From eba0efd9aaef79149de08d1affe969c5213c0fe7 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <contact@guillaume-gomez.fr>
Date: Mon, 23 Mar 2026 12:11:17 +0100
Subject: [PATCH] Remove more `BuiltinLintDiag` in `rustc_attr_parsing`

---
 .../src/attributes/cfg_select.rs                | 14 ++++++++++----
 compiler/rustc_attr_parsing/src/errors.rs       | 17 +++++++++++++++++
 compiler/rustc_lint/src/early/diagnostics.rs    |  7 -------
 compiler/rustc_lint/src/lints.rs                | 17 -----------------
 compiler/rustc_lint_defs/src/lib.rs             |  4 ----
 5 files changed, 27 insertions(+), 32 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/attributes/cfg_select.rs b/compiler/rustc_attr_parsing/src/attributes/cfg_select.rs
index f3612afe69e5..4ff224006ca8 100644
--- a/compiler/rustc_attr_parsing/src/attributes/cfg_select.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/cfg_select.rs
@@ -2,18 +2,18 @@
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::{AttrStyle, NodeId, token};
 use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::Diagnostic;
 use rustc_feature::{AttributeTemplate, Features};
 use rustc_hir::attrs::CfgEntry;
 use rustc_hir::{AttrPath, Target};
 use rustc_parse::exp;
 use rustc_parse::parser::{Parser, Recovery};
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::UNREACHABLE_CFG_SELECT_PREDICATES;
 use rustc_span::{ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::parser::{AllowExprMetavar, MetaItemOrLitParser};
-use crate::{AttributeParser, ParsedDescription, ShouldEmit, parse_cfg_entry};
+use crate::{AttributeParser, ParsedDescription, ShouldEmit, errors, parse_cfg_entry};
 
 #[derive(Clone)]
 pub enum CfgSelectPredicate {
@@ -153,11 +153,17 @@ fn lint_unreachable(
 
     let branch_is_unreachable = |predicate: CfgSelectPredicate, wildcard_span| {
         let span = predicate.span();
-        p.psess.buffer_lint(
+        p.psess.dyn_buffer_lint(
             UNREACHABLE_CFG_SELECT_PREDICATES,
             span,
             lint_node_id,
-            BuiltinLintDiag::UnreachableCfg { span, wildcard_span },
+            move |dcx, level| match wildcard_span {
+                Some(wildcard_span) => {
+                    errors::UnreachableCfgSelectPredicateWildcard { span, wildcard_span }
+                        .into_diag(dcx, level)
+                }
+                None => errors::UnreachableCfgSelectPredicate { span }.into_diag(dcx, level),
+            },
         );
     };
 
diff --git a/compiler/rustc_attr_parsing/src/errors.rs b/compiler/rustc_attr_parsing/src/errors.rs
index 4eb9425b34bb..d4236416dd6a 100644
--- a/compiler/rustc_attr_parsing/src/errors.rs
+++ b/compiler/rustc_attr_parsing/src/errors.rs
@@ -26,6 +26,13 @@ pub(crate) struct ItemFollowingInnerAttr {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag("unreachable configuration predicate")]
+pub(crate) struct UnreachableCfgSelectPredicate {
+    #[label("this configuration predicate is never reached")]
+    pub span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag("most attributes are not supported in `where` clauses")]
 #[help("only `#[cfg]` and `#[cfg_attr]` are supported")]
@@ -33,3 +40,13 @@ pub(crate) struct UnsupportedAttributesInWhere {
     #[primary_span]
     pub span: MultiSpan,
 }
+
+#[derive(Diagnostic)]
+#[diag("unreachable configuration predicate")]
+pub(crate) struct UnreachableCfgSelectPredicateWildcard {
+    #[label("this configuration predicate is never reached")]
+    pub span: Span,
+
+    #[label("always matches")]
+    pub wildcard_span: Span,
+}
diff --git a/compiler/rustc_lint/src/early/diagnostics.rs b/compiler/rustc_lint/src/early/diagnostics.rs
index 43bb3971d7ac..a6d7f0a11e32 100644
--- a/compiler/rustc_lint/src/early/diagnostics.rs
+++ b/compiler/rustc_lint/src/early/diagnostics.rs
@@ -224,13 +224,6 @@ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
                 }
                 .into_diag(dcx, level)
             }
-            BuiltinLintDiag::UnreachableCfg { span, wildcard_span } => match wildcard_span {
-                Some(wildcard_span) => {
-                    lints::UnreachableCfgSelectPredicateWildcard { span, wildcard_span }
-                        .into_diag(dcx, level)
-                }
-                None => lints::UnreachableCfgSelectPredicate { span }.into_diag(dcx, level),
-            },
 
             BuiltinLintDiag::UnusedCrateDependency { extern_crate, local_crate } => {
                 lints::UnusedCrateDependency { extern_crate, local_crate }.into_diag(dcx, level)
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
index c7c92356c378..f9cc259bdf4f 100644
--- a/compiler/rustc_lint/src/lints.rs
+++ b/compiler/rustc_lint/src/lints.rs
@@ -3709,23 +3709,6 @@ pub(crate) struct UnknownCrateTypesSuggestion {
     pub snippet: Symbol,
 }
 
-#[derive(Diagnostic)]
-#[diag("unreachable configuration predicate")]
-pub(crate) struct UnreachableCfgSelectPredicate {
-    #[label("this configuration predicate is never reached")]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag("unreachable configuration predicate")]
-pub(crate) struct UnreachableCfgSelectPredicateWildcard {
-    #[label("this configuration predicate is never reached")]
-    pub span: Span,
-
-    #[label("always matches")]
-    pub wildcard_span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag("positional format arguments are not allowed here")]
 #[help(
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index 0faa50442961..6314add5f1ae 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -732,10 +732,6 @@ pub enum BuiltinLintDiag {
         local_crate: Symbol,
     },
     AttributeLint(AttributeLintKind),
-    UnreachableCfg {
-        span: Span,
-        wildcard_span: Option<Span>,
-    },
 }
 
 #[derive(Debug, HashStable_Generic)]