 @@
-error: const `impl` for trait `Try` which is not `const`
-  --> $DIR/trait-default-body-stability.rs:19:12
-   |
-LL | impl const Try for T {
-   |            ^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
-error: const `impl` for trait `FromResidual` which is not `const`
-  --> $DIR/trait-default-body-stability.rs:34:12
-   |
-LL | impl const FromResidual for T {
-   |            ^^^^^^^^^^^^ this trait is not `const`
-   |
-   = note: marking a trait with `const` ensures all default method bodies are `const`
-   = note: adding a non-const method body in the future would be a breaking change
-
-error[E0015]: `?` is not allowed on `T` in constant functions
-  --> $DIR/trait-default-body-stability.rs:46:9
-   |
-LL |         T?
-   |         ^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error[E0015]: `?` is not allowed on `T` in constant functions
-  --> $DIR/trait-default-body-stability.rs:46:9
-   |
-LL |         T?
-   |         ^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0015`.