Rollup of 8 pull requests

compiler/rustc_data_structures/src/unhash.rs

@@ -3,6 +3,7 @@ use std::hash::{BuildHasherDefault, Hasher};
 
 pub type UnhashMap<K, V> = HashMap<K, V, BuildHasherDefault<Unhasher>>;
 pub type UnhashSet<V> = HashSet<V, BuildHasherDefault<Unhasher>>;
+pub type UnindexMap<K, V> = indexmap::IndexMap<K, V, BuildHasherDefault<Unhasher>>;
 
 /// This no-op hasher expects only a single `write_u64` call. It's intended for
 /// map keys that already have hash-like quality, like `Fingerprint`.

compiler/rustc_hir_analysis/src/check/check.rs

@@ -8,7 +8,9 @@ use rustc_hir::Node;
 use rustc_hir::def::{CtorKind, DefKind};
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::Obligation;
-use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
+use rustc_lint_defs::builtin::{
+    REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS, UNSUPPORTED_FN_PTR_CALLING_CONVENTIONS,
+};
 use rustc_middle::middle::resolve_bound_vars::ResolvedArg;
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::span_bug;
@@ -52,16 +54,18 @@ pub fn check_abi(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) {
             });
         }
     }
+}
 
-    // This ABI is only allowed on function pointers
-    if abi == Abi::CCmseNonSecureCall {
-        struct_span_code_err!(
-            tcx.dcx(),
-            span,
-            E0781,
-            "the `\"C-cmse-nonsecure-call\"` ABI is only allowed on function pointers"
-        )
-        .emit();
+pub fn check_abi_fn_ptr(tcx: TyCtxt<'_>, hir_id: hir::HirId, span: Span, abi: Abi) {
+    match tcx.sess.target.is_abi_supported(abi) {
+        Some(true) => (),
+        Some(false) | None => {
+            tcx.node_span_lint(UNSUPPORTED_FN_PTR_CALLING_CONVENTIONS, hir_id, span, |lint| {
+                lint.primary_message(
+                    "use of calling convention not supported on this target on function pointer",
+                );
+            });
+        }
     }
 }
 

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -73,7 +73,7 @@ pub mod wfcheck;
 
 use std::num::NonZero;
 
-pub use check::check_abi;
+pub use check::{check_abi, check_abi_fn_ptr};
 use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
 use rustc_errors::{Diag, ErrorGuaranteed, pluralize, struct_span_code_err};
 use rustc_hir::def_id::{DefId, LocalDefId};

compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs

@@ -1,6 +1,5 @@
-use rustc_errors::DiagCtxtHandle;
-use rustc_hir as hir;
-use rustc_hir::HirId;
+use rustc_errors::{DiagCtxtHandle, E0781, struct_span_code_err};
+use rustc_hir::{self as hir, HirId};
 use rustc_middle::ty::layout::LayoutError;
 use rustc_middle::ty::{self, ParamEnv, TyCtxt};
 use rustc_span::Span;
@@ -26,7 +25,19 @@ pub(crate) fn validate_cmse_abi<'tcx>(
             ..
         }) = hir_node
         else {
-            // might happen when this ABI is used incorrectly. That will be handled elsewhere
+            let span = match tcx.parent_hir_node(hir_id) {
+                hir::Node::Item(hir::Item {
+                    kind: hir::ItemKind::ForeignMod { .. }, span, ..
+                }) => *span,
+                _ => tcx.hir().span(hir_id),
+            };
+            struct_span_code_err!(
+                tcx.dcx(),
+                span,
+                E0781,
+                "the `\"C-cmse-nonsecure-call\"` ABI is only allowed on function pointers"
+            )
+            .emit();
             return;
         };
 

compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs

@@ -1,6 +1,6 @@
 use rustc_ast::TraitObjectSyntax;
 use rustc_errors::codes::*;
-use rustc_errors::{Diag, EmissionGuarantee, StashKey};
+use rustc_errors::{Diag, EmissionGuarantee, ErrorGuaranteed, StashKey, Suggestions};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_lint_defs::Applicability;
@@ -15,13 +15,16 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     ///
     /// *Bare* trait object types are ones that aren't preceded by the keyword `dyn`.
     /// In edition 2021 and onward we emit a hard error for them.
-    pub(super) fn prohibit_or_lint_bare_trait_object_ty(&self, self_ty: &hir::Ty<'_>) {
+    pub(super) fn prohibit_or_lint_bare_trait_object_ty(
+        &self,
+        self_ty: &hir::Ty<'_>,
+    ) -> Option<ErrorGuaranteed> {
         let tcx = self.tcx();
 
         let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) =
             self_ty.kind
         else {
-            return;
+            return None;
         };
 
         let in_path = match tcx.parent_hir_node(self_ty.hir_id) {
@@ -70,8 +73,8 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         }
 
         if self_ty.span.edition().at_least_rust_2021() {
-            let msg = "trait objects must include the `dyn` keyword";
-            let label = "add `dyn` keyword before this trait";
+            let msg = "expected a type, found a trait";
+            let label = "you can add the `dyn` keyword if you want a trait object";
             let mut diag =
                 rustc_errors::struct_span_code_err!(self.dcx(), self_ty.span, E0782, "{}", msg);
             if self_ty.span.can_be_used_for_suggestions()
@@ -83,7 +86,17 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             // Check if the impl trait that we are considering is an impl of a local trait.
             self.maybe_suggest_blanket_trait_impl(self_ty, &mut diag);
             self.maybe_suggest_assoc_ty_bound(self_ty, &mut diag);
-            diag.stash(self_ty.span, StashKey::TraitMissingMethod);
+            // In case there is an associate type with the same name
+            // Add the suggestion to this error
+            if let Some(mut sugg) =
+                tcx.dcx().steal_non_err(self_ty.span, StashKey::AssociatedTypeSuggestion)
+                && let Suggestions::Enabled(ref mut s1) = diag.suggestions
+                && let Suggestions::Enabled(ref mut s2) = sugg.suggestions
+            {
+                s1.append(s2);
+                sugg.cancel();
+            }
+            diag.stash(self_ty.span, StashKey::TraitMissingMethod)
         } else {
             tcx.node_span_lint(BARE_TRAIT_OBJECTS, self_ty.hir_id, self_ty.span, |lint| {
                 lint.primary_message("trait objects without an explicit `dyn` are deprecated");
@@ -96,6 +109,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 }
                 self.maybe_suggest_blanket_trait_impl(self_ty, lint);
             });
+            None
         }
     }
 
@@ -174,41 +188,31 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         // 1. Independent functions
         // 2. Functions inside trait blocks
         // 3. Functions inside impl blocks
-        let (sig, generics, owner) = match tcx.hir_node_by_def_id(parent_id) {
+        let (sig, generics) = match tcx.hir_node_by_def_id(parent_id) {
             hir::Node::Item(hir::Item { kind: hir::ItemKind::Fn(sig, generics, _), .. }) => {
-                (sig, generics, None)
+                (sig, generics)
             }
             hir::Node::TraitItem(hir::TraitItem {
                 kind: hir::TraitItemKind::Fn(sig, _),
                 generics,
-                owner_id,
                 ..
-            }) => (sig, generics, Some(tcx.parent(owner_id.to_def_id()))),
+            }) => (sig, generics),
             hir::Node::ImplItem(hir::ImplItem {
                 kind: hir::ImplItemKind::Fn(sig, _),
                 generics,
-                owner_id,
                 ..
-            }) => (sig, generics, Some(tcx.parent(owner_id.to_def_id()))),
+            }) => (sig, generics),
             _ => return false,
         };
         let Ok(trait_name) = tcx.sess.source_map().span_to_snippet(self_ty.span) else {
             return false;
         };
         let impl_sugg = vec![(self_ty.span.shrink_to_lo(), "impl ".to_string())];
-        let mut is_downgradable = true;
-
         // Check if trait object is safe for suggesting dynamic dispatch.
         let is_dyn_compatible = match self_ty.kind {
             hir::TyKind::TraitObject(objects, ..) => {
                 objects.iter().all(|(o, _)| match o.trait_ref.path.res {
-                    Res::Def(DefKind::Trait, id) => {
-                        if Some(id) == owner {
-                            // For recursive traits, don't downgrade the error. (#119652)
-                            is_downgradable = false;
-                        }
-                        tcx.is_dyn_compatible(id)
-                    }
+                    Res::Def(DefKind::Trait, id) => tcx.is_dyn_compatible(id),
                     _ => false,
                 })
             }
@@ -255,9 +259,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                     suggestion,
                     Applicability::MachineApplicable,
                 );
-            } else if is_downgradable {
-                // We'll emit the dyn-compatibility error already, with a structured suggestion.
-                diag.downgrade_to_delayed_bug();
             }
             return true;
         }
@@ -281,10 +282,6 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             );
             if !is_dyn_compatible {
                 diag.note(format!("`{trait_name}` it is dyn-incompatible, so it can't be `dyn`"));
-                if is_downgradable {
-                    // We'll emit the dyn-compatibility error already, with a structured suggestion.
-                    diag.downgrade_to_delayed_bug();
-                }
             } else {
                 // No ampersand in suggestion if it's borrowed already
                 let (dyn_str, paren_dyn_str) =

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -53,6 +53,7 @@ use rustc_trait_selection::traits::{self, ObligationCtxt};
 use tracing::{debug, debug_span, instrument};
 
 use crate::bounds::Bounds;
+use crate::check::check_abi_fn_ptr;
 use crate::errors::{AmbiguousLifetimeBound, BadReturnTypeNotation, WildPatTy};
 use crate::hir_ty_lowering::errors::{GenericsArgsErrExtend, prohibit_assoc_item_constraint};
 use crate::hir_ty_lowering::generics::{check_generic_arg_count, lower_generic_args};
@@ -2063,13 +2064,18 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 )
             }
             hir::TyKind::TraitObject(bounds, lifetime, repr) => {
-                self.prohibit_or_lint_bare_trait_object_ty(hir_ty);
-
-                let repr = match repr {
-                    TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
-                    TraitObjectSyntax::DynStar => ty::DynStar,
-                };
-                self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, repr)
+                if let Some(guar) = self.prohibit_or_lint_bare_trait_object_ty(hir_ty) {
+                    // Don't continue with type analysis if the `dyn` keyword is missing
+                    // It generates confusing errors, especially if the user meant to use another
+                    // keyword like `impl`
+                    Ty::new_error(tcx, guar)
+                } else {
+                    let repr = match repr {
+                        TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
+                        TraitObjectSyntax::DynStar => ty::DynStar,
+                    };
+                    self.lower_trait_object_ty(hir_ty.span, hir_ty.hir_id, bounds, lifetime, repr)
+                }
             }
             // If we encounter a fully qualified path with RTN generics, then it must have
             // *not* gone through `lower_ty_maybe_return_type_notation`, and therefore
@@ -2337,6 +2343,12 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let fn_ty = tcx.mk_fn_sig(input_tys, output_ty, decl.c_variadic, safety, abi);
         let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars);
 
+        if let hir::Node::Ty(hir::Ty { kind: hir::TyKind::BareFn(bare_fn_ty), span, .. }) =
+            tcx.hir_node(hir_id)
+        {
+            check_abi_fn_ptr(tcx, hir_id, *span, bare_fn_ty.abi);
+        }
+
         // reject function types that violate cmse ABI requirements
         cmse::validate_cmse_abi(self.tcx(), self.dcx(), hir_id, abi, bare_fn_ty);
 

compiler/rustc_lint_defs/src/builtin.rs

@@ -124,6 +124,7 @@ declare_lint_pass! {
         UNSTABLE_NAME_COLLISIONS,
         UNSTABLE_SYNTAX_PRE_EXPANSION,
         UNSUPPORTED_CALLING_CONVENTIONS,
+        UNSUPPORTED_FN_PTR_CALLING_CONVENTIONS,
         UNUSED_ASSIGNMENTS,
         UNUSED_ASSOCIATED_TYPE_BOUNDS,
         UNUSED_ATTRIBUTES,
@@ -3839,6 +3840,50 @@ declare_lint! {
     };
 }
 
+declare_lint! {
+    /// The `unsupported_fn_ptr_calling_conventions` lint is output whenever there is a use of
+    /// a target dependent calling convention on a target that does not support this calling
+    /// convention on a function pointer.
+    ///
+    /// For example `stdcall` does not make much sense for a x86_64 or, more apparently, powerpc
+    /// code, because this calling convention was never specified for those targets.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,ignore (needs specific targets)
+    /// fn stdcall_ptr(f: extern "stdcall" fn ()) {
+    ///     f()
+    /// }
+    /// ```
+    ///
+    /// This will produce:
+    ///
+    /// ```text
+    /// warning: use of calling convention not supported on this target on function pointer
+    ///   --> $DIR/unsupported.rs:34:15
+    ///    |
+    /// LL | fn stdcall_ptr(f: extern "stdcall" fn()) {
+    ///    |               ^^^^^^^^^^^^^^^^^^^^^^^^
+    ///    |
+    ///    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    ///    = note: for more information, see issue #130260 <https://github.com/rust-lang/rust/issues/130260>
+    ///    = note: `#[warn(unsupported_fn_ptr_calling_conventions)]` on by default
+    /// ```
+    ///
+    /// ### Explanation
+    ///
+    /// On most of the targets the behaviour of `stdcall` and similar calling conventions is not
+    /// defined at all, but was previously accepted due to a bug in the implementation of the
+    /// compiler.
+    pub UNSUPPORTED_FN_PTR_CALLING_CONVENTIONS,
+    Warn,
+    "use of unsupported calling convention for function pointer",
+    @future_incompatible = FutureIncompatibleInfo {
+        reason: FutureIncompatibilityReason::FutureReleaseErrorDontReportInDeps,
+        reference: "issue #130260 <https://github.com/rust-lang/rust/issues/130260>",
+    };
+}
+
 declare_lint! {
     /// The `break_with_label_and_loop` lint detects labeled `break` expressions with
     /// an unlabeled loop as their value expression.

compiler/rustc_passes/messages.ftl

@@ -739,6 +739,12 @@ passes_unrecognized_repr_hint =
     unrecognized representation hint
     .help = valid reprs are `Rust` (default), `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
 
+passes_unstable_attr_for_already_stable_feature =
+    can't mark as unstable using an already stable feature
+    .label = this feature is already stable
+    .item = the stability attribute annotates this item
+    .help = consider removing the attribute
+
 passes_unused =
     unused attribute
     .suggestion = remove this attribute

compiler/rustc_passes/src/errors.rs

@@ -1480,6 +1480,17 @@ pub(crate) struct CannotStabilizeDeprecated {
     pub item_sp: Span,
 }
 
+#[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> {

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,