Rollup merge of #119888 - weiznich:stablize_diagnostic_namespace, r=compiler-errors

Stabilize the `#[diagnostic]` namespace and `#[diagnostic::on_unimplemented]` attribute

This PR stabilizes the `#[diagnostic]` attribute namespace and a minimal option of the `#[diagnostic::on_unimplemented]` attribute.

The `#[diagnostic]` attribute namespace is meant to provide a home for attributes that allow users to influence error messages emitted by the compiler. The compiler is not guaranteed to use any of this hints, however it should accept any (non-)existing attribute in this namespace and potentially emit lint-warnings for unused attributes and options. This is meant to allow discarding certain attributes/options in the future to allow fundamental changes to the compiler without the need to keep then non-meaningful options working.

The `#[diagnostic::on_unimplemented]` attribute is allowed to appear on a trait definition. This allows crate authors to hint the compiler to emit a specific error message if a certain trait is not implemented. For the `#[diagnostic::on_unimplemented]` attribute the following options are implemented:

* `message` which provides the text for the top level error message
* `label` which provides the text for the label shown inline in the broken code in the error message
* `note` which provides additional notes.

The `note` option can appear several times, which results in several note messages being emitted. If any of the other options appears several times the first occurrence of the relevant option specifies the actually used value. Any other occurrence generates an lint warning. For any other non-existing option a lint-warning is generated.

All three options accept a text as argument. This text is allowed to contain format parameters referring to generic argument or `Self` by name via the `{Self}` or `{NameOfGenericArgument}` syntax. For any non-existing argument a lint warning is generated.

This allows to have a trait definition like:

```rust
#[diagnostic::on_unimplemented(
    message = "My Message for `ImportantTrait<{A}>` is not implemented for `{Self}`",
    label = "My Label",
    note = "Note 1",
    note = "Note 2"
)]
trait ImportantTrait<A> {}

```

which then generates for the following code

```rust
fn use_my_trait(_: impl ImportantTrait<i32>) {}

fn main() {
    use_my_trait(String::new());
}
```

this error message:

```
error[E0277]: My Message for `ImportantTrait<i32>` is not implemented for `String`
  --> src/main.rs:14:18
   |
14 |     use_my_trait(String::new());
   |     ------------ ^^^^^^^^^^^^^ My Label
   |     |
   |     required by a bound introduced by this call
   |
   = help: the trait `ImportantTrait<i32>` is not implemented for `String`
   = note: Note 1
   = note: Note 2
```

[Playground with the unstable feature](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=05133acce8e1d163d481e97631f17536)

Fixes #111996

27 files changed, 93 insertions, 273 deletions

diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index d9e3f028697..2e14238f950 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -206,14 +206,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 );
             }
         }
-        if !attr.is_doc_comment()
-            && let [seg, _] = attr.get_normal_item().path.segments.as_slice()
-            && seg.ident.name == sym::diagnostic
-            && !self.features.diagnostic_namespace
-        {
-            let msg = "`#[diagnostic]` attribute name space is experimental";
-            gate!(self, diagnostic_namespace, seg.ident.span, msg);
-        }
 
         // Emit errors for non-staged-api crates.
         if !self.features.staged_api {
diff --git a/compiler/rustc_feature/src/accepted.rs b/compiler/rustc_feature/src/accepted.rs
index 1b2993dabdb..7e5197f16f9 100644
--- a/compiler/rustc_feature/src/accepted.rs
+++ b/compiler/rustc_feature/src/accepted.rs
@@ -146,6 +146,8 @@ declare_features! (
     (accepted, derive_default_enum, "1.62.0", Some(86985)),
     /// Allows the use of destructuring assignments.
     (accepted, destructuring_assignment, "1.59.0", Some(71126)),
+    /// Allows using the `#[diagnostic]` attribute tool namespace
+    (accepted, diagnostic_namespace, "CURRENT_RUSTC_VERSION", Some(111996)),
     /// Allows `#[doc(alias = "...")]`.
     (accepted, doc_alias, "1.48.0", Some(50146)),
     /// Allows `..` in tuple (struct) patterns.
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 17c4d81474e..9f4bead21dc 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -436,8 +436,6 @@ declare_features! (
     (unstable, deprecated_safe, "1.61.0", Some(94978)),
     /// Allows having using `suggestion` in the `#[deprecated]` attribute.
     (unstable, deprecated_suggestion, "1.61.0", Some(94785)),
-    /// Allows using the `#[diagnostic]` attribute tool namespace
-    (unstable, diagnostic_namespace, "1.73.0", Some(111996)),
     /// Controls errors in trait implementations.
     (unstable, do_not_recommend, "1.67.0", Some(51992)),
     /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 7b735d48bdf..0f7885769c2 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -202,6 +202,7 @@
 //
 // Language features:
 // tidy-alphabetical-start
+#![cfg_attr(bootstrap, feature(diagnostic_namespace))]
 #![cfg_attr(bootstrap, feature(platform_intrinsics))]
 #![feature(abi_unadjusted)]
 #![feature(adt_const_params)]
@@ -223,7 +224,6 @@
 #![feature(const_trait_impl)]
 #![feature(decl_macro)]
 #![feature(deprecated_suggestion)]
-#![feature(diagnostic_namespace)]
 #![feature(doc_cfg)]
 #![feature(doc_cfg_hide)]
 #![feature(doc_notable_trait)]
diff --git a/src/doc/unstable-book/src/language-features/diagnostic-namespace.md b/src/doc/unstable-book/src/language-features/diagnostic-namespace.md
deleted file mode 100644
index 7c46811a27a..00000000000
--- a/src/doc/unstable-book/src/language-features/diagnostic-namespace.md
+++ /dev/null
@@ -1,84 +0,0 @@
-# `diagnostic_namespace`
-
-The tracking issue for this feature is: [#111996]
-
-[#111996]: https://github.com/rust-lang/rust/issues/111996
-
-------------------------
-
-The `diagnostic_namespace` feature permits customization of compilation errors.
-
-## diagnostic::on_unimplemented
-
-With [#114452] support for `diagnostic::on_unimplemented` was added.
-
-When used on a trait declaration, the following options are available:
-
-* `message` to customize the primary error message
-* `note` to add a customized note message to an error message
-* `label` to customize the label part of the error message
-
-The attribute will hint to the compiler to use these in error messages:
-```rust
-// some library
-#![feature(diagnostic_namespace)]
-
-#[diagnostic::on_unimplemented(
-    message = "cannot insert element",
-    label = "cannot be put into a table",
-    note = "see <link> for more information about the Table api"
-)]
-pub trait Element {
-    // ...
-}
-```
-
-```rust,compile_fail,E0277
-# #![feature(diagnostic_namespace)]
-#
-# #[diagnostic::on_unimplemented(
-#    message = "cannot insert element",
-#    label = "cannot be put into a table",
-#    note = "see <link> for more information about the Table api"
-# )]
-# pub trait Element {
-#    // ...
-# }
-# struct Table;
-# impl Table {
-#    fn insert<T: Element>(&self, element: T) {
-#        // ..
-#    }
-# }
-# fn main() {
-#    let table = Table;
-#    let element = ();
-// user code
-table.insert(element);
-# }
-```
-
-```text
-error[E0277]: cannot insert element
-  --> src/main.rs:24:18
-   |
-24 |     table.insert(element);
-   |           ------ ^^^^^^^ cannot be put into a table
-   |           |
-   |           required by a bound introduced by this call
-   |
-   = help: the trait `Element` is not implemented for `<type>`
-   = note: see <link> for more information about the Table api
-note: required by a bound in `Table::insert`
-  --> src/main.rs:15:18
-   |
-15 |     fn insert<T: Element>(&self, element: T) {
-   |                  ^^^^^^^ required by this bound in `Table::insert`
-
-For more information about this error, try `rustc --explain E0277`.
-```
-
-See [RFC 3368] for more information.
-
-[#114452]: https://github.com/rust-lang/rust/pull/114452
-[RFC 3368]: https://github.com/rust-lang/rfcs/blob/master/text/3368-diagnostic-attribute-namespace.md
diff --git a/tests/ui/diagnostic_namespace/existing_proc_macros.rs b/tests/ui/diagnostic_namespace/existing_proc_macros.rs
index 2bc58aea8fc..014ec46f1b9 100644
--- a/tests/ui/diagnostic_namespace/existing_proc_macros.rs
+++ b/tests/ui/diagnostic_namespace/existing_proc_macros.rs
@@ -1,4 +1,3 @@
-#![feature(diagnostic_namespace)]
 //@ check-pass
 //@ aux-build:proc-macro-helper.rs
 
diff --git a/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.rs b/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.rs
deleted file mode 100644
index b08e291621f..00000000000
--- a/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-#[diagnostic::non_existing_attribute]
-//~^ERROR `#[diagnostic]` attribute name space is experimental [E0658]
-//~|WARNING unknown diagnostic attribute [unknown_or_malformed_diagnostic_attributes]
-pub trait Bar {
-}
-
-#[diagnostic::non_existing_attribute(with_option = "foo")]
-//~^ERROR `#[diagnostic]` attribute name space is experimental [E0658]
-//~|WARNING unknown diagnostic attribute [unknown_or_malformed_diagnostic_attributes]
-struct Foo;
-
-fn main() {
-}
diff --git a/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.stderr b/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.stderr
deleted file mode 100644
index 38424c13d86..00000000000
--- a/tests/ui/diagnostic_namespace/feature-gate-diagnostic_namespace.stderr
+++ /dev/null
@@ -1,37 +0,0 @@
-error[E0658]: `#[diagnostic]` attribute name space is experimental
-  --> $DIR/feature-gate-diagnostic_namespace.rs:1:3
-   |
-LL | #[diagnostic::non_existing_attribute]
-   |   ^^^^^^^^^^
-   |
-   = note: see issue #111996 <https://github.com/rust-lang/rust/issues/111996> for more information
-   = help: add `#![feature(diagnostic_namespace)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error[E0658]: `#[diagnostic]` attribute name space is experimental
-  --> $DIR/feature-gate-diagnostic_namespace.rs:7:3
-   |
-LL | #[diagnostic::non_existing_attribute(with_option = "foo")]
-   |   ^^^^^^^^^^
-   |
-   = note: see issue #111996 <https://github.com/rust-lang/rust/issues/111996> for more information
-   = help: add `#![feature(diagnostic_namespace)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-warning: unknown diagnostic attribute
-  --> $DIR/feature-gate-diagnostic_namespace.rs:1:15
-   |
-LL | #[diagnostic::non_existing_attribute]
-   |               ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
-
-warning: unknown diagnostic attribute
-  --> $DIR/feature-gate-diagnostic_namespace.rs:7:15
-   |
-LL | #[diagnostic::non_existing_attribute(with_option = "foo")]
-   |               ^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors; 2 warnings emitted
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.rs b/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.rs
index 95465701bf8..f6957b1448d 100644
--- a/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.rs
+++ b/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.rs
@@ -1,4 +1,3 @@
-#![feature(diagnostic_namespace)]
 //@ check-pass
 #[diagnostic::non_existing_attribute]
 //~^WARN unknown diagnostic attribute
diff --git a/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.stderr b/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.stderr
index 753077b365e..c073ec9b103 100644
--- a/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.stderr
+++ b/tests/ui/diagnostic_namespace/non_existing_attributes_accepted.stderr
@@ -1,5 +1,5 @@
 warning: unknown diagnostic attribute
-  --> $DIR/non_existing_attributes_accepted.rs:3:15
+  --> $DIR/non_existing_attributes_accepted.rs:2:15
    |
 LL | #[diagnostic::non_existing_attribute]
    |               ^^^^^^^^^^^^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL | #[diagnostic::non_existing_attribute]
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: unknown diagnostic attribute
-  --> $DIR/non_existing_attributes_accepted.rs:8:15
+  --> $DIR/non_existing_attributes_accepted.rs:7:15
    |
 LL | #[diagnostic::non_existing_attribute(with_option = "foo")]
    |               ^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/auxiliary/other.rs b/tests/ui/diagnostic_namespace/on_unimplemented/auxiliary/other.rs
index 884bab2800a..512ef6330e5 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/auxiliary/other.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/auxiliary/other.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(
     message = "Message",
     note = "Note",
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.rs b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.rs
index eb985c062f3..30a85ff2199 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(
     on(_Self = "&str"),
     //~^WARN malformed `on_unimplemented` attribute
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.stderr
index 75a701f0b5f..e34b917f67e 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_accept_options_of_the_internal_rustc_attribute.stderr
@@ -1,5 +1,5 @@
 warning: `#[diagnostic::on_unimplemented]` can only be applied to trait definitions
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:24:1
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:22:1
    |
 LL | #[diagnostic::on_unimplemented(message = "Not allowed to apply it on a impl")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL | #[diagnostic::on_unimplemented(message = "Not allowed to apply it on a impl
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:4:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:2:5
    |
 LL |     on(_Self = "&str"),
    |     ^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -15,7 +15,7 @@ LL |     on(_Self = "&str"),
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:10:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:8:5
    |
 LL |     parent_label = "in this scope",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -23,7 +23,7 @@ LL |     parent_label = "in this scope",
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:13:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:11:5
    |
 LL |     append_const_msg
    |     ^^^^^^^^^^^^^^^^ invalid option found here
@@ -31,7 +31,7 @@ LL |     append_const_msg
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:19:32
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:17:32
    |
 LL | #[diagnostic::on_unimplemented = "Message"]
    |                                ^^^^^^^^^^^ invalid option found here
@@ -39,7 +39,7 @@ LL | #[diagnostic::on_unimplemented = "Message"]
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: there is no parameter `from_desugaring` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -47,7 +47,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `direct` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -55,7 +55,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `cause` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -63,7 +63,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `integral` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -71,7 +71,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `integer` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -79,7 +79,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `float` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -87,7 +87,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `_Self` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -95,7 +95,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `crate_local` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -103,7 +103,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `Trait` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -111,7 +111,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: there is no parameter `ItemContext` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -119,7 +119,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:4:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:2:5
    |
 LL |     on(_Self = "&str"),
    |     ^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -128,7 +128,7 @@ LL |     on(_Self = "&str"),
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:10:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:8:5
    |
 LL |     parent_label = "in this scope",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -137,7 +137,7 @@ LL |     parent_label = "in this scope",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:13:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:11:5
    |
 LL |     append_const_msg
    |     ^^^^^^^^^^^^^^^^ invalid option found here
@@ -146,7 +146,7 @@ LL |     append_const_msg
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: trait has `()` and `i32` as params
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:61:15
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:59:15
    |
 LL |     takes_foo(());
    |     --------- ^^ trait has `()` and `i32` as params
@@ -156,18 +156,18 @@ LL |     takes_foo(());
    = help: the trait `Foo<i32>` is not implemented for `()`
    = note: trait has `()` and `i32` as params
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:17:1
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:15:1
    |
 LL | trait Foo<T> {}
    | ^^^^^^^^^^^^
 note: required by a bound in `takes_foo`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:56:22
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:54:22
    |
 LL | fn takes_foo(_: impl Foo<i32>) {}
    |                      ^^^^^^^^ required by this bound in `takes_foo`
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:19:32
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:17:32
    |
 LL | #[diagnostic::on_unimplemented = "Message"]
    |                                ^^^^^^^^^^^ invalid option found here
@@ -176,7 +176,7 @@ LL | #[diagnostic::on_unimplemented = "Message"]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: the trait bound `(): Bar` is not satisfied
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:63:15
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:61:15
    |
 LL |     takes_bar(());
    |     --------- ^^ the trait `Bar` is not implemented for `()`
@@ -185,13 +185,13 @@ LL |     takes_bar(());
    |
    = help: the trait `Bar` is implemented for `i32`
 note: required by a bound in `takes_bar`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:57:22
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:55:22
    |
 LL | fn takes_bar(_: impl Bar) {}
    |                      ^^^ required by this bound in `takes_bar`
 
 warning: there is no parameter `from_desugaring` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -200,7 +200,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `direct` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -209,7 +209,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `cause` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -218,7 +218,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `integral` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -227,7 +227,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `integer` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:31:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:29:5
    |
 LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -236,7 +236,7 @@ LL |     message = "{from_desugaring}{direct}{cause}{integral}{integer}",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `float` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -245,7 +245,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `_Self` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -254,7 +254,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `crate_local` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -263,7 +263,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `Trait` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -272,7 +272,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: there is no parameter `ItemContext` on trait `Baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:42:5
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:40:5
    |
 LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -281,7 +281,7 @@ LL |     label = "{float}{_Self}{crate_local}{Trait}{ItemContext}"
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: {from_desugaring}{direct}{cause}{integral}{integer}
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:65:15
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:63:15
    |
 LL |     takes_baz(());
    |     --------- ^^ {float}{_Self}{crate_local}{Trait}{ItemContext}
@@ -290,12 +290,12 @@ LL |     takes_baz(());
    |
    = help: the trait `Baz` is not implemented for `()`
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:54:1
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:52:1
    |
 LL | trait Baz {}
    | ^^^^^^^^^
 note: required by a bound in `takes_baz`
-  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:58:22
+  --> $DIR/do_not_accept_options_of_the_internal_rustc_attribute.rs:56:22
    |
 LL | fn takes_baz(_: impl Baz) {}
    |                      ^^^ required by this bound in `takes_baz`
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.rs b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.rs
index 12fe988170a..b4234066bb1 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(unsupported = "foo")]
 //~^WARN malformed `on_unimplemented` attribute
 //~|WARN malformed `on_unimplemented` attribute
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.stderr
index 11263580b15..dc0c1948236 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/do_not_fail_parsing_on_invalid_options_1.stderr
@@ -1,5 +1,5 @@
 warning: `#[diagnostic::on_unimplemented]` can only be applied to trait definitions
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:8:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:6:1
    |
 LL | #[diagnostic::on_unimplemented(message = "Baz")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,7 +7,7 @@ LL | #[diagnostic::on_unimplemented(message = "Baz")]
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:3:32
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:1:32
    |
 LL | #[diagnostic::on_unimplemented(unsupported = "foo")]
    |                                ^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -15,7 +15,7 @@ LL | #[diagnostic::on_unimplemented(unsupported = "foo")]
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:12:50
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:10:50
    |
 LL | #[diagnostic::on_unimplemented(message = "Boom", unsupported = "Bar")]
    |                                                  ^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -23,7 +23,7 @@ LL | #[diagnostic::on_unimplemented(message = "Boom", unsupported = "Bar")]
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:17:50
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:15:50
    |
 LL | #[diagnostic::on_unimplemented(message = "Boom", on(_Self = "i32", message = "whatever"))]
    |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -31,7 +31,7 @@ LL | #[diagnostic::on_unimplemented(message = "Boom", on(_Self = "i32", message
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:22:32
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:20:32
    |
 LL | #[diagnostic::on_unimplemented = "boom"]
    |                                ^^^^^^^^ invalid option found here
@@ -39,7 +39,7 @@ LL | #[diagnostic::on_unimplemented = "boom"]
    = help: only `message`, `note` and `label` are allowed as options
 
 warning: missing options for `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:26:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:24:1
    |
 LL | #[diagnostic::on_unimplemented]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -47,7 +47,7 @@ LL | #[diagnostic::on_unimplemented]
    = help: at least one of the `message`, `note` and `label` options are expected
 
 warning: there is no parameter `DoesNotExist` on trait `Test`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:31:32
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:29:32
    |
 LL | #[diagnostic::on_unimplemented(message = "{DoesNotExist}")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -55,7 +55,7 @@ LL | #[diagnostic::on_unimplemented(message = "{DoesNotExist}")]
    = help: expect either a generic argument name or `{Self}` as format argument
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:3:32
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:1:32
    |
 LL | #[diagnostic::on_unimplemented(unsupported = "foo")]
    |                                ^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -64,7 +64,7 @@ LL | #[diagnostic::on_unimplemented(unsupported = "foo")]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: the trait bound `i32: Foo` is not satisfied
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:43:14
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:41:14
    |
 LL |     take_foo(1_i32);
    |     -------- ^^^^^ the trait `Foo` is not implemented for `i32`
@@ -72,18 +72,18 @@ LL |     take_foo(1_i32);
    |     required by a bound introduced by this call
    |
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:6:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:4:1
    |
 LL | trait Foo {}
    | ^^^^^^^^^
 note: required by a bound in `take_foo`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:36:21
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:34:21
    |
 LL | fn take_foo(_: impl Foo) {}
    |                     ^^^ required by this bound in `take_foo`
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:12:50
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:10:50
    |
 LL | #[diagnostic::on_unimplemented(message = "Boom", unsupported = "Bar")]
    |                                                  ^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -92,7 +92,7 @@ LL | #[diagnostic::on_unimplemented(message = "Boom", unsupported = "Bar")]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: Boom
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:45:14
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:43:14
    |
 LL |     take_baz(1_i32);
    |     -------- ^^^^^ the trait `Baz` is not implemented for `i32`
@@ -100,18 +100,18 @@ LL |     take_baz(1_i32);
    |     required by a bound introduced by this call
    |
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:15:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:13:1
    |
 LL | trait Baz {}
    | ^^^^^^^^^
 note: required by a bound in `take_baz`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:37:21
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:35:21
    |
 LL | fn take_baz(_: impl Baz) {}
    |                     ^^^ required by this bound in `take_baz`
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:17:50
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:15:50
    |
 LL | #[diagnostic::on_unimplemented(message = "Boom", on(_Self = "i32", message = "whatever"))]
    |                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ invalid option found here
@@ -120,7 +120,7 @@ LL | #[diagnostic::on_unimplemented(message = "Boom", on(_Self = "i32", message
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: Boom
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:47:15
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:45:15
    |
 LL |     take_boom(1_i32);
    |     --------- ^^^^^ the trait `Boom` is not implemented for `i32`
@@ -128,18 +128,18 @@ LL |     take_boom(1_i32);
    |     required by a bound introduced by this call
    |
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:20:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:18:1
    |
 LL | trait Boom {}
    | ^^^^^^^^^^
 note: required by a bound in `take_boom`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:38:22
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:36:22
    |
 LL | fn take_boom(_: impl Boom) {}
    |                      ^^^^ required by this bound in `take_boom`
 
 warning: missing options for `on_unimplemented` attribute
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:26:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:24:1
    |
 LL | #[diagnostic::on_unimplemented]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -148,7 +148,7 @@ LL | #[diagnostic::on_unimplemented]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: the trait bound `i32: Whatever` is not satisfied
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:49:19
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:47:19
    |
 LL |     take_whatever(1_i32);
    |     ------------- ^^^^^ the trait `Whatever` is not implemented for `i32`
@@ -156,18 +156,18 @@ LL |     take_whatever(1_i32);
    |     required by a bound introduced by this call
    |
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:29:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:27:1
    |
 LL | trait Whatever {}
    | ^^^^^^^^^^^^^^
 note: required by a bound in `take_whatever`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:39:26
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:37:26
    |
 LL | fn take_whatever(_: impl Whatever) {}
    |                          ^^^^^^^^ required by this bound in `take_whatever`
 
 warning: there is no parameter `DoesNotExist` on trait `Test`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:31:32
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:29:32
    |
 LL | #[diagnostic::on_unimplemented(message = "{DoesNotExist}")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -176,7 +176,7 @@ LL | #[diagnostic::on_unimplemented(message = "{DoesNotExist}")]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: {DoesNotExist}
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:51:15
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:49:15
    |
 LL |     take_test(());
    |     --------- ^^ the trait `Test` is not implemented for `()`
@@ -184,12 +184,12 @@ LL |     take_test(());
    |     required by a bound introduced by this call
    |
 help: this trait has no implementations, consider adding one
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:34:1
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:32:1
    |
 LL | trait Test {}
    | ^^^^^^^^^^
 note: required by a bound in `take_test`
-  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:40:22
+  --> $DIR/do_not_fail_parsing_on_invalid_options_1.rs:38:22
    |
 LL | fn take_test(_: impl Test) {}
    |                      ^^^^ required by this bound in `take_test`
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.rs b/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.rs
deleted file mode 100644
index 609a840c118..00000000000
--- a/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.rs
+++ /dev/null
@@ -1,7 +0,0 @@
-#[diagnostic::on_unimplemented(message = "Foo")]
-//~^ERROR `#[diagnostic]` attribute name space is experimental [E0658]
-pub trait Bar {
-}
-
-fn main() {
-}
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.stderr
deleted file mode 100644
index 719322fa0f5..00000000000
--- a/tests/ui/diagnostic_namespace/on_unimplemented/feature-gate-diagnostic_on_unimplemented.stderr
+++ /dev/null
@@ -1,13 +0,0 @@
-error[E0658]: `#[diagnostic]` attribute name space is experimental
-  --> $DIR/feature-gate-diagnostic_on_unimplemented.rs:1:3
-   |
-LL | #[diagnostic::on_unimplemented(message = "Foo")]
-   |   ^^^^^^^^^^
-   |
-   = note: see issue #111996 <https://github.com/rust-lang/rust/issues/111996> for more information
-   = help: add `#![feature(diagnostic_namespace)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs b/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs
index 0893f29c4a3..5b25fb234bc 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(
     if(Self = "()"),
     //~^WARN malformed `on_unimplemented` attribute
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.stderr
index e00846da77b..56d125e20e5 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/ignore_unsupported_options_and_continue_to_use_fallback.stderr
@@ -1,5 +1,5 @@
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:4:5
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:2:5
    |
 LL |     if(Self = "()"),
    |     ^^^^^^^^^^^^^^^ invalid option found here
@@ -8,7 +8,7 @@ LL |     if(Self = "()"),
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: `message` is ignored due to previous definition of `message`
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:10:32
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:8:32
    |
 LL |     message = "custom message",
    |     -------------------------- `message` is first declared here
@@ -17,7 +17,7 @@ LL | #[diagnostic::on_unimplemented(message = "fallback!!")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^ `message` is already declared here
 
 warning: malformed `on_unimplemented` attribute
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:4:5
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:2:5
    |
 LL |     if(Self = "()"),
    |     ^^^^^^^^^^^^^^^ invalid option found here
@@ -26,7 +26,7 @@ LL |     if(Self = "()"),
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: `message` is ignored due to previous definition of `message`
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:10:32
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:8:32
    |
 LL |     message = "custom message",
    |     -------------------------- `message` is first declared here
@@ -37,7 +37,7 @@ LL | #[diagnostic::on_unimplemented(message = "fallback!!")]
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: custom message
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:20:15
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:18:15
    |
 LL |     takes_foo(());
    |     --------- ^^ fallback label
@@ -48,12 +48,12 @@ LL |     takes_foo(());
    = note: custom note
    = note: fallback note
 help: this trait has no implementations, consider adding one
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:15:1
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:13:1
    |
 LL | trait Foo {}
    | ^^^^^^^^^
 note: required by a bound in `takes_foo`
-  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:17:22
+  --> $DIR/ignore_unsupported_options_and_continue_to_use_fallback.rs:15:22
    |
 LL | fn takes_foo(_: impl Foo) {}
    |                      ^^^ required by this bound in `takes_foo`
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.rs b/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.rs
index 34cdb99c754..a5982f6492c 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(message = "Foo", label = "Bar", note = "Baz", note = "Boom")]
 trait Foo {}
 
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.stderr
index c72321d4617..93a0d0b3f41 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/multiple_notes.stderr
@@ -1,5 +1,5 @@
 error[E0277]: Foo
-  --> $DIR/multiple_notes.rs:14:15
+  --> $DIR/multiple_notes.rs:12:15
    |
 LL |     takes_foo(());
    |     --------- ^^ Bar
@@ -10,18 +10,18 @@ LL |     takes_foo(());
    = note: Baz
    = note: Boom
 help: this trait has no implementations, consider adding one
-  --> $DIR/multiple_notes.rs:4:1
+  --> $DIR/multiple_notes.rs:2:1
    |
 LL | trait Foo {}
    | ^^^^^^^^^
 note: required by a bound in `takes_foo`
-  --> $DIR/multiple_notes.rs:10:22
+  --> $DIR/multiple_notes.rs:8:22
    |
 LL | fn takes_foo(_: impl Foo) {}
    |                      ^^^ required by this bound in `takes_foo`
 
 error[E0277]: Bar
-  --> $DIR/multiple_notes.rs:16:15
+  --> $DIR/multiple_notes.rs:14:15
    |
 LL |     takes_bar(());
    |     --------- ^^ Foo
@@ -32,12 +32,12 @@ LL |     takes_bar(());
    = note: Baz
    = note: Baz2
 help: this trait has no implementations, consider adding one
-  --> $DIR/multiple_notes.rs:8:1
+  --> $DIR/multiple_notes.rs:6:1
    |
 LL | trait Bar {}
    | ^^^^^^^^^
 note: required by a bound in `takes_bar`
-  --> $DIR/multiple_notes.rs:11:22
+  --> $DIR/multiple_notes.rs:9:22
    |
 LL | fn takes_bar(_: impl Bar) {}
    |                      ^^^ required by this bound in `takes_bar`
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.rs b/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.rs
index 797edbc9ec5..7ca03127759 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(message = "Foo", label = "Bar", note = "Baz")]
 trait Foo {}
 
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.stderr
index de57f7044bf..6b17f40c6dd 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/on_unimplemented_simple.stderr
@@ -1,5 +1,5 @@
 error[E0277]: Foo
-  --> $DIR/on_unimplemented_simple.rs:9:15
+  --> $DIR/on_unimplemented_simple.rs:7:15
    |
 LL |     takes_foo(());
    |     --------- ^^ Bar
@@ -9,12 +9,12 @@ LL |     takes_foo(());
    = help: the trait `Foo` is not implemented for `()`
    = note: Baz
 help: this trait has no implementations, consider adding one
-  --> $DIR/on_unimplemented_simple.rs:4:1
+  --> $DIR/on_unimplemented_simple.rs:2:1
    |
 LL | trait Foo {}
    | ^^^^^^^^^
 note: required by a bound in `takes_foo`
-  --> $DIR/on_unimplemented_simple.rs:6:22
+  --> $DIR/on_unimplemented_simple.rs:4:22
    |
 LL | fn takes_foo(_: impl Foo) {}
    |                      ^^^ required by this bound in `takes_foo`
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.rs b/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.rs
index a7becd2f88f..8c0b8150417 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.rs
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic::on_unimplemented(
     message = "first message",
     label = "first label",
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.stderr
index d30754dcf10..43ab6bf25a1 100644
--- a/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.stderr
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/report_warning_on_duplicated_options.stderr
@@ -1,5 +1,5 @@
 warning: `message` is ignored due to previous definition of `message`
-  --> $DIR/report_warning_on_duplicated_options.rs:9:5
+  --> $DIR/report_warning_on_duplicated_options.rs:7:5
    |
 LL |     message = "first message",
    |     ------------------------- `message` is first declared here
@@ -10,7 +10,7 @@ LL |     message = "second message",
    = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
 
 warning: `label` is ignored due to previous definition of `label`
-  --> $DIR/report_warning_on_duplicated_options.rs:12:5
+  --> $DIR/report_warning_on_duplicated_options.rs:10:5
    |
 LL |     label = "first label",
    |     --------------------- `label` is first declared here
@@ -19,7 +19,7 @@ LL |     label = "second label",
    |     ^^^^^^^^^^^^^^^^^^^^^^ `label` is already declared here
 
 warning: `message` is ignored due to previous definition of `message`
-  --> $DIR/report_warning_on_duplicated_options.rs:9:5
+  --> $DIR/report_warning_on_duplicated_options.rs:7:5
    |
 LL |     message = "first message",
    |     ------------------------- `message` is first declared here
@@ -30,7 +30,7 @@ LL |     message = "second message",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 warning: `label` is ignored due to previous definition of `label`
-  --> $DIR/report_warning_on_duplicated_options.rs:12:5
+  --> $DIR/report_warning_on_duplicated_options.rs:10:5
    |
 LL |     label = "first label",
    |     --------------------- `label` is first declared here
@@ -41,7 +41,7 @@ LL |     label = "second label",
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0277]: first message
-  --> $DIR/report_warning_on_duplicated_options.rs:23:15
+  --> $DIR/report_warning_on_duplicated_options.rs:21:15
    |
 LL |     takes_foo(());
    |     --------- ^^ first label
@@ -52,12 +52,12 @@ LL |     takes_foo(());
    = note: custom note
    = note: second note
 help: this trait has no implementations, consider adding one
-  --> $DIR/report_warning_on_duplicated_options.rs:17:1
+  --> $DIR/report_warning_on_duplicated_options.rs:15:1
    |
 LL | trait Foo {}
    | ^^^^^^^^^
 note: required by a bound in `takes_foo`
-  --> $DIR/report_warning_on_duplicated_options.rs:20:22
+  --> $DIR/report_warning_on_duplicated_options.rs:18:22
    |
 LL | fn takes_foo(_: impl Foo) {}
    |                      ^^^ required by this bound in `takes_foo`
diff --git a/tests/ui/diagnostic_namespace/requires_path.rs b/tests/ui/diagnostic_namespace/requires_path.rs
index e8d6ca73ad0..4f3a1319caf 100644
--- a/tests/ui/diagnostic_namespace/requires_path.rs
+++ b/tests/ui/diagnostic_namespace/requires_path.rs
@@ -1,5 +1,3 @@
-#![feature(diagnostic_namespace)]
-
 #[diagnostic]
 //~^ERROR cannot find attribute `diagnostic` in this scope
 pub struct Bar;
diff --git a/tests/ui/diagnostic_namespace/requires_path.stderr b/tests/ui/diagnostic_namespace/requires_path.stderr
index 5d07d3a22d5..e02aacac8c1 100644
--- a/tests/ui/diagnostic_namespace/requires_path.stderr
+++ b/tests/ui/diagnostic_namespace/requires_path.stderr
@@ -1,5 +1,5 @@
 error: cannot find attribute `diagnostic` in this scope
-  --> $DIR/requires_path.rs:3:3
+  --> $DIR/requires_path.rs:1:3
    |
 LL | #[diagnostic]
    |   ^^^^^^^^^^