| //! Some lints that are only useful in the compiler or crates that use compiler internals, such as |
| //! Clippy. |
| |
| use crate::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext}; |
| use rustc_ast as ast; |
| use rustc_errors::Applicability; |
| use rustc_hir::def::Res; |
| use rustc_hir::{def_id::DefId, Expr, ExprKind, GenericArg, PatKind, Path, PathSegment, QPath}; |
| use rustc_hir::{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; |
| use tracing::debug; |
| |
| declare_tool_lint! { |
| 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 replace = match cx.tcx.get_diagnostic_name(def_id) { |
| Some(sym::HashMap) => "FxHashMap", |
| Some(sym::HashSet) => "FxHashSet", |
| _ => return, |
| }; |
| cx.struct_span_lint(DEFAULT_HASH_TYPES, path.span, |lint| { |
| let msg = format!( |
| "prefer `{}` over `{}`, it has better performance", |
| replace, |
| cx.tcx.item_name(def_id) |
| ); |
| lint.build(&msg) |
| .note(&format!("a `use rustc_data_structures::fx::{}` may be necessary", replace)) |
| .emit(); |
| }); |
| } |
| } |
| |
| /// Helper function for lints that check for expressions with calls and use typeck results to |
| /// get the `DefId` and `SubstsRef` of the function. |
| fn typeck_results_of_method_fn<'tcx>( |
| cx: &LateContext<'tcx>, |
| expr: &Expr<'_>, |
| ) -> Option<(Span, DefId, ty::subst::SubstsRef<'tcx>)> { |
| // FIXME(rustdoc): Lints which use this function use typecheck results which can cause |
| // `rustdoc` to error if there are resolution failures. |
| // |
| // As internal lints are currently always run if there are `unstable_options`, they are added |
| // to the lint store of rustdoc. Internal lints are also not used via the `lint_mod` query. |
| // Crate lints run outside of a query so rustdoc currently doesn't disable them. |
| // |
| // Instead of relying on this, either change crate lints to a query disabled by rustdoc, only |
| // run internal lints if the user is explicitly opting in or figure out a different way to |
| // avoid running lints for rustdoc. |
| if cx.tcx.sess.opts.actually_rustdoc { |
| return None; |
| } |
| |
| 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_substs(expr.hir_id))) |
| }, |
| _ => { |
| match cx.typeck_results().node_type(expr.hir_id).kind() { |
| &ty::FnDef(def_id, substs) => Some((expr.span, def_id, substs)), |
| _ => None, |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| 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, substs)) = typeck_results_of_method_fn(cx, expr) else { return }; |
| if let Ok(Some(instance)) = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, substs) { |
| let def_id = instance.def_id(); |
| if cx.tcx.has_attr(def_id, sym::rustc_lint_query_instability) { |
| cx.struct_span_lint(POTENTIAL_QUERY_INSTABILITY, span, |lint| { |
| let msg = format!( |
| "using `{}` can result in unstable query results", |
| cx.tcx.item_name(def_id) |
| ); |
| lint.build(&msg) |
| .note("if you believe this case to be fine, allow this lint and add a comment explaining your rationale") |
| .emit(); |
| }) |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| 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! { |
| 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: &'tcx rustc_hir::Path<'tcx>, |
| _: rustc_hir::HirId, |
| ) { |
| if let Some(segment) = path.segments.iter().nth_back(1) |
| && let Some(res) = &segment.res |
| && lint_ty_kind_usage(cx, res) |
| { |
| let span = path.span.with_hi( |
| segment.args.map_or(segment.ident.span, |a| a.span_ext).hi() |
| ); |
| cx.struct_span_lint(USAGE_OF_TY_TYKIND, path.span, |lint| { |
| lint.build("usage of `ty::TyKind::<kind>`") |
| .span_suggestion( |
| span, |
| "try using `ty::<kind>` directly", |
| "ty", |
| Applicability::MaybeIncorrect, // ty maybe needs an import |
| ) |
| .emit(); |
| }); |
| } |
| } |
| |
| 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) { |
| cx.struct_span_lint(USAGE_OF_TY_TYKIND, path.span, |lint| { |
| let hir = cx.tcx.hir(); |
| match hir.find(hir.get_parent_node(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 |
| { |
| lint.build("usage of `ty::TyKind::<kind>`") |
| .span_suggestion( |
| path.span, |
| "try using `ty::<kind>` directly", |
| "ty", |
| Applicability::MaybeIncorrect, // ty maybe needs an import |
| ) |
| .emit(); |
| return; |
| } |
| } |
| Some(Node::Expr(Expr { |
| kind: ExprKind::Path(qpath), |
| .. |
| })) => { |
| if let QPath::TypeRelative(qpath_ty, ..) = qpath |
| && qpath_ty.hir_id == ty.hir_id |
| { |
| lint.build("usage of `ty::TyKind::<kind>`") |
| .span_suggestion( |
| path.span, |
| "try using `ty::<kind>` directly", |
| "ty", |
| Applicability::MaybeIncorrect, // ty maybe needs an import |
| ) |
| .emit(); |
| return; |
| } |
| } |
| // 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 |
| { |
| lint.build("usage of `ty::TyKind::<kind>`") |
| .span_suggestion( |
| path.span, |
| "try using `ty::<kind>` directly", |
| "ty", |
| Applicability::MaybeIncorrect, // ty maybe needs an import |
| ) |
| .emit(); |
| return; |
| } |
| } |
| _ => {} |
| } |
| lint.build("usage of `ty::TyKind`").help("try using `Ty` instead").emit(); |
| }) |
| } else if !ty.span.from_expansion() && let Some(t) = is_ty_or_ty_ctxt(cx, &path) { |
| if path.segments.len() > 1 { |
| cx.struct_span_lint(USAGE_OF_QUALIFIED_TY, path.span, |lint| { |
| lint.build(&format!("usage of qualified `ty::{}`", t)) |
| .span_suggestion( |
| path.span, |
| "try importing it and using it unqualified", |
| t, |
| // The import probably needs to be changed |
| Applicability::MaybeIncorrect, |
| ) |
| .emit(); |
| }) |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| 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::SelfTy { trait_: None, alias_to: Some((did, _)) } => { |
| if let ty::Adt(adt, substs) = cx.tcx.type_of(did).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, substs[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.name.ident().to_string()) |
| } else { |
| None |
| } |
| }) |
| .collect::<Vec<_>>(); |
| |
| if !lifetimes.is_empty() { |
| return format!("<{}>", lifetimes.join(", ")); |
| } |
| } |
| |
| String::new() |
| } |
| |
| declare_tool_lint! { |
| 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.struct_span_lint( |
| LINT_PASS_IMPL_WITHOUT_MACRO, |
| lint_pass.path.span, |
| |lint| { |
| lint.build("implementing `LintPass` by hand") |
| .help("try using `declare_lint_pass!` or `impl_lint_pass!` instead") |
| .emit(); |
| }, |
| ) |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| 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 v = nested |
| .value_str() |
| .expect("#[doc(keyword = \"...\")] expected a value!"); |
| if is_doc_keyword(v) { |
| return; |
| } |
| cx.struct_span_lint(EXISTING_DOC_KEYWORD, attr.span, |lint| { |
| lint.build(&format!( |
| "Found non-existing keyword `{}` used in \ |
| `#[doc(keyword = \"...\")]`", |
| v, |
| )) |
| .help("only existing keywords are allowed in core/std") |
| .emit(); |
| }); |
| } |
| } |
| } |
| } |
| } |
| } |
| |
| declare_tool_lint! { |
| pub rustc::UNTRANSLATABLE_DIAGNOSTIC, |
| Allow, |
| "prevent creation of diagnostics which cannot be translated", |
| report_in_external_macro: true |
| } |
| |
| declare_tool_lint! { |
| pub rustc::DIAGNOSTIC_OUTSIDE_OF_IMPL, |
| Allow, |
| "prevent creation of diagnostics outside of `SessionDiagnostic`/`AddSubdiagnostic` impls", |
| report_in_external_macro: true |
| } |
| |
| declare_lint_pass!(Diagnostics => [ UNTRANSLATABLE_DIAGNOSTIC, DIAGNOSTIC_OUTSIDE_OF_IMPL ]); |
| |
| impl LateLintPass<'_> for Diagnostics { |
| fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { |
| let Some((span, def_id, substs)) = typeck_results_of_method_fn(cx, expr) else { return }; |
| debug!(?span, ?def_id, ?substs); |
| if let Ok(Some(instance)) = ty::Instance::resolve(cx.tcx, cx.param_env, def_id, substs) && |
| !cx.tcx.has_attr(instance.def_id(), sym::rustc_lint_diagnostics) |
| { |
| return; |
| } |
| |
| let mut found_impl = false; |
| for (_, parent) in cx.tcx.hir().parent_iter(expr.hir_id) { |
| 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::SessionDiagnostic | sym::AddSubdiagnostic) |
| { |
| found_impl = true; |
| break; |
| } |
| } |
| debug!(?found_impl); |
| if !found_impl { |
| cx.struct_span_lint(DIAGNOSTIC_OUTSIDE_OF_IMPL, span, |lint| { |
| lint.build("diagnostics should only be created in `SessionDiagnostic`/`AddSubdiagnostic` impls") |
| .emit(); |
| }) |
| } |
| |
| let mut found_diagnostic_message = false; |
| for ty in substs.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_diagnostic_message { |
| cx.struct_span_lint(UNTRANSLATABLE_DIAGNOSTIC, span, |lint| { |
| lint.build("diagnostics should be created using translatable messages").emit(); |
| }) |
| } |
| } |
| } |
