From 26d2c3068254f2ed31eca7eb36a1524aea4ad93e Mon Sep 17 00:00:00 2001
From: mejrs <59372212+mejrs@users.noreply.github.com>
Date: Mon, 20 Apr 2026 21:00:45 +0200
Subject: [PATCH] Move diagnostic::on_move target check

---
 .../src/attributes/diagnostic/on_move.rs      | 14 ++++++++++
 compiler/rustc_attr_parsing/src/errors.rs     |  4 +++
 compiler/rustc_passes/src/check_attr.rs       | 27 +++----------------
 3 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/attributes/diagnostic/on_move.rs b/compiler/rustc_attr_parsing/src/attributes/diagnostic/on_move.rs
index 2b62ab7f3d11..feb48fa868d4 100644
--- a/compiler/rustc_attr_parsing/src/attributes/diagnostic/on_move.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/diagnostic/on_move.rs
@@ -1,10 +1,13 @@
+use rustc_errors::Diagnostic;
 use rustc_feature::template;
 use rustc_hir::attrs::AttributeKind;
+use rustc_session::lint::builtin::MISPLACED_DIAGNOSTIC_ATTRIBUTES;
 use rustc_span::sym;
 
 use crate::attributes::diagnostic::*;
 use crate::attributes::prelude::*;
 use crate::context::{AcceptContext, Stage};
+use crate::errors::DiagnosticOnMoveOnlyForAdt;
 use crate::parser::ArgParser;
 use crate::target_checking::{ALL_TARGETS, AllowedTargets};
 
@@ -29,6 +32,15 @@ fn parse<'sess, S: Stage>(
         let span = cx.attr_span;
         self.span = Some(span);
 
+        if !matches!(cx.target, Target::Enum | Target::Struct | Target::Union) {
+            cx.emit_dyn_lint(
+                MISPLACED_DIAGNOSTIC_ATTRIBUTES,
+                move |dcx, level| DiagnosticOnMoveOnlyForAdt.into_diag(dcx, level),
+                span,
+            );
+            return;
+        }
+
         let Some(items) = parse_list(cx, args, mode) else { return };
 
         if let Some(directive) = parse_directive_items(cx, mode, items.mixed(), true) {
@@ -44,6 +56,8 @@ impl<S: Stage> AttributeParser<S> for OnMoveParser {
             this.parse(cx, args, Mode::DiagnosticOnMove);
         },
     )];
+
+    // "Allowed" for all targets but noop if used on not-adt.
     const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS);
 
     fn finalize(self, _cx: &FinalizeContext<'_, '_, S>) -> Option<AttributeKind> {
diff --git a/compiler/rustc_attr_parsing/src/errors.rs b/compiler/rustc_attr_parsing/src/errors.rs
index 8e1050852181..89ebbcae3507 100644
--- a/compiler/rustc_attr_parsing/src/errors.rs
+++ b/compiler/rustc_attr_parsing/src/errors.rs
@@ -259,3 +259,7 @@ pub(crate) struct DiagnosticOnConstOnlyForTraitImpls {
     #[label("not a trait impl")]
     pub target_span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag("`#[diagnostic::on_move]` can only be applied to enums, structs or unions")]
+pub(crate) struct DiagnosticOnMoveOnlyForAdt;
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index ecc83628971c..bd794d2d00f7 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -61,10 +61,6 @@ struct DiagnosticOnConstOnlyForNonConstTraitImpls {
     item_span: Span,
 }
 
-#[derive(Diagnostic)]
-#[diag("`#[diagnostic::on_move]` can only be applied to enums, structs or unions")]
-struct DiagnosticOnMoveOnlyForAdt;
-
 #[derive(Diagnostic)]
 #[diag("`#[diagnostic::on_unknown]` can only be applied to `use` statements")]
 struct DiagnosticOnUnknownOnlyForImports {
@@ -218,8 +214,8 @@ fn check_attributes(
                 Attribute::Parsed(AttributeKind::OnUnimplemented{span, directive}) => {self.check_diagnostic_on_unimplemented(*span, hir_id, target,directive.as_deref())},
                 Attribute::Parsed(AttributeKind::OnUnknown { span, .. }) => { self.check_diagnostic_on_unknown(*span, hir_id, target) },
                 Attribute::Parsed(AttributeKind::OnConst{span, ..}) => {self.check_diagnostic_on_const(*span, hir_id, target, item)}
-                Attribute::Parsed(AttributeKind::OnMove { span, directive }) => {
-                    self.check_diagnostic_on_move(*span, hir_id, target, directive.as_deref())
+                Attribute::Parsed(AttributeKind::OnMove { directive , .. }) => {
+                    self.check_diagnostic_on_move(hir_id, directive.as_deref())
                 },
                 Attribute::Parsed(
                     // tidy-alphabetical-start
@@ -613,23 +609,8 @@ fn check_diagnostic_on_const(
         // ...whose generics would that be, anyway? The traits' or the impls'?
     }
 
-    /// Checks if `#[diagnostic::on_move]` is applied to an ADT definition
-    fn check_diagnostic_on_move(
-        &self,
-        attr_span: Span,
-        hir_id: HirId,
-        target: Target,
-        directive: Option<&Directive>,
-    ) {
-        if !matches!(target, Target::Enum | Target::Struct | Target::Union) {
-            self.tcx.emit_node_span_lint(
-                MISPLACED_DIAGNOSTIC_ATTRIBUTES,
-                hir_id,
-                attr_span,
-                DiagnosticOnMoveOnlyForAdt,
-            );
-        }
-
+    /// Checks use of generic formatting parameters in `#[diagnostic::on_move]`
+    fn check_diagnostic_on_move(&self, hir_id: HirId, directive: Option<&Directive>) {
         if let Some(directive) = directive {
             if let Node::Item(Item {
                 kind: