diff --git a/compiler/rustc_attr_parsing/src/interface.rs b/compiler/rustc_attr_parsing/src/interface.rs
index 06738b9c7337..902f2419c46d 100644
--- a/compiler/rustc_attr_parsing/src/interface.rs
+++ b/compiler/rustc_attr_parsing/src/interface.rs
@@ -10,7 +10,7 @@
 use rustc_hir::lints::AttributeLintKind;
 use rustc_hir::{AttrArgs, AttrItem, AttrPath, Attribute, HashIgnoredAttrId, Target};
 use rustc_session::Session;
-use rustc_session::lint::{BuiltinLintDiag, LintId};
+use rustc_session::lint::LintId;
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, sym};
 
 use crate::context::{AcceptContext, FinalizeContext, FinalizeFn, SharedContext, Stage};
@@ -124,14 +124,7 @@ pub fn parse_limited_all<'a>(
             target,
             OmitDoc::Skip,
             std::convert::identity,
-            |lint_id, span, kind| {
-                sess.psess.buffer_lint(
-                    lint_id.lint,
-                    span,
-                    target_node_id,
-                    BuiltinLintDiag::AttributeLint(kind),
-                )
-            },
+            |lint_id, span, kind| sess.psess.buffer_lint(lint_id.lint, span, target_node_id, kind),
         )
     }
 
@@ -230,12 +223,7 @@ pub fn parse_single_args<T, I>(
         let mut parser =
             Self { features, tools: None, parse_only: None, sess, stage: Early { emit_errors } };
         let mut emit_lint = |lint_id: LintId, span: Span, kind: AttributeLintKind| {
-            sess.psess.buffer_lint(
-                lint_id.lint,
-                span,
-                target_node_id,
-                BuiltinLintDiag::AttributeLint(kind),
-            )
+            sess.psess.buffer_lint(lint_id.lint, span, target_node_id, kind)
         };
         if let Some(safety) = attr_safety {
             parser.check_attribute_safety(&attr_path, inner_span, safety, &mut emit_lint)
diff --git a/compiler/rustc_attr_parsing/src/validate_attr.rs b/compiler/rustc_attr_parsing/src/validate_attr.rs
index e2521c9abf5f..eb3c4796f02d 100644
--- a/compiler/rustc_attr_parsing/src/validate_attr.rs
+++ b/compiler/rustc_attr_parsing/src/validate_attr.rs
@@ -14,7 +14,6 @@
 use rustc_hir::lints::AttributeLintKind;
 use rustc_parse::parse_in;
 use rustc_session::errors::report_lit_error;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
 use rustc_session::parse::ParseSess;
 use rustc_span::{Span, Symbol, sym};
@@ -208,11 +207,11 @@ fn emit_malformed_attribute(
             ILL_FORMED_ATTRIBUTE_INPUT,
             span,
             ast::CRATE_NODE_ID,
-            BuiltinLintDiag::AttributeLint(AttributeLintKind::IllFormedAttributeInput {
+            AttributeLintKind::IllFormedAttributeInput {
                 suggestions: suggestions.clone(),
                 docs: template.docs,
                 help: None,
-            }),
+            },
         );
     } else {
         suggestions.sort();
diff --git a/compiler/rustc_errors/src/decorate_diag.rs b/compiler/rustc_errors/src/decorate_diag.rs
index 321591469889..18c0c571fd1b 100644
--- a/compiler/rustc_errors/src/decorate_diag.rs
+++ b/compiler/rustc_errors/src/decorate_diag.rs
@@ -5,11 +5,11 @@
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::MultiSpan;
-use rustc_lint_defs::{BuiltinLintDiag, Lint, LintId};
+use rustc_lint_defs::{AttributeLintKind, Lint, LintId};
 
 use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 
-/// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
+/// We can't implement `Diagnostic` for `AttributeLintKind`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
     /// The third argument of the closure is a `Session`. However, due to the dependency tree,
@@ -22,7 +22,7 @@ pub enum DecorateDiagCompat {
                 + 'static,
         >,
     ),
-    Builtin(BuiltinLintDiag),
+    Builtin(AttributeLintKind),
 }
 
 impl std::fmt::Debug for DecorateDiagCompat {
@@ -38,9 +38,9 @@ fn from(d: D) -> Self {
     }
 }
 
-impl From<BuiltinLintDiag> for DecorateDiagCompat {
+impl From<AttributeLintKind> for DecorateDiagCompat {
     #[inline]
-    fn from(b: BuiltinLintDiag) -> Self {
+    fn from(b: AttributeLintKind) -> Self {
         Self::Builtin(b)
     }
 }
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index 635185be1cb7..e55cfc052ac4 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -17,7 +17,7 @@
 
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
-use crate::{DecorateBuiltinLint, DiagAndSess};
+use crate::{DecorateAttrLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -42,10 +42,10 @@ fn check_id(&mut self, id: ast::NodeId) {
                     self.context.opt_span_lint(
                         lint_id.lint,
                         span,
-                        DecorateBuiltinLint {
+                        DecorateAttrLint {
                             sess: self.context.sess(),
                             tcx: self.tcx,
-                            diagnostic: b,
+                            diagnostic: &b,
                         },
                     );
                 }
diff --git a/compiler/rustc_lint/src/early/diagnostics.rs b/compiler/rustc_lint/src/early/diagnostics.rs
index fe1a0bf1394e..0f27e04babd4 100644
--- a/compiler/rustc_lint/src/early/diagnostics.rs
+++ b/compiler/rustc_lint/src/early/diagnostics.rs
@@ -6,7 +6,6 @@
 use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 
 use crate::lints;
 
@@ -25,25 +24,6 @@ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
     }
 }
 
-/// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
-/// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
-pub struct DecorateBuiltinLint<'sess, 'tcx> {
-    pub sess: &'sess Session,
-    pub tcx: Option<TyCtxt<'tcx>>,
-    pub diagnostic: BuiltinLintDiag,
-}
-
-impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
-    fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
-        match self.diagnostic {
-            BuiltinLintDiag::AttributeLint(kind) => {
-                DecorateAttrLint { sess: self.sess, tcx: self.tcx, diagnostic: &kind }
-                    .into_diag(dcx, level)
-            }
-        }
-    }
-}
-
 /// This is a diagnostic struct that will decorate a `AttributeLintKind`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateAttrLint<'a, 'sess, 'tcx> {
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index c76fafcde2ee..6f6aa0f96e75 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -129,7 +129,7 @@
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
+pub use early::diagnostics::{DecorateAttrLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index b24adda06f98..36070dac276f 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -652,13 +652,6 @@ pub enum DeprecatedSinceKind {
     InVersion(String),
 }
 
-// This could be a closure, but then implementing derive trait
-// becomes hacky (and it gets allocated).
-#[derive(Debug)]
-pub enum BuiltinLintDiag {
-    AttributeLint(AttributeLintKind),
-}
-
 #[derive(Debug, HashStable_Generic)]
 pub enum AttributeLintKind {
     UnusedDuplicate {