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