From ace320fba3df37d7d33aefb80bb7734971bf3264 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <contact@guillaume-gomez.fr>
Date: Mon, 20 Apr 2026 00:50:55 +0200
Subject: [PATCH] Remove `AttributeLintKind::AmbiguousDeriveHelpers` variant

---
 .../rustc_attr_parsing/src/attributes/proc_macro_attrs.rs   | 6 +++---
 compiler/rustc_attr_parsing/src/errors.rs                   | 4 ++++
 compiler/rustc_lint/src/early/diagnostics.rs                | 4 ----
 compiler/rustc_lint/src/lints.rs                            | 4 ----
 compiler/rustc_lint_defs/src/lib.rs                         | 1 -
 5 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs b/compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs
index 7cb59856b8a2..76dc171c6831 100644
--- a/compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/proc_macro_attrs.rs
@@ -1,4 +1,4 @@
-use rustc_hir::lints::AttributeLintKind;
+use rustc_errors::Diagnostic;
 use rustc_session::lint::builtin::AMBIGUOUS_DERIVE_HELPERS;
 
 use super::prelude::*;
@@ -125,9 +125,9 @@ fn parse_derive_like<S: Stage>(
                 return None;
             }
             if rustc_feature::is_builtin_attr_name(ident.name) {
-                cx.emit_lint(
+                cx.emit_dyn_lint(
                     AMBIGUOUS_DERIVE_HELPERS,
-                    AttributeLintKind::AmbiguousDeriveHelpers,
+                    |dcx, level| crate::errors::AmbiguousDeriveHelpers.into_diag(dcx, level),
                     ident.span,
                 );
             }
diff --git a/compiler/rustc_attr_parsing/src/errors.rs b/compiler/rustc_attr_parsing/src/errors.rs
index 8148a859958b..24cff14e17d8 100644
--- a/compiler/rustc_attr_parsing/src/errors.rs
+++ b/compiler/rustc_attr_parsing/src/errors.rs
@@ -177,3 +177,7 @@ pub(crate) struct DocAliasDuplicated {
 #[derive(Diagnostic)]
 #[diag("only `hide` or `show` are allowed in `#[doc(auto_cfg(...))]`")]
 pub(crate) struct DocAutoCfgExpectsHideOrShow;
+
+#[derive(Diagnostic)]
+#[diag("there exists a built-in attribute with the same name")]
+pub(crate) struct AmbiguousDeriveHelpers;
diff --git a/compiler/rustc_lint/src/early/diagnostics.rs b/compiler/rustc_lint/src/early/diagnostics.rs
index fb59cd35ad46..24ddef1c14eb 100644
--- a/compiler/rustc_lint/src/early/diagnostics.rs
+++ b/compiler/rustc_lint/src/early/diagnostics.rs
@@ -43,10 +43,6 @@ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
                     .into_diag(dcx, level)
             }
 
-            &AttributeLintKind::AmbiguousDeriveHelpers => {
-                lints::AmbiguousDeriveHelpers.into_diag(dcx, level)
-            }
-
             &AttributeLintKind::DocAutoCfgHideShowUnexpectedItem { attr_name } => {
                 lints::DocAutoCfgHideShowUnexpectedItem { attr_name }.into_diag(dcx, level)
             }
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index b92efc408ae8..93f32104bcf1 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -3303,10 +3303,6 @@ fn add_to_diag<G: EmissionGuarantee>(self, diag: &mut Diag<'_, G>) {
 )]
 pub(crate) struct ExpectedNameValue;
 
-#[derive(Diagnostic)]
-#[diag("there exists a built-in attribute with the same name")]
-pub(crate) struct AmbiguousDeriveHelpers;
-
 #[derive(Diagnostic)]
 #[diag("`#![doc(auto_cfg({$attr_name}(...)))]` only accepts identifiers or key/value items")]
 pub(crate) struct DocAutoCfgHideShowUnexpectedItem {
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index 29da46770d52..24991ac03e98 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -659,7 +659,6 @@ pub enum AttributeLintKind {
     DocAutoCfgHideShowUnexpectedItem { attr_name: Symbol },
     DocAutoCfgHideShowExpectsList { attr_name: Symbol },
     DocInvalid,
-    AmbiguousDeriveHelpers,
     DocUnknownInclude { span: Span, inner: &'static str, value: Symbol },
     DocUnknownSpotlight { span: Span },
     DocUnknownPasses { name: Symbol, span: Span },