| 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, Symbol}; |
| |
| 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( |
| "call to unsafe function", |
| "consult the function's documentation for information on how to avoid \ |
| undefined behavior", |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ) |
| } |
| |
| if let ty::FnDef(func_id, _) = func_ty.kind { |
| self.check_target_features(func_id); |
| } |
| } |
| |
| TerminatorKind::InlineAsm { .. } => self.require_unsafe( |
| "use of inline assembly", |
| "inline assembly is entirely unchecked and can cause undefined behavior", |
| UnsafetyViolationKind::General, |
| ), |
| } |
| 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::Nop => { |
| // safe (at least as emitted during MIR construction) |
| } |
| |
| StatementKind::LlvmInlineAsm { .. } => self.require_unsafe( |
| "use of inline assembly", |
| "inline assembly is entirely unchecked and can cause undefined behavior", |
| UnsafetyViolationKind::General, |
| ), |
| } |
| 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( |
| "initializing type with `rustc_layout_scalar_valid_range` attr", |
| "initializing a layout restricted type's field with a value \ |
| outside the valid range is undefined behavior", |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ), |
| } |
| } |
| &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( |
| "cast of pointer to int", |
| "casting pointers to integers in constants", |
| UnsafetyViolationKind::General, |
| ); |
| } |
| _ => {} |
| } |
| } |
| _ => {} |
| } |
| 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( |
| "borrow of packed field", |
| "fields of packed structs might be misaligned: dereferencing a \ |
| misaligned pointer or even just creating a misaligned reference \ |
| is undefined behavior", |
| UnsafetyViolationKind::BorrowPacked, |
| ); |
| } |
| } |
| |
| 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( |
| "borrow of packed field", |
| "fields of packed structs might be misaligned: dereferencing a \ |
| misaligned pointer or even just creating a misaligned reference \ |
| is undefined behavior", |
| UnsafetyViolationKind::BorrowPacked, |
| ); |
| } |
| } |
| 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( |
| "use of mutable static", |
| "mutable statics can be mutated by multiple threads: aliasing \ |
| violations or data races will cause undefined behavior", |
| UnsafetyViolationKind::General, |
| ); |
| return; |
| } else if self.tcx.is_foreign_item(def_id) { |
| self.require_unsafe( |
| "use of extern static", |
| "extern statics are not controlled by the Rust type system: \ |
| invalid data, aliasing violations or data races will cause \ |
| undefined behavior", |
| UnsafetyViolationKind::General, |
| ); |
| 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( |
| "dereference of raw pointer", |
| "raw pointers may be NULL, dangling or unaligned; they can violate \ |
| aliasing rules and cause data races: all of these are undefined \ |
| behavior", |
| UnsafetyViolationKind::General, |
| ), |
| 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( |
| "assignment to non-`Copy` union field", |
| "the previous content of the field will be dropped, which \ |
| causes undefined behavior if the field was not properly \ |
| initialized", |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ) |
| } else { |
| // write to non-move union, safe |
| } |
| } else { |
| self.require_unsafe( |
| "access to union field", |
| "the field may not be properly initialized: using \ |
| uninitialized data will cause undefined behavior", |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ) |
| } |
| } |
| } |
| _ => {} |
| } |
| self.source_info = source_info; |
| } |
| } |
| } |
| |
| impl<'a, 'tcx> UnsafetyChecker<'a, 'tcx> { |
| fn require_unsafe( |
| &mut self, |
| description: &'static str, |
| details: &'static str, |
| kind: UnsafetyViolationKind, |
| ) { |
| 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, |
| description: Symbol::intern(description), |
| details: Symbol::intern(details), |
| kind, |
| }], |
| &[], |
| ); |
| } |
| |
| 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 (description, details) = if is_mut_use { |
| ( |
| "mutation of layout constrained field", |
| "mutating layout constrained fields cannot statically be \ |
| checked for valid values", |
| ) |
| |
| // 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) |
| { |
| ( |
| "borrow of layout constrained field with interior \ |
| mutability", |
| "references to fields of layout constrained fields \ |
| lose the constraints. Coupled with interior mutability, \ |
| the field can be changed to invalid values", |
| ) |
| } else { |
| continue; |
| }; |
| self.require_unsafe( |
| description, |
| details, |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| /// 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( |
| "call to function with `#[target_feature]`", |
| "can only be called if the required target features are available", |
| UnsafetyViolationKind::GeneralAndConstFn, |
| ) |
| } |
| } |
| } |
| |
| pub(crate) fn provide(providers: &mut Providers) { |
| *providers = Providers { unsafety_check_result, 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().as_local_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: TyCtxt<'_>, def_id: LocalDefId) -> UnsafetyCheckResult { |
| debug!("unsafety_violations({:?})", def_id); |
| |
| // N.B., this borrow is valid because all the consumers of |
| // `mir_built` force this. |
| let body = &tcx.mir_built(def_id).borrow(); |
| |
| let param_env = tcx.param_env(def_id); |
| |
| let id = tcx.hir().as_local_hir_id(def_id); |
| 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_id.to_def_id()), is_min_const_fn(tcx, def_id.to_def_id())) |
| } |
| hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_) => (true, false), |
| }; |
| let mut checker = |
| UnsafetyChecker::new(const_context, min_const_fn, body, def_id, tcx, param_env); |
| checker.visit_body(&body); |
| |
| check_unused_unsafe(tcx, def_id, &checker.used_unsafe, &mut checker.inherited_blocks); |
| 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().as_local_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, description, details, kind } in |
| violations.iter() |
| { |
| // 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.as_str()) |
| .note(&details.as_str()) |
| .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(&details.as_str()) |
| .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.as_str()) |
| .note(&details.as_str()) |
| .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.as_str()) |
| .note(&details.as_str()) |
| .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 |
| } |
