Rollup of 5 pull requests

compiler/rustc_arena/src/lib.rs

@@ -74,7 +74,7 @@ impl<T> ArenaChunk<T> {
     #[inline]
     unsafe fn new(capacity: usize) -> ArenaChunk<T> {
         ArenaChunk {
-            storage: NonNull::new(Box::into_raw(Box::new_uninit_slice(capacity))).unwrap(),
+            storage: NonNull::new_unchecked(Box::into_raw(Box::new_uninit_slice(capacity))),
             entries: 0,
         }
     }
@@ -85,7 +85,7 @@ impl<T> ArenaChunk<T> {
         // The branch on needs_drop() is an -O1 performance optimization.
         // Without the branch, dropping TypedArena<u8> takes linear time.
         if mem::needs_drop::<T>() {
-            let slice = &mut *(self.storage.as_mut());
+            let slice = self.storage.as_mut();
             ptr::drop_in_place(MaybeUninit::slice_assume_init_mut(&mut slice[..len]));
         }
     }
@@ -104,7 +104,7 @@ impl<T> ArenaChunk<T> {
                 // A pointer as large as possible for zero-sized elements.
                 ptr::invalid_mut(!0)
             } else {
-                self.start().add((*self.storage.as_ptr()).len())
+                self.start().add(self.storage.len())
             }
         }
     }
@@ -288,7 +288,7 @@ impl<T> TypedArena<T> {
                 // If the previous chunk's len is less than HUGE_PAGE
                 // bytes, then this chunk will be least double the previous
                 // chunk's size.
-                new_cap = (*last_chunk.storage.as_ptr()).len().min(HUGE_PAGE / elem_size / 2);
+                new_cap = last_chunk.storage.len().min(HUGE_PAGE / elem_size / 2);
                 new_cap *= 2;
             } else {
                 new_cap = PAGE / elem_size;
@@ -396,7 +396,7 @@ impl DroplessArena {
                 // If the previous chunk's len is less than HUGE_PAGE
                 // bytes, then this chunk will be least double the previous
                 // chunk's size.
-                new_cap = (*last_chunk.storage.as_ptr()).len().min(HUGE_PAGE / 2);
+                new_cap = last_chunk.storage.len().min(HUGE_PAGE / 2);
                 new_cap *= 2;
             } else {
                 new_cap = PAGE;

compiler/rustc_feature/src/builtin_attrs.rs

@@ -344,7 +344,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
     ungated!(link_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
     ungated!(no_link, Normal, template!(Word), WarnFollowing),
-    ungated!(repr, Normal, template!(List: "C"), DuplicatesOk, @only_local: true),
+    ungated!(repr, Normal, template!(List: "C"), DuplicatesOk),
     ungated!(export_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
     ungated!(link_section, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
     ungated!(no_mangle, Normal, template!(Word), WarnFollowing, @only_local: true),

compiler/rustc_lint/src/types.rs

@@ -1250,17 +1250,45 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
         }
     }
 
-    fn check_foreign_fn(&mut self, def_id: LocalDefId, decl: &hir::FnDecl<'_>) {
+    /// Check if a function's argument types and result type are "ffi-safe".
+    ///
+    /// Argument types and the result type are checked for functions with external ABIs.
+    /// For functions with internal ABIs, argument types and the result type are walked to find
+    /// fn-ptr types that have external ABIs, as these still need checked.
+    fn check_maybe_foreign_fn(
+        &mut self,
+        abi: SpecAbi,
+        def_id: LocalDefId,
+        decl: &'tcx hir::FnDecl<'_>,
+    ) {
         let sig = self.cx.tcx.fn_sig(def_id).subst_identity();
         let sig = self.cx.tcx.erase_late_bound_regions(sig);
 
+        let is_internal_abi = self.is_internal_abi(abi);
+        let check_ty = |this: &mut ImproperCTypesVisitor<'a, 'tcx>,
+                        hir_ty: &'tcx hir::Ty<'_>,
+                        ty: Ty<'tcx>,
+                        is_return_type: bool| {
+            // If this function has an external ABI, then its arguments and return type should be
+            // checked..
+            if !is_internal_abi {
+                this.check_type_for_ffi_and_report_errors(hir_ty.span, ty, false, is_return_type);
+                return;
+            }
+
+            // ..but if this function has an internal ABI, then search the argument or return type
+            // for any fn-ptr types with external ABI, which should be checked..
+            for (fn_ptr_ty, span) in this.find_fn_ptr_ty_with_external_abi(hir_ty, ty) {
+                this.check_type_for_ffi_and_report_errors(span, fn_ptr_ty, false, is_return_type);
+            }
+        };
+
         for (input_ty, input_hir) in iter::zip(sig.inputs(), decl.inputs) {
-            self.check_type_for_ffi_and_report_errors(input_hir.span, *input_ty, false, false);
+            check_ty(self, input_hir, *input_ty, false);
         }
 
         if let hir::FnRetTy::Return(ref ret_hir) = decl.output {
-            let ret_ty = sig.output();
-            self.check_type_for_ffi_and_report_errors(ret_hir.span, ret_ty, false, true);
+            check_ty(self, ret_hir, sig.output(), true);
         }
     }
 
@@ -1275,28 +1303,134 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
             SpecAbi::Rust | SpecAbi::RustCall | SpecAbi::RustIntrinsic | SpecAbi::PlatformIntrinsic
         )
     }
+
+    /// Find any fn-ptr types with external ABIs in `ty`.
+    ///
+    /// For example, `Option<extern "C" fn()>` returns `extern "C" fn()`
+    fn find_fn_ptr_ty_with_external_abi(
+        &self,
+        hir_ty: &hir::Ty<'tcx>,
+        ty: Ty<'tcx>,
+    ) -> Vec<(Ty<'tcx>, Span)> {
+        struct FnPtrFinder<'parent, 'a, 'tcx> {
+            visitor: &'parent ImproperCTypesVisitor<'a, 'tcx>,
+            spans: Vec<Span>,
+            tys: Vec<Ty<'tcx>>,
+        }
+
+        impl<'parent, 'a, 'tcx> hir::intravisit::Visitor<'_> for FnPtrFinder<'parent, 'a, 'tcx> {
+            fn visit_ty(&mut self, ty: &'_ hir::Ty<'_>) {
+                debug!(?ty);
+                if let hir::TyKind::BareFn(hir::BareFnTy { abi, .. }) = ty.kind
+                    && !self.visitor.is_internal_abi(*abi)
+                {
+                    self.spans.push(ty.span);
+                }
+
+                hir::intravisit::walk_ty(self, ty)
+            }
+        }
+
+        impl<'vis, 'a, 'tcx> ty::visit::TypeVisitor<TyCtxt<'tcx>> for FnPtrFinder<'vis, 'a, 'tcx> {
+            type BreakTy = Ty<'tcx>;
+
+            fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+                if let ty::FnPtr(sig) = ty.kind() && !self.visitor.is_internal_abi(sig.abi()) {
+                    self.tys.push(ty);
+                }
+
+                ty.super_visit_with(self)
+            }
+        }
+
+        let mut visitor = FnPtrFinder { visitor: &*self, spans: Vec::new(), tys: Vec::new() };
+        self.cx
+            .tcx
+            .try_normalize_erasing_regions(self.cx.param_env, ty)
+            .unwrap_or(ty)
+            .visit_with(&mut visitor);
+        hir::intravisit::Visitor::visit_ty(&mut visitor, hir_ty);
+
+        iter::zip(visitor.tys.drain(..), visitor.spans.drain(..)).collect()
+    }
 }
 
 impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations {
-    fn check_foreign_item(&mut self, cx: &LateContext<'_>, it: &hir::ForeignItem<'_>) {
+    fn check_foreign_item(&mut self, cx: &LateContext<'tcx>, it: &hir::ForeignItem<'tcx>) {
         let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Declaration };
         let abi = cx.tcx.hir().get_foreign_abi(it.hir_id());
 
-        if !vis.is_internal_abi(abi) {
-            match it.kind {
-                hir::ForeignItemKind::Fn(ref decl, _, _) => {
-                    vis.check_foreign_fn(it.owner_id.def_id, decl);
-                }
-                hir::ForeignItemKind::Static(ref ty, _) => {
-                    vis.check_foreign_static(it.owner_id, ty.span);
-                }
-                hir::ForeignItemKind::Type => (),
+        match it.kind {
+            hir::ForeignItemKind::Fn(ref decl, _, _) => {
+                vis.check_maybe_foreign_fn(abi, it.owner_id.def_id, decl);
             }
+            hir::ForeignItemKind::Static(ref ty, _) if !vis.is_internal_abi(abi) => {
+                vis.check_foreign_static(it.owner_id, ty.span);
+            }
+            hir::ForeignItemKind::Static(..) | hir::ForeignItemKind::Type => (),
         }
     }
 }
 
+impl ImproperCTypesDefinitions {
+    fn check_ty_maybe_containing_foreign_fnptr<'tcx>(
+        &mut self,
+        cx: &LateContext<'tcx>,
+        hir_ty: &'tcx hir::Ty<'_>,
+        ty: Ty<'tcx>,
+    ) {
+        let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition };
+        for (fn_ptr_ty, span) in vis.find_fn_ptr_ty_with_external_abi(hir_ty, ty) {
+            vis.check_type_for_ffi_and_report_errors(span, fn_ptr_ty, true, false);
+        }
+    }
+}
+
+/// `ImproperCTypesDefinitions` checks items outside of foreign items (e.g. stuff that isn't in
+/// `extern "C" { }` blocks):
+///
+/// - `extern "<abi>" fn` definitions are checked in the same way as the
+///   `ImproperCtypesDeclarations` visitor checks functions if `<abi>` is external (e.g. "C").
+/// - All other items which contain types (e.g. other functions, struct definitions, etc) are
+///   checked for extern fn-ptrs with external ABIs.
 impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
+        match item.kind {
+            hir::ItemKind::Static(ty, ..)
+            | hir::ItemKind::Const(ty, ..)
+            | hir::ItemKind::TyAlias(ty, ..) => {
+                self.check_ty_maybe_containing_foreign_fnptr(
+                    cx,
+                    ty,
+                    cx.tcx.type_of(item.owner_id).subst_identity(),
+                );
+            }
+            // See `check_fn`..
+            hir::ItemKind::Fn(..) => {}
+            // See `check_field_def`..
+            hir::ItemKind::Union(..) | hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) => {}
+            // Doesn't define something that can contain a external type to be checked.
+            hir::ItemKind::Impl(..)
+            | hir::ItemKind::TraitAlias(..)
+            | hir::ItemKind::Trait(..)
+            | hir::ItemKind::OpaqueTy(..)
+            | hir::ItemKind::GlobalAsm(..)
+            | hir::ItemKind::ForeignMod { .. }
+            | hir::ItemKind::Mod(..)
+            | hir::ItemKind::Macro(..)
+            | hir::ItemKind::Use(..)
+            | hir::ItemKind::ExternCrate(..) => {}
+        }
+    }
+
+    fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &'tcx hir::FieldDef<'tcx>) {
+        self.check_ty_maybe_containing_foreign_fnptr(
+            cx,
+            field.ty,
+            cx.tcx.type_of(field.def_id).subst_identity(),
+        );
+    }
+
     fn check_fn(
         &mut self,
         cx: &LateContext<'tcx>,
@@ -1315,9 +1449,7 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDefinitions {
         };
 
         let mut vis = ImproperCTypesVisitor { cx, mode: CItemKind::Definition };
-        if !vis.is_internal_abi(abi) {
-            vis.check_foreign_fn(id, decl);
-        }
+        vis.check_maybe_foreign_fn(abi, id, decl);
     }
 }
 

compiler/rustc_target/src/abi/call/x86_64.rs

@@ -153,9 +153,9 @@ fn reg_component(cls: &[Option<Class>], i: &mut usize, size: Size) -> Option<Reg
     }
 }
 
-fn cast_target(cls: &[Option<Class>], size: Size) -> CastTarget {
+fn cast_target(cls: &[Option<Class>], size: Size) -> Option<CastTarget> {
     let mut i = 0;
-    let lo = reg_component(cls, &mut i, size).unwrap();
+    let lo = reg_component(cls, &mut i, size)?;
     let offset = Size::from_bytes(8) * (i as u64);
     let mut target = CastTarget::from(lo);
     if size > offset {
@@ -164,7 +164,7 @@ fn cast_target(cls: &[Option<Class>], size: Size) -> CastTarget {
         }
     }
     assert_eq!(reg_component(cls, &mut i, Size::ZERO), None);
-    target
+    Some(target)
 }
 
 const MAX_INT_REGS: usize = 6; // RDI, RSI, RDX, RCX, R8, R9
@@ -227,7 +227,9 @@ where
                 // split into sized chunks passed individually
                 if arg.layout.is_aggregate() {
                     let size = arg.layout.size;
-                    arg.cast_to(cast_target(cls, size))
+                    if let Some(cast_target) = cast_target(cls, size) {
+                        arg.cast_to(cast_target);
+                    }
                 } else {
                     arg.extend_integer_width_to(32);
                 }

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -3,7 +3,8 @@ use rustc_infer::infer::at::ToTrace;
 use rustc_infer::infer::canonical::CanonicalVarValues;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use rustc_infer::infer::{
-    DefineOpaqueTypes, InferCtxt, InferOk, LateBoundRegionConversionTime, TyCtxtInferExt,
+    DefineOpaqueTypes, InferCtxt, InferOk, LateBoundRegionConversionTime, RegionVariableOrigin,
+    TyCtxtInferExt,
 };
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::ObligationCause;
@@ -223,18 +224,20 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
         {
             debug!("rerunning goal to check result is stable");
             let (_orig_values, canonical_goal) = self.canonicalize_goal(goal);
-            let canonical_response =
+            let new_canonical_response =
                 EvalCtxt::evaluate_canonical_goal(self.tcx(), self.search_graph, canonical_goal)?;
-            if !canonical_response.value.var_values.is_identity() {
+            if !new_canonical_response.value.var_values.is_identity() {
                 bug!(
                     "unstable result: re-canonicalized goal={canonical_goal:#?} \
-                     response={canonical_response:#?}"
+                    first_response={canonical_response:#?} \
+                    second_response={new_canonical_response:#?}"
                 );
             }
-            if certainty != canonical_response.value.certainty {
+            if certainty != new_canonical_response.value.certainty {
                 bug!(
                     "unstable certainty: {certainty:#?} re-canonicalized goal={canonical_goal:#?} \
-                     response={canonical_response:#?}"
+                     first_response={canonical_response:#?} \
+                     second_response={new_canonical_response:#?}"
                 );
             }
         }
@@ -434,6 +437,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         })
     }
 
+    pub(super) fn next_region_infer(&self) -> ty::Region<'tcx> {
+        self.infcx.next_region_var(RegionVariableOrigin::MiscVariable(DUMMY_SP))
+    }
+
     pub(super) fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx> {
         self.infcx.next_const_var(
             ty,