Auto merge of #100982 - fee1-dead-contrib:const-impl-requires-const-trait, r=oli-obk

Require `#[const_trait]` on `Trait` for `impl const Trait`

r? `@oli-obk`

54 files changed, 248 insertions, 174 deletions

diff --git a/src/test/ui/const-generics/const_trait_fn-issue-88433.rs b/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
index 8724fa69825..6e04cfaec31 100644
--- a/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
+++ b/src/test/ui/const-generics/const_trait_fn-issue-88433.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Func<T> {
     type Output;
 
diff --git a/src/test/ui/const-generics/issue-93647.rs b/src/test/ui/const-generics/issue-93647.rs
index c1a6bf6e34d..806540e1775 100644
--- a/src/test/ui/const-generics/issue-93647.rs
+++ b/src/test/ui/const-generics/issue-93647.rs
@@ -1,6 +1,6 @@
 struct X<const N: usize = {
     (||1usize)()
-    //~^ ERROR cannot call
+    //~^ ERROR cannot call non-const closure
 }>;
 
 fn main() {}
diff --git a/src/test/ui/const-generics/issues/issue-88119.rs b/src/test/ui/const-generics/issues/issue-88119.rs
index 70dfa7f708b..647b0eea86d 100644
--- a/src/test/ui/const-generics/issues/issue-88119.rs
+++ b/src/test/ui/const-generics/issues/issue-88119.rs
@@ -3,6 +3,7 @@
 #![allow(incomplete_features)]
 #![feature(const_trait_impl, generic_const_exprs)]
 
+#[const_trait]
 trait ConstName {
     const NAME_BYTES: &'static [u8];
 }
diff --git a/src/test/ui/const-generics/issues/issue-98629.rs b/src/test/ui/const-generics/issues/issue-98629.rs
index fc8666bbcdb..1d2d3012a6e 100644
--- a/src/test/ui/const-generics/issues/issue-98629.rs
+++ b/src/test/ui/const-generics/issues/issue-98629.rs
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Trait {
     const N: usize;
 }
diff --git a/src/test/ui/const-generics/issues/issue-98629.stderr b/src/test/ui/const-generics/issues/issue-98629.stderr
index 53570220882..4a248be76a9 100644
--- a/src/test/ui/const-generics/issues/issue-98629.stderr
+++ b/src/test/ui/const-generics/issues/issue-98629.stderr
@@ -1,5 +1,5 @@
 error[E0046]: not all trait items implemented, missing: `N`
-  --> $DIR/issue-98629.rs:7:1
+  --> $DIR/issue-98629.rs:8:1
    |
 LL |     const N: usize;
    |     -------------- `N` from trait
diff --git a/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr b/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
index 0e6be6d01ed..c685922c456 100644
--- a/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-overflow-3b.stderr
@@ -4,13 +4,13 @@ error[E0308]: mismatched types
 LL |     = [0; (i8::MAX + 1u8) as usize];
    |                      ^^^ expected `i8`, found `u8`
 
-error[E0277]: cannot add `u8` to `i8`
+error[E0277]: cannot add `u8` to `i8` in const contexts
   --> $DIR/const-eval-overflow-3b.rs:16:20
    |
 LL |     = [0; (i8::MAX + 1u8) as usize];
    |                    ^ no implementation for `i8 + u8`
    |
-   = help: the trait `Add<u8>` is not implemented for `i8`
+   = help: the trait `~const Add<u8>` is not implemented for `i8`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
index 4fa017e04e9..b396079240a 100644
--- a/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
+++ b/src/test/ui/consts/const-eval/const-eval-overflow-4b.stderr
@@ -4,13 +4,13 @@ error[E0308]: mismatched types
 LL |     : [u32; (i8::MAX as i8 + 1u8) as usize]
    |                              ^^^ expected `i8`, found `u8`
 
-error[E0277]: cannot add `u8` to `i8`
+error[E0277]: cannot add `u8` to `i8` in const contexts
   --> $DIR/const-eval-overflow-4b.rs:9:28
    |
 LL |     : [u32; (i8::MAX as i8 + 1u8) as usize]
    |                            ^ no implementation for `i8 + u8`
    |
-   = help: the trait `Add<u8>` is not implemented for `i8`
+   = help: the trait `~const Add<u8>` is not implemented for `i8`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/consts/const-fn-error.rs b/src/test/ui/consts/const-fn-error.rs
index abe68c17a0d..50b7ce1f8c0 100644
--- a/src/test/ui/consts/const-fn-error.rs
+++ b/src/test/ui/consts/const-fn-error.rs
@@ -3,10 +3,10 @@ const X : usize = 2;
 const fn f(x: usize) -> usize {
     let mut sum = 0;
     for i in 0..x {
-        //~^ ERROR mutable references
-        //~| ERROR cannot convert
-        //~| ERROR cannot call non-const fn
+        //~^ ERROR cannot convert
         //~| ERROR `for` is not allowed in a `const fn`
+        //~| ERROR mutable references are not allowed in constant functions
+        //~| ERROR cannot call non-const fn
         sum += i;
     }
     sum
diff --git a/src/test/ui/consts/const-for.rs b/src/test/ui/consts/const-for.rs
index 58bcb5f74cc..8db24853558 100644
--- a/src/test/ui/consts/const-for.rs
+++ b/src/test/ui/consts/const-for.rs
@@ -3,8 +3,8 @@
 
 const _: () = {
     for _ in 0..5 {}
-    //~^ error: cannot convert
-    //~| error: cannot call non-const fn
+    //~^ error: cannot call
+    //~| error: cannot convert
 };
 
 fn main() {}
diff --git a/src/test/ui/consts/issue-56164.rs b/src/test/ui/consts/issue-56164.rs
index 094ca377e03..fd02d215480 100644
--- a/src/test/ui/consts/issue-56164.rs
+++ b/src/test/ui/consts/issue-56164.rs
@@ -1,11 +1,11 @@
 const fn foo() { (||{})() }
 //~^ ERROR cannot call non-const closure
-//~| ERROR erroneous constant used [const_err]
-//~| WARNING this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+//~| ERROR erroneous constant
+//~| WARN this was previously accepted
 
 const fn bad(input: fn()) {
     input()
-    //~^ ERROR function pointer
+    //~^ ERROR function pointer calls are not allowed
 }
 
 fn main() {
diff --git a/src/test/ui/consts/issue-94675.rs b/src/test/ui/consts/issue-94675.rs
index 0604aab3bcd..ce21ebdb9ac 100644
--- a/src/test/ui/consts/issue-94675.rs
+++ b/src/test/ui/consts/issue-94675.rs
@@ -7,9 +7,8 @@ struct Foo<'a> {
 impl<'a> Foo<'a> {
     const fn spam(&mut self, baz: &mut Vec<u32>) {
         self.bar[0] = baz.len();
-        //~^ ERROR cannot call non-const fn `Vec::<u32>::len` in constant functions
-        //~| ERROR the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
-        //~| ERROR cannot call non-const operator in constant functions
+        //~^ the trait bound `Vec<usize>: ~const Index<_>` is not satisfied
+        //~| the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
     }
 }
 
diff --git a/src/test/ui/consts/issue-94675.stderr b/src/test/ui/consts/issue-94675.stderr
index 6665e42835b..7ae293ffbf8 100644
--- a/src/test/ui/consts/issue-94675.stderr
+++ b/src/test/ui/consts/issue-94675.stderr
@@ -1,10 +1,15 @@
-error[E0015]: cannot call non-const fn `Vec::<u32>::len` in constant functions
-  --> $DIR/issue-94675.rs:9:27
+error[E0277]: the trait bound `Vec<usize>: ~const Index<_>` is not satisfied
+  --> $DIR/issue-94675.rs:9:9
    |
 LL |         self.bar[0] = baz.len();
-   |                           ^^^^^
+   |         ^^^^^^^^^^^ vector indices are of type `usize` or ranges of `usize`
+   |
+   = help: the trait `~const Index<_>` is not implemented for `Vec<usize>`
+note: the trait `Index<_>` is implemented for `Vec<usize>`, but that implementation is not `const`
+  --> $DIR/issue-94675.rs:9:9
    |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+LL |         self.bar[0] = baz.len();
+   |         ^^^^^^^^^^^
 
 error[E0277]: the trait bound `Vec<usize>: ~const IndexMut<usize>` is not satisfied
   --> $DIR/issue-94675.rs:9:9
@@ -18,21 +23,11 @@ note: the trait `IndexMut<usize>` is implemented for `Vec<usize>`, but that impl
    |
 LL |         self.bar[0] = baz.len();
    |         ^^^^^^^^^^^
-
-error[E0015]: cannot call non-const operator in constant functions
-  --> $DIR/issue-94675.rs:9:9
-   |
-LL |         self.bar[0] = baz.len();
-   |         ^^^^^^^^^^^
-   |
-note: impl defined here, but it is not `const`
-  --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
-LL | impl<T, I: SliceIndex<[T]>, A: Allocator> IndexMut<I> for Vec<T, A> {
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+LL | impl<'a> Foo<'a> where Vec<usize>: ~const IndexMut<usize> {
+   |                  ++++++++++++++++++++++++++++++++++++++++
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0015, E0277.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/consts/unstable-const-fn-in-libcore.rs b/src/test/ui/consts/unstable-const-fn-in-libcore.rs
index 16b36c8d56d..b9e7e1405f9 100644
--- a/src/test/ui/consts/unstable-const-fn-in-libcore.rs
+++ b/src/test/ui/consts/unstable-const-fn-in-libcore.rs
@@ -4,7 +4,7 @@
 // gate was not enabled in libcore.
 
 #![stable(feature = "core", since = "1.6.0")]
-#![feature(staged_api)]
+#![feature(staged_api, const_trait_impl)]
 
 enum Opt<T> {
     Some(T),
@@ -14,12 +14,12 @@ enum Opt<T> {
 impl<T> Opt<T> {
     #[rustc_const_unstable(feature = "foo", issue = "none")]
     #[stable(feature = "rust1", since = "1.0.0")]
-    const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
+    const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
     //~^ ERROR destructors cannot be evaluated at compile-time
     //~| ERROR destructors cannot be evaluated at compile-time
         match self {
             Opt::Some(t) => t,
-            Opt::None => f(), //~ ERROR E0015
+            Opt::None => f(),
         }
     }
 }
diff --git a/src/test/ui/consts/unstable-const-fn-in-libcore.stderr b/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
index 180f9f10cc6..fee74bd0a6c 100644
--- a/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
+++ b/src/test/ui/consts/unstable-const-fn-in-libcore.stderr
@@ -1,34 +1,21 @@
-error[E0015]: cannot call non-const closure in constant functions
-  --> $DIR/unstable-const-fn-in-libcore.rs:22:26
-   |
-LL |             Opt::None => f(),
-   |                          ^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-help: consider further restricting this bound
-   |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T + ~const std::ops::FnOnce<()>>(self, f: F) -> T {
-   |                                              +++++++++++++++++++++++++++++
-
 error[E0493]: destructors cannot be evaluated at compile-time
-  --> $DIR/unstable-const-fn-in-libcore.rs:17:53
+  --> $DIR/unstable-const-fn-in-libcore.rs:17:60
    |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
-   |                                                     ^ constant functions cannot evaluate destructors
+LL |     const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
+   |                                                            ^ constant functions cannot evaluate destructors
 ...
 LL |     }
    |     - value is dropped here
 
 error[E0493]: destructors cannot be evaluated at compile-time
-  --> $DIR/unstable-const-fn-in-libcore.rs:17:47
+  --> $DIR/unstable-const-fn-in-libcore.rs:17:54
    |
-LL |     const fn unwrap_or_else<F: FnOnce() -> T>(self, f: F) -> T {
-   |                                               ^^^^ constant functions cannot evaluate destructors
+LL |     const fn unwrap_or_else<F: ~const FnOnce() -> T>(self, f: F) -> T {
+   |                                                      ^^^^ constant functions cannot evaluate destructors
 ...
 LL |     }
    |     - value is dropped here
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0015, E0493.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0493`.
diff --git a/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr b/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
index 26986684f0c..81f3f269432 100644
--- a/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
+++ b/src/test/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.stderr
@@ -15,13 +15,13 @@ help: Unicode character '−' (Minus Sign) looks like '-' (Minus/Hyphen), but it
 LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e-11; // m³⋅kg⁻¹⋅s⁻²
    |                                                     ~
 
-error[E0277]: cannot subtract `{integer}` from `{float}`
+error[E0277]: cannot subtract `{integer}` from `{float}` in const contexts
   --> $DIR/issue-49746-unicode-confusable-in-float-literal-expt.rs:1:53
    |
 LL | const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
    |                                                     ^ no implementation for `{float} - {integer}`
    |
-   = help: the trait `Sub<{integer}>` is not implemented for `{float}`
+   = help: the trait `~const Sub<{integer}>` is not implemented for `{float}`
    = help: the following other types implement trait `Sub<Rhs>`:
              <&'a f32 as Sub<f32>>
              <&'a f64 as Sub<f64>>
diff --git a/src/test/ui/issues/issue-25901.rs b/src/test/ui/issues/issue-25901.rs
index ba12e1ad021..1f7b341a97e 100644
--- a/src/test/ui/issues/issue-25901.rs
+++ b/src/test/ui/issues/issue-25901.rs
@@ -2,7 +2,7 @@ struct A;
 struct B;
 
 static S: &'static B = &A;
-//~^ ERROR cannot perform deref coercion on `A` in statics
+//~^ ERROR the trait bound
 
 use std::ops::Deref;
 
diff --git a/src/test/ui/issues/issue-25901.stderr b/src/test/ui/issues/issue-25901.stderr
index c6c80e41cf6..b9cac32229a 100644
--- a/src/test/ui/issues/issue-25901.stderr
+++ b/src/test/ui/issues/issue-25901.stderr
@@ -1,23 +1,15 @@
-error[E0015]: cannot perform deref coercion on `A` in statics
+error[E0277]: the trait bound `A: Deref` is not satisfied
   --> $DIR/issue-25901.rs:4:24
    |
 LL | static S: &'static B = &A;
-   |                        ^^
-   |
-   = note: attempting to deref into `B`
-note: deref defined here
-  --> $DIR/issue-25901.rs:10:5
+   |                        ^^ the trait `~const Deref` is not implemented for `A`
    |
-LL |     type Target = B;
-   |     ^^^^^^^^^^^
-note: impl defined here, but it is not `const`
-  --> $DIR/issue-25901.rs:9:1
+note: the trait `Deref` is implemented for `A`, but that implementation is not `const`
+  --> $DIR/issue-25901.rs:4:24
    |
-LL | impl Deref for A {
-   | ^^^^^^^^^^^^^^^^
-   = note: calls in statics are limited to constant functions, tuple structs and tuple variants
-   = note: consider wrapping this expression in `Lazy::new(|| ...)` from the `once_cell` crate: https://crates.io/crates/once_cell
+LL | static S: &'static B = &A;
+   |                        ^^
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/issues/issue-50582.stderr b/src/test/ui/issues/issue-50582.stderr
index 3d527eb6b4e..53ecc6112ff 100644
--- a/src/test/ui/issues/issue-50582.stderr
+++ b/src/test/ui/issues/issue-50582.stderr
@@ -7,13 +7,13 @@ LL |     Vec::<[(); 1 + for x in 0..1 {}]>::new();
    = note: see issue #87575 <https://github.com/rust-lang/rust/issues/87575> for more information
    = help: add `#![feature(const_for)]` to the crate attributes to enable
 
-error[E0277]: cannot add `()` to `{integer}`
+error[E0277]: cannot add `()` to `{integer}` in const contexts
   --> $DIR/issue-50582.rs:2:18
    |
 LL |     Vec::<[(); 1 + for x in 0..1 {}]>::new();
    |                  ^ no implementation for `{integer} + ()`
    |
-   = help: the trait `Add<()>` is not implemented for `{integer}`
+   = help: the trait `~const Add<()>` is not implemented for `{integer}`
    = help: the following other types implement trait `Add<Rhs>`:
              <&'a f32 as Add<f32>>
              <&'a f64 as Add<f64>>
diff --git a/src/test/ui/never_type/issue-52443.rs b/src/test/ui/never_type/issue-52443.rs
index cebcca944af..0498a8a1625 100644
--- a/src/test/ui/never_type/issue-52443.rs
+++ b/src/test/ui/never_type/issue-52443.rs
@@ -9,6 +9,6 @@ fn main() {
     [(); { for _ in 0usize.. {}; 0}];
     //~^ ERROR `for` is not allowed in a `const`
     //~| ERROR cannot convert
-    //~| ERROR mutable references are not allowed in constants
-    //~| ERROR cannot call non-const fn
+    //~| ERROR mutable references
+    //~| ERROR cannot call
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
index 99eacaa837f..7d9dae52cf1 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
@@ -10,6 +10,7 @@ impl std::ops::Add for NonConstAdd {
     }
 }
 
+#[const_trait]
 trait Foo {
     type Bar: ~const std::ops::Add;
 }
@@ -19,6 +20,7 @@ impl const Foo for NonConstAdd {
     //~^ ERROR: cannot add `NonConstAdd` to `NonConstAdd` in const contexts
 }
 
+#[const_trait]
 trait Baz {
     type Qux: std::ops::Add;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
index 64501c52374..ce2425010ad 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr
@@ -1,17 +1,17 @@
 error[E0277]: cannot add `NonConstAdd` to `NonConstAdd` in const contexts
-  --> $DIR/assoc-type.rs:18:16
+  --> $DIR/assoc-type.rs:19:16
    |
 LL |     type Bar = NonConstAdd;
    |                ^^^^^^^^^^^ no implementation for `NonConstAdd + NonConstAdd`
    |
    = help: the trait `~const Add` is not implemented for `NonConstAdd`
 note: the trait `Add` is implemented for `NonConstAdd`, but that implementation is not `const`
-  --> $DIR/assoc-type.rs:18:16
+  --> $DIR/assoc-type.rs:19:16
    |
 LL |     type Bar = NonConstAdd;
    |                ^^^^^^^^^^^
 note: required by a bound in `Foo::Bar`
-  --> $DIR/assoc-type.rs:14:15
+  --> $DIR/assoc-type.rs:15:15
    |
 LL |     type Bar: ~const std::ops::Add;
    |               ^^^^^^^^^^^^^^^^^^^^ required by this bound in `Foo::Bar`
diff --git a/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs b/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
index 19e9006094b..589e3f02420 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/auxiliary/staged-api.rs
@@ -3,6 +3,7 @@
 #![stable(feature = "rust1", since = "1.0.0")]
 
 #[stable(feature = "rust1", since = "1.0.0")]
+#[const_trait]
 pub trait MyTrait {
     #[stable(feature = "rust1", since = "1.0.0")]
     fn func();
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
index 24b9235bb9a..dd993397420 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.rs
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait Plus {
     fn plus(self, rhs: Self) -> Self;
 }
@@ -23,7 +24,6 @@ pub const fn add_i32(a: i32, b: i32) -> i32 {
 pub const fn add_u32(a: u32, b: u32) -> u32 {
     a.plus(b)
     //~^ ERROR the trait bound
-    //~| ERROR cannot call non-const fn
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
index 1fc9db27761..d9ad8043153 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-fail.stderr
@@ -1,24 +1,19 @@
 error[E0277]: the trait bound `u32: ~const Plus` is not satisfied
-  --> $DIR/call-const-trait-method-fail.rs:24:7
+  --> $DIR/call-const-trait-method-fail.rs:25:7
    |
 LL |     a.plus(b)
-   |       ^^^^^^^ the trait `~const Plus` is not implemented for `u32`
+   |       ^^^^ the trait `~const Plus` is not implemented for `u32`
    |
 note: the trait `Plus` is implemented for `u32`, but that implementation is not `const`
-  --> $DIR/call-const-trait-method-fail.rs:24:7
+  --> $DIR/call-const-trait-method-fail.rs:25:7
    |
 LL |     a.plus(b)
-   |       ^^^^^^^
-
-error[E0015]: cannot call non-const fn `<u32 as Plus>::plus` in constant functions
-  --> $DIR/call-const-trait-method-fail.rs:24:7
-   |
-LL |     a.plus(b)
-   |       ^^^^^^^
+   |       ^^^^
+help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
    |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
+LL | pub const fn add_u32(a: u32, b: u32) -> u32 where u32: ~const Plus {
+   |                                             ++++++++++++++++++++++
 
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-Some errors have detailed explanations: E0015, E0277.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
index cf38bc3c964..b64161b6aa0 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-const-trait-method-pass.rs
@@ -21,6 +21,7 @@ impl const PartialEq for Int {
     }
 }
 
+#[const_trait]
 pub trait Plus {
     fn plus(self, rhs: Self) -> Self;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs b/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
index 89dc47aad3d..50c46579086 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-in-impl.rs
@@ -1,6 +1,7 @@
 // check-pass
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait MyPartialEq {
     fn eq(&self, other: &Self) -> bool;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
index b3e3dd62be8..52984fb6be4 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.rs
@@ -1,6 +1,7 @@
 #![feature(const_trait_impl)]
 
 struct S;
+#[const_trait]
 trait T {
     fn foo();
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
index 9e49785c589..c8783de4c3e 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-check-fns-in-const-impl.stderr
@@ -1,5 +1,5 @@
 error[E0015]: cannot call non-const fn `non_const` in constant functions
-  --> $DIR/const-check-fns-in-const-impl.rs:11:16
+  --> $DIR/const-check-fns-in-const-impl.rs:12:16
    |
 LL |     fn foo() { non_const() }
    |                ^^^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs b/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
index 04462c0a11b..8b4c4065815 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-drop.rs
@@ -48,6 +48,7 @@ mod t {
     pub struct HasConstDrop(pub ConstDrop);
     pub struct TrivialFields(pub u8, pub i8, pub usize, pub isize);
 
+    #[const_trait]
     pub trait SomeTrait {
         fn foo();
     }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
index 470c653dd47..837124db04e 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.rs
@@ -1,9 +1,11 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {}
 
 const impl Foo for i32 {} //~ ERROR: expected identifier, found keyword
 
+#[const_trait]
 trait Bar {}
 
 const impl<T: Foo> Bar for T {} //~ ERROR: expected identifier, found keyword
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
index 709084c86e0..7217fc85543 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-recovery.stderr
@@ -1,5 +1,5 @@
 error: expected identifier, found keyword `impl`
-  --> $DIR/const-impl-recovery.rs:5:7
+  --> $DIR/const-impl-recovery.rs:6:7
    |
 LL | const impl Foo for i32 {}
    |       ^^^^ expected identifier, found keyword
@@ -11,7 +11,7 @@ LL + impl const Foo for i32 {}
    |
 
 error: expected identifier, found keyword `impl`
-  --> $DIR/const-impl-recovery.rs:9:7
+  --> $DIR/const-impl-recovery.rs:11:7
    |
 LL | const impl<T: Foo> Bar for T {}
    |       ^^^^ expected identifier, found keyword
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs
new file mode 100644
index 00000000000..1aff0562785
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs
@@ -0,0 +1,9 @@
+#![feature(const_trait_impl)]
+
+pub trait A {}
+//~^ NOTE: this trait must be annotated with `#[const_trait]`
+
+impl const A for () {}
+//~^ ERROR: const `impl`s must be for traits marked with `#[const_trait]`
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr
new file mode 100644
index 00000000000..6b465a9c62e
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr
@@ -0,0 +1,14 @@
+error: const `impl`s must be for traits marked with `#[const_trait]`
+  --> $DIR/const-impl-requires-const-trait.rs:6:1
+   |
+LL | impl const A for () {}
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+note: this trait must be annotated with `#[const_trait]`
+  --> $DIR/const-impl-requires-const-trait.rs:3:1
+   |
+LL | pub trait A {}
+   | ^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
index af4d3909e40..4c630d33c55 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.gated.stderr
@@ -1,5 +1,5 @@
 error: fatal error triggered by #[rustc_error]
-  --> $DIR/feature-gate.rs:13:1
+  --> $DIR/feature-gate.rs:14:1
    |
 LL | fn main() {}
    | ^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
index 7bac72e1bb6..0b409fbaac9 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.rs
@@ -5,6 +5,7 @@
 #![feature(rustc_attrs)]
 
 struct S;
+#[const_trait] //[stock]~ ERROR `const_trait` is a temporary placeholder
 trait T {}
 impl const T for S {}
 //[stock]~^ ERROR const trait impls are experimental
diff --git a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
index 91a8bb578a8..0e938c1c55d 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/feature-gate.stock.stderr
@@ -1,5 +1,5 @@
 error[E0658]: const trait impls are experimental
-  --> $DIR/feature-gate.rs:9:6
+  --> $DIR/feature-gate.rs:10:6
    |
 LL | impl const T for S {}
    |      ^^^^^
@@ -7,6 +7,15 @@ LL | impl const T for S {}
    = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
    = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
 
-error: aborting due to previous error
+error[E0658]: `const_trait` is a temporary placeholder for marking a trait that is suitable for `const` `impls` and all default bodies as `const`, which may be removed or renamed in the future.
+  --> $DIR/feature-gate.rs:8:1
+   |
+LL | #[const_trait]
+   | ^^^^^^^^^^^^^^
+   |
+   = note: see issue #67792 <https://github.com/rust-lang/rust/issues/67792> for more information
+   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
index 80a4442de2c..337c733403b 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait MyTrait {
     fn method(&self) -> Option<()>;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
index 32df63e449d..6d2be1daa37 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/hir-const-check.stderr
@@ -1,5 +1,5 @@
 error[E0658]: `?` is not allowed in a `const fn`
-  --> $DIR/hir-const-check.rs:11:9
+  --> $DIR/hir-const-check.rs:12:9
    |
 LL |         Some(())?;
    |         ^^^^^^^^^
diff --git a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
index 2cef803a90e..f8ac793e4c1 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/inherent-impl-const-bounds.rs
@@ -3,7 +3,9 @@
 
 struct S;
 
+#[const_trait]
 trait A {}
+#[const_trait]
 trait B {}
 
 impl const A for S {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
index 1004bb28c59..9f3f38ad4bc 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-100222.rs
@@ -16,6 +16,7 @@ pub trait IndexMut where Self: Index {
 
 impl Index for () { type Output = (); }
 
+#[cfg(not(any(nn, yn)))]
 impl const IndexMut for <() as Index>::Output {
     const C: <Self as Index>::Output = ();
     type Assoc = <Self as Index>::Output;
@@ -24,6 +25,15 @@ impl const IndexMut for <() as Index>::Output {
     {}
 }
 
+#[cfg(any(nn, yn))]
+impl IndexMut for <() as Index>::Output {
+    const C: <Self as Index>::Output = ();
+    type Assoc = <Self as Index>::Output;
+    fn foo(&mut self, x: <Self as Index>::Output) -> <Self as Index>::Output
+        where <Self as Index>::Output:,
+    {}
+}
+
 const C: <() as Index>::Output = ();
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
index 97c27ce1a1c..4d346965394 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-92230-wf-super-trait-env.rs
@@ -4,7 +4,9 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 pub trait Super {}
+#[const_trait]
 pub trait Sub: Super {}
 
 impl<A> const Super for &A where A: ~const Super {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs b/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs
new file mode 100644
index 00000000000..a851136009c
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/nested-closure.rs
@@ -0,0 +1,12 @@
+// check-pass
+
+#![feature(const_trait_impl, once_cell)]
+
+use std::sync::LazyLock;
+
+static EXTERN_FLAGS: LazyLock<String> = LazyLock::new(|| {
+    let x = || String::new();
+    x()
+});
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs b/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
index defef9e0409..1a4509b1869 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/non-const-op-in-closure-in-const.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Convert<T> {
     fn to(self) -> T;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs b/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs
new file mode 100644
index 00000000000..4520a36960c
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/static-const-trait-bound.rs
@@ -0,0 +1,18 @@
+// check-pass
+pub struct S<T, F: FnOnce() -> T = fn() -> T> {
+    f: F,
+    x: Option<T>,
+}
+
+impl<T, F: FnOnce() -> T> S<T, F> {
+    pub const fn new(f: F) -> Self {
+        Self { f, x: None }
+    }
+}
+
+#[derive(Default)]
+pub struct Foo;
+
+static LOCKED_CALLSITES: S<Foo> = S::new(Default::default);
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
index af465cad3d2..3e2b81368a5 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.rs
@@ -1,8 +1,10 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {
     fn a(&self);
 }
+#[const_trait]
 trait Bar: ~const Foo {}
 
 struct S;
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
index 9e8b8f8c6ba..9787792ab13 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail.stderr
@@ -1,16 +1,16 @@
 error[E0277]: the trait bound `S: ~const Foo` is not satisfied
-  --> $DIR/super-traits-fail.rs:13:12
+  --> $DIR/super-traits-fail.rs:15:12
    |
 LL | impl const Bar for S {}
    |            ^^^ the trait `~const Foo` is not implemented for `S`
    |
 note: the trait `Foo` is implemented for `S`, but that implementation is not `const`
-  --> $DIR/super-traits-fail.rs:13:12
+  --> $DIR/super-traits-fail.rs:15:12
    |
 LL | impl const Bar for S {}
    |            ^^^
 note: required by a bound in `Bar`
-  --> $DIR/super-traits-fail.rs:6:12
+  --> $DIR/super-traits-fail.rs:8:12
    |
 LL | trait Bar: ~const Foo {}
    |            ^^^^^^^^^^ required by this bound in `Bar`
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
index aded4ca9a99..df96f6fb4ab 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits.rs
@@ -1,9 +1,12 @@
 // check-pass
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {
     fn a(&self);
 }
+
+#[const_trait]
 trait Bar: ~const Foo {}
 
 struct S;
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs
new file mode 100644
index 00000000000..7a88ec35c8f
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs
@@ -0,0 +1,29 @@
+// Like trait-where-clause.rs, but we are calling from a const context.
+// Checking the validity of traits' where clauses happen at a later stage.
+// (`rustc_const_eval` instead of `rustc_typeck`) Therefore one file as a
+// test is not enough.
+#![feature(const_trait_impl)]
+
+trait Bar {}
+
+trait Foo {
+    fn a();
+    fn b() where Self: ~const Bar;
+    fn c<T: ~const Bar>();
+}
+
+const fn test1<T: ~const Foo + Bar>() {
+    T::a();
+    T::b();
+    //~^ ERROR the trait bound
+    T::c::<T>();
+    //~^ ERROR the trait bound
+}
+
+const fn test2<T: ~const Foo + ~const Bar>() {
+    T::a();
+    T::b();
+    T::c::<T>();
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr
new file mode 100644
index 00000000000..13d8639de30
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.stderr
@@ -0,0 +1,35 @@
+error[E0277]: the trait bound `T: ~const Bar` is not satisfied
+  --> $DIR/trait-where-clause-const.rs:17:5
+   |
+LL |     T::b();
+   |     ^^^^^^ the trait `~const Bar` is not implemented for `T`
+   |
+note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/trait-where-clause-const.rs:17:5
+   |
+LL |     T::b();
+   |     ^^^^^^
+help: consider further restricting this bound
+   |
+LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
+   |                                    ++++++++++++
+
+error[E0277]: the trait bound `T: ~const Bar` is not satisfied
+  --> $DIR/trait-where-clause-const.rs:19:5
+   |
+LL |     T::c::<T>();
+   |     ^^^^^^^^^^^ the trait `~const Bar` is not implemented for `T`
+   |
+note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/trait-where-clause-const.rs:19:5
+   |
+LL |     T::c::<T>();
+   |     ^^^^^^^^^^^
+help: consider further restricting this bound
+   |
+LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
+   |                                    ++++++++++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
index b7cf9a13b79..4b8b004069d 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-run.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Bar {
     fn bar() -> u8;
 }
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
index d37ed3bb8dd..5bd23a8cb20 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.rs
@@ -8,7 +8,7 @@ trait Foo {
     fn c<T: ~const Bar>();
 }
 
-const fn test1<T: ~const Foo + Bar>() {
+fn test1<T: Foo>() {
     T::a();
     T::b();
     //~^ ERROR the trait bound
@@ -16,21 +16,7 @@ const fn test1<T: ~const Foo + Bar>() {
     //~^ ERROR the trait bound
 }
 
-const fn test2<T: ~const Foo + ~const Bar>() {
-    T::a();
-    T::b();
-    T::c::<T>();
-}
-
-fn test3<T: Foo>() {
-    T::a();
-    T::b();
-    //~^ ERROR the trait bound
-    T::c::<T>();
-    //~^ ERROR the trait bound
-}
-
-fn test4<T: Foo + Bar>() {
+fn test2<T: Foo + Bar>() {
     T::a();
     T::b();
     T::c::<T>();
diff --git a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
index fd5fe25ddcf..96365d33433 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause.stderr
@@ -1,47 +1,5 @@
-error[E0277]: the trait bound `T: ~const Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:13:5
-   |
-LL |     T::b();
-   |     ^^^^ the trait `~const Bar` is not implemented for `T`
-   |
-note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
-  --> $DIR/trait-where-clause.rs:13:5
-   |
-LL |     T::b();
-   |     ^^^^
-note: required by a bound in `Foo::b`
-  --> $DIR/trait-where-clause.rs:7:24
-   |
-LL |     fn b() where Self: ~const Bar;
-   |                        ^^^^^^^^^^ required by this bound in `Foo::b`
-help: consider further restricting this bound
-   |
-LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
-   |                                    ++++++++++++
-
-error[E0277]: the trait bound `T: ~const Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:15:12
-   |
-LL |     T::c::<T>();
-   |            ^ the trait `~const Bar` is not implemented for `T`
-   |
-note: the trait `Bar` is implemented for `T`, but that implementation is not `const`
-  --> $DIR/trait-where-clause.rs:15:12
-   |
-LL |     T::c::<T>();
-   |            ^
-note: required by a bound in `Foo::c`
-  --> $DIR/trait-where-clause.rs:8:13
-   |
-LL |     fn c<T: ~const Bar>();
-   |             ^^^^^^^^^^ required by this bound in `Foo::c`
-help: consider further restricting this bound
-   |
-LL | const fn test1<T: ~const Foo + Bar + ~const Bar>() {
-   |                                    ++++++++++++
-
 error[E0277]: the trait bound `T: Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:27:5
+  --> $DIR/trait-where-clause.rs:13:5
    |
 LL |     T::b();
    |     ^^^^ the trait `Bar` is not implemented for `T`
@@ -53,11 +11,11 @@ LL |     fn b() where Self: ~const Bar;
    |                        ^^^^^^^^^^ required by this bound in `Foo::b`
 help: consider further restricting this bound
    |
-LL | fn test3<T: Foo + Bar>() {
+LL | fn test1<T: Foo + Bar>() {
    |                 +++++
 
 error[E0277]: the trait bound `T: Bar` is not satisfied
-  --> $DIR/trait-where-clause.rs:29:12
+  --> $DIR/trait-where-clause.rs:15:12
    |
 LL |     T::c::<T>();
    |            ^ the trait `Bar` is not implemented for `T`
@@ -69,9 +27,9 @@ LL |     fn c<T: ~const Bar>();
    |             ^^^^^^^^^^ required by this bound in `Foo::c`
 help: consider further restricting this bound
    |
-LL | fn test3<T: Foo + Bar>() {
+LL | fn test1<T: Foo + Bar>() {
    |                 +++++
 
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/stability-attribute/missing-const-stability.rs b/src/test/ui/stability-attribute/missing-const-stability.rs
index d89886af314..6eff899bfbf 100644
--- a/src/test/ui/stability-attribute/missing-const-stability.rs
+++ b/src/test/ui/stability-attribute/missing-const-stability.rs
@@ -19,6 +19,7 @@ impl Foo {
 }
 
 #[stable(feature = "stable", since = "1.0.0")]
+#[const_trait]
 pub trait Bar {
     #[stable(feature = "stable", since = "1.0.0")]
     fn fun();
diff --git a/src/test/ui/stability-attribute/missing-const-stability.stderr b/src/test/ui/stability-attribute/missing-const-stability.stderr
index 10978728fa3..4cfbe152891 100644
--- a/src/test/ui/stability-attribute/missing-const-stability.stderr
+++ b/src/test/ui/stability-attribute/missing-const-stability.stderr
@@ -5,7 +5,7 @@ LL | pub const fn foo() {}
    | ^^^^^^^^^^^^^^^^^^^^^
 
 error: implementation has missing const stability attribute
-  --> $DIR/missing-const-stability.rs:27:1
+  --> $DIR/missing-const-stability.rs:28:1
    |
 LL | / impl const Bar for Foo {
 LL | |