Auto merge of rust-lang#129595 - matthiaskrgr:rollup-4udn7nn, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#129288 (Use subtyping for `UnsafeFnPointer` coercion, too)
 - rust-lang#129405 (Fixing span manipulation and indentation of the suggestion introduced by rust-lang#126187)
 - rust-lang#129518 (gitignore: ignore ICE reports regardless of directory)
 - rust-lang#129519 (Remove redundant flags from `lower_ty_common` that can be inferred from the HIR)
 - rust-lang#129525 (rustdoc: clean up tuple <-> primitive conversion docs)
 - rust-lang#129526 (Use `FxHasher` on new solver unconditionally)
 - rust-lang#129544 (Removes dead code from the compiler)
 - rust-lang#129553 (add back test for stable-const-can-only-call-stable-const)
 - rust-lang#129590 (Avoid taking reference of &TyKind)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

.gitignore

@@ -56,7 +56,9 @@ build/
 /src/tools/x/target
 # Created by default with `src/ci/docker/run.sh`
 /obj/
-/rustc-ice*
+
+## ICE reports
+rustc-ice-*.txt
 
 ## Temporary files
 *~

Cargo.lock

@@ -4536,6 +4536,7 @@ dependencies = [
  "bitflags 2.6.0",
  "derive-where",
  "indexmap",
+ "rustc-hash",
  "rustc_ast_ir",
  "rustc_data_structures",
  "rustc_index",

compiler/rustc_borrowck/src/borrowck_errors.rs

@@ -290,7 +290,7 @@ impl<'infcx, 'tcx> crate::MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
         ty: Ty<'_>,
         is_index: Option<bool>,
     ) -> Diag<'infcx> {
-        let type_name = match (&ty.kind(), is_index) {
+        let type_name = match (ty.kind(), is_index) {
             (&ty::Array(_, _), Some(true)) | (&ty::Array(_, _), None) => "array",
             (&ty::Slice(_), _) => "slice",
             _ => span_bug!(move_from_span, "this path should not cause illegal move"),

compiler/rustc_borrowck/src/places_conflict.rs

@@ -201,7 +201,7 @@ fn place_components_conflict<'tcx>(
 
             let base_ty = base.ty(body, tcx).ty;
 
-            match (elem, &base_ty.kind(), access) {
+            match (elem, base_ty.kind(), access) {
                 (_, _, Shallow(Some(ArtificialField::ArrayLength)))
                 | (_, _, Shallow(Some(ArtificialField::FakeBorrow))) => {
                     // The array length is like additional fields on the

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2043,9 +2043,9 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
                         let ty_fn_ptr_from = tcx.safe_to_unsafe_fn_ty(fn_sig);
 
-                        if let Err(terr) = self.eq_types(
-                            *ty,
+                        if let Err(terr) = self.sub_types(
                             ty_fn_ptr_from,
+                            *ty,
                             location.to_locations(),
                             ConstraintCategory::Cast { unsize_to: None },
                         ) {

compiler/rustc_const_eval/messages.ftl

@@ -419,7 +419,7 @@ const_eval_unstable_const_fn = `{$def_path}` is not yet stable as a const fn
 const_eval_unstable_in_stable =
     const-stable function cannot use `#[feature({$gate})]`
     .unstable_sugg = if it is not part of the public API, make this function unstably const
-    .bypass_sugg = otherwise `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks
+    .bypass_sugg = otherwise `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (but requires team approval)
 
 const_eval_unterminated_c_string =
     reading a null-terminated string starting at {$pointer} with no null found before end of allocation

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -388,7 +388,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let (src_pointee_ty, dest_pointee_ty) =
             self.tcx.struct_lockstep_tails_for_codegen(source_ty, cast_ty, self.param_env);
 
-        match (&src_pointee_ty.kind(), &dest_pointee_ty.kind()) {
+        match (src_pointee_ty.kind(), dest_pointee_ty.kind()) {
             (&ty::Array(_, length), &ty::Slice(_)) => {
                 let ptr = self.read_pointer(src)?;
                 let val = Immediate::new_slice(
@@ -478,9 +478,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         dest: &PlaceTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx> {
         trace!("Unsizing {:?} of type {} into {}", *src, src.layout.ty, cast_ty.ty);
-        match (&src.layout.ty.kind(), &cast_ty.ty.kind()) {
+        match (src.layout.ty.kind(), cast_ty.ty.kind()) {
             (&ty::Ref(_, s, _), &ty::Ref(_, c, _) | &ty::RawPtr(c, _))
-            | (&ty::RawPtr(s, _), &ty::RawPtr(c, _)) => self.unsize_into_ptr(src, dest, *s, *c),
+            | (&ty::RawPtr(s, _), &ty::RawPtr(c, _)) => self.unsize_into_ptr(src, dest, s, c),
             (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
                 assert_eq!(def_a, def_b); // implies same number of fields
 

compiler/rustc_hir_analysis/src/collect.rs

@@ -392,7 +392,7 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
     }
 
     fn re_infer(&self, span: Span, reason: RegionInferReason<'_>) -> ty::Region<'tcx> {
-        if let RegionInferReason::BorrowedObjectLifetimeDefault = reason {
+        if let RegionInferReason::ObjectLifetimeDefault = reason {
             let e = struct_span_code_err!(
                 self.dcx(),
                 span,

compiler/rustc_hir_analysis/src/hir_ty_lowering/errors.rs

@@ -608,7 +608,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
 
         let mut bound_span_label = |self_ty: Ty<'_>, obligation: &str, quiet: &str| {
             let msg = format!("`{}`", if obligation.len() > 50 { quiet } else { obligation });
-            match &self_ty.kind() {
+            match self_ty.kind() {
                 // Point at the type that couldn't satisfy the bound.
                 ty::Adt(def, _) => {
                     bound_spans.get_mut_or_insert_default(tcx.def_span(def.did())).push(msg)

compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs

@@ -15,11 +15,7 @@ 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<'_>,
-        in_path: bool,
-    ) {
+    pub(super) fn prohibit_or_lint_bare_trait_object_ty(&self, self_ty: &hir::Ty<'_>) {
         let tcx = self.tcx();
 
         let hir::TyKind::TraitObject([poly_trait_ref, ..], _, TraitObjectSyntax::None) =
@@ -28,6 +24,21 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
             return;
         };
 
+        let in_path = match tcx.parent_hir_node(self_ty.hir_id) {
+            hir::Node::Ty(hir::Ty {
+                kind: hir::TyKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            })
+            | hir::Node::Expr(hir::Expr {
+                kind: hir::ExprKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            })
+            | hir::Node::Pat(hir::Pat {
+                kind: hir::PatKind::Path(hir::QPath::TypeRelative(qself, _)),
+                ..
+            }) if qself.hir_id == self_ty.hir_id => true,
+            _ => false,
+        };
         let needs_bracket = in_path
             && !tcx
                 .sess