diff options
Diffstat (limited to 'compiler/rustc_mir/src/transform/check_unsafety.rs')
| -rw-r--r-- | compiler/rustc_mir/src/transform/check_unsafety.rs | 733 |
1 files changed, 733 insertions, 0 deletions
diff --git a/compiler/rustc_mir/src/transform/check_unsafety.rs b/compiler/rustc_mir/src/transform/check_unsafety.rs new file mode 100644 index 00000000000..c3e04e698db --- /dev/null +++ b/compiler/rustc_mir/src/transform/check_unsafety.rs @@ -0,0 +1,733 @@ +use rustc_data_structures::fx::FxHashSet; +use rustc_errors::struct_span_err; +use rustc_hir as hir; +use rustc_hir::def_id::{DefId, LocalDefId}; +use rustc_hir::hir_id::HirId; +use rustc_hir::intravisit; +use rustc_hir::Node; +use rustc_middle::mir::visit::{MutatingUseContext, PlaceContext, Visitor}; +use rustc_middle::mir::*; +use rustc_middle::ty::cast::CastTy; +use rustc_middle::ty::query::Providers; +use rustc_middle::ty::{self, TyCtxt}; +use rustc_session::lint::builtin::{SAFE_PACKED_BORROWS, UNSAFE_OP_IN_UNSAFE_FN, UNUSED_UNSAFE}; +use rustc_session::lint::Level; +use rustc_span::symbol::sym; + +use std::ops::Bound; + +use crate::const_eval::is_min_const_fn; +use crate::util; + +pub struct UnsafetyChecker<'a, 'tcx> { + body: &'a Body<'tcx>, + body_did: LocalDefId, + const_context: bool, + min_const_fn: bool, + violations: Vec<UnsafetyViolation>, + source_info: SourceInfo, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + /// Mark an `unsafe` block as used, so we don't lint it. + used_unsafe: FxHashSet<hir::HirId>, + inherited_blocks: Vec<(hir::HirId, bool)>, +} + +impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> { + fn new( + const_context: bool, + min_const_fn: bool, + body: &'a Body<'tcx>, + body_did: LocalDefId, + tcx: TyCtxt<'tcx>, + param_env: ty::ParamEnv<'tcx>, + ) -> Self { + // sanity check + if min_const_fn { + assert!(const_context); + } + Self { + body, + body_did, + const_context, + min_const_fn, + violations: vec![], + source_info: SourceInfo::outermost(body.span), + tcx, + param_env, + used_unsafe: Default::default(), + inherited_blocks: vec![], + } + } +} + +impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> { + fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) { + self.source_info = terminator.source_info; + match terminator.kind { + TerminatorKind::Goto { .. } + | TerminatorKind::SwitchInt { .. } + | TerminatorKind::Drop { .. } + | TerminatorKind::Yield { .. } + | TerminatorKind::Assert { .. } + | TerminatorKind::DropAndReplace { .. } + | TerminatorKind::GeneratorDrop + | TerminatorKind::Resume + | TerminatorKind::Abort + | TerminatorKind::Return + | TerminatorKind::Unreachable + | TerminatorKind::FalseEdge { .. } + | TerminatorKind::FalseUnwind { .. } => { + // safe (at least as emitted during MIR construction) + } + + TerminatorKind::Call { ref func, .. } => { + let func_ty = func.ty(self.body, self.tcx); + let sig = func_ty.fn_sig(self.tcx); + if let hir::Unsafety::Unsafe = sig.unsafety() { + self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::CallToUnsafeFunction, + ) + } + + if let ty::FnDef(func_id, _) = func_ty.kind { + self.check_target_features(func_id); + } + } + + TerminatorKind::InlineAsm { .. } => self.require_unsafe( + UnsafetyViolationKind::General, + UnsafetyViolationDetails::UseOfInlineAssembly, + ), + } + self.super_terminator(terminator, location); + } + + fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) { + self.source_info = statement.source_info; + match statement.kind { + StatementKind::Assign(..) + | StatementKind::FakeRead(..) + | StatementKind::SetDiscriminant { .. } + | StatementKind::StorageLive(..) + | StatementKind::StorageDead(..) + | StatementKind::Retag { .. } + | StatementKind::AscribeUserType(..) + | StatementKind::Coverage(..) + | StatementKind::Nop => { + // safe (at least as emitted during MIR construction) + } + + StatementKind::LlvmInlineAsm { .. } => self.require_unsafe( + UnsafetyViolationKind::General, + UnsafetyViolationDetails::UseOfInlineAssembly, + ), + } + self.super_statement(statement, location); + } + + fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) { + match rvalue { + Rvalue::Aggregate(box ref aggregate, _) => match aggregate { + &AggregateKind::Array(..) | &AggregateKind::Tuple => {} + &AggregateKind::Adt(ref def, ..) => { + match self.tcx.layout_scalar_valid_range(def.did) { + (Bound::Unbounded, Bound::Unbounded) => {} + _ => self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::InitializingTypeWith, + ), + } + } + &AggregateKind::Closure(def_id, _) | &AggregateKind::Generator(def_id, _, _) => { + let UnsafetyCheckResult { violations, unsafe_blocks } = + self.tcx.unsafety_check_result(def_id.expect_local()); + self.register_violations(&violations, &unsafe_blocks); + } + }, + // casting pointers to ints is unsafe in const fn because the const evaluator cannot + // possibly know what the result of various operations like `address / 2` would be + // pointers during const evaluation have no integral address, only an abstract one + Rvalue::Cast(CastKind::Misc, ref operand, cast_ty) + if self.const_context && self.tcx.features().const_raw_ptr_to_usize_cast => + { + let operand_ty = operand.ty(self.body, self.tcx); + let cast_in = CastTy::from_ty(operand_ty).expect("bad input type for cast"); + let cast_out = CastTy::from_ty(cast_ty).expect("bad output type for cast"); + match (cast_in, cast_out) { + (CastTy::Ptr(_) | CastTy::FnPtr, CastTy::Int(_)) => { + self.require_unsafe( + UnsafetyViolationKind::General, + UnsafetyViolationDetails::CastOfPointerToInt, + ); + } + _ => {} + } + } + _ => {} + } + self.super_rvalue(rvalue, location); + } + + fn visit_place(&mut self, place: &Place<'tcx>, context: PlaceContext, _location: Location) { + // On types with `scalar_valid_range`, prevent + // * `&mut x.field` + // * `x.field = y;` + // * `&x.field` if `field`'s type has interior mutability + // because either of these would allow modifying the layout constrained field and + // insert values that violate the layout constraints. + if context.is_mutating_use() || context.is_borrow() { + self.check_mut_borrowing_layout_constrained_field(*place, context.is_mutating_use()); + } + + if context.is_borrow() { + if util::is_disaligned(self.tcx, self.body, self.param_env, *place) { + self.require_unsafe( + UnsafetyViolationKind::BorrowPacked, + UnsafetyViolationDetails::BorrowOfPackedField, + ); + } + } + + for (i, elem) in place.projection.iter().enumerate() { + let proj_base = &place.projection[..i]; + if context.is_borrow() { + if util::is_disaligned(self.tcx, self.body, self.param_env, *place) { + self.require_unsafe( + UnsafetyViolationKind::BorrowPacked, + UnsafetyViolationDetails::BorrowOfPackedField, + ); + } + } + let source_info = self.source_info; + if let [] = proj_base { + let decl = &self.body.local_decls[place.local]; + if decl.internal { + if let Some(box LocalInfo::StaticRef { def_id, .. }) = decl.local_info { + if self.tcx.is_mutable_static(def_id) { + self.require_unsafe( + UnsafetyViolationKind::General, + UnsafetyViolationDetails::UseOfMutableStatic, + ); + return; + } else if self.tcx.is_foreign_item(def_id) { + self.require_unsafe( + UnsafetyViolationKind::General, + UnsafetyViolationDetails::UseOfExternStatic, + ); + return; + } + } else { + // Internal locals are used in the `move_val_init` desugaring. + // We want to check unsafety against the source info of the + // desugaring, rather than the source info of the RHS. + self.source_info = self.body.local_decls[place.local].source_info; + } + } + } + let base_ty = Place::ty_from(place.local, proj_base, self.body, self.tcx).ty; + match base_ty.kind { + ty::RawPtr(..) => self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::DerefOfRawPointer, + ), + ty::Adt(adt, _) => { + if adt.is_union() { + if context == PlaceContext::MutatingUse(MutatingUseContext::Store) + || context == PlaceContext::MutatingUse(MutatingUseContext::Drop) + || context == PlaceContext::MutatingUse(MutatingUseContext::AsmOutput) + { + let elem_ty = match elem { + ProjectionElem::Field(_, ty) => ty, + _ => span_bug!( + self.source_info.span, + "non-field projection {:?} from union?", + place + ), + }; + if !elem_ty.is_copy_modulo_regions( + self.tcx.at(self.source_info.span), + self.param_env, + ) { + self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::AssignToNonCopyUnionField, + ) + } else { + // write to non-move union, safe + } + } else { + self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::AccessToUnionField, + ) + } + } + } + _ => {} + } + self.source_info = source_info; + } + } +} + +impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> { + fn require_unsafe(&mut self, kind: UnsafetyViolationKind, details: UnsafetyViolationDetails) { + let source_info = self.source_info; + let lint_root = self.body.source_scopes[self.source_info.scope] + .local_data + .as_ref() + .assert_crate_local() + .lint_root; + self.register_violations( + &[UnsafetyViolation { source_info, lint_root, kind, details }], + &[], + ); + } + + fn register_violations( + &mut self, + violations: &[UnsafetyViolation], + unsafe_blocks: &[(hir::HirId, bool)], + ) { + let safety = self.body.source_scopes[self.source_info.scope] + .local_data + .as_ref() + .assert_crate_local() + .safety; + let within_unsafe = match safety { + // `unsafe` blocks are required in safe code + Safety::Safe => { + for violation in violations { + let mut violation = *violation; + match violation.kind { + UnsafetyViolationKind::GeneralAndConstFn + | UnsafetyViolationKind::General => {} + UnsafetyViolationKind::BorrowPacked => { + if self.min_const_fn { + // const fns don't need to be backwards compatible and can + // emit these violations as a hard error instead of a backwards + // compat lint + violation.kind = UnsafetyViolationKind::General; + } + } + UnsafetyViolationKind::UnsafeFn + | UnsafetyViolationKind::UnsafeFnBorrowPacked => { + bug!("`UnsafetyViolationKind::UnsafeFn` in an `Safe` context") + } + } + if !self.violations.contains(&violation) { + self.violations.push(violation) + } + } + false + } + // With the RFC 2585, no longer allow `unsafe` operations in `unsafe fn`s + Safety::FnUnsafe if self.tcx.features().unsafe_block_in_unsafe_fn => { + for violation in violations { + let mut violation = *violation; + + if violation.kind == UnsafetyViolationKind::BorrowPacked { + violation.kind = UnsafetyViolationKind::UnsafeFnBorrowPacked; + } else { + violation.kind = UnsafetyViolationKind::UnsafeFn; + } + if !self.violations.contains(&violation) { + self.violations.push(violation) + } + } + false + } + // `unsafe` function bodies allow unsafe without additional unsafe blocks (before RFC 2585) + Safety::BuiltinUnsafe | Safety::FnUnsafe => true, + Safety::ExplicitUnsafe(hir_id) => { + // mark unsafe block as used if there are any unsafe operations inside + if !violations.is_empty() { + self.used_unsafe.insert(hir_id); + } + // only some unsafety is allowed in const fn + if self.min_const_fn { + for violation in violations { + match violation.kind { + // these unsafe things are stable in const fn + UnsafetyViolationKind::GeneralAndConstFn => {} + // these things are forbidden in const fns + UnsafetyViolationKind::General + | UnsafetyViolationKind::BorrowPacked => { + let mut violation = *violation; + // const fns don't need to be backwards compatible and can + // emit these violations as a hard error instead of a backwards + // compat lint + violation.kind = UnsafetyViolationKind::General; + if !self.violations.contains(&violation) { + self.violations.push(violation) + } + } + UnsafetyViolationKind::UnsafeFn + | UnsafetyViolationKind::UnsafeFnBorrowPacked => bug!( + "`UnsafetyViolationKind::UnsafeFn` in an `ExplicitUnsafe` context" + ), + } + } + } + true + } + }; + self.inherited_blocks.extend( + unsafe_blocks.iter().map(|&(hir_id, is_used)| (hir_id, is_used && !within_unsafe)), + ); + } + fn check_mut_borrowing_layout_constrained_field( + &mut self, + place: Place<'tcx>, + is_mut_use: bool, + ) { + let mut cursor = place.projection.as_ref(); + while let &[ref proj_base @ .., elem] = cursor { + cursor = proj_base; + + match elem { + // Modifications behind a dereference don't affect the value of + // the pointer. + ProjectionElem::Deref => return, + ProjectionElem::Field(..) => { + let ty = + Place::ty_from(place.local, proj_base, &self.body.local_decls, self.tcx).ty; + if let ty::Adt(def, _) = ty.kind { + if self.tcx.layout_scalar_valid_range(def.did) + != (Bound::Unbounded, Bound::Unbounded) + { + let details = if is_mut_use { + UnsafetyViolationDetails::MutationOfLayoutConstrainedField + + // Check `is_freeze` as late as possible to avoid cycle errors + // with opaque types. + } else if !place + .ty(self.body, self.tcx) + .ty + .is_freeze(self.tcx.at(self.source_info.span), self.param_env) + { + UnsafetyViolationDetails::BorrowOfLayoutConstrainedField + } else { + continue; + }; + self.require_unsafe(UnsafetyViolationKind::GeneralAndConstFn, details); + } + } + } + _ => {} + } + } + } + + /// Checks whether calling `func_did` needs an `unsafe` context or not, i.e. whether + /// the called function has target features the calling function hasn't. + fn check_target_features(&mut self, func_did: DefId) { + let callee_features = &self.tcx.codegen_fn_attrs(func_did).target_features; + let self_features = &self.tcx.codegen_fn_attrs(self.body_did).target_features; + + // Is `callee_features` a subset of `calling_features`? + if !callee_features.iter().all(|feature| self_features.contains(feature)) { + self.require_unsafe( + UnsafetyViolationKind::GeneralAndConstFn, + UnsafetyViolationDetails::CallToFunctionWith, + ) + } + } +} + +pub(crate) fn provide(providers: &mut Providers) { + *providers = Providers { + unsafety_check_result: |tcx, def_id| { + if let Some(def) = ty::WithOptConstParam::try_lookup(def_id, tcx) { + tcx.unsafety_check_result_for_const_arg(def) + } else { + unsafety_check_result(tcx, ty::WithOptConstParam::unknown(def_id)) + } + }, + unsafety_check_result_for_const_arg: |tcx, (did, param_did)| { + unsafety_check_result( + tcx, + ty::WithOptConstParam { did, const_param_did: Some(param_did) }, + ) + }, + unsafe_derive_on_repr_packed, + ..*providers + }; +} + +struct UnusedUnsafeVisitor<'a> { + used_unsafe: &'a FxHashSet<hir::HirId>, + unsafe_blocks: &'a mut Vec<(hir::HirId, bool)>, +} + +impl<'a, 'tcx> intravisit::Visitor<'tcx> for UnusedUnsafeVisitor<'a> { + type Map = intravisit::ErasedMap<'tcx>; + + fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> { + intravisit::NestedVisitorMap::None + } + + fn visit_block(&mut self, block: &'tcx hir::Block<'tcx>) { + intravisit::walk_block(self, block); + + if let hir::BlockCheckMode::UnsafeBlock(hir::UnsafeSource::UserProvided) = block.rules { + self.unsafe_blocks.push((block.hir_id, self.used_unsafe.contains(&block.hir_id))); + } + } +} + +fn check_unused_unsafe( + tcx: TyCtxt<'_>, + def_id: LocalDefId, + used_unsafe: &FxHashSet<hir::HirId>, + unsafe_blocks: &mut Vec<(hir::HirId, bool)>, +) { + let body_id = tcx.hir().maybe_body_owned_by(tcx.hir().local_def_id_to_hir_id(def_id)); + + let body_id = match body_id { + Some(body) => body, + None => { + debug!("check_unused_unsafe({:?}) - no body found", def_id); + return; + } + }; + let body = tcx.hir().body(body_id); + debug!("check_unused_unsafe({:?}, body={:?}, used_unsafe={:?})", def_id, body, used_unsafe); + + let mut visitor = UnusedUnsafeVisitor { used_unsafe, unsafe_blocks }; + intravisit::Visitor::visit_body(&mut visitor, body); +} + +fn unsafety_check_result<'tcx>( + tcx: TyCtxt<'tcx>, + def: ty::WithOptConstParam<LocalDefId>, +) -> &'tcx UnsafetyCheckResult { + debug!("unsafety_violations({:?})", def); + + // N.B., this borrow is valid because all the consumers of + // `mir_built` force this. + let body = &tcx.mir_built(def).borrow(); + + let param_env = tcx.param_env(def.did); + + let id = tcx.hir().local_def_id_to_hir_id(def.did); + let (const_context, min_const_fn) = match tcx.hir().body_owner_kind(id) { + hir::BodyOwnerKind::Closure => (false, false), + hir::BodyOwnerKind::Fn => { + (tcx.is_const_fn_raw(def.did.to_def_id()), is_min_const_fn(tcx, def.did.to_def_id())) + } + hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => (true, false), + }; + let mut checker = + UnsafetyChecker::new(const_context, min_const_fn, body, def.did, tcx, param_env); + checker.visit_body(&body); + + check_unused_unsafe(tcx, def.did, &checker.used_unsafe, &mut checker.inherited_blocks); + + tcx.arena.alloc(UnsafetyCheckResult { + violations: checker.violations.into(), + unsafe_blocks: checker.inherited_blocks.into(), + }) +} + +fn unsafe_derive_on_repr_packed(tcx: TyCtxt<'_>, def_id: LocalDefId) { + let lint_hir_id = tcx.hir().local_def_id_to_hir_id(def_id); + + tcx.struct_span_lint_hir(SAFE_PACKED_BORROWS, lint_hir_id, tcx.def_span(def_id), |lint| { + // FIXME: when we make this a hard error, this should have its + // own error code. + let message = if tcx.generics_of(def_id).own_requires_monomorphization() { + "`#[derive]` can't be used on a `#[repr(packed)]` struct with \ + type or const parameters (error E0133)" + .to_string() + } else { + "`#[derive]` can't be used on a `#[repr(packed)]` struct that \ + does not derive Copy (error E0133)" + .to_string() + }; + lint.build(&message).emit() + }); +} + +/// Returns the `HirId` for an enclosing scope that is also `unsafe`. +fn is_enclosed( + tcx: TyCtxt<'_>, + used_unsafe: &FxHashSet<hir::HirId>, + id: hir::HirId, +) -> Option<(String, hir::HirId)> { + let parent_id = tcx.hir().get_parent_node(id); + if parent_id != id { + if used_unsafe.contains(&parent_id) { + Some(("block".to_string(), parent_id)) + } else if let Some(Node::Item(&hir::Item { + kind: hir::ItemKind::Fn(ref sig, _, _), .. + })) = tcx.hir().find(parent_id) + { + if sig.header.unsafety == hir::Unsafety::Unsafe + && !tcx.features().unsafe_block_in_unsafe_fn + { + Some(("fn".to_string(), parent_id)) + } else { + None + } + } else { + is_enclosed(tcx, used_unsafe, parent_id) + } + } else { + None + } +} + +fn report_unused_unsafe(tcx: TyCtxt<'_>, used_unsafe: &FxHashSet<hir::HirId>, id: hir::HirId) { + let span = tcx.sess.source_map().guess_head_span(tcx.hir().span(id)); + tcx.struct_span_lint_hir(UNUSED_UNSAFE, id, span, |lint| { + let msg = "unnecessary `unsafe` block"; + let mut db = lint.build(msg); + db.span_label(span, msg); + if let Some((kind, id)) = is_enclosed(tcx, used_unsafe, id) { + db.span_label( + tcx.sess.source_map().guess_head_span(tcx.hir().span(id)), + format!("because it's nested under this `unsafe` {}", kind), + ); + } + db.emit(); + }); +} + +fn builtin_derive_def_id(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> { + debug!("builtin_derive_def_id({:?})", def_id); + if let Some(impl_def_id) = tcx.impl_of_method(def_id) { + if tcx.has_attr(impl_def_id, sym::automatically_derived) { + debug!("builtin_derive_def_id({:?}) - is {:?}", def_id, impl_def_id); + Some(impl_def_id) + } else { + debug!("builtin_derive_def_id({:?}) - not automatically derived", def_id); + None + } + } else { + debug!("builtin_derive_def_id({:?}) - not a method", def_id); + None + } +} + +pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) { + debug!("check_unsafety({:?})", def_id); + + // closures are handled by their parent fn. + if tcx.is_closure(def_id.to_def_id()) { + return; + } + + let UnsafetyCheckResult { violations, unsafe_blocks } = tcx.unsafety_check_result(def_id); + + for &UnsafetyViolation { source_info, lint_root, kind, details } in violations.iter() { + let (description, note) = details.description_and_note(); + + // Report an error. + let unsafe_fn_msg = + if unsafe_op_in_unsafe_fn_allowed(tcx, lint_root) { " function or" } else { "" }; + + match kind { + UnsafetyViolationKind::GeneralAndConstFn | UnsafetyViolationKind::General => { + // once + struct_span_err!( + tcx.sess, + source_info.span, + E0133, + "{} is unsafe and requires unsafe{} block", + description, + unsafe_fn_msg, + ) + .span_label(source_info.span, description) + .note(note) + .emit(); + } + UnsafetyViolationKind::BorrowPacked => { + if let Some(impl_def_id) = builtin_derive_def_id(tcx, def_id.to_def_id()) { + // If a method is defined in the local crate, + // the impl containing that method should also be. + tcx.ensure().unsafe_derive_on_repr_packed(impl_def_id.expect_local()); + } else { + tcx.struct_span_lint_hir( + SAFE_PACKED_BORROWS, + lint_root, + source_info.span, + |lint| { + lint.build(&format!( + "{} is unsafe and requires unsafe{} block (error E0133)", + description, unsafe_fn_msg, + )) + .note(note) + .emit() + }, + ) + } + } + UnsafetyViolationKind::UnsafeFn => tcx.struct_span_lint_hir( + UNSAFE_OP_IN_UNSAFE_FN, + lint_root, + source_info.span, + |lint| { + lint.build(&format!( + "{} is unsafe and requires unsafe block (error E0133)", + description, + )) + .span_label(source_info.span, description) + .note(note) + .emit(); + }, + ), + UnsafetyViolationKind::UnsafeFnBorrowPacked => { + // When `unsafe_op_in_unsafe_fn` is disallowed, the behavior of safe and unsafe functions + // should be the same in terms of warnings and errors. Therefore, with `#[warn(safe_packed_borrows)]`, + // a safe packed borrow should emit a warning *but not an error* in an unsafe function, + // just like in a safe function, even if `unsafe_op_in_unsafe_fn` is `deny`. + // + // Also, `#[warn(unsafe_op_in_unsafe_fn)]` can't cause any new errors. Therefore, with + // `#[deny(safe_packed_borrows)]` and `#[warn(unsafe_op_in_unsafe_fn)]`, a packed borrow + // should only issue a warning for the sake of backwards compatibility. + // + // The solution those 2 expectations is to always take the minimum of both lints. + // This prevent any new errors (unless both lints are explicitely set to `deny`). + let lint = if tcx.lint_level_at_node(SAFE_PACKED_BORROWS, lint_root).0 + <= tcx.lint_level_at_node(UNSAFE_OP_IN_UNSAFE_FN, lint_root).0 + { + SAFE_PACKED_BORROWS + } else { + UNSAFE_OP_IN_UNSAFE_FN + }; + tcx.struct_span_lint_hir(&lint, lint_root, source_info.span, |lint| { + lint.build(&format!( + "{} is unsafe and requires unsafe block (error E0133)", + description, + )) + .span_label(source_info.span, description) + .note(note) + .emit(); + }) + } + } + } + + let (mut unsafe_used, mut unsafe_unused): (FxHashSet<_>, Vec<_>) = Default::default(); + for &(block_id, is_used) in unsafe_blocks.iter() { + if is_used { + unsafe_used.insert(block_id); + } else { + unsafe_unused.push(block_id); + } + } + // The unused unsafe blocks might not be in source order; sort them so that the unused unsafe + // error messages are properly aligned and the issue-45107 and lint-unused-unsafe tests pass. + unsafe_unused.sort_by_cached_key(|hir_id| tcx.hir().span(*hir_id)); + + for &block_id in &unsafe_unused { + report_unused_unsafe(tcx, &unsafe_used, block_id); + } +} + +fn unsafe_op_in_unsafe_fn_allowed(tcx: TyCtxt<'_>, id: HirId) -> bool { + tcx.lint_level_at_node(UNSAFE_OP_IN_UNSAFE_FN, id).0 == Level::Allow +} |