1 #![feature(box_patterns)]
2 #![feature(in_band_lifetimes)]
4 #![feature(rustc_private)]
5 #![recursion_limit = "512"]
6 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
7 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
8 // warn on the same lints as `clippy_lints`
9 #![warn(trivial_casts, trivial_numeric_casts)]
10 // warn on lints, that are included in `rust-lang/rust`s bootstrap
11 #![warn(rust_2018_idioms, unused_lifetimes)]
12 // warn on rustc internal lints
13 #![warn(rustc::internal)]
15 // FIXME: switch to something more ergonomic here, once available.
16 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
17 extern crate rustc_ast;
18 extern crate rustc_ast_pretty;
19 extern crate rustc_attr;
20 extern crate rustc_data_structures;
21 extern crate rustc_errors;
22 extern crate rustc_hir;
23 extern crate rustc_infer;
24 extern crate rustc_lexer;
25 extern crate rustc_lint;
26 extern crate rustc_middle;
27 extern crate rustc_mir;
28 extern crate rustc_session;
29 extern crate rustc_span;
30 extern crate rustc_target;
31 extern crate rustc_trait_selection;
32 extern crate rustc_typeck;
37 #[allow(clippy::module_name_repetitions)]
44 pub mod eager_or_lazy;
48 pub mod numeric_literal;
51 pub mod qualify_min_const_fn;
58 pub use self::attrs::*;
59 pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, SpanlessHash};
61 use std::collections::hash_map::Entry;
62 use std::hash::BuildHasherDefault;
64 use if_chain::if_chain;
65 use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
66 use rustc_data_structures::unhash::UnhashMap;
68 use rustc_hir::def::{DefKind, Res};
69 use rustc_hir::def_id::DefId;
70 use rustc_hir::intravisit::{self, walk_expr, ErasedMap, FnKind, NestedVisitorMap, Visitor};
71 use rustc_hir::LangItem::{ResultErr, ResultOk};
73 def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
74 ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path,
75 PathSegment, QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
77 use rustc_lint::{LateContext, Level, Lint, LintContext};
78 use rustc_middle::hir::exports::Export;
79 use rustc_middle::hir::map::Map;
80 use rustc_middle::ty as rustc_ty;
81 use rustc_middle::ty::{layout::IntegerExt, DefIdTree, Ty, TyCtxt, TypeFoldable};
82 use rustc_semver::RustcVersion;
83 use rustc_session::Session;
84 use rustc_span::hygiene::{ExpnKind, MacroKind};
85 use rustc_span::source_map::original_sp;
87 use rustc_span::symbol::{kw, Symbol};
88 use rustc_span::{Span, DUMMY_SP};
89 use rustc_target::abi::Integer;
91 use crate::consts::{constant, Constant};
92 use crate::ty::{can_partially_move_ty, is_recursively_primitive_type};
94 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
95 if let Ok(version) = RustcVersion::parse(msrv) {
97 } else if let Some(sess) = sess {
98 if let Some(span) = span {
99 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
105 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
106 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
110 macro_rules! extract_msrv_attr {
112 extract_msrv_attr!(@LateContext, ());
115 extract_msrv_attr!(@EarlyContext);
117 (@$context:ident$(, $call:tt)?) => {
118 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
119 use $crate::get_unique_inner_attr;
120 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
122 if let Some(msrv) = msrv_attr.value_str() {
123 self.msrv = $crate::parse_msrv(
125 Some(cx.sess$($call)?),
126 Some(msrv_attr.span),
129 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
138 /// Returns `true` if the two spans come from differing expansions (i.e., one is
139 /// from a macro and one isn't).
141 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
142 rhs.ctxt() != lhs.ctxt()
145 /// If the given expression is a local binding, find the initializer expression.
146 /// If that initializer expression is another local binding, find its initializer again.
147 /// This process repeats as long as possible (but usually no more than once). Initializer
148 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
161 /// let def = abc + 2;
162 /// // ^^^^^^^ output
166 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
167 while let Some(init) = path_to_local(expr)
168 .and_then(|id| find_binding_init(cx, id))
169 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
176 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
177 /// By only considering immutable bindings, we guarantee that the returned expression represents the
178 /// value of the binding wherever it is referenced.
180 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
181 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
182 /// canonical binding `HirId`.
183 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
184 let hir = cx.tcx.hir();
186 if let Some(Node::Binding(pat)) = hir.find(hir_id);
187 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
188 let parent = hir.get_parent_node(hir_id);
189 if let Some(Node::Local(local)) = hir.find(parent);
197 /// Returns `true` if the given `NodeId` is inside a constant context
202 /// if in_constant(cx, expr.hir_id) {
206 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
207 let parent_id = cx.tcx.hir().get_parent_item(id);
208 match cx.tcx.hir().get(parent_id) {
210 kind: ItemKind::Const(..) | ItemKind::Static(..),
213 | Node::TraitItem(&TraitItem {
214 kind: TraitItemKind::Const(..),
217 | Node::ImplItem(&ImplItem {
218 kind: ImplItemKind::Const(..),
221 | Node::AnonConst(_) => true,
223 kind: ItemKind::Fn(ref sig, ..),
226 | Node::ImplItem(&ImplItem {
227 kind: ImplItemKind::Fn(ref sig, _),
229 }) => sig.header.constness == Constness::Const,
234 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
235 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
236 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
237 if let QPath::Resolved(_, path) = qpath {
238 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
239 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
240 return cx.tcx.parent(ctor_id) == Some(item_id);
247 /// Returns `true` if this `span` was expanded by any macro.
249 pub fn in_macro(span: Span) -> bool {
250 if span.from_expansion() {
251 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
257 /// Checks if given pattern is a wildcard (`_`)
258 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
259 matches!(pat.kind, PatKind::Wild)
262 /// Checks if the first type parameter is a lang item.
263 pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
264 let ty = get_qpath_generic_tys(qpath).next()?;
266 if let TyKind::Path(qpath) = &ty.kind {
267 cx.qpath_res(qpath, ty.hir_id)
269 .map_or(false, |id| {
270 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
278 /// Checks if the first type parameter is a diagnostic item.
279 pub fn is_ty_param_diagnostic_item(
280 cx: &LateContext<'_>,
283 ) -> Option<&'tcx hir::Ty<'tcx>> {
284 let ty = get_qpath_generic_tys(qpath).next()?;
286 if let TyKind::Path(qpath) = &ty.kind {
287 cx.qpath_res(qpath, ty.hir_id)
289 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
296 /// Checks if the method call given in `expr` belongs to the given trait.
297 /// This is a deprecated function, consider using [`is_trait_method`].
298 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
299 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
300 let trt_id = cx.tcx.trait_of_item(def_id);
301 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
304 /// Checks if a method is defined in an impl of a diagnostic item
305 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
306 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
307 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
308 return cx.tcx.is_diagnostic_item(diag_item, adt.did);
314 /// Checks if a method is in a diagnostic item trait
315 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
316 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
317 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
322 /// Checks if the method call given in `expr` belongs to the given trait.
323 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
325 .type_dependent_def_id(expr.hir_id)
326 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
329 /// Checks if an expression references a variable of the given name.
330 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
331 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
332 if let [p] = path.segments {
333 return p.ident.name == var;
339 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
341 QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
342 QPath::TypeRelative(_, seg) => seg,
343 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
347 pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
349 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
350 QPath::TypeRelative(_, s) => s.args,
351 QPath::LangItem(..) => None,
355 pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
356 get_qpath_generics(path)
357 .map_or([].as_ref(), |a| a.args)
360 if let hir::GenericArg::Type(ty) = a {
368 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
370 QPath::Resolved(_, path) => path.segments.get(0),
371 QPath::TypeRelative(_, seg) => Some(seg),
372 QPath::LangItem(..) => None,
376 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
377 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
378 /// `QPath::Resolved.1.res.opt_def_id()`.
380 /// Matches a `QPath` against a slice of segment string literals.
382 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
383 /// `rustc_hir::QPath`.
387 /// match_qpath(path, &["std", "rt", "begin_unwind"])
389 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
391 QPath::Resolved(_, path) => match_path(path, segments),
392 QPath::TypeRelative(ty, segment) => match ty.kind {
393 TyKind::Path(ref inner_path) => {
394 if let [prefix @ .., end] = segments {
395 if match_qpath(inner_path, prefix) {
396 return segment.ident.name.as_str() == *end;
403 QPath::LangItem(..) => false,
407 /// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
408 pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
409 if let ExprKind::Path(p) = &expr.kind {
410 cx.qpath_res(p, expr.hir_id)
416 /// Resolves the path to a `DefId` and checks if it matches the given path.
417 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
418 cx.qpath_res(path, hir_id)
420 .map_or(false, |id| match_def_path(cx, id, segments))
423 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
424 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
425 expr_path_res(cx, expr)
427 .map_or(false, |id| match_def_path(cx, id, segments))
430 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
431 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
432 /// `QPath::Resolved.1.res.opt_def_id()`.
434 /// Matches a `Path` against a slice of segment string literals.
436 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
437 /// `rustc_hir::Path`.
442 /// if match_path(&trait_ref.path, &paths::HASH) {
443 /// // This is the `std::hash::Hash` trait.
446 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
447 /// // This is a `rustc_middle::lint::Lint`.
450 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
454 .zip(segments.iter().rev())
455 .all(|(a, b)| a.ident.name.as_str() == *b)
458 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
459 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
460 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
461 if let Res::Local(id) = path.res {
468 /// Returns true if the expression is a path to a local with the specified `HirId`.
469 /// Use this function to see if an expression matches a function argument or a match binding.
470 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
471 path_to_local(expr) == Some(id)
474 /// Gets the definition associated to a path.
475 #[allow(clippy::shadow_unrelated)] // false positive #6563
476 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
477 macro_rules! try_res {
481 None => return Res::Err,
485 fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export<HirId>> {
486 tcx.item_children(def_id)
488 .find(|item| item.ident.name.as_str() == name)
491 let (krate, first, path) = match *path {
492 [krate, first, ref path @ ..] => (krate, first, path),
493 _ => return Res::Err,
496 let crates = tcx.crates();
497 let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
498 let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
502 // `get_def_path` seems to generate these empty segments for extern blocks.
503 // We can just ignore them.
504 .filter(|segment| !segment.is_empty())
505 // for each segment, find the child item
506 .try_fold(first, |item, segment| {
507 let def_id = item.res.def_id();
508 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
510 } else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
511 // it is not a child item so check inherent impl items
512 tcx.inherent_impls(def_id)
514 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
522 /// Convenience function to get the `DefId` of a trait by path.
523 /// It could be a trait or trait alias.
524 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
525 match path_to_res(cx, path) {
526 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
531 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
533 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
536 /// struct Point(isize, isize);
538 /// impl std::ops::Add for Point {
539 /// type Output = Self;
541 /// fn add(self, other: Self) -> Self {
546 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
547 // Get the implemented trait for the current function
548 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
550 if parent_impl != hir::CRATE_HIR_ID;
551 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
552 if let hir::ItemKind::Impl(impl_) = &item.kind;
553 then { return impl_.of_trait.as_ref(); }
558 /// Checks if the top level expression can be moved into a closure as is.
559 pub fn can_move_expr_to_closure_no_visit(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, jump_targets: &[HirId]) -> bool {
561 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
562 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
563 if jump_targets.contains(&id) =>
568 | ExprKind::Continue(_)
570 | ExprKind::Yield(..)
571 | ExprKind::InlineAsm(_)
572 | ExprKind::LlvmInlineAsm(_) => false,
573 // Accessing a field of a local value can only be done if the type isn't
575 ExprKind::Field(base_expr, _)
578 ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
579 ) && can_partially_move_ty(cx, cx.typeck_results().expr_ty(base_expr)) =>
581 // TODO: check if the local has been partially moved. Assume it has for now.
588 /// Checks if the expression can be moved into a closure as is.
589 pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
590 struct V<'cx, 'tcx> {
591 cx: &'cx LateContext<'tcx>,
595 impl Visitor<'tcx> for V<'_, 'tcx> {
596 type Map = ErasedMap<'tcx>;
597 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
598 NestedVisitorMap::None
601 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
602 if !self.allow_closure {
605 if let ExprKind::Loop(b, ..) = e.kind {
606 self.loops.push(e.hir_id);
610 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops);
625 /// Returns the method names and argument list of nested method call expressions that make up
626 /// `expr`. method/span lists are sorted with the most recent call first.
627 pub fn method_calls<'tcx>(
628 expr: &'tcx Expr<'tcx>,
630 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
631 let mut method_names = Vec::with_capacity(max_depth);
632 let mut arg_lists = Vec::with_capacity(max_depth);
633 let mut spans = Vec::with_capacity(max_depth);
635 let mut current = expr;
636 for _ in 0..max_depth {
637 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
638 if args.iter().any(|e| e.span.from_expansion()) {
641 method_names.push(path.ident.name);
642 arg_lists.push(&**args);
650 (method_names, arg_lists, spans)
653 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
655 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
656 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
657 /// containing the `Expr`s for
658 /// `.bar()` and `.baz()`
659 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
660 let mut current = expr;
661 let mut matched = Vec::with_capacity(methods.len());
662 for method_name in methods.iter().rev() {
663 // method chains are stored last -> first
664 if let ExprKind::MethodCall(path, _, args, _) = current.kind {
665 if path.ident.name.as_str() == *method_name {
666 if args.iter().any(|e| e.span.from_expansion()) {
669 matched.push(args); // build up `matched` backwards
670 current = &args[0]; // go to parent expression
678 // Reverse `matched` so that it is in the same order as `methods`.
683 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
684 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
687 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
690 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
691 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
692 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
693 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
694 Some(def_id) == cx.tcx.lang_items().panic_impl()
697 /// Gets the name of the item the expression is in, if available.
698 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
699 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
700 match cx.tcx.hir().find(parent_id) {
702 Node::Item(Item { ident, .. })
703 | Node::TraitItem(TraitItem { ident, .. })
704 | Node::ImplItem(ImplItem { ident, .. }),
705 ) => Some(ident.name),
710 /// Gets the name of a `Pat`, if any.
711 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
713 PatKind::Binding(.., ref spname, _) => Some(spname.name),
714 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
715 PatKind::Box(p) | PatKind::Ref(p, _) => get_pat_name(&*p),
720 pub struct ContainsName {
725 impl<'tcx> Visitor<'tcx> for ContainsName {
726 type Map = Map<'tcx>;
728 fn visit_name(&mut self, _: Span, name: Symbol) {
729 if self.name == name {
733 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
734 NestedVisitorMap::None
738 /// Checks if an `Expr` contains a certain name.
739 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
740 let mut cn = ContainsName { name, result: false };
745 /// Returns `true` if `expr` contains a return expression
746 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
747 struct RetCallFinder {
751 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
752 type Map = Map<'tcx>;
754 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
758 if let hir::ExprKind::Ret(..) = &expr.kind {
761 hir::intravisit::walk_expr(self, expr);
765 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
766 hir::intravisit::NestedVisitorMap::None
770 let mut visitor = RetCallFinder { found: false };
771 visitor.visit_expr(expr);
775 struct FindMacroCalls<'a, 'b> {
776 names: &'a [&'b str],
780 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
781 type Map = Map<'tcx>;
783 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
784 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
785 self.result.push(expr.span);
787 // and check sub-expressions
788 intravisit::walk_expr(self, expr);
791 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
792 NestedVisitorMap::None
796 /// Finds calls of the specified macros in a function body.
797 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
798 let mut fmc = FindMacroCalls {
802 fmc.visit_expr(&body.value);
806 /// Extends the span to the beginning of the spans line, incl. whitespaces.
811 /// // will be converted to
813 /// // ^^^^^^^^^^^^^^
815 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
816 let span = original_sp(span, DUMMY_SP);
817 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
818 let line_no = source_map_and_line.line;
819 let line_start = source_map_and_line.sf.lines[line_no];
820 Span::new(line_start, span.hi(), span.ctxt())
823 /// Gets the parent node, if any.
824 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
825 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
828 /// Gets the parent expression, if any –- this is useful to constrain a lint.
829 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
830 get_parent_expr_for_hir(cx, e.hir_id)
833 /// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
835 pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
836 match get_parent_node(cx.tcx, hir_id) {
837 Some(Node::Expr(parent)) => Some(parent),
842 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
843 let map = &cx.tcx.hir();
844 let enclosing_node = map
845 .get_enclosing_scope(hir_id)
846 .and_then(|enclosing_id| map.find(enclosing_id));
847 enclosing_node.and_then(|node| match node {
848 Node::Block(block) => Some(block),
850 kind: ItemKind::Fn(_, _, eid),
853 | Node::ImplItem(&ImplItem {
854 kind: ImplItemKind::Fn(_, eid),
856 }) => match cx.tcx.hir().body(eid).value.kind {
857 ExprKind::Block(block, _) => Some(block),
864 /// Gets the loop enclosing the given expression, if any.
865 pub fn get_enclosing_loop(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
867 for (_, node) in map.parent_iter(expr.hir_id) {
871 kind: ExprKind::Loop(..),
875 Node::Expr(_) | Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
882 /// Gets the parent node if it's an impl block.
883 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
885 match map.parent_iter(id).next() {
889 kind: ItemKind::Impl(imp),
897 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
898 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
900 let mut iter = map.parent_iter(expr.hir_id);
902 Some((arm_id, Node::Arm(..))) => matches!(
907 kind: ExprKind::Match(_, [_, else_arm], MatchSource::IfLetDesugar { .. }),
911 if else_arm.hir_id == arm_id
916 kind: ExprKind::If(_, _, Some(else_expr)),
919 )) => else_expr.hir_id == expr.hir_id,
924 /// Checks whether the given expression is a constant integer of the given value.
925 /// unlike `is_integer_literal`, this version does const folding
926 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
927 if is_integer_literal(e, value) {
930 let map = cx.tcx.hir();
931 let parent_item = map.get_parent_item(e.hir_id);
932 if let Some((Constant::Int(v), _)) = map
933 .maybe_body_owned_by(parent_item)
934 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
942 /// Checks whether the given expression is a constant literal of the given value.
943 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
944 // FIXME: use constant folding
945 if let ExprKind::Lit(ref spanned) = expr.kind {
946 if let LitKind::Int(v, _) = spanned.node {
953 /// Returns `true` if the given `Expr` has been coerced before.
955 /// Examples of coercions can be found in the Nomicon at
956 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
958 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
959 /// information on adjustments and coercions.
960 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
961 cx.typeck_results().adjustments().get(e.hir_id).is_some()
964 /// Returns the pre-expansion span if is this comes from an expansion of the
966 /// See also `is_direct_expn_of`.
968 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
970 if span.from_expansion() {
971 let data = span.ctxt().outer_expn_data();
972 let new_span = data.call_site;
974 if let ExpnKind::Macro {
975 kind: MacroKind::Bang,
980 if mac_name.as_str() == name {
981 return Some(new_span);
992 /// Returns the pre-expansion span if the span directly comes from an expansion
993 /// of the macro `name`.
994 /// The difference with `is_expn_of` is that in
998 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1000 /// `is_direct_expn_of`.
1002 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1003 if span.from_expansion() {
1004 let data = span.ctxt().outer_expn_data();
1005 let new_span = data.call_site;
1007 if let ExpnKind::Macro {
1008 kind: MacroKind::Bang,
1013 if mac_name.as_str() == name {
1014 return Some(new_span);
1022 /// Convenience function to get the return type of a function.
1023 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1024 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1025 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1026 cx.tcx.erase_late_bound_regions(ret_ty)
1029 /// Checks if an expression is constructing a tuple-like enum variant or struct
1030 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1031 if let ExprKind::Call(fun, _) = expr.kind {
1032 if let ExprKind::Path(ref qp) = fun.kind {
1033 let res = cx.qpath_res(qp, fun.hir_id);
1035 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1036 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1044 /// Returns `true` if a pattern is refutable.
1045 // TODO: should be implemented using rustc/mir_build/thir machinery
1046 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1047 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1049 cx.qpath_res(qpath, id),
1050 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1054 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1055 i.any(|pat| is_refutable(cx, pat))
1059 PatKind::Wild => false,
1060 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1061 PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
1062 PatKind::Lit(..) | PatKind::Range(..) => true,
1063 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1064 PatKind::Or(pats) => {
1065 // TODO: should be the honest check, that pats is exhaustive set
1066 are_refutable(cx, pats.iter().map(|pat| &**pat))
1068 PatKind::Tuple(pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1069 PatKind::Struct(ref qpath, fields, _) => {
1070 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1072 PatKind::TupleStruct(ref qpath, pats, _) => {
1073 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1075 PatKind::Slice(head, ref middle, tail) => {
1076 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1077 rustc_ty::Slice(..) => {
1078 // [..] is the only irrefutable slice pattern.
1079 !head.is_empty() || middle.is_none() || !tail.is_empty()
1081 rustc_ty::Array(..) => {
1082 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
1093 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1094 /// the function once on the given pattern.
1095 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1096 if let PatKind::Or(pats) = pat.kind {
1097 pats.iter().copied().for_each(f);
1103 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1104 /// implementations have.
1105 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1106 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
1109 /// Remove blocks around an expression.
1111 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1113 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1114 while let ExprKind::Block(block, ..) = expr.kind {
1115 match (block.stmts.is_empty(), block.expr.as_ref()) {
1116 (true, Some(e)) => expr = e,
1123 pub fn is_self(slf: &Param<'_>) -> bool {
1124 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1125 name.name == kw::SelfLower
1131 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1133 if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind;
1134 if let Res::SelfTy(..) = path.res;
1142 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1143 (0..decl.inputs.len()).map(move |i| &body.params[i])
1146 /// Checks if a given expression is a match expression expanded from the `?`
1147 /// operator or the `try` macro.
1148 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1149 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1151 if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
1152 if is_lang_ctor(cx, path, ResultOk);
1153 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1154 if path_to_local_id(arm.body, hir_id);
1162 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1163 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1164 is_lang_ctor(cx, path, ResultErr)
1170 if let ExprKind::Match(_, arms, ref source) = expr.kind {
1171 // desugared from a `?` operator
1172 if let MatchSource::TryDesugar = *source {
1178 if arms[0].guard.is_none();
1179 if arms[1].guard.is_none();
1180 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) ||
1181 (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1191 /// Returns `true` if the lint is allowed in the current context
1193 /// Useful for skipping long running code when it's unnecessary
1194 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1195 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1198 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1199 while let PatKind::Ref(subpat, _) = pat.kind {
1205 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1206 Integer::from_int_ty(&tcx, ity).size().bits()
1209 #[allow(clippy::cast_possible_wrap)]
1210 /// Turn a constant int byte representation into an i128
1211 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1212 let amt = 128 - int_bits(tcx, ity);
1213 ((u as i128) << amt) >> amt
1216 #[allow(clippy::cast_sign_loss)]
1217 /// clip unused bytes
1218 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1219 let amt = 128 - int_bits(tcx, ity);
1220 ((u as u128) << amt) >> amt
1223 /// clip unused bytes
1224 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1225 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1226 let amt = 128 - bits;
1230 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1231 let map = &tcx.hir();
1232 let mut prev_enclosing_node = None;
1233 let mut enclosing_node = node;
1234 while Some(enclosing_node) != prev_enclosing_node {
1235 if is_automatically_derived(map.attrs(enclosing_node)) {
1238 prev_enclosing_node = Some(enclosing_node);
1239 enclosing_node = map.get_parent_item(enclosing_node);
1244 /// Matches a function call with the given path and returns the arguments.
1249 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1251 pub fn match_function_call<'tcx>(
1252 cx: &LateContext<'tcx>,
1253 expr: &'tcx Expr<'_>,
1255 ) -> Option<&'tcx [Expr<'tcx>]> {
1257 if let ExprKind::Call(fun, args) = expr.kind;
1258 if let ExprKind::Path(ref qpath) = fun.kind;
1259 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1260 if match_def_path(cx, fun_def_id, path);
1268 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1270 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1271 let search_path = cx.get_def_path(did);
1274 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1277 /// Checks if the given `DefId` matches the path.
1278 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1279 // We should probably move to Symbols in Clippy as well rather than interning every time.
1280 let path = cx.get_def_path(did);
1281 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1284 pub fn match_panic_call(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1285 if let ExprKind::Call(func, [arg]) = expr.kind {
1286 expr_path_res(cx, func)
1288 .map_or(false, |id| match_panic_def_id(cx, id))
1295 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1296 match_any_def_paths(
1300 &paths::BEGIN_PANIC,
1301 &paths::BEGIN_PANIC_FMT,
1303 &paths::PANICKING_PANIC,
1304 &paths::PANICKING_PANIC_FMT,
1305 &paths::PANICKING_PANIC_STR,
1311 /// Returns the list of condition expressions and the list of blocks in a
1312 /// sequence of `if/else`.
1313 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1314 /// `if a { c } else if b { d } else { e }`.
1315 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1316 let mut conds = Vec::new();
1317 let mut blocks: Vec<&Block<'_>> = Vec::new();
1319 while let ExprKind::If(cond, then_expr, ref else_expr) = expr.kind {
1321 if let ExprKind::Block(block, _) = then_expr.kind {
1324 panic!("ExprKind::If node is not an ExprKind::Block");
1327 if let Some(else_expr) = *else_expr {
1334 // final `else {..}`
1335 if !blocks.is_empty() {
1336 if let ExprKind::Block(block, _) = expr.kind {
1344 /// Checks if the given function kind is an async function.
1345 pub fn is_async_fn(kind: FnKind<'_>) -> bool {
1346 matches!(kind, FnKind::ItemFn(_, _, header, _) if header.asyncness == IsAsync::Async)
1349 /// Peels away all the compiler generated code surrounding the body of an async function,
1350 pub fn get_async_fn_body(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
1351 if let ExprKind::Call(
1354 kind: ExprKind::Closure(_, _, body, _, _),
1359 if let ExprKind::Block(
1364 kind: ExprKind::DropTemps(expr),
1370 ) = tcx.hir().body(body).value.kind
1378 // Finds the `#[must_use]` attribute, if any
1379 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1380 attrs.iter().find(|a| a.has_name(sym::must_use))
1383 // check if expr is calling method or function with #[must_use] attribute
1384 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1385 let did = match expr.kind {
1386 ExprKind::Call(path, _) => if_chain! {
1387 if let ExprKind::Path(ref qpath) = path.kind;
1388 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1395 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1399 did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
1402 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1403 pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
1404 let map = tcx.hir();
1405 let mut child_id = expr.hir_id;
1406 let mut iter = map.parent_iter(child_id);
1410 Some((id, Node::Block(_))) => child_id = id,
1411 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1412 Some((_, Node::Expr(expr))) => match expr.kind {
1413 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1414 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1415 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1416 _ => break Some(Node::Expr(expr)),
1418 Some((_, node)) => break Some(node),
1423 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1424 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1426 get_expr_use_or_unification_node(tcx, expr),
1427 None | Some(Node::Stmt(Stmt {
1428 kind: StmtKind::Expr(_)
1430 | StmtKind::Local(Local {
1432 kind: PatKind::Wild,
1442 /// Checks if the expression is the final expression returned from a block.
1443 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1444 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1447 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1448 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1449 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1450 attr.path == sym::no_std
1457 /// Check if parent of a hir node is a trait implementation block.
1458 /// For example, `f` in
1460 /// impl Trait for S {
1464 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1465 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1466 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1472 /// Check if it's even possible to satisfy the `where` clause for the item.
1474 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1477 /// fn foo() where i32: Iterator {
1478 /// for _ in 2i32 {}
1481 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1482 use rustc_trait_selection::traits;
1488 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1489 traits::impossible_predicates(
1491 traits::elaborate_predicates(cx.tcx, predicates)
1492 .map(|o| o.predicate)
1493 .collect::<Vec<_>>(),
1497 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1498 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1500 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1503 kind: ExprKind::Path(qpath),
1504 hir_id: path_hir_id,
1508 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
1513 /// This function checks if any of the lints in the slice is enabled for the provided `HirId`.
1514 /// A lint counts as enabled with any of the levels: `Level::Forbid` | `Level::Deny` | `Level::Warn`
1517 /// #[deny(clippy::YOUR_AWESOME_LINT)]
1518 /// println!("Hello, World!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == true
1520 /// #[allow(clippy::YOUR_AWESOME_LINT)]
1521 /// println!("See you soon!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == false
1523 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1524 lints.iter().any(|lint| {
1526 cx.tcx.lint_level_at_node(lint, id),
1527 (Level::Forbid | Level::Deny | Level::Warn, _)
1532 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1533 /// slice iff the given expression is a slice of primitives (as defined in the
1534 /// `is_recursively_primitive_type` function) and None otherwise.
1535 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1536 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1537 let expr_kind = expr_type.kind();
1538 let is_primitive = match expr_kind {
1539 rustc_ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1540 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1541 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1542 is_recursively_primitive_type(element_type)
1551 // if we have wrappers like Array, Slice or Tuple, print these
1552 // and get the type enclosed in the slice ref
1553 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1554 rustc_ty::Slice(..) => return Some("slice".into()),
1555 rustc_ty::Array(..) => return Some("array".into()),
1556 rustc_ty::Tuple(..) => return Some("tuple".into()),
1558 // is_recursively_primitive_type() should have taken care
1559 // of the rest and we can rely on the type that is found
1560 let refs_peeled = expr_type.peel_refs();
1561 return Some(refs_peeled.walk().last().unwrap().to_string());
1568 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1569 /// `hash` must be comformed with `eq`
1570 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1572 Hash: Fn(&T) -> u64,
1573 Eq: Fn(&T, &T) -> bool,
1576 [a, b] if eq(a, b) => return vec![(a, b)],
1577 _ if exprs.len() <= 2 => return vec![],
1581 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1583 let mut map: UnhashMap<u64, Vec<&_>> =
1584 UnhashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1587 match map.entry(hash(expr)) {
1588 Entry::Occupied(mut o) => {
1591 match_expr_list.push((o, expr));
1594 o.get_mut().push(expr);
1596 Entry::Vacant(v) => {
1597 v.insert(vec![expr]);
1605 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
1606 /// references removed.
1607 pub fn peel_hir_pat_refs(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
1608 fn peel(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
1609 if let PatKind::Ref(pat, _) = pat.kind {
1610 peel(pat, count + 1)
1618 /// Peels of expressions while the given closure returns `Some`.
1619 pub fn peel_hir_expr_while<'tcx>(
1620 mut expr: &'tcx Expr<'tcx>,
1621 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
1622 ) -> &'tcx Expr<'tcx> {
1623 while let Some(e) = f(expr) {
1629 /// Peels off up to the given number of references on the expression. Returns the underlying
1630 /// expression and the number of references removed.
1631 pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
1632 let mut remaining = count;
1633 let e = peel_hir_expr_while(expr, |e| match e.kind {
1634 ExprKind::AddrOf(BorrowKind::Ref, _, e) if remaining != 0 => {
1640 (e, count - remaining)
1643 /// Peels off all references on the expression. Returns the underlying expression and the number of
1644 /// references removed.
1645 pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
1647 let e = peel_hir_expr_while(expr, |e| match e.kind {
1648 ExprKind::AddrOf(BorrowKind::Ref, _, e) => {
1658 macro_rules! unwrap_cargo_metadata {
1659 ($cx: ident, $lint: ident, $deps: expr) => {{
1660 let mut command = cargo_metadata::MetadataCommand::new();
1665 match command.exec() {
1666 Ok(metadata) => metadata,
1668 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1675 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1677 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1678 if let Res::Def(_, def_id) = path.res;
1680 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)