Auto merge of #18317 - lnicola:sync-from-rust, r=Veykril

minor: sync from downstream

4 files changed, 51 insertions, 3 deletions

diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 44a62383e6e..4516ea94cad 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -243,6 +243,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                     self.check_generic_attr(hir_id, attr, target, Target::Fn);
                     self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
                 }
+                [sym::autodiff, ..] => {
+                    self.check_autodiff(hir_id, attr, span, target)
+                }
                 [sym::coroutine, ..] => {
                     self.check_coroutine(attr, target);
                 }
@@ -2299,7 +2302,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 })),
                 terr,
                 false,
-                false,
             );
             diag.emit();
             self.abort.set(true);
@@ -2345,6 +2347,18 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             self.dcx().emit_err(errors::RustcPubTransparent { span, attr_span });
         }
     }
+
+    /// Checks if `#[autodiff]` is applied to an item other than a function item.
+    fn check_autodiff(&self, _hir_id: HirId, _attr: &Attribute, span: Span, target: Target) {
+        debug!("check_autodiff");
+        match target {
+            Target::Fn => {}
+            _ => {
+                self.dcx().emit_err(errors::AutoDiffAttr { attr_span: span });
+                self.abort.set(true);
+            }
+        }
+    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 4f00c90fa3b..6dc3dfba58f 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -20,6 +20,14 @@ use crate::lang_items::Duplicate;
 #[diag(passes_incorrect_do_not_recommend_location)]
 pub(crate) struct IncorrectDoNotRecommendLocation;
 
+#[derive(Diagnostic)]
+#[diag(passes_autodiff_attr)]
+pub(crate) struct AutoDiffAttr {
+    #[primary_span]
+    #[label]
+    pub attr_span: Span,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(passes_outer_crate_level_attr)]
 pub(crate) struct OuterCrateLevelAttr;
@@ -1481,6 +1489,17 @@ pub(crate) struct CannotStabilizeDeprecated {
 }
 
 #[derive(Diagnostic)]
+#[diag(passes_unstable_attr_for_already_stable_feature)]
+pub(crate) struct UnstableAttrForAlreadyStableFeature {
+    #[primary_span]
+    #[label]
+    #[help]
+    pub span: Span,
+    #[label(passes_item)]
+    pub item_sp: Span,
+}
+
+#[derive(Diagnostic)]
 #[diag(passes_missing_stability_attr)]
 pub(crate) struct MissingStabilityAttr<'a> {
     #[primary_span]
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index 8ad14b6eb74..a4c3d789176 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -579,11 +579,10 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
             Array,
             Ptr,
             Ref,
+            PinnedRef,
             BareFn,
             Never,
             Tup,
-            AnonStruct,
-            AnonUnion,
             Path,
             Pat,
             TraitObject,
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index 46b67e930d5..751c87a9fe5 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -10,6 +10,7 @@ use rustc_attr::{
 };
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::unord::{ExtendUnord, UnordMap, UnordSet};
+use rustc_feature::ACCEPTED_FEATURES;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId, LocalModDefId};
@@ -246,12 +247,27 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
                 }
             }
 
+            if let Stability { level: Unstable { .. }, feature } = stab {
+                if ACCEPTED_FEATURES.iter().find(|f| f.name == feature).is_some() {
+                    self.tcx
+                        .dcx()
+                        .emit_err(errors::UnstableAttrForAlreadyStableFeature { span, item_sp });
+                }
+            }
             if let Stability { level: Unstable { implied_by: Some(implied_by), .. }, feature } =
                 stab
             {
                 self.index.implications.insert(implied_by, feature);
             }
 
+            if let Some(ConstStability { level: Unstable { .. }, feature, .. }) = const_stab {
+                if ACCEPTED_FEATURES.iter().find(|f| f.name == feature).is_some() {
+                    self.tcx.dcx().emit_err(errors::UnstableAttrForAlreadyStableFeature {
+                        span: const_span.unwrap(), // If const_stab contains Some(..), same is true for const_span
+                        item_sp,
+                    });
+                }
+            }
             if let Some(ConstStability {
                 level: Unstable { implied_by: Some(implied_by), .. },
                 feature,