Rollup merge of #132056 - weiznich:diagnostic_do_not_recommend_final_tests, r=compiler-errors

Stabilize `#[diagnostic::do_not_recommend]`

This PR seeks to stabilize the `#[diagnostic::do_not_recommend]`attribute.

This attribute was first proposed as `#[do_not_recommend`] attribute in RFC 2397 (https://github.com/rust-lang/rfcs/pull/2397). It gives the crate authors the ability to not suggest to the compiler to not show certain traits in its error messages.

With the presence of the `#[diagnostic]` tool attribute namespace it was decided to move the attribute there, as that lowers the amount of guarantees the compiler needs to give about the exact way this influences error messages. It turns the attribute into a hint which can be ignored. In addition to the original proposed functionality this attribute now also hides the marked trait in help messages ("This trait is implemented by: ").

The attribute does not accept any argument and can only be placed on trait implementations. If it is placed somewhere else a lint warning is emitted and the attribute is otherwise ignored. If an argument is detected a lint warning is emitted and the argument is ignored. This follows the rules outlined by the diagnostic namespace.

This attribute allows crates like diesel to improve their error messages drastically. The most common example here is the following error message:

```
error[E0277]: the trait bound `&str: Expression` is not satisfied
  --> /home/weiznich/Documents/rust/rust/tests/ui/diagnostic_namespace/do_not_recommend.rs:53:15
   |
LL |     SelectInt.check("bar");
   |               ^^^^^ the trait `Expression` is not implemented for `&str`, which is required by `&str: AsExpression<Integer>`
   |
   = help: the following other types implement trait `Expression`:
             Bound<T>
             SelectInt
note: required for `&str` to implement `AsExpression<Integer>`
  --> /home/weiznich/Documents/rust/rust/tests/ui/diagnostic_namespace/do_not_recommend.rs:26:13
   |
LL | impl<T, ST> AsExpression<ST> for T
   |             ^^^^^^^^^^^^^^^^     ^
LL | where
LL |     T: Expression<SqlType = ST>,
   |        ------------------------ unsatisfied trait bound introduced here
```

By applying the new attribute to the wild card trait implementation of
`AsExpression` for `T: Expression` the error message becomes:

```
error[E0277]: the trait bound `&str: AsExpression<Integer>` is not satisfied
  --> $DIR/as_expression.rs:55:15
   |
LL |     SelectInt.check("bar");
   |               ^^^^^ the trait `AsExpression<Integer>` is not implemented for `&str`
   |
   = help: the trait `AsExpression<Text>` is implemented for `&str`
   = help: for that trait implementation, expected `Text`, found `Integer`
```

which makes it much easier for users to understand that they are facing a type mismatch.

Other explored example usages include:

* This standard library error message: https://github.com/rust-lang/rust/pull/128008
* That bevy derived example:
https://github.com/rust-lang/rust/blob/e1f306899514ea80abc1d1c9f6a57762afb304a3/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs (No
more tuple pyramids)

Fixes #51992

r? ``@compiler-errors``

This PR also adds a few more tests, makes sure that all the tests are run for the old and new trait solver and adds a check that the attribute does not contain arguments.

41 files changed, 300 insertions, 152 deletions

diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index 21fd11c1c5d..5a9b8c43e74 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -178,6 +178,8 @@ declare_features! (
     (accepted, destructuring_assignment, "1.59.0", Some(71126)),
     /// Allows using the `#[diagnostic]` attribute tool namespace
     (accepted, diagnostic_namespace, "1.78.0", Some(111996)),
+    /// Controls errors in trait implementations.
+    (accepted, do_not_recommend, "CURRENT_RUSTC_VERSION", Some(51992)),
     /// Allows `#[doc(alias = "...")]`.
     (accepted, doc_alias, "1.48.0", Some(50146)),
     /// Allows `..` in tuple (struct) patterns.
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index a065db7f7d0..4b9f62fa764 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -1187,10 +1187,9 @@ pub static BUILTIN_ATTRIBUTE_MAP: LazyLock<FxHashMap<Symbol, &BuiltinAttribute>>
         map
     });
 
-pub fn is_stable_diagnostic_attribute(sym: Symbol, features: &Features) -> bool {
+pub fn is_stable_diagnostic_attribute(sym: Symbol, _features: &Features) -> bool {
     match sym {
-        sym::on_unimplemented => true,
-        sym::do_not_recommend => features.do_not_recommend(),
+        sym::on_unimplemented | sym::do_not_recommend => true,
         _ => false,
     }
 }
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 6570f9b565f..ebb07195a28 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -462,8 +462,6 @@ declare_features! (
     (unstable, deprecated_suggestion, "1.61.0", Some(94785)),
     /// Allows deref patterns.
     (incomplete, deref_patterns, "1.79.0", Some(87121)),
-    /// Controls errors in trait implementations.
-    (unstable, do_not_recommend, "1.67.0", Some(51992)),
     /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
     (unstable, doc_auto_cfg, "1.58.0", Some(43781)),
     /// Allows `#[doc(cfg(...))]`.
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index fd133ba878e..9cc94b75624 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -357,6 +357,9 @@ passes_ignored_derived_impls =
 passes_implied_feature_not_exist =
     feature `{$implied_by}` implying `{$feature}` does not exist
 
+passes_incorrect_do_not_recommend_args =
+    `#[diagnostic::do_not_recommend]` does not expect any arguments
+
 passes_incorrect_do_not_recommend_location =
     `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
 
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index ce7947ad3ec..2310dd9dc72 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -115,7 +115,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         for attr in attrs {
             match attr.path().as_slice() {
                 [sym::diagnostic, sym::do_not_recommend, ..] => {
-                    self.check_do_not_recommend(attr.span, hir_id, target)
+                    self.check_do_not_recommend(attr.span, hir_id, target, attr, item)
                 }
                 [sym::diagnostic, sym::on_unimplemented, ..] => {
                     self.check_diagnostic_on_unimplemented(attr.span, hir_id, target)
@@ -348,8 +348,21 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     /// Checks if `#[diagnostic::do_not_recommend]` is applied on a trait impl.
-    fn check_do_not_recommend(&self, attr_span: Span, hir_id: HirId, target: Target) {
-        if !matches!(target, Target::Impl) {
+    fn check_do_not_recommend(
+        &self,
+        attr_span: Span,
+        hir_id: HirId,
+        target: Target,
+        attr: &Attribute,
+        item: Option<ItemLike<'_>>,
+    ) {
+        if !matches!(target, Target::Impl)
+            || matches!(
+                item,
+                Some(ItemLike::Item(hir::Item {  kind: hir::ItemKind::Impl(_impl),.. }))
+                    if _impl.of_trait.is_none()
+            )
+        {
             self.tcx.emit_node_span_lint(
                 UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
                 hir_id,
@@ -357,6 +370,14 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 errors::IncorrectDoNotRecommendLocation,
             );
         }
+        if !attr.is_word() {
+            self.tcx.emit_node_span_lint(
+                UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                hir_id,
+                attr_span,
+                errors::DoNotRecommendDoesNotExpectArgs,
+            );
+        }
     }
 
     /// Checks if `#[diagnostic::on_unimplemented]` is applied to a trait definition
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index f71d5284052..5e7bfa5e3bb 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -20,6 +20,10 @@ use crate::lang_items::Duplicate;
 #[diag(passes_incorrect_do_not_recommend_location)]
 pub(crate) struct IncorrectDoNotRecommendLocation;
 
+#[derive(LintDiagnostic)]
+#[diag(passes_incorrect_do_not_recommend_args)]
+pub(crate) struct DoNotRecommendDoesNotExpectArgs;
+
 #[derive(Diagnostic)]
 #[diag(passes_autodiff_attr)]
 pub(crate) struct AutoDiffAttr {
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index edee19c280a..b24e343c58d 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -689,8 +689,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             && let [namespace, attribute, ..] = &*path.segments
             && namespace.ident.name == sym::diagnostic
             && !(attribute.ident.name == sym::on_unimplemented
-                || (attribute.ident.name == sym::do_not_recommend
-                    && self.tcx.features().do_not_recommend()))
+                || attribute.ident.name == sym::do_not_recommend)
         {
             let distance =
                 edit_distance(attribute.ident.name.as_str(), sym::on_unimplemented.as_str(), 5);
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 922866f95dc..18bd9bb8118 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -108,12 +108,12 @@
 // Library features:
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(coverage_attribute))]
+#![cfg_attr(bootstrap, feature(do_not_recommend))]
 #![feature(array_ptr_get)]
 #![feature(asm_experimental_arch)]
 #![feature(const_eval_select)]
 #![feature(const_typed_swap)]
 #![feature(core_intrinsics)]
-#![feature(do_not_recommend)]
 #![feature(internal_impls_macro)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.current.stderr
index 5d0c1826411..28e7975c7a2 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.current.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.current.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `&str: AsExpression<Integer>` is not satisfied
-  --> $DIR/as_expression.rs:57:15
+  --> $DIR/as_expression.rs:55:15
    |
 LL |     SelectInt.check("bar");
    |               ^^^^^ the trait `AsExpression<Integer>` is not implemented for `&str`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.next.stderr
index 1e1eae852f9..1b76669ccb0 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.next.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.next.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `&str: AsExpression<<SelectInt as Expression>::SqlType>` is not satisfied
-  --> $DIR/as_expression.rs:57:21
+  --> $DIR/as_expression.rs:55:21
    |
 LL |     SelectInt.check("bar");
    |               ----- ^^^^^ the trait `AsExpression<<SelectInt as Expression>::SqlType>` is not implemented for `&str`
@@ -8,7 +8,7 @@ LL |     SelectInt.check("bar");
    |
    = help: the trait `AsExpression<Text>` is implemented for `&str`
 note: required by a bound in `Foo::check`
-  --> $DIR/as_expression.rs:48:12
+  --> $DIR/as_expression.rs:46:12
    |
 LL |     fn check<T>(&self, _: T) -> <T as AsExpression<<Self as Expression>::SqlType>>::Expression
    |        ----- required by a bound in this associated function
@@ -17,7 +17,7 @@ LL |         T: AsExpression<Self::SqlType>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `Foo::check`
 
 error[E0277]: the trait bound `&str: AsExpression<Integer>` is not satisfied
-  --> $DIR/as_expression.rs:57:15
+  --> $DIR/as_expression.rs:55:15
    |
 LL |     SelectInt.check("bar");
    |               ^^^^^ the trait `AsExpression<Integer>` is not implemented for `&str`
@@ -27,7 +27,7 @@ LL |     SelectInt.check("bar");
    = help: for that trait implementation, expected `Text`, found `Integer`
 
 error[E0271]: type mismatch resolving `<SelectInt as Expression>::SqlType == Text`
-  --> $DIR/as_expression.rs:57:5
+  --> $DIR/as_expression.rs:55:5
    |
 LL |     SelectInt.check("bar");
    |     ^^^^^^^^^^^^^^^^^^^^^^ expected `Text`, found `Integer`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs
index 37b4429f694..583b3c4675a 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/as_expression.rs
@@ -2,8 +2,6 @@
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
 
-#![feature(do_not_recommend)]
-
 pub trait Expression {
     type SqlType;
 }
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.rs b/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.rs
deleted file mode 100644
index 5548fa2f52e..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-#![allow(unknown_or_malformed_diagnostic_attributes)]
-
-trait Foo {}
-
-#[diagnostic::do_not_recommend]
-impl<A> Foo for (A,) {}
-
-#[diagnostic::do_not_recommend]
-impl<A, B> Foo for (A, B) {}
-
-#[diagnostic::do_not_recommend]
-impl<A, B, C> Foo for (A, B, C) {}
-
-impl Foo for i32 {}
-
-fn check(a: impl Foo) {}
-
-fn main() {
-    check(());
-    //~^ ERROR the trait bound `(): Foo` is not satisfied
-}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.stderr
deleted file mode 100644
index be17476524a..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/do_not_apply_attribute_without_feature_flag.stderr
+++ /dev/null
@@ -1,25 +0,0 @@
-error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/do_not_apply_attribute_without_feature_flag.rs:19:11
-   |
-LL |     check(());
-   |     ----- ^^ the trait `Foo` is not implemented for `()`
-   |     |
-   |     required by a bound introduced by this call
-   |
-   = help: the following other types implement trait `Foo`:
-             (A, B)
-             (A, B, C)
-             (A,)
-note: required by a bound in `check`
-  --> $DIR/do_not_apply_attribute_without_feature_flag.rs:16:18
-   |
-LL | fn check(a: impl Foo) {}
-   |                  ^^^ required by this bound in `check`
-help: use a unary tuple instead
-   |
-LL |     check(((),));
-   |           +  ++
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.current.stderr
new file mode 100644
index 00000000000..47597a5d405
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.current.stderr
@@ -0,0 +1,22 @@
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:10:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
+
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:14:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted = "foo")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:18:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted(42))]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 3 warnings emitted
+
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.next.stderr
new file mode 100644
index 00000000000..47597a5d405
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.next.stderr
@@ -0,0 +1,22 @@
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:10:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
+
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:14:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted = "foo")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` does not expect any arguments
+  --> $DIR/does_not_acccept_args.rs:18:1
+   |
+LL | #[diagnostic::do_not_recommend(not_accepted(42))]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 3 warnings emitted
+
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.rs b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.rs
new file mode 100644
index 00000000000..eeff5e2e6e8
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/does_not_acccept_args.rs
@@ -0,0 +1,22 @@
+//@ check-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+trait Foo {}
+trait Bar {}
+trait Baz {}
+
+#[diagnostic::do_not_recommend(not_accepted)]
+//~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
+impl<T> Foo for T where T: Send {}
+
+#[diagnostic::do_not_recommend(not_accepted = "foo")]
+//~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
+impl<T> Bar for T where T: Send {}
+
+#[diagnostic::do_not_recommend(not_accepted(42))]
+//~^ WARNING `#[diagnostic::do_not_recommend]` does not expect any arguments
+impl<T> Baz for T where T: Send {}
+
+fn main() {}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.rs b/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.rs
deleted file mode 100644
index 5a26d28188c..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-#![feature(do_not_recommend)]
-
-pub trait Foo {}
-
-impl Foo for i32 {}
-
-pub trait Bar {}
-
-#[diagnostic::do_not_recommend]
-impl<T: Foo> Bar for T {}
-
-fn stuff<T: Bar>(_: T) {}
-
-fn main() {
-    stuff(1u8);
-    //~^ the trait bound `u8: Bar` is not satisfied
-}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.stderr
deleted file mode 100644
index 3951231fa2e..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/feature-gate-do_not_recommend.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error[E0277]: the trait bound `u8: Bar` is not satisfied
-  --> $DIR/feature-gate-do_not_recommend.rs:15:11
-   |
-LL |     stuff(1u8);
-   |           ^^^ the trait `Bar` is not implemented for `u8`
-   |
-note: required by a bound in `stuff`
-  --> $DIR/feature-gate-do_not_recommend.rs:12:13
-   |
-LL | fn stuff<T: Bar>(_: T) {}
-   |             ^^^ required by this bound in `stuff`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.current.stderr
index c83fd46db58..ee6ebabadd9 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.current.stderr
@@ -1,5 +1,5 @@
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:4:1
+  --> $DIR/incorrect-locations.rs:6:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,46 +7,52 @@ LL | #[diagnostic::do_not_recommend]
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:8:1
+  --> $DIR/incorrect-locations.rs:10:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:12:1
+  --> $DIR/incorrect-locations.rs:14:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:16:1
+  --> $DIR/incorrect-locations.rs:18:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:20:1
+  --> $DIR/incorrect-locations.rs:22:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:24:1
+  --> $DIR/incorrect-locations.rs:26:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:28:1
+  --> $DIR/incorrect-locations.rs:30:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
-  --> $DIR/incorrect-locations.rs:32:1
+  --> $DIR/incorrect-locations.rs:34:1
    |
 LL | #[diagnostic::do_not_recommend]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-warning: 8 warnings emitted
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:38:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 9 warnings emitted
 
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.next.stderr
new file mode 100644
index 00000000000..ee6ebabadd9
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.next.stderr
@@ -0,0 +1,58 @@
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:6:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:10:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:14:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:18:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:22:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:26:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:30:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:34:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
+  --> $DIR/incorrect-locations.rs:38:1
+   |
+LL | #[diagnostic::do_not_recommend]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: 9 warnings emitted
+
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.rs b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.rs
index 400ef83873e..1cf436aa2af 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/incorrect-locations.rs
@@ -1,5 +1,7 @@
 //@ check-pass
-#![feature(do_not_recommend)]
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
 
 #[diagnostic::do_not_recommend]
 //~^WARN `#[diagnostic::do_not_recommend]` can only be placed
@@ -19,6 +21,10 @@ enum Enum {}
 
 #[diagnostic::do_not_recommend]
 //~^WARN `#[diagnostic::do_not_recommend]` can only be placed
+impl Enum {}
+
+#[diagnostic::do_not_recommend]
+//~^WARN `#[diagnostic::do_not_recommend]` can only be placed
 extern "C" {}
 
 #[diagnostic::do_not_recommend]
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/nested.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/nested.current.stderr
new file mode 100644
index 00000000000..b14c68d6897
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/nested.current.stderr
@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `(): Root` is not satisfied
+  --> $DIR/nested.rs:21:18
+   |
+LL |     needs_root::<()>();
+   |                  ^^ the trait `Root` is not implemented for `()`
+   |
+note: required by a bound in `needs_root`
+  --> $DIR/nested.rs:18:18
+   |
+LL | fn needs_root<T: Root>() {}
+   |                  ^^^^ required by this bound in `needs_root`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/nested.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/nested.next.stderr
new file mode 100644
index 00000000000..b14c68d6897
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/nested.next.stderr
@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `(): Root` is not satisfied
+  --> $DIR/nested.rs:21:18
+   |
+LL |     needs_root::<()>();
+   |                  ^^ the trait `Root` is not implemented for `()`
+   |
+note: required by a bound in `needs_root`
+  --> $DIR/nested.rs:18:18
+   |
+LL | fn needs_root<T: Root>() {}
+   |                  ^^^^ required by this bound in `needs_root`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/nested.rs b/tests/ui/diagnostic_namespace/do_not_recommend/nested.rs
new file mode 100644
index 00000000000..6534157d1fb
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/nested.rs
@@ -0,0 +1,23 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+trait Root {}
+trait DontRecommend {}
+trait Other {}
+trait Child {}
+
+#[diagnostic::do_not_recommend]
+impl<T> Root for T where T: DontRecommend {}
+
+impl<T> DontRecommend for T where T: Other {}
+
+#[diagnostic::do_not_recommend]
+impl<T> Other for T where T: Child {}
+
+fn needs_root<T: Root>() {}
+
+fn main() {
+    needs_root::<()>();
+    //~^ ERROR the trait bound `(): Root` is not satisfied
+}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/simple.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/simple.current.stderr
index 729cb5694e2..884b13c17b8 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/simple.current.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/simple.current.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `*mut (): Foo` is not satisfied
-  --> $DIR/simple.rs:17:17
+  --> $DIR/simple.rs:15:17
    |
 LL |     needs_foo::<*mut ()>();
    |                 ^^^^^^^ the trait `Foo` is not implemented for `*mut ()`
    |
 note: required by a bound in `needs_foo`
-  --> $DIR/simple.rs:12:17
+  --> $DIR/simple.rs:10:17
    |
 LL | fn needs_foo<T: Foo>() {}
    |                 ^^^ required by this bound in `needs_foo`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/simple.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/simple.next.stderr
index 729cb5694e2..884b13c17b8 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/simple.next.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/simple.next.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `*mut (): Foo` is not satisfied
-  --> $DIR/simple.rs:17:17
+  --> $DIR/simple.rs:15:17
    |
 LL |     needs_foo::<*mut ()>();
    |                 ^^^^^^^ the trait `Foo` is not implemented for `*mut ()`
    |
 note: required by a bound in `needs_foo`
-  --> $DIR/simple.rs:12:17
+  --> $DIR/simple.rs:10:17
    |
 LL | fn needs_foo<T: Foo>() {}
    |                 ^^^ required by this bound in `needs_foo`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/simple.rs b/tests/ui/diagnostic_namespace/do_not_recommend/simple.rs
index 780649b009c..6bca2b724d2 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/simple.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/simple.rs
@@ -2,8 +2,6 @@
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
 
-#![feature(do_not_recommend)]
-
 trait Foo {}
 
 #[diagnostic::do_not_recommend]
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.current.stderr
index 41a10a61e1d..d8605806395 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.current.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.current.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `(): Root` is not satisfied
-  --> $DIR/stacked.rs:19:18
+  --> $DIR/stacked.rs:17:18
    |
 LL |     needs_root::<()>();
    |                  ^^ the trait `Root` is not implemented for `()`
    |
 note: required by a bound in `needs_root`
-  --> $DIR/stacked.rs:16:18
+  --> $DIR/stacked.rs:14:18
    |
 LL | fn needs_root<T: Root>() {}
    |                  ^^^^ required by this bound in `needs_root`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.next.stderr
index 41a10a61e1d..d8605806395 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.next.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.next.stderr
@@ -1,11 +1,11 @@
 error[E0277]: the trait bound `(): Root` is not satisfied
-  --> $DIR/stacked.rs:19:18
+  --> $DIR/stacked.rs:17:18
    |
 LL |     needs_root::<()>();
    |                  ^^ the trait `Root` is not implemented for `()`
    |
 note: required by a bound in `needs_root`
-  --> $DIR/stacked.rs:16:18
+  --> $DIR/stacked.rs:14:18
    |
 LL | fn needs_root<T: Root>() {}
    |                  ^^^^ required by this bound in `needs_root`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.rs b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.rs
index fc355bdc4e2..842e04b9d90 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/stacked.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/stacked.rs
@@ -2,8 +2,6 @@
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
 
-#![feature(do_not_recommend)]
-
 trait Root {}
 trait DontRecommend {}
 trait Other {}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.current.stderr
index ca9a6ebc1c4..95ccbb92a89 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.current.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.current.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/supress_suggestions_in_help.rs:23:11
+  --> $DIR/supress_suggestions_in_help.rs:21:11
    |
 LL |     check(());
    |     ----- ^^ the trait `Foo` is not implemented for `()`
@@ -8,7 +8,7 @@ LL |     check(());
    |
    = help: the trait `Foo` is implemented for `i32`
 note: required by a bound in `check`
-  --> $DIR/supress_suggestions_in_help.rs:20:18
+  --> $DIR/supress_suggestions_in_help.rs:18:18
    |
 LL | fn check(a: impl Foo) {}
    |                  ^^^ required by this bound in `check`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.next.stderr
index ca9a6ebc1c4..95ccbb92a89 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.next.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.next.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `(): Foo` is not satisfied
-  --> $DIR/supress_suggestions_in_help.rs:23:11
+  --> $DIR/supress_suggestions_in_help.rs:21:11
    |
 LL |     check(());
    |     ----- ^^ the trait `Foo` is not implemented for `()`
@@ -8,7 +8,7 @@ LL |     check(());
    |
    = help: the trait `Foo` is implemented for `i32`
 note: required by a bound in `check`
-  --> $DIR/supress_suggestions_in_help.rs:20:18
+  --> $DIR/supress_suggestions_in_help.rs:18:18
    |
 LL | fn check(a: impl Foo) {}
    |                  ^^^ required by this bound in `check`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs
index ef6f255c351..2c7c1516123 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs
@@ -2,8 +2,6 @@
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
 
-#![feature(do_not_recommend)]
-
 trait Foo {}
 
 #[diagnostic::do_not_recommend]
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.current.stderr
index bcede8a255f..b53febbb71a 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.current.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.current.stderr
@@ -1,11 +1,11 @@
 error[E0277]: Very important message!
-  --> $DIR/type_mismatch.rs:25:14
+  --> $DIR/type_mismatch.rs:23:14
    |
 LL |     verify::<u8>();
    |              ^^ the trait `TheImportantOne` is not implemented for `u8`
    |
 note: required by a bound in `verify`
-  --> $DIR/type_mismatch.rs:22:14
+  --> $DIR/type_mismatch.rs:20:14
    |
 LL | fn verify<T: TheImportantOne>() {}
    |              ^^^^^^^^^^^^^^^ required by this bound in `verify`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.next.stderr
index bcede8a255f..b53febbb71a 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.next.stderr
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.next.stderr
@@ -1,11 +1,11 @@
 error[E0277]: Very important message!
-  --> $DIR/type_mismatch.rs:25:14
+  --> $DIR/type_mismatch.rs:23:14
    |
 LL |     verify::<u8>();
    |              ^^ the trait `TheImportantOne` is not implemented for `u8`
    |
 note: required by a bound in `verify`
-  --> $DIR/type_mismatch.rs:22:14
+  --> $DIR/type_mismatch.rs:20:14
    |
 LL | fn verify<T: TheImportantOne>() {}
    |              ^^^^^^^^^^^^^^^ required by this bound in `verify`
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.rs b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.rs
index d6721ccc848..7f30fdb06c7 100644
--- a/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.rs
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/type_mismatch.rs
@@ -2,8 +2,6 @@
 //@ ignore-compare-mode-next-solver (explicit revisions)
 //@[next] compile-flags: -Znext-solver
 
-#![feature(do_not_recommend)]
-
 #[diagnostic::on_unimplemented(message = "Very important message!")]
 trait TheImportantOne {}
 
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.rs b/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.rs
deleted file mode 100644
index ccc687aa5b3..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-#![deny(unknown_or_malformed_diagnostic_attributes)]
-trait Foo {}
-
-#[diagnostic::do_not_recommend]
-//~^ ERROR unknown diagnostic attribute [unknown_or_malformed_diagnostic_attributes]
-impl Foo for i32 {}
-
-fn main() {}
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.stderr
deleted file mode 100644
index d8332229d4f..00000000000
--- a/tests/ui/diagnostic_namespace/do_not_recommend/unstable-feature.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: unknown diagnostic attribute
-  --> $DIR/unstable-feature.rs:4:15
-   |
-LL | #[diagnostic::do_not_recommend]
-   |               ^^^^^^^^^^^^^^^^
-   |
-note: the lint level is defined here
-  --> $DIR/unstable-feature.rs:1:9
-   |
-LL | #![deny(unknown_or_malformed_diagnostic_attributes)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.current.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.current.stderr
new file mode 100644
index 00000000000..a8429ff60f8
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.current.stderr
@@ -0,0 +1,10 @@
+error: lifetime may not live long enough
+  --> $DIR/with_lifetime.rs:17:5
+   |
+LL | fn foo<'a>(a: &'a ()) {
+   |        -- lifetime `'a` defined here
+LL |     needs_root::<&'a ()>();
+   |     ^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.next.stderr b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.next.stderr
new file mode 100644
index 00000000000..a8429ff60f8
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.next.stderr
@@ -0,0 +1,10 @@
+error: lifetime may not live long enough
+  --> $DIR/with_lifetime.rs:17:5
+   |
+LL | fn foo<'a>(a: &'a ()) {
+   |        -- lifetime `'a` defined here
+LL |     needs_root::<&'a ()>();
+   |     ^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'static`
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.rs b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.rs
new file mode 100644
index 00000000000..6a67d83d5fe
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/do_not_recommend/with_lifetime.rs
@@ -0,0 +1,23 @@
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+trait Root {}
+trait DontRecommend {}
+
+impl<T> Root for T where T: DontRecommend {}
+
+// this has no effect yet for resolving the trait error below
+#[diagnostic::do_not_recommend]
+impl<T> DontRecommend for &'static T {}
+
+fn needs_root<T: Root>() {}
+
+fn foo<'a>(a: &'a ()) {
+    needs_root::<&'a ()>();
+    //~^ ERROR lifetime may not live long enough
+}
+
+fn main() {
+    foo(&());
+}