| //! Some lints that are only useful in the compiler or crates that use compiler internals, such as |
| //! Clippy. |
| |
| use crate::lints::{ |
| BadOptAccessDiag, DefaultHashTypesDiag, DiagOutOfImpl, LintPassByHand, NonExistentDocKeyword, |
| QueryInstability, SpanUseEqCtxtDiag, TyQualified, TykindDiag, TykindKind, UntranslatableDiag, |
| UntranslatableDiagnosticTrivial, |
| }; |
| use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext}; |
| use rustc_ast as ast; |
| use rustc_hir::def::Res; |
| use rustc_hir::{def_id::DefId, Expr, ExprKind, GenericArg, PatKind, Path, PathSegment, QPath}; |
| use rustc_hir::{BinOp, BinOpKind, HirId, Impl, Item, ItemKind, Node, Pat, Ty, TyKind}; |
| use rustc_middle::ty; |
| use rustc_session::{declare_lint_pass, declare_tool_lint}; |
| use rustc_span::hygiene::{ExpnKind, MacroKind}; |
| use rustc_span::symbol::{kw, sym, Symbol}; |
| use rustc_span::Span; |
| |
| declare_tool_lint! { |
| /// The `default_hash_type` lint detects use of [`std::collections::HashMap`]/[`std::collections::HashSet`], |
| /// suggesting the use of `FxHashMap`/`FxHashSet`. |
| /// |
| /// This can help as `FxHasher` can perform better than the default hasher. DOS protection is not |
| /// required as input is assumed to be trusted. |
| pub rustc::DEFAULT_HASH_TYPES, |
| Allow, |
| "forbid HashMap and HashSet and suggest the FxHash* variants", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(DefaultHashTypes => [DEFAULT_HASH_TYPES]); |
| |
| impl LateLintPass<'_> for DefaultHashTypes { |
| fn check_path(&mut self, cx: &LateContext<'_>, path: &Path<'_>, hir_id: HirId) { |
| let Res::Def(rustc_hir::def::DefKind::Struct, def_id) = path.res else { return }; |
| if matches!(cx.tcx.hir().get(hir_id), Node::Item(Item { kind: ItemKind::Use(..), .. })) { |
| // don't lint imports, only actual usages |
| return; |
| } |
| let preferred = match cx.tcx.get_diagnostic_name(def_id) { |
| Some(sym::HashMap) => "FxHashMap", |
| Some(sym::HashSet) => "FxHashSet", |
| _ => return, |
| }; |
| cx.emit_spanned_lint( |
| DEFAULT_HASH_TYPES, |
| path.span, |
| DefaultHashTypesDiag { preferred, used: cx.tcx.item_name(def_id) }, |
| ); |
| } |
| } |
| |
| /// Helper function for lints that check for expressions with calls and use typeck results to |
| /// get the `DefId` and `GenericArgsRef` of the function. |
| fn typeck_results_of_method_fn<'tcx>( |
| cx: &LateContext<'tcx>, |
| expr: &Expr<'_>, |
| ) -> Option<(Span, DefId, ty::GenericArgsRef<'tcx>)> { |
| match expr.kind { |
| ExprKind::MethodCall(segment, ..) |
| if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) => |
| { |
| Some((segment.ident.span, def_id, cx.typeck_results().node_args(expr.hir_id))) |
| } |
| _ => match cx.typeck_results().node_type(expr.hir_id).kind() { |
| &ty::FnDef(def_id, args) => Some((expr.span, def_id, args)), |
| _ => None, |
| }, |
| } |
| } |
| |
| declare_tool_lint! { |
| /// The `potential_query_instability` lint detects use of methods which can lead to |
| /// potential query instability, such as iterating over a `HashMap`. |
| /// |
| /// Due to the [incremental compilation](https://rustc-dev-guide.rust-lang.org/queries/incremental-compilation.html) model, |
| /// queries must return deterministic, stable results. `HashMap` iteration order can change between compilations, |
| /// and will introduce instability if query results expose the order. |
| pub rustc::POTENTIAL_QUERY_INSTABILITY, |
| Allow, |
| "require explicit opt-in when using potentially unstable methods or functions", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(QueryStability => [POTENTIAL_QUERY_INSTABILITY]); |
| |
| impl LateLintPass<'_> for QueryStability { |
| fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { |
| let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return }; |
| if let Ok(Some(instance)) = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, args) { |
| let def_id = instance.def_id(); |
| if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) { |
| cx.emit_spanned_lint( |
| POTENTIAL_QUERY_INSTABILITY, |
| span, |
| QueryInstability { query: cx.tcx.item_name(def_id) }, |
| ); |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| /// The `usage_of_ty_tykind` lint detects usages of `ty::TyKind::<kind>`, |
| /// where `ty::<kind>` would suffice. |
| pub rustc::USAGE_OF_TY_TYKIND, |
| Allow, |
| "usage of `ty::TyKind` outside of the `ty::sty` module", |
| report_in_external_macro: true |
| } |
| |
| declare_tool_lint! { |
| /// The `usage_of_qualified_ty` lint detects usages of `ty::TyKind`, |
| /// where `Ty` should be used instead. |
| pub rustc::USAGE_OF_QUALIFIED_TY, |
| Allow, |
| "using `ty::{Ty,TyCtxt}` instead of importing it", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(TyTyKind => [ |
| USAGE_OF_TY_TYKIND, |
| USAGE_OF_QUALIFIED_TY, |
| ]); |
| |
| impl<'tcx> LateLintPass<'tcx> for TyTyKind { |
| fn check_path( |
| &mut self, |
| cx: &LateContext<'tcx>, |
| path: &rustc_hir::Path<'tcx>, |
| _: rustc_hir::HirId, |
| ) { |
| if let Some(segment) = path.segments.iter().nth_back(1) |
| && lint_ty_kind_usage(cx, &segment.res) |
| { |
| let span = |
| path.span.with_hi(segment.args.map_or(segment.ident.span, |a| a.span_ext).hi()); |
| cx.emit_spanned_lint(USAGE_OF_TY_TYKIND, path.span, TykindKind { suggestion: span }); |
| } |
| } |
| |
| fn check_ty(&mut self, cx: &LateContext<'_>, ty: &'tcx Ty<'tcx>) { |
| match &ty.kind { |
| TyKind::Path(QPath::Resolved(_, path)) => { |
| if lint_ty_kind_usage(cx, &path.res) { |
| let hir = cx.tcx.hir(); |
| let span = match hir.find_parent(ty.hir_id) { |
| Some(Node::Pat(Pat { |
| kind: |
| PatKind::Path(qpath) |
| | PatKind::TupleStruct(qpath, ..) |
| | PatKind::Struct(qpath, ..), |
| .. |
| })) => { |
| if let QPath::TypeRelative(qpath_ty, ..) = qpath |
| && qpath_ty.hir_id == ty.hir_id |
| { |
| Some(path.span) |
| } else { |
| None |
| } |
| } |
| Some(Node::Expr(Expr { kind: ExprKind::Path(qpath), .. })) => { |
| if let QPath::TypeRelative(qpath_ty, ..) = qpath |
| && qpath_ty.hir_id == ty.hir_id |
| { |
| Some(path.span) |
| } else { |
| None |
| } |
| } |
| // Can't unify these two branches because qpath below is `&&` and above is `&` |
| // and `A | B` paths don't play well together with adjustments, apparently. |
| Some(Node::Expr(Expr { kind: ExprKind::Struct(qpath, ..), .. })) => { |
| if let QPath::TypeRelative(qpath_ty, ..) = qpath |
| && qpath_ty.hir_id == ty.hir_id |
| { |
| Some(path.span) |
| } else { |
| None |
| } |
| } |
| _ => None, |
| }; |
| |
| match span { |
| Some(span) => { |
| cx.emit_spanned_lint( |
| USAGE_OF_TY_TYKIND, |
| path.span, |
| TykindKind { suggestion: span }, |
| ); |
| } |
| None => cx.emit_spanned_lint(USAGE_OF_TY_TYKIND, path.span, TykindDiag), |
| } |
| } else if !ty.span.from_expansion() |
| && path.segments.len() > 1 |
| && let Some(ty) = is_ty_or_ty_ctxt(cx, &path) |
| { |
| cx.emit_spanned_lint( |
| USAGE_OF_QUALIFIED_TY, |
| path.span, |
| TyQualified { ty, suggestion: path.span }, |
| ); |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| fn lint_ty_kind_usage(cx: &LateContext<'_>, res: &Res) -> bool { |
| if let Some(did) = res.opt_def_id() { |
| cx.tcx.is_diagnostic_item(sym::TyKind, did) || cx.tcx.is_diagnostic_item(sym::IrTyKind, did) |
| } else { |
| false |
| } |
| } |
| |
| fn is_ty_or_ty_ctxt(cx: &LateContext<'_>, path: &Path<'_>) -> Option<String> { |
| match &path.res { |
| Res::Def(_, def_id) => { |
| if let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(*def_id) { |
| return Some(format!("{}{}", name, gen_args(path.segments.last().unwrap()))); |
| } |
| } |
| // Only lint on `&Ty` and `&TyCtxt` if it is used outside of a trait. |
| Res::SelfTyAlias { alias_to: did, is_trait_impl: false, .. } => { |
| if let ty::Adt(adt, args) = cx.tcx.type_of(did).instantiate_identity().kind() { |
| if let Some(name @ (sym::Ty | sym::TyCtxt)) = cx.tcx.get_diagnostic_name(adt.did()) |
| { |
| // NOTE: This path is currently unreachable as `Ty<'tcx>` is |
| // defined as a type alias meaning that `impl<'tcx> Ty<'tcx>` |
| // is not actually allowed. |
| // |
| // I(@lcnr) still kept this branch in so we don't miss this |
| // if we ever change it in the future. |
| return Some(format!("{}<{}>", name, args[0])); |
| } |
| } |
| } |
| _ => (), |
| } |
| |
| None |
| } |
| |
| fn gen_args(segment: &PathSegment<'_>) -> String { |
| if let Some(args) = &segment.args { |
| let lifetimes = args |
| .args |
| .iter() |
| .filter_map(|arg| { |
| if let GenericArg::Lifetime(lt) = arg { Some(lt.ident.to_string()) } else { None } |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !lifetimes.is_empty() { |
| return format!("<{}>", lifetimes.join(", ")); |
| } |
| } |
| |
| String::new() |
| } |
| |
| declare_tool_lint! { |
| /// The `lint_pass_impl_without_macro` detects manual implementations of a lint |
| /// pass, without using [`declare_lint_pass`] or [`impl_lint_pass`]. |
| pub rustc::LINT_PASS_IMPL_WITHOUT_MACRO, |
| Allow, |
| "`impl LintPass` without the `declare_lint_pass!` or `impl_lint_pass!` macros" |
| } |
| |
| declare_lint_pass!(LintPassImpl => [LINT_PASS_IMPL_WITHOUT_MACRO]); |
| |
| impl EarlyLintPass for LintPassImpl { |
| fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) { |
| if let ast::ItemKind::Impl(box ast::Impl { of_trait: Some(lint_pass), .. }) = &item.kind { |
| if let Some(last) = lint_pass.path.segments.last() { |
| if last.ident.name == sym::LintPass { |
| let expn_data = lint_pass.path.span.ctxt().outer_expn_data(); |
| let call_site = expn_data.call_site; |
| if expn_data.kind != ExpnKind::Macro(MacroKind::Bang, sym::impl_lint_pass) |
| && call_site.ctxt().outer_expn_data().kind |
| != ExpnKind::Macro(MacroKind::Bang, sym::declare_lint_pass) |
| { |
| cx.emit_spanned_lint( |
| LINT_PASS_IMPL_WITHOUT_MACRO, |
| lint_pass.path.span, |
| LintPassByHand, |
| ); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| /// The `existing_doc_keyword` lint detects use `#[doc()]` keywords |
| /// that don't exist, e.g. `#[doc(keyword = "..")]`. |
| pub rustc::EXISTING_DOC_KEYWORD, |
| Allow, |
| "Check that documented keywords in std and core actually exist", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(ExistingDocKeyword => [EXISTING_DOC_KEYWORD]); |
| |
| fn is_doc_keyword(s: Symbol) -> bool { |
| s <= kw::Union |
| } |
| |
| impl<'tcx> LateLintPass<'tcx> for ExistingDocKeyword { |
| fn check_item(&mut self, cx: &LateContext<'_>, item: &rustc_hir::Item<'_>) { |
| for attr in cx.tcx.hir().attrs(item.hir_id()) { |
| if !attr.has_name(sym::doc) { |
| continue; |
| } |
| if let Some(list) = attr.meta_item_list() { |
| for nested in list { |
| if nested.has_name(sym::keyword) { |
| let keyword = nested |
| .value_str() |
| .expect("#[doc(keyword = \"...\")] expected a value!"); |
| if is_doc_keyword(keyword) { |
| return; |
| } |
| cx.emit_spanned_lint( |
| EXISTING_DOC_KEYWORD, |
| attr.span, |
| NonExistentDocKeyword { keyword }, |
| ); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| /// The `untranslatable_diagnostic` lint detects diagnostics created |
| /// without using translatable Fluent strings. |
| /// |
| /// More details on translatable diagnostics can be found [here](https://rustc-dev-guide.rust-lang.org/diagnostics/translation.html). |
| pub rustc::UNTRANSLATABLE_DIAGNOSTIC, |
| Allow, |
| "prevent creation of diagnostics which cannot be translated", |
| report_in_external_macro: true |
| } |
| |
| declare_tool_lint! { |
| /// The `diagnostic_outside_of_impl` lint detects diagnostics created manually, |
| /// and inside an `IntoDiagnostic`/`AddToDiagnostic` implementation, |
| /// or a `#[derive(Diagnostic)]`/`#[derive(Subdiagnostic)]` expansion. |
| /// |
| /// More details on diagnostics implementations can be found [here](https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html). |
| pub rustc::DIAGNOSTIC_OUTSIDE_OF_IMPL, |
| Allow, |
| "prevent creation of diagnostics outside of `IntoDiagnostic`/`AddToDiagnostic` impls", |
| report_in_external_macro: true |
| } |
| |
| declare_tool_lint! { |
| /// The `untranslatable_diagnostic_trivial` lint detects diagnostics created using only static strings. |
| pub rustc::UNTRANSLATABLE_DIAGNOSTIC_TRIVIAL, |
| Deny, |
| "prevent creation of diagnostics which cannot be translated, which use only static strings", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(Diagnostics => [ UNTRANSLATABLE_DIAGNOSTIC, DIAGNOSTIC_OUTSIDE_OF_IMPL, UNTRANSLATABLE_DIAGNOSTIC_TRIVIAL ]); |
| |
| impl LateLintPass<'_> for Diagnostics { |
| fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { |
| let Some((span, def_id, args)) = typeck_results_of_method_fn(cx, expr) else { return }; |
| debug!(?span, ?def_id, ?args); |
| let has_attr = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, args) |
| .ok() |
| .flatten() |
| .is_some_and(|inst| cx.tcx.has_attr(inst.def_id(), sym::rustc_lint_diagnostics)); |
| if !has_attr { |
| return; |
| } |
| |
| let mut found_parent_with_attr = false; |
| let mut found_impl = false; |
| for (hir_id, parent) in cx.tcx.hir().parent_iter(expr.hir_id) { |
| if let Some(owner_did) = hir_id.as_owner() { |
| found_parent_with_attr = found_parent_with_attr |
| || cx.tcx.has_attr(owner_did, sym::rustc_lint_diagnostics); |
| } |
| |
| debug!(?parent); |
| if let Node::Item(Item { kind: ItemKind::Impl(impl_), .. }) = parent |
| && let Impl { of_trait: Some(of_trait), .. } = impl_ |
| && let Some(def_id) = of_trait.trait_def_id() |
| && let Some(name) = cx.tcx.get_diagnostic_name(def_id) |
| && matches!(name, sym::IntoDiagnostic | sym::AddToDiagnostic | sym::DecorateLint) |
| { |
| found_impl = true; |
| break; |
| } |
| } |
| debug!(?found_impl); |
| if !found_parent_with_attr && !found_impl { |
| cx.emit_spanned_lint(DIAGNOSTIC_OUTSIDE_OF_IMPL, span, DiagOutOfImpl); |
| } |
| |
| let mut found_diagnostic_message = false; |
| for ty in args.types() { |
| debug!(?ty); |
| if let Some(adt_def) = ty.ty_adt_def() |
| && let Some(name) = cx.tcx.get_diagnostic_name(adt_def.did()) |
| && matches!(name, sym::DiagnosticMessage | sym::SubdiagnosticMessage) |
| { |
| found_diagnostic_message = true; |
| break; |
| } |
| } |
| debug!(?found_diagnostic_message); |
| if !found_parent_with_attr && !found_diagnostic_message { |
| cx.emit_spanned_lint(UNTRANSLATABLE_DIAGNOSTIC, span, UntranslatableDiag); |
| } |
| } |
| } |
| |
| impl EarlyLintPass for Diagnostics { |
| #[allow(unused_must_use)] |
| fn check_stmt(&mut self, cx: &EarlyContext<'_>, stmt: &ast::Stmt) { |
| // Looking for a straight chain of method calls from 'struct_span_err' to 'emit'. |
| let ast::StmtKind::Semi(expr) = &stmt.kind else { |
| return; |
| }; |
| let ast::ExprKind::MethodCall(meth) = &expr.kind else { |
| return; |
| }; |
| if meth.seg.ident.name != sym::emit || !meth.args.is_empty() { |
| return; |
| } |
| let mut segments = vec![]; |
| let mut cur = &meth.receiver; |
| let fake = &[].into(); |
| loop { |
| match &cur.kind { |
| ast::ExprKind::Call(func, args) => { |
| if let ast::ExprKind::Path(_, path) = &func.kind { |
| segments.push((path.segments.last().unwrap().ident.name, args)) |
| } |
| break; |
| } |
| ast::ExprKind::MethodCall(method) => { |
| segments.push((method.seg.ident.name, &method.args)); |
| cur = &method.receiver; |
| } |
| ast::ExprKind::MacCall(mac) => { |
| segments.push((mac.path.segments.last().unwrap().ident.name, fake)); |
| break; |
| } |
| _ => { |
| break; |
| } |
| } |
| } |
| segments.reverse(); |
| if segments.is_empty() { |
| return; |
| } |
| if segments[0].0.as_str() != "struct_span_err" { |
| return; |
| } |
| if !segments.iter().all(|(name, args)| { |
| let arg = match name.as_str() { |
| "struct_span_err" | "span_note" | "span_label" | "span_help" if args.len() == 2 => { |
| &args[1] |
| } |
| "note" | "help" if args.len() == 1 => &args[0], |
| _ => { |
| return false; |
| } |
| }; |
| if let ast::ExprKind::Lit(lit) = arg.kind |
| && let ast::token::LitKind::Str = lit.kind |
| { |
| true |
| } else { |
| false |
| } |
| }) { |
| return; |
| } |
| cx.emit_spanned_lint( |
| UNTRANSLATABLE_DIAGNOSTIC_TRIVIAL, |
| stmt.span, |
| UntranslatableDiagnosticTrivial, |
| ); |
| } |
| } |
| |
| declare_tool_lint! { |
| /// The `bad_opt_access` lint detects accessing options by field instead of |
| /// the wrapper function. |
| pub rustc::BAD_OPT_ACCESS, |
| Deny, |
| "prevent using options by field access when there is a wrapper function", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(BadOptAccess => [ BAD_OPT_ACCESS ]); |
| |
| impl LateLintPass<'_> for BadOptAccess { |
| fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { |
| let ExprKind::Field(base, target) = expr.kind else { return }; |
| let Some(adt_def) = cx.typeck_results().expr_ty(base).ty_adt_def() else { return }; |
| // Skip types without `#[rustc_lint_opt_ty]` - only so that the rest of the lint can be |
| // avoided. |
| if !cx.tcx.has_attr(adt_def.did(), sym::rustc_lint_opt_ty) { |
| return; |
| } |
| |
| for field in adt_def.all_fields() { |
| if field.name == target.name |
| && let Some(attr) = |
| cx.tcx.get_attr(field.did, sym::rustc_lint_opt_deny_field_access) |
| && let Some(items) = attr.meta_item_list() |
| && let Some(item) = items.first() |
| && let Some(lit) = item.lit() |
| && let ast::LitKind::Str(val, _) = lit.kind |
| { |
| cx.emit_spanned_lint( |
| BAD_OPT_ACCESS, |
| expr.span, |
| BadOptAccessDiag { msg: val.as_str() }, |
| ); |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| pub rustc::SPAN_USE_EQ_CTXT, |
| Allow, |
| "forbid uses of `==` with `Span::ctxt`, suggest `Span::eq_ctxt` instead", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(SpanUseEqCtxt => [SPAN_USE_EQ_CTXT]); |
| |
| impl<'tcx> LateLintPass<'tcx> for SpanUseEqCtxt { |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) { |
| if let ExprKind::Binary(BinOp { node: BinOpKind::Eq, .. }, lhs, rhs) = expr.kind { |
| if is_span_ctxt_call(cx, lhs) && is_span_ctxt_call(cx, rhs) { |
| cx.emit_spanned_lint(SPAN_USE_EQ_CTXT, expr.span, SpanUseEqCtxtDiag); |
| } |
| } |
| } |
| } |
| |
| fn is_span_ctxt_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { |
| match &expr.kind { |
| ExprKind::MethodCall(..) => cx |
| .typeck_results() |
| .type_dependent_def_id(expr.hir_id) |
| .is_some_and(|call_did| cx.tcx.is_diagnostic_item(sym::SpanCtxt, call_did)), |
| |
| _ => false, |
| } |
| } |