Merging upstream version 1.66.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

73 files changed, 726 insertions, 258 deletions

diff --git a/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs b/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs
new file mode 100644
index 000000000..780a510c5
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/assoc-type-const-bound-usage.rs
@@ -0,0 +1,14 @@
+// check-pass
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Foo {
+    type Assoc: ~const Foo;
+    fn foo() {}
+}
+
+const fn foo<T: ~const Foo>() {
+    <T as Foo>::Assoc::foo();
+}
+
+fn main() {}
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 99eacaa83..7d9dae52c 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 64501c523..89177b0f1 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
@@ -1,24 +1,20 @@
 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`
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | impl const Foo for NonConstAdd where NonConstAdd: ~const Add {
-   |                                +++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
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 19e900609..589e3f024 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 24b9235bb..dd9933974 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 1fc9db277..7350909ba 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 +1,15 @@
 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)
-   |       ^^^^^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-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 cf38bc3c9..b64161b6a 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 89dc47aad..50c465790 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/call-generic-method-fail.stderr b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-fail.stderr
index 83d395dda..31e6dbdab 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-fail.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-fail.stderr
@@ -9,7 +9,6 @@ note: the trait `PartialEq<_>` is implemented for `T`, but that implementation i
    |
 LL |     *t == *t
    |        ^^
-   = help: the trait `PartialEq<&B>` is implemented for `&A`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs
index d3e14a53a..414a8c87d 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs
@@ -2,13 +2,18 @@
 
 struct S;
 
-impl PartialEq for S {
+#[const_trait]
+trait Foo {
+    fn eq(&self, _: &Self) -> bool;
+}
+
+impl Foo for S {
     fn eq(&self, _: &S) -> bool {
         true
     }
 }
 
-const fn equals_self<T: ~const PartialEq>(t: &T) -> bool {
+const fn equals_self<T: ~const Foo>(t: &T) -> bool {
     true
 }
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr
index 0a2a5f0f2..706f52343 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr
@@ -1,26 +1,21 @@
-error[E0277]: can't compare `S` with `S` in const contexts
-  --> $DIR/call-generic-method-nonconst.rs:18:34
+error[E0277]: the trait bound `S: ~const Foo` is not satisfied
+  --> $DIR/call-generic-method-nonconst.rs:23:34
    |
 LL | pub const EQ: bool = equals_self(&S);
-   |                      ----------- ^^ no implementation for `S == S`
+   |                      ----------- ^^ the trait `~const Foo` is not implemented for `S`
    |                      |
    |                      required by a bound introduced by this call
    |
-   = help: the trait `~const PartialEq` is not implemented for `S`
-note: the trait `PartialEq` is implemented for `S`, but that implementation is not `const`
-  --> $DIR/call-generic-method-nonconst.rs:18:34
+note: the trait `Foo` is implemented for `S`, but that implementation is not `const`
+  --> $DIR/call-generic-method-nonconst.rs:23:34
    |
 LL | pub const EQ: bool = equals_self(&S);
    |                                  ^^
 note: required by a bound in `equals_self`
-  --> $DIR/call-generic-method-nonconst.rs:11:25
-   |
-LL | const fn equals_self<T: ~const PartialEq>(t: &T) -> bool {
-   |                         ^^^^^^^^^^^^^^^^ required by this bound in `equals_self`
-help: consider annotating `S` with `#[derive(PartialEq)]`
-   |
-LL | #[derive(PartialEq)]
+  --> $DIR/call-generic-method-nonconst.rs:16:25
    |
+LL | const fn equals_self<T: ~const Foo>(t: &T) -> bool {
+   |                         ^^^^^^^^^^ required by this bound in `equals_self`
 
 error: aborting due to previous error
 
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 b3e3dd62b..52984fb6b 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 9e49785c5..c8783de4c 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-default-method-bodies.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-default-method-bodies.stderr
index fddc8d37f..c64930db9 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-default-method-bodies.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-default-method-bodies.stderr
@@ -11,10 +11,6 @@ note: the trait `ConstDefaultFn` is implemented for `NonConstImpl`, but that imp
    |
 LL |     NonConstImpl.a();
    |     ^^^^^^^^^^^^
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | const fn test() where NonConstImpl: ~const ConstDefaultFn {
-   |                 +++++++++++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.precise.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.precise.stderr
index 2295a822f..796c0d388 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.precise.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.precise.stderr
@@ -1,5 +1,5 @@
 error[E0277]: can't drop `NonTrivialDrop` in const contexts
-  --> $DIR/const-drop-fail.rs:43:5
+  --> $DIR/const-drop-fail.rs:44:5
    |
 LL |         const _: () = check($exp);
    |                       ----- required by a bound introduced by this call
@@ -9,7 +9,7 @@ LL |     NonTrivialDrop,
    |
    = note: the trait bound `NonTrivialDrop: ~const Destruct` is not satisfied
 note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+  --> $DIR/const-drop-fail.rs:35:19
    |
 LL | const fn check<T: ~const Destruct>(_: T) {}
    |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
@@ -21,7 +21,7 @@ LL |     &mut NonTrivialDrop,
    |     ++++
 
 error[E0277]: can't drop `NonTrivialDrop` in const contexts
-  --> $DIR/const-drop-fail.rs:45:5
+  --> $DIR/const-drop-fail.rs:46:5
    |
 LL |         const _: () = check($exp);
    |                       ----- required by a bound introduced by this call
@@ -30,7 +30,7 @@ LL |     ConstImplWithDropGlue(NonTrivialDrop),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `ConstImplWithDropGlue`, the trait `~const Destruct` is not implemented for `NonTrivialDrop`
    |
 note: the trait `Destruct` is implemented for `NonTrivialDrop`, but that implementation is not `const`
-  --> $DIR/const-drop-fail.rs:45:5
+  --> $DIR/const-drop-fail.rs:46:5
    |
 LL |     ConstImplWithDropGlue(NonTrivialDrop),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -40,39 +40,60 @@ note: required because it appears within the type `ConstImplWithDropGlue`
 LL | struct ConstImplWithDropGlue(NonTrivialDrop);
    |        ^^^^^^^^^^^^^^^^^^^^^
 note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+  --> $DIR/const-drop-fail.rs:35:19
    |
 LL | const fn check<T: ~const Destruct>(_: T) {}
    |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
 
-error[E0277]: the trait bound `ConstDropImplWithBounds<NonTrivialDrop>: ~const Destruct` is not satisfied
-  --> $DIR/const-drop-fail.rs:47:5
+error[E0277]: the trait bound `NonTrivialDrop: ~const A` is not satisfied
+  --> $DIR/const-drop-fail.rs:48:47
    |
-LL |         const _: () = check($exp);
-   |                       ----- required by a bound introduced by this call
-...
 LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `~const Destruct` is not implemented for `ConstDropImplWithBounds<NonTrivialDrop>`
+   |     ----------------------------------------- ^^^^^^^^^^^ the trait `~const A` is not implemented for `NonTrivialDrop`
+   |     |
+   |     required by a bound introduced by this call
    |
-note: required for `ConstDropImplWithBounds<NonTrivialDrop>` to implement `~const Destruct`
-  --> $DIR/const-drop-fail.rs:28:25
+note: the trait `A` is implemented for `NonTrivialDrop`, but that implementation is not `const`
+  --> $DIR/const-drop-fail.rs:48:47
    |
-LL | impl<T: ~const A> const Drop for ConstDropImplWithBounds<T> {
-   |                         ^^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: 1 redundant requirement hidden
-   = note: required for `ConstDropImplWithBounds<NonTrivialDrop>` to implement `~const Destruct`
-note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |                                               ^^^^^^^^^^^
+note: required by a bound in `ConstDropImplWithBounds`
+  --> $DIR/const-drop-fail.rs:27:35
    |
-LL | const fn check<T: ~const Destruct>(_: T) {}
-   |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
-help: consider borrowing here
+LL | struct ConstDropImplWithBounds<T: ~const A>(PhantomData<T>);
+   |                                   ^^^^^^^^ required by this bound in `ConstDropImplWithBounds`
+
+error[E0277]: the trait bound `NonTrivialDrop: ~const A` is not satisfied
+  --> $DIR/const-drop-fail.rs:48:5
    |
-LL |     &ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     +
-LL |     &mut ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     ++++
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `~const A` is not implemented for `NonTrivialDrop`
+   |
+note: the trait `A` is implemented for `NonTrivialDrop`, but that implementation is not `const`
+  --> $DIR/const-drop-fail.rs:48:5
+   |
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `ConstDropImplWithBounds`
+  --> $DIR/const-drop-fail.rs:27:35
+   |
+LL | struct ConstDropImplWithBounds<T: ~const A>(PhantomData<T>);
+   |                                   ^^^^^^^^ required by this bound in `ConstDropImplWithBounds`
+
+error[E0367]: `Drop` impl requires `T: ~const A` but the struct it is implemented for does not
+  --> $DIR/const-drop-fail.rs:55:9
+   |
+LL | impl<T: ~const A> const Drop for ConstDropImplWithNonConstBounds<T> {
+   |         ^^^^^^^^
+   |
+note: the implementor must specify the same requirement
+  --> $DIR/const-drop-fail.rs:53:1
+   |
+LL | struct ConstDropImplWithNonConstBounds<T: A>(PhantomData<T>);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0277`.
+Some errors have detailed explanations: E0277, E0367.
+For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.rs b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.rs
index 001dd430a..d36c7f81c 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.rs
@@ -19,11 +19,12 @@ impl const Drop for ConstImplWithDropGlue {
     fn drop(&mut self) {}
 }
 
-trait A { fn a() { println!("A"); } }
+#[const_trait]
+trait A { fn a() { } }
 
 impl A for NonTrivialDrop {}
 
-struct ConstDropImplWithBounds<T: A>(PhantomData<T>);
+struct ConstDropImplWithBounds<T: ~const A>(PhantomData<T>);
 
 impl<T: ~const A> const Drop for ConstDropImplWithBounds<T> {
     fn drop(&mut self) {
@@ -46,6 +47,16 @@ check_all! {
     //~^ ERROR can't drop
     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
     //~^ ERROR the trait bound
+    //~| ERROR the trait bound
+}
+
+struct ConstDropImplWithNonConstBounds<T: A>(PhantomData<T>);
+
+impl<T: ~const A> const Drop for ConstDropImplWithNonConstBounds<T> {
+//~^ ERROR `Drop` impl requires `T: ~const A` but the struct it is implemented for does not
+    fn drop(&mut self) {
+        T::a();
+    }
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.stock.stderr b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.stock.stderr
index 2295a822f..796c0d388 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.stock.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-drop-fail.stock.stderr
@@ -1,5 +1,5 @@
 error[E0277]: can't drop `NonTrivialDrop` in const contexts
-  --> $DIR/const-drop-fail.rs:43:5
+  --> $DIR/const-drop-fail.rs:44:5
    |
 LL |         const _: () = check($exp);
    |                       ----- required by a bound introduced by this call
@@ -9,7 +9,7 @@ LL |     NonTrivialDrop,
    |
    = note: the trait bound `NonTrivialDrop: ~const Destruct` is not satisfied
 note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+  --> $DIR/const-drop-fail.rs:35:19
    |
 LL | const fn check<T: ~const Destruct>(_: T) {}
    |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
@@ -21,7 +21,7 @@ LL |     &mut NonTrivialDrop,
    |     ++++
 
 error[E0277]: can't drop `NonTrivialDrop` in const contexts
-  --> $DIR/const-drop-fail.rs:45:5
+  --> $DIR/const-drop-fail.rs:46:5
    |
 LL |         const _: () = check($exp);
    |                       ----- required by a bound introduced by this call
@@ -30,7 +30,7 @@ LL |     ConstImplWithDropGlue(NonTrivialDrop),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ within `ConstImplWithDropGlue`, the trait `~const Destruct` is not implemented for `NonTrivialDrop`
    |
 note: the trait `Destruct` is implemented for `NonTrivialDrop`, but that implementation is not `const`
-  --> $DIR/const-drop-fail.rs:45:5
+  --> $DIR/const-drop-fail.rs:46:5
    |
 LL |     ConstImplWithDropGlue(NonTrivialDrop),
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -40,39 +40,60 @@ note: required because it appears within the type `ConstImplWithDropGlue`
 LL | struct ConstImplWithDropGlue(NonTrivialDrop);
    |        ^^^^^^^^^^^^^^^^^^^^^
 note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+  --> $DIR/const-drop-fail.rs:35:19
    |
 LL | const fn check<T: ~const Destruct>(_: T) {}
    |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
 
-error[E0277]: the trait bound `ConstDropImplWithBounds<NonTrivialDrop>: ~const Destruct` is not satisfied
-  --> $DIR/const-drop-fail.rs:47:5
+error[E0277]: the trait bound `NonTrivialDrop: ~const A` is not satisfied
+  --> $DIR/const-drop-fail.rs:48:47
    |
-LL |         const _: () = check($exp);
-   |                       ----- required by a bound introduced by this call
-...
 LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `~const Destruct` is not implemented for `ConstDropImplWithBounds<NonTrivialDrop>`
+   |     ----------------------------------------- ^^^^^^^^^^^ the trait `~const A` is not implemented for `NonTrivialDrop`
+   |     |
+   |     required by a bound introduced by this call
    |
-note: required for `ConstDropImplWithBounds<NonTrivialDrop>` to implement `~const Destruct`
-  --> $DIR/const-drop-fail.rs:28:25
+note: the trait `A` is implemented for `NonTrivialDrop`, but that implementation is not `const`
+  --> $DIR/const-drop-fail.rs:48:47
    |
-LL | impl<T: ~const A> const Drop for ConstDropImplWithBounds<T> {
-   |                         ^^^^     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: 1 redundant requirement hidden
-   = note: required for `ConstDropImplWithBounds<NonTrivialDrop>` to implement `~const Destruct`
-note: required by a bound in `check`
-  --> $DIR/const-drop-fail.rs:34:19
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |                                               ^^^^^^^^^^^
+note: required by a bound in `ConstDropImplWithBounds`
+  --> $DIR/const-drop-fail.rs:27:35
    |
-LL | const fn check<T: ~const Destruct>(_: T) {}
-   |                   ^^^^^^^^^^^^^^^ required by this bound in `check`
-help: consider borrowing here
+LL | struct ConstDropImplWithBounds<T: ~const A>(PhantomData<T>);
+   |                                   ^^^^^^^^ required by this bound in `ConstDropImplWithBounds`
+
+error[E0277]: the trait bound `NonTrivialDrop: ~const A` is not satisfied
+  --> $DIR/const-drop-fail.rs:48:5
    |
-LL |     &ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     +
-LL |     &mut ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
-   |     ++++
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `~const A` is not implemented for `NonTrivialDrop`
+   |
+note: the trait `A` is implemented for `NonTrivialDrop`, but that implementation is not `const`
+  --> $DIR/const-drop-fail.rs:48:5
+   |
+LL |     ConstDropImplWithBounds::<NonTrivialDrop>(PhantomData),
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `ConstDropImplWithBounds`
+  --> $DIR/const-drop-fail.rs:27:35
+   |
+LL | struct ConstDropImplWithBounds<T: ~const A>(PhantomData<T>);
+   |                                   ^^^^^^^^ required by this bound in `ConstDropImplWithBounds`
+
+error[E0367]: `Drop` impl requires `T: ~const A` but the struct it is implemented for does not
+  --> $DIR/const-drop-fail.rs:55:9
+   |
+LL | impl<T: ~const A> const Drop for ConstDropImplWithNonConstBounds<T> {
+   |         ^^^^^^^^
+   |
+note: the implementor must specify the same requirement
+  --> $DIR/const-drop-fail.rs:53:1
+   |
+LL | struct ConstDropImplWithNonConstBounds<T: A>(PhantomData<T>);
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 3 previous errors
+error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0277`.
+Some errors have detailed explanations: E0277, E0367.
+For more information about an error, try `rustc --explain E0277`.
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 04462c0a1..b0fc3adf9 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();
     }
@@ -59,7 +60,7 @@ mod t {
         fn foo() {}
     }
 
-    pub struct ConstDropWithBound<T: SomeTrait>(pub core::marker::PhantomData<T>);
+    pub struct ConstDropWithBound<T: ~const SomeTrait>(pub core::marker::PhantomData<T>);
 
     impl<T: ~const SomeTrait> const Drop for ConstDropWithBound<T> {
         fn drop(&mut self) {
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 470c653dd..837124db0 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 709084c86..7217fc855 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 000000000..2b4963991
--- /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 {}
+//~^ HELP: mark `A` as const
+
+impl const A for () {}
+//~^ ERROR: const `impl` for trait `A` which is not 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 000000000..478adcf3e
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.stderr
@@ -0,0 +1,14 @@
+error: const `impl` for trait `A` which is not marked with `#[const_trait]`
+  --> $DIR/const-impl-requires-const-trait.rs:6:12
+   |
+LL | pub trait A {}
+   | - help: mark `A` as const: `#[const_trait]`
+...
+LL | impl const A for () {}
+   |            ^
+   |
+   = note: marking a trait with `#[const_trait]` ensures all default method bodies are `const`
+   = note: adding a non-const method body in the future would be a breaking change
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/cross-crate.gatednc.stderr b/src/test/ui/rfc-2632-const-trait-impl/cross-crate.gatednc.stderr
index d4fa44b4b..925ae53e3 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/cross-crate.gatednc.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/cross-crate.gatednc.stderr
@@ -11,10 +11,6 @@ note: the trait `cross_crate::MyTrait` is implemented for `cross_crate::NonConst
    |
 LL |     NonConst.func();
    |     ^^^^^^^^
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | const fn const_context() where cross_crate::NonConst: ~const cross_crate::MyTrait {
-   |                          ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/cross-crate.stocknc.stderr b/src/test/ui/rfc-2632-const-trait-impl/cross-crate.stocknc.stderr
index 71ecd9b06..11db0c2b8 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/cross-crate.stocknc.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/cross-crate.stocknc.stderr
@@ -11,10 +11,6 @@ note: the trait `cross_crate::MyTrait` is implemented for `cross_crate::NonConst
    |
 LL |     NonConst.func();
    |     ^^^^^^^^
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | const fn const_context() where cross_crate::NonConst: ~const cross_crate::MyTrait {
-   |                          ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.rs b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.rs
index d27291231..96acdc300 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.rs
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Tr {}
 impl Tr for () {}
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.stderr b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.stderr
index 7542b81fe..a244ab10c 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-body-checking.stderr
@@ -1,23 +1,19 @@
 error[E0277]: the trait bound `(): ~const Tr` is not satisfied
-  --> $DIR/default-method-body-is-const-body-checking.rs:11:15
+  --> $DIR/default-method-body-is-const-body-checking.rs:12:15
    |
 LL |         foo::<()>();
    |               ^^ the trait `~const Tr` is not implemented for `()`
    |
 note: the trait `Tr` is implemented for `()`, but that implementation is not `const`
-  --> $DIR/default-method-body-is-const-body-checking.rs:11:15
+  --> $DIR/default-method-body-is-const-body-checking.rs:12:15
    |
 LL |         foo::<()>();
    |               ^^
 note: required by a bound in `foo`
-  --> $DIR/default-method-body-is-const-body-checking.rs:6:28
+  --> $DIR/default-method-body-is-const-body-checking.rs:7:28
    |
 LL | const fn foo<T>() where T: ~const Tr {}
    |                            ^^^^^^^^^ required by this bound in `foo`
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | pub trait Foo where (): ~const Tr {
-   |               +++++++++++++++++++
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-same-trait-ck.stderr b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-same-trait-ck.stderr
index 85285ba84..c2c16921c 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-same-trait-ck.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/default-method-body-is-const-same-trait-ck.stderr
@@ -11,10 +11,6 @@ note: the trait `Tr` is implemented for `()`, but that implementation is not `co
    |
 LL |         ().a()
    |         ^^
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | pub trait Tr where (): ~const Tr {
-   |              +++++++++++++++++++
 
 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 af4d3909e..4c630d33c 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 7bac72e1b..0b409fbaa 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 91a8bb578..0e938c1c5 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 80a4442de..337c73340 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 32df63e44..6d2be1daa 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 2cef803a9..f8ac793e4 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 1004bb28c..9f3f38ad4 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-102156.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-102156.rs
new file mode 100644
index 000000000..fe4e91081
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-102156.rs
@@ -0,0 +1,15 @@
+#![feature(allocator_api)]
+#![feature(const_trait_impl)]
+
+use core::convert::{From, TryFrom};
+//~^ ERROR
+//~| ERROR
+
+use std::pin::Pin;
+use std::alloc::Allocator;
+impl<T: ?Sized, A: Allocator> const From<Box<T, A>> for Pin<Box<T, A>>
+where
+    A: 'static,
+{}
+
+pub fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-102156.stderr b/src/test/ui/rfc-2632-const-trait-impl/issue-102156.stderr
new file mode 100644
index 000000000..8bf00eaff
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-102156.stderr
@@ -0,0 +1,19 @@
+error[E0433]: failed to resolve: maybe a missing crate `core`?
+  --> $DIR/issue-102156.rs:4:5
+   |
+LL | use core::convert::{From, TryFrom};
+   |     ^^^^ maybe a missing crate `core`?
+   |
+   = help: consider adding `extern crate core` to use the `core` crate
+
+error[E0433]: failed to resolve: maybe a missing crate `core`?
+  --> $DIR/issue-102156.rs:4:5
+   |
+LL | use core::convert::{From, TryFrom};
+   |     ^^^^ maybe a missing crate `core`?
+   |
+   = help: consider adding `extern crate core` to use the `core` crate
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0433`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-102985.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-102985.rs
new file mode 100644
index 000000000..07d3f51ed
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-102985.rs
@@ -0,0 +1,12 @@
+#![feature(const_trait_impl)]
+
+struct Bug {
+    inner: [(); match || 1 {
+        n => n(),
+        //~^ ERROR the trait bound
+        //~| ERROR the trait bound
+        //~| ERROR cannot call non-const closure in constants
+    }],
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-102985.stderr b/src/test/ui/rfc-2632-const-trait-impl/issue-102985.stderr
new file mode 100644
index 000000000..b98ccbe5d
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-102985.stderr
@@ -0,0 +1,41 @@
+error[E0277]: the trait bound `[closure@$DIR/issue-102985.rs:4:23: 4:25]: ~const Fn<()>` is not satisfied
+  --> $DIR/issue-102985.rs:5:14
+   |
+LL |         n => n(),
+   |              ^^^ expected an `Fn<()>` closure, found `[closure@$DIR/issue-102985.rs:4:23: 4:25]`
+   |
+   = help: the trait `~const Fn<()>` is not implemented for closure `[closure@$DIR/issue-102985.rs:4:23: 4:25]`
+note: the trait `Fn<()>` is implemented for `[closure@$DIR/issue-102985.rs:4:23: 4:25]`, but that implementation is not `const`
+  --> $DIR/issue-102985.rs:5:14
+   |
+LL |         n => n(),
+   |              ^^^
+   = note: wrap the `[closure@$DIR/issue-102985.rs:4:23: 4:25]` in a closure with no arguments: `|| { /* code */ }`
+
+error[E0277]: the trait bound `[closure@$DIR/issue-102985.rs:4:23: 4:25]: ~const Fn<()>` is not satisfied
+  --> $DIR/issue-102985.rs:5:14
+   |
+LL |         n => n(),
+   |              ^^^ expected an `Fn<()>` closure, found `[closure@$DIR/issue-102985.rs:4:23: 4:25]`
+   |
+   = help: the trait `~const Fn<()>` is not implemented for closure `[closure@$DIR/issue-102985.rs:4:23: 4:25]`
+note: the trait `Fn<()>` is implemented for `[closure@$DIR/issue-102985.rs:4:23: 4:25]`, but that implementation is not `const`
+  --> $DIR/issue-102985.rs:5:14
+   |
+LL |         n => n(),
+   |              ^^^
+   = note: wrap the `[closure@$DIR/issue-102985.rs:4:23: 4:25]` in a closure with no arguments: `|| { /* code */ }`
+
+error[E0015]: cannot call non-const closure in constants
+  --> $DIR/issue-102985.rs:5:14
+   |
+LL |         n => n(),
+   |              ^^^
+   |
+   = note: closures need an RFC before allowed to be called in constants
+   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0015, E0277.
+For more information about an error, try `rustc --explain E0015`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-103677.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-103677.rs
new file mode 100644
index 000000000..d81724a36
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-103677.rs
@@ -0,0 +1,5 @@
+// check-pass
+
+const _: fn(&String) = |s| { &*s as &str; };
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-90052.rs b/src/test/ui/rfc-2632-const-trait-impl/issue-90052.rs
new file mode 100644
index 000000000..21ddf4ab4
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-90052.rs
@@ -0,0 +1,9 @@
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Bar {}
+
+fn foo<T>() where T: ~const Bar {}
+//~^ ERROR `~const` is not allowed
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/issue-90052.stderr b/src/test/ui/rfc-2632-const-trait-impl/issue-90052.stderr
new file mode 100644
index 000000000..b2a936537
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/issue-90052.stderr
@@ -0,0 +1,14 @@
+error: `~const` is not allowed here
+  --> $DIR/issue-90052.rs:6:22
+   |
+LL | fn foo<T>() where T: ~const Bar {}
+   |                      ^^^^^^^^^^
+   |
+note: this function is not `const`, so it cannot have `~const` trait bounds
+  --> $DIR/issue-90052.rs:6:4
+   |
+LL | fn foo<T>() where T: ~const Bar {}
+   |    ^^^
+
+error: aborting due to previous error
+
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 97c27ce1a..4d3469653 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 000000000..a85113600
--- /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 defef9e04..1a4509b18 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/specializing-constness-2.rs b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.rs
new file mode 100644
index 000000000..633543700
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.rs
@@ -0,0 +1,31 @@
+#![feature(const_trait_impl, min_specialization, rustc_attrs)]
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub trait Sup {}
+
+impl const Sup for () {}
+
+#[const_trait]
+pub trait A {
+    fn a() -> u32;
+}
+
+impl<T: Default> A for T {
+    default fn a() -> u32 {
+        2
+    }
+}
+
+impl<T: Default + ~const Sup> const A for T {
+    fn a() -> u32 {
+        3
+    }
+}
+
+const fn generic<T: Default>() {
+    <T as A>::a();
+    //~^ ERROR: the trait bound `T: ~const Sup` is not satisfied
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr
new file mode 100644
index 000000000..c554671e1
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness-2.stderr
@@ -0,0 +1,19 @@
+error[E0277]: the trait bound `T: ~const Sup` is not satisfied
+  --> $DIR/specializing-constness-2.rs:27:5
+   |
+LL |     <T as A>::a();
+   |     ^^^^^^^^^^^^^ the trait `~const Sup` is not implemented for `T`
+   |
+note: required for `T` to implement `~const A`
+  --> $DIR/specializing-constness-2.rs:20:37
+   |
+LL | impl<T: Default + ~const Sup> const A for T {
+   |                                     ^     ^
+help: consider further restricting this bound
+   |
+LL | const fn generic<T: Default + ~const Sup>() {
+   |                             ++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs
new file mode 100644
index 000000000..ff0cd489d
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.rs
@@ -0,0 +1,26 @@
+#![feature(const_trait_impl, min_specialization, rustc_attrs)]
+
+#[rustc_specialization_trait]
+#[const_trait]
+pub trait Sup {}
+
+impl const Sup for () {}
+
+#[const_trait]
+pub trait A {
+    fn a() -> u32;
+}
+
+impl<T: ~const Default> const A for T {
+    default fn a() -> u32 {
+        2
+    }
+}
+
+impl<T: Default + Sup> A for T { //~ ERROR: cannot specialize
+    fn a() -> u32 {
+        3
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr
new file mode 100644
index 000000000..3296c109c
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/specializing-constness.stderr
@@ -0,0 +1,8 @@
+error: cannot specialize on trait `Default`
+  --> $DIR/specializing-constness.rs:20:9
+   |
+LL | impl<T: Default + Sup> A for T {
+   |         ^^^^^^^
+
+error: aborting due to previous error
+
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 000000000..4520a3696
--- /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-2.nn.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.nn.stderr
new file mode 100644
index 000000000..d4f42b787
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.nn.stderr
@@ -0,0 +1,8 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-2.rs:11:19
+   |
+LL | trait Bar: ~const Foo {}
+   |                   ^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.ny.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.ny.stderr
new file mode 100644
index 000000000..d4f42b787
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.ny.stderr
@@ -0,0 +1,8 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-2.rs:11:19
+   |
+LL | trait Bar: ~const Foo {}
+   |                   ^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.rs
index 7b38c15af..d183efde2 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.rs
@@ -1,14 +1,19 @@
 #![feature(const_trait_impl)]
 
+// revisions: yy yn ny nn
+
+#[cfg_attr(any(yy, yn), const_trait)]
 trait Foo {
     fn a(&self);
 }
+
+#[cfg_attr(any(yy, ny), const_trait)]
 trait Bar: ~const Foo {}
+//[ny,nn]~^ ERROR: ~const can only be applied to `#[const_trait]`
 
 const fn foo<T: Bar>(x: &T) {
     x.a();
-    //~^ ERROR the trait bound
-    //~| ERROR cannot call
+    //[yn,yy]~^ ERROR the trait bound
 }
 
 fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.stderr
deleted file mode 100644
index 1766cdbee..000000000
--- a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.stderr
+++ /dev/null
@@ -1,24 +0,0 @@
-error[E0277]: the trait bound `T: ~const Foo` is not satisfied
-  --> $DIR/super-traits-fail-2.rs:9:7
-   |
-LL |     x.a();
-   |       ^^^ the trait `~const Foo` is not implemented for `T`
-   |
-note: the trait `Foo` is implemented for `T`, but that implementation is not `const`
-  --> $DIR/super-traits-fail-2.rs:9:7
-   |
-LL |     x.a();
-   |       ^^^
-
-error[E0015]: cannot call non-const fn `<T as Foo>::a` in constant functions
-  --> $DIR/super-traits-fail-2.rs:9:7
-   |
-LL |     x.a();
-   |       ^^^
-   |
-   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
-
-error: aborting due to 2 previous errors
-
-Some errors have detailed explanations: E0015, E0277.
-For more information about an error, try `rustc --explain E0015`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yn.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yn.stderr
new file mode 100644
index 000000000..b52eb2c03
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yn.stderr
@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `T: ~const Foo` is not satisfied
+  --> $DIR/super-traits-fail-2.rs:15:5
+   |
+LL |     x.a();
+   |     ^ - required by a bound introduced by this call
+   |     |
+   |     the trait `~const Foo` is not implemented for `T`
+   |
+note: the trait `Foo` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/super-traits-fail-2.rs:15:5
+   |
+LL |     x.a();
+   |     ^
+help: consider further restricting this bound
+   |
+LL | const fn foo<T: Bar + ~const Foo>(x: &T) {
+   |                     ++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yy.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yy.stderr
new file mode 100644
index 000000000..b52eb2c03
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-2.yy.stderr
@@ -0,0 +1,21 @@
+error[E0277]: the trait bound `T: ~const Foo` is not satisfied
+  --> $DIR/super-traits-fail-2.rs:15:5
+   |
+LL |     x.a();
+   |     ^ - required by a bound introduced by this call
+   |     |
+   |     the trait `~const Foo` is not implemented for `T`
+   |
+note: the trait `Foo` is implemented for `T`, but that implementation is not `const`
+  --> $DIR/super-traits-fail-2.rs:15:5
+   |
+LL |     x.a();
+   |     ^
+help: consider further restricting this bound
+   |
+LL | const fn foo<T: Bar + ~const Foo>(x: &T) {
+   |                     ++++++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.nn.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.nn.stderr
new file mode 100644
index 000000000..d433e1cfa
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.nn.stderr
@@ -0,0 +1,14 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-3.rs:12:19
+   |
+LL | trait Bar: ~const Foo {}
+   |                   ^^^
+
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-3.rs:15:24
+   |
+LL | const fn foo<T: ~const Bar>(x: &T) {
+   |                        ^^^
+
+error: aborting due to 2 previous errors
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.ny.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.ny.stderr
new file mode 100644
index 000000000..2a7e8e00b
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.ny.stderr
@@ -0,0 +1,8 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-3.rs:12:19
+   |
+LL | trait Bar: ~const Foo {}
+   |                   ^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.rs b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.rs
new file mode 100644
index 000000000..70d2936d3
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.rs
@@ -0,0 +1,20 @@
+#![feature(const_trait_impl)]
+
+// revisions: yy yn ny nn
+//[yy] check-pass
+
+#[cfg_attr(any(yy, yn), const_trait)]
+trait Foo {
+    fn a(&self);
+}
+
+#[cfg_attr(any(yy, ny), const_trait)]
+trait Bar: ~const Foo {}
+//[ny,nn]~^ ERROR: ~const can only be applied to `#[const_trait]`
+
+const fn foo<T: ~const Bar>(x: &T) {
+    //[yn,nn]~^ ERROR: ~const can only be applied to `#[const_trait]`
+    x.a();
+}
+
+fn main() {}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.yn.stderr b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.yn.stderr
new file mode 100644
index 000000000..e5978c12a
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/super-traits-fail-3.yn.stderr
@@ -0,0 +1,8 @@
+error: ~const can only be applied to `#[const_trait]` traits
+  --> $DIR/super-traits-fail-3.rs:15:24
+   |
+LL | const fn foo<T: ~const Bar>(x: &T) {
+   |                        ^^^
+
+error: aborting due to previous error
+
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 af465cad3..3e2b81368 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 9e8b8f8c6..1f8f312df 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
@@ -1,23 +1,19 @@
 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`
-help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
-   |
-LL | impl const Bar for S where S: ~const Foo {}
-   |                      +++++++++++++++++++
 
 error: aborting due to previous error
 
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 aded4ca9a..df96f6fb4 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/tilde-const-and-const-params.rs b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs
new file mode 100644
index 000000000..78a64b901
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.rs
@@ -0,0 +1,34 @@
+#![feature(const_trait_impl)]
+#![feature(generic_arg_infer)]
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+struct Foo<const N: usize>;
+
+impl<const N: usize> Foo<N> {
+   fn add<A: ~const Add42>(self) -> Foo<{ A::add(N) }> {
+      Foo
+   }
+}
+
+#[const_trait]
+trait Add42 {
+    fn add(a: usize) -> usize;
+}
+
+impl const Add42 for () {
+    fn add(a: usize) -> usize {
+        a + 42
+    }
+}
+
+fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
+    //~^ ERROR `~const` is not allowed here
+    Foo
+}
+
+fn main() {
+   let foo = Foo::<0>;
+   let foo = bar::<(), _>(foo);
+   let _foo = bar::<(), _>(foo);
+}
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.stderr b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.stderr
new file mode 100644
index 000000000..aae72f36e
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-and-const-params.stderr
@@ -0,0 +1,14 @@
+error: `~const` is not allowed here
+  --> $DIR/tilde-const-and-const-params.rs:25:11
+   |
+LL | fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
+   |           ^^^^^^^^^^^^
+   |
+note: this function is not `const`, so it cannot have `~const` trait bounds
+  --> $DIR/tilde-const-and-const-params.rs:25:4
+   |
+LL | fn bar<A: ~const Add42, const N: usize>(_: Foo<N>) -> Foo<{ A::add(N) }> {
+   |    ^^^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
index b4302f3e7..5bd52151f 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.rs
@@ -1,6 +1,7 @@
 #![feature(const_trait_impl)]
 #![feature(associated_type_bounds)]
 
+#[const_trait]
 trait T {}
 struct S;
 impl T for S {}
@@ -17,12 +18,6 @@ fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
 fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
 //~^ ERROR `~const` is not allowed
 
-fn generic<P: ~const T>() {}
-//~^ ERROR `~const` is not allowed
-
-fn where_clause<P>() where P: ~const T {}
-//~^ ERROR `~const` is not allowed
-
 struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
 //~^ ERROR `~const` and `?` are mutually exclusive
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
index 033ec21ba..84867cb4a 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde-const-invalid-places.stderr
@@ -1,56 +1,40 @@
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:8:19
+  --> $DIR/tilde-const-invalid-places.rs:9:19
    |
 LL | fn rpit() -> impl ~const T { S }
    |                   ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: `impl Trait`s cannot have `~const` trait bounds
 
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:11:17
+  --> $DIR/tilde-const-invalid-places.rs:12:17
    |
 LL | fn apit(_: impl ~const T) {}
    |                 ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: `impl Trait`s cannot have `~const` trait bounds
 
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:14:50
+  --> $DIR/tilde-const-invalid-places.rs:15:50
    |
 LL | fn rpit_assoc_bound() -> impl IntoIterator<Item: ~const T> { Some(S) }
    |                                                  ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: `impl Trait`s cannot have `~const` trait bounds
 
 error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:17:48
+  --> $DIR/tilde-const-invalid-places.rs:18:48
    |
 LL | fn apit_assoc_bound(_: impl IntoIterator<Item: ~const T>) {}
    |                                                ^^^^^^^^
    |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
-
-error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:20:15
-   |
-LL | fn generic<P: ~const T>() {}
-   |               ^^^^^^^^
-   |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
-
-error: `~const` is not allowed here
-  --> $DIR/tilde-const-invalid-places.rs:23:31
-   |
-LL | fn where_clause<P>() where P: ~const T {}
-   |                               ^^^^^^^^
-   |
-   = note: only allowed on bounds on traits' associated types and functions, const fns, const impls and its associated functions
+   = note: `impl Trait`s cannot have `~const` trait bounds
 
 error: `~const` and `?` are mutually exclusive
-  --> $DIR/tilde-const-invalid-places.rs:26:25
+  --> $DIR/tilde-const-invalid-places.rs:21:25
    |
 LL | struct TildeQuestion<T: ~const ?Sized>(std::marker::PhantomData<T>);
    |                         ^^^^^^^^^^^^^
 
-error: aborting due to 7 previous errors
+error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/rfc-2632-const-trait-impl/tilde_const_on_impl_bound.rs b/src/test/ui/rfc-2632-const-trait-impl/tilde_const_on_impl_bound.rs
new file mode 100644
index 000000000..285cef571
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/tilde_const_on_impl_bound.rs
@@ -0,0 +1,17 @@
+// check-pass
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Foo {
+    fn foo(&self) {}
+}
+
+struct Bar<T>(T);
+
+impl<T: ~const Foo> Bar<T> {
+    const fn foo(&self) {
+        self.0.foo()
+    }
+}
+
+fn main() {}
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 000000000..bfe98b98c
--- /dev/null
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-const.rs
@@ -0,0 +1,31 @@
+// 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_hir_analysis`) Therefore one file as a
+// test is not enough.
+#![feature(const_trait_impl)]
+
+#[const_trait]
+trait Bar {}
+
+#[const_trait]
+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 000000000..f2846b6a6
--- /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:19:5
+   |
+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:19:5
+   |
+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:21:5
+   |
+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:21:5
+   |
+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 b7cf9a13b..4b8b00406 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-self-referential.rs b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-self-referential.rs
index acea58eae..3b028ac48 100644
--- a/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-self-referential.rs
+++ b/src/test/ui/rfc-2632-const-trait-impl/trait-where-clause-self-referential.rs
@@ -2,6 +2,7 @@
 
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Foo {
     fn bar() where Self: ~const Foo;
 }
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 d37ed3bb8..85ca5fc90 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
@@ -1,5 +1,6 @@
 #![feature(const_trait_impl)]
 
+#[const_trait]
 trait Bar {}
 
 trait Foo {
@@ -8,7 +9,7 @@ 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 +17,7 @@ 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 fd5fe25dd..11f0c4016 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
@@ -1,77 +1,35 @@
-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:14:5
    |
 LL |     T::b();
    |     ^^^^ the trait `Bar` is not implemented for `T`
    |
 note: required by a bound in `Foo::b`
-  --> $DIR/trait-where-clause.rs:7:24
+  --> $DIR/trait-where-clause.rs:8:24
    |
 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:16:12
    |
 LL |     T::c::<T>();
    |            ^ the trait `Bar` is not implemented for `T`
    |
 note: required by a bound in `Foo::c`
-  --> $DIR/trait-where-clause.rs:8:13
+  --> $DIR/trait-where-clause.rs:9:13
    |
 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`.