diff options
Diffstat (limited to 'compiler/rustc_lint/src/types.rs')
| -rw-r--r-- | compiler/rustc_lint/src/types.rs | 218 |
1 files changed, 191 insertions, 27 deletions
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs index c04053d18..6dade43a1 100644 --- a/compiler/rustc_lint/src/types.rs +++ b/compiler/rustc_lint/src/types.rs @@ -1,12 +1,13 @@ use crate::{ fluent_generated as fluent, lints::{ - AtomicOrderingFence, AtomicOrderingLoad, AtomicOrderingStore, ImproperCTypes, - InvalidAtomicOrderingDiag, InvalidNanComparisons, InvalidNanComparisonsSuggestion, - OnlyCastu8ToChar, OverflowingBinHex, OverflowingBinHexSign, OverflowingBinHexSignBitSub, - OverflowingBinHexSub, OverflowingInt, OverflowingIntHelp, OverflowingLiteral, - OverflowingUInt, RangeEndpointOutOfRange, UnusedComparisons, UseInclusiveRange, - VariantSizeDifferencesDiag, + AmbiguousWidePointerComparisons, AmbiguousWidePointerComparisonsAddrMetadataSuggestion, + AmbiguousWidePointerComparisonsAddrSuggestion, AtomicOrderingFence, AtomicOrderingLoad, + AtomicOrderingStore, ImproperCTypes, InvalidAtomicOrderingDiag, InvalidNanComparisons, + InvalidNanComparisonsSuggestion, OnlyCastu8ToChar, OverflowingBinHex, + OverflowingBinHexSign, OverflowingBinHexSignBitSub, OverflowingBinHexSub, OverflowingInt, + OverflowingIntHelp, OverflowingLiteral, OverflowingUInt, RangeEndpointOutOfRange, + UnusedComparisons, UseInclusiveRange, VariantSizeDifferencesDiag, }, }; use crate::{LateContext, LateLintPass, LintContext}; @@ -17,10 +18,10 @@ use rustc_errors::DiagnosticMessage; use rustc_hir as hir; use rustc_hir::{is_range_literal, Expr, ExprKind, Node}; use rustc_middle::ty::layout::{IntegerExt, LayoutOf, SizeSkeleton}; -use rustc_middle::ty::GenericArgsRef; use rustc_middle::ty::{ self, AdtKind, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, }; +use rustc_middle::ty::{GenericArgsRef, TypeAndMut}; use rustc_span::def_id::LocalDefId; use rustc_span::source_map; use rustc_span::symbol::sym; @@ -28,6 +29,7 @@ use rustc_span::{Span, Symbol}; use rustc_target::abi::{Abi, Size, WrappingRange}; use rustc_target::abi::{Integer, TagEncoding, Variants}; use rustc_target::spec::abi::Abi as SpecAbi; +use rustc_type_ir::DynKind; use std::iter; use std::ops::ControlFlow; @@ -136,6 +138,37 @@ declare_lint! { "detects invalid floating point NaN comparisons" } +declare_lint! { + /// The `ambiguous_wide_pointer_comparisons` lint checks comparison + /// of `*const/*mut ?Sized` as the operands. + /// + /// ### Example + /// + /// ```rust + /// # struct A; + /// # struct B; + /// + /// # trait T {} + /// # impl T for A {} + /// # impl T for B {} + /// + /// let ab = (A, B); + /// let a = &ab.0 as *const dyn T; + /// let b = &ab.1 as *const dyn T; + /// + /// let _ = a == b; + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// The comparison includes metadata which may not be expected. + AMBIGUOUS_WIDE_POINTER_COMPARISONS, + Warn, + "detects ambiguous wide pointer comparisons" +} + #[derive(Copy, Clone)] pub struct TypeLimits { /// Id of the last visited negated expression @@ -144,7 +177,12 @@ pub struct TypeLimits { negated_expr_span: Option<Span>, } -impl_lint_pass!(TypeLimits => [UNUSED_COMPARISONS, OVERFLOWING_LITERALS, INVALID_NAN_COMPARISONS]); +impl_lint_pass!(TypeLimits => [ + UNUSED_COMPARISONS, + OVERFLOWING_LITERALS, + INVALID_NAN_COMPARISONS, + AMBIGUOUS_WIDE_POINTER_COMPARISONS +]); impl TypeLimits { pub fn new() -> TypeLimits { @@ -164,7 +202,7 @@ fn lint_overflowing_range_endpoint<'tcx>( ) -> bool { // Look past casts to support cases like `0..256 as u8` let (expr, lit_span) = if let Node::Expr(par_expr) = - cx.tcx.hir().get(cx.tcx.hir().parent_id(expr.hir_id)) + cx.tcx.hir_node(cx.tcx.hir().parent_id(expr.hir_id)) && let ExprKind::Cast(_, _) = par_expr.kind { (par_expr, expr.span) @@ -175,7 +213,7 @@ fn lint_overflowing_range_endpoint<'tcx>( // We only want to handle exclusive (`..`) ranges, // which are represented as `ExprKind::Struct`. let par_id = cx.tcx.hir().parent_id(expr.hir_id); - let Node::ExprField(field) = cx.tcx.hir().get(par_id) else { return false }; + let Node::ExprField(field) = cx.tcx.hir_node(par_id) else { return false }; let Node::Expr(struct_expr) = cx.tcx.hir().get_parent(field.hir_id) else { return false }; if !is_range_literal(struct_expr) { return false; @@ -460,7 +498,7 @@ fn lint_uint_literal<'tcx>( }; if lit_val < min || lit_val > max { let parent_id = cx.tcx.hir().parent_id(e.hir_id); - if let Node::Expr(par_e) = cx.tcx.hir().get(parent_id) { + if let Node::Expr(par_e) = cx.tcx.hir_node(parent_id) { match par_e.kind { hir::ExprKind::Cast(..) => { if let ty::Char = cx.typeck_results().expr_ty(par_e).kind() { @@ -620,10 +658,110 @@ fn lint_nan<'tcx>( cx.emit_spanned_lint(INVALID_NAN_COMPARISONS, e.span, lint); } +fn lint_wide_pointer<'tcx>( + cx: &LateContext<'tcx>, + e: &'tcx hir::Expr<'tcx>, + binop: hir::BinOpKind, + l: &'tcx hir::Expr<'tcx>, + r: &'tcx hir::Expr<'tcx>, +) { + let ptr_unsized = |mut ty: Ty<'tcx>| -> Option<(usize, bool)> { + let mut refs = 0; + // here we remove any "implicit" references and count the number + // of them to correctly suggest the right number of deref + while let ty::Ref(_, inner_ty, _) = ty.kind() { + ty = *inner_ty; + refs += 1; + } + match ty.kind() { + ty::RawPtr(TypeAndMut { mutbl: _, ty }) => (!ty.is_sized(cx.tcx, cx.param_env)) + .then(|| (refs, matches!(ty.kind(), ty::Dynamic(_, _, DynKind::Dyn)))), + _ => None, + } + }; + + // PartialEq::{eq,ne} takes references, remove any explicit references + let l = l.peel_borrows(); + let r = r.peel_borrows(); + + let Some(l_ty) = cx.typeck_results().expr_ty_opt(l) else { + return; + }; + let Some(r_ty) = cx.typeck_results().expr_ty_opt(r) else { + return; + }; + + let Some((l_ty_refs, l_inner_ty_is_dyn)) = ptr_unsized(l_ty) else { + return; + }; + let Some((r_ty_refs, r_inner_ty_is_dyn)) = ptr_unsized(r_ty) else { + return; + }; + + let (Some(l_span), Some(r_span)) = + (l.span.find_ancestor_inside(e.span), r.span.find_ancestor_inside(e.span)) + else { + return cx.emit_spanned_lint( + AMBIGUOUS_WIDE_POINTER_COMPARISONS, + e.span, + AmbiguousWidePointerComparisons::Spanless, + ); + }; + + let ne = if binop == hir::BinOpKind::Ne { "!" } else { "" }; + let is_eq_ne = matches!(binop, hir::BinOpKind::Eq | hir::BinOpKind::Ne); + let is_dyn_comparison = l_inner_ty_is_dyn && r_inner_ty_is_dyn; + + let left = e.span.shrink_to_lo().until(l_span.shrink_to_lo()); + let middle = l_span.shrink_to_hi().until(r_span.shrink_to_lo()); + let right = r_span.shrink_to_hi().until(e.span.shrink_to_hi()); + + let deref_left = &*"*".repeat(l_ty_refs); + let deref_right = &*"*".repeat(r_ty_refs); + + cx.emit_spanned_lint( + AMBIGUOUS_WIDE_POINTER_COMPARISONS, + e.span, + AmbiguousWidePointerComparisons::Spanful { + addr_metadata_suggestion: (is_eq_ne && !is_dyn_comparison).then(|| { + AmbiguousWidePointerComparisonsAddrMetadataSuggestion { + ne, + deref_left, + deref_right, + left, + middle, + right, + } + }), + addr_suggestion: if is_eq_ne { + AmbiguousWidePointerComparisonsAddrSuggestion::AddrEq { + ne, + deref_left, + deref_right, + left, + middle, + right, + } + } else { + AmbiguousWidePointerComparisonsAddrSuggestion::Cast { + deref_left, + deref_right, + // those two Options are required for correctness as having + // an empty span and an empty suggestion is not permitted + left_before: (l_ty_refs != 0).then_some(left), + right_before: (r_ty_refs != 0).then(|| r_span.shrink_to_lo()), + left: l_span.shrink_to_hi(), + right, + } + }, + }, + ); +} + impl<'tcx> LateLintPass<'tcx> for TypeLimits { fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx hir::Expr<'tcx>) { match e.kind { - hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => { + hir::ExprKind::Unary(hir::UnOp::Neg, expr) => { // Propagate negation, if the negation itself isn't negated if self.negated_expr_id != Some(e.hir_id) { self.negated_expr_id = Some(expr.hir_id); @@ -632,14 +770,30 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits { } hir::ExprKind::Binary(binop, ref l, ref r) => { if is_comparison(binop) { - if !check_limits(cx, binop, &l, &r) { + if !check_limits(cx, binop, l, r) { cx.emit_spanned_lint(UNUSED_COMPARISONS, e.span, UnusedComparisons); } else { lint_nan(cx, e, binop, l, r); + lint_wide_pointer(cx, e, binop.node, l, r); } } } - hir::ExprKind::Lit(ref lit) => lint_literal(cx, self, e, lit), + hir::ExprKind::Lit(lit) => lint_literal(cx, self, e, lit), + hir::ExprKind::Call(path, [l, r]) + if let ExprKind::Path(ref qpath) = path.kind + && let Some(def_id) = cx.qpath_res(qpath, path.hir_id).opt_def_id() + && let Some(diag_item) = cx.tcx.get_diagnostic_name(def_id) + && let Some(binop) = partialeq_binop(diag_item) => + { + lint_wide_pointer(cx, e, binop, l, r); + } + hir::ExprKind::MethodCall(_, l, [r], _) + if let Some(def_id) = cx.typeck_results().type_dependent_def_id(e.hir_id) + && let Some(diag_item) = cx.tcx.get_diagnostic_name(def_id) + && let Some(binop) = partialeq_binop(diag_item) => + { + lint_wide_pointer(cx, e, binop, l, r); + } _ => {} }; @@ -685,7 +839,7 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits { ty::Int(int_ty) => { let (min, max) = int_ty_range(int_ty); let lit_val: i128 = match lit.kind { - hir::ExprKind::Lit(ref li) => match li.node { + hir::ExprKind::Lit(li) => match li.node { ast::LitKind::Int( v, ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed, @@ -699,7 +853,7 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits { ty::Uint(uint_ty) => { let (min, max): (u128, u128) = uint_ty_range(uint_ty); let lit_val: u128 = match lit.kind { - hir::ExprKind::Lit(ref li) => match li.node { + hir::ExprKind::Lit(li) => match li.node { ast::LitKind::Int(v, _) => v, _ => return true, }, @@ -722,6 +876,16 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits { | hir::BinOpKind::Gt ) } + + fn partialeq_binop(diag_item: Symbol) -> Option<hir::BinOpKind> { + if diag_item == sym::cmp_partialeq_eq { + Some(hir::BinOpKind::Eq) + } else if diag_item == sym::cmp_partialeq_ne { + Some(hir::BinOpKind::Ne) + } else { + None + } + } } } @@ -1015,7 +1179,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { // We can't completely trust `repr(C)` markings, so make sure the fields are actually safe. let mut all_phantom = !variant.fields.is_empty(); for field in &variant.fields { - all_phantom &= match self.check_field_type_for_ffi(cache, &field, args) { + all_phantom &= match self.check_field_type_for_ffi(cache, field, args) { FfiSafe => false, // `()` fields are FFI-safe! FfiUnsafe { ty, .. } if ty.is_unit() => false, @@ -1234,7 +1398,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { }; } - let sig = tcx.erase_late_bound_regions(sig); + let sig = tcx.instantiate_bound_regions_with_erased(sig); for arg in sig.inputs() { match self.check_type_for_ffi(cache, *arg) { FfiSafe => {} @@ -1391,7 +1555,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { /// types that have external ABIs, as these still need checked. fn check_fn(&mut self, def_id: LocalDefId, decl: &'tcx hir::FnDecl<'_>) { let sig = self.cx.tcx.fn_sig(def_id).instantiate_identity(); - let sig = self.cx.tcx.erase_late_bound_regions(sig); + let sig = self.cx.tcx.instantiate_bound_regions_with_erased(sig); for (input_ty, input_hir) in iter::zip(sig.inputs(), decl.inputs) { for (fn_ptr_ty, span) in self.find_fn_ptr_ty_with_external_abi(input_hir, *input_ty) { @@ -1399,7 +1563,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { } } - if let hir::FnRetTy::Return(ref ret_hir) = decl.output { + if let hir::FnRetTy::Return(ret_hir) = decl.output { for (fn_ptr_ty, span) in self.find_fn_ptr_ty_with_external_abi(ret_hir, sig.output()) { self.check_type_for_ffi_and_report_errors(span, fn_ptr_ty, false, true); } @@ -1409,13 +1573,13 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> { /// Check if a function's argument types and result type are "ffi-safe". fn check_foreign_fn(&mut self, def_id: LocalDefId, decl: &'tcx hir::FnDecl<'_>) { let sig = self.cx.tcx.fn_sig(def_id).instantiate_identity(); - let sig = self.cx.tcx.erase_late_bound_regions(sig); + let sig = self.cx.tcx.instantiate_bound_regions_with_erased(sig); 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); } - if let hir::FnRetTy::Return(ref ret_hir) = decl.output { + if let hir::FnRetTy::Return(ret_hir) = decl.output { self.check_type_for_ffi_and_report_errors(ret_hir.span, sig.output(), false, true); } } @@ -1487,13 +1651,13 @@ impl<'tcx> LateLintPass<'tcx> for ImproperCTypesDeclarations { let abi = cx.tcx.hir().get_foreign_abi(it.hir_id()); match it.kind { - hir::ForeignItemKind::Fn(ref decl, _, _) if !vis.is_internal_abi(abi) => { + hir::ForeignItemKind::Fn(decl, _, _) if !vis.is_internal_abi(abi) => { vis.check_foreign_fn(it.owner_id.def_id, decl); } - hir::ForeignItemKind::Static(ref ty, _) if !vis.is_internal_abi(abi) => { + hir::ForeignItemKind::Static(ty, _) if !vis.is_internal_abi(abi) => { vis.check_foreign_static(it.owner_id, ty.span); } - hir::ForeignItemKind::Fn(ref decl, _, _) => vis.check_fn(it.owner_id.def_id, decl), + hir::ForeignItemKind::Fn(decl, _, _) => vis.check_fn(it.owner_id.def_id, decl), hir::ForeignItemKind::Static(..) | hir::ForeignItemKind::Type => (), } } @@ -1705,7 +1869,7 @@ impl InvalidAtomicOrdering { sym::AtomicI64, sym::AtomicI128, ]; - if let ExprKind::MethodCall(ref method_path, _, args, _) = &expr.kind + if let ExprKind::MethodCall(method_path, _, args, _) = &expr.kind && recognized_names.contains(&method_path.ident.name) && let Some(m_def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) && let Some(impl_did) = cx.tcx.impl_of_method(m_def_id) @@ -1766,7 +1930,7 @@ impl InvalidAtomicOrdering { } fn check_memory_fence(cx: &LateContext<'_>, expr: &Expr<'_>) { - if let ExprKind::Call(ref func, ref args) = expr.kind + if let ExprKind::Call(func, args) = expr.kind && let ExprKind::Path(ref func_qpath) = func.kind && let Some(def_id) = cx.qpath_res(func_qpath, func.hir_id).opt_def_id() && matches!(cx.tcx.get_diagnostic_name(def_id), Some(sym::fence | sym::compiler_fence)) |