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`

3 files changed, 10 insertions, 18 deletions

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>>