| //! 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::{ |
| GenericArg, HirId, Item, ItemKind, MutTy, Mutability, Node, Path, PathSegment, QPath, 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}; |
| |
| 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 def_id = match path.res { |
| Res::Def(rustc_hir::def::DefKind::Struct, id) => id, |
| _ => 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 = if cx.tcx.is_diagnostic_item(sym::hashmap_type, def_id) { |
| "FxHashMap" |
| } else if cx.tcx.is_diagnostic_item(sym::hashset_type, def_id) { |
| "FxHashSet" |
| } else { |
| 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(); |
| }); |
| } |
| } |
| |
| 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::TY_PASS_BY_REFERENCE, |
| Allow, |
| "passing `Ty` or `TyCtxt` by reference", |
| 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, |
| TY_PASS_BY_REFERENCE, |
| USAGE_OF_QUALIFIED_TY, |
| ]); |
| |
| impl<'tcx> LateLintPass<'tcx> for TyTyKind { |
| fn check_path(&mut self, cx: &LateContext<'_>, path: &'tcx Path<'tcx>, _: HirId) { |
| let segments = path.segments.iter().rev().skip(1).rev(); |
| |
| if let Some(last) = segments.last() { |
| let span = path.span.with_hi(last.ident.span.hi()); |
| if lint_ty_kind_usage(cx, last) { |
| cx.struct_span_lint(USAGE_OF_TY_TYKIND, span, |lint| { |
| lint.build("usage of `ty::TyKind::<kind>`") |
| .span_suggestion( |
| span, |
| "try using ty::<kind> directly", |
| "ty".to_string(), |
| 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) => { |
| if let QPath::Resolved(_, path) = qpath { |
| if let Some(last) = path.segments.iter().last() { |
| if lint_ty_kind_usage(cx, last) { |
| cx.struct_span_lint(USAGE_OF_TY_TYKIND, path.span, |lint| { |
| lint.build("usage of `ty::TyKind`") |
| .help("try using `Ty` instead") |
| .emit(); |
| }) |
| } else { |
| if ty.span.from_expansion() { |
| return; |
| } |
| if let Some(t) = is_ty_or_ty_ctxt(cx, ty) { |
| 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 using it unqualified", |
| t, |
| // The import probably needs to be changed |
| Applicability::MaybeIncorrect, |
| ) |
| .emit(); |
| }) |
| } |
| } |
| } |
| } |
| } |
| } |
| TyKind::Rptr(_, MutTy { ty: inner_ty, mutbl: Mutability::Not }) => { |
| if let Some(impl_did) = cx.tcx.impl_of_method(ty.hir_id.owner.to_def_id()) { |
| if cx.tcx.impl_trait_ref(impl_did).is_some() { |
| return; |
| } |
| } |
| if let Some(t) = is_ty_or_ty_ctxt(cx, &inner_ty) { |
| cx.struct_span_lint(TY_PASS_BY_REFERENCE, ty.span, |lint| { |
| lint.build(&format!("passing `{}` by reference", t)) |
| .span_suggestion( |
| ty.span, |
| "try passing by value", |
| t, |
| // Changing type of function argument |
| Applicability::MaybeIncorrect, |
| ) |
| .emit(); |
| }) |
| } |
| } |
| _ => {} |
| } |
| } |
| } |
| |
| fn lint_ty_kind_usage(cx: &LateContext<'_>, segment: &PathSegment<'_>) -> bool { |
| if let Some(res) = segment.res { |
| if let Some(did) = res.opt_def_id() { |
| return cx.tcx.is_diagnostic_item(sym::TyKind, did); |
| } |
| } |
| |
| false |
| } |
| |
| fn is_ty_or_ty_ctxt(cx: &LateContext<'_>, ty: &Ty<'_>) -> Option<String> { |
| if let TyKind::Path(qpath) = &ty.kind { |
| if let QPath::Resolved(_, path) = qpath { |
| match path.res { |
| Res::Def(_, did) => { |
| if cx.tcx.is_diagnostic_item(sym::Ty, did) { |
| return Some(format!("Ty{}", gen_args(path.segments.last().unwrap()))); |
| } else if cx.tcx.is_diagnostic_item(sym::TyCtxt, did) { |
| return Some(format!("TyCtxt{}", gen_args(path.segments.last().unwrap()))); |
| } |
| } |
| // Only lint on `&Ty` and `&TyCtxt` if it is used outside of a trait. |
| Res::SelfTy(None, Some((did, _))) => { |
| if let ty::Adt(adt, substs) = cx.tcx.type_of(did).kind() { |
| if cx.tcx.is_diagnostic_item(sym::Ty, 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!("Ty<{}>", substs[0])); |
| } else if cx.tcx.is_diagnostic_item(sym::TyCtxt, adt.did) { |
| return Some(format!("TyCtxt<{}>", 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::ImplKind { 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(); |
| }); |
| } |
| } |
| } |
| } |
| } |
| } |
