1 #![feature(array_chunks)]
2 #![feature(box_patterns)]
3 #![feature(control_flow_enum)]
5 #![cfg_attr(bootstrap, feature(let_chains))]
6 #![feature(lint_reasons)]
8 #![feature(rustc_private)]
9 #![recursion_limit = "512"]
10 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
11 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
12 // warn on the same lints as `clippy_lints`
13 #![warn(trivial_casts, trivial_numeric_casts)]
14 // warn on lints, that are included in `rust-lang/rust`s bootstrap
15 #![warn(rust_2018_idioms, unused_lifetimes)]
16 // warn on rustc internal lints
17 #![warn(rustc::internal)]
19 // FIXME: switch to something more ergonomic here, once available.
20 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
21 extern crate rustc_ast;
22 extern crate rustc_ast_pretty;
23 extern crate rustc_attr;
24 extern crate rustc_data_structures;
25 extern crate rustc_errors;
26 extern crate rustc_hir;
27 extern crate rustc_infer;
28 extern crate rustc_lexer;
29 extern crate rustc_lint;
30 extern crate rustc_middle;
31 extern crate rustc_session;
32 extern crate rustc_span;
33 extern crate rustc_target;
34 extern crate rustc_trait_selection;
35 extern crate rustc_typeck;
46 pub mod eager_or_lazy;
51 pub mod numeric_literal;
54 pub mod qualify_min_const_fn;
62 pub use self::attrs::*;
63 pub use self::check_proc_macro::{is_from_proc_macro, is_span_if, is_span_match};
64 pub use self::hir_utils::{
65 both, count_eq, eq_expr_value, hash_expr, hash_stmt, over, HirEqInterExpr, SpanlessEq, SpanlessHash,
68 use std::collections::hash_map::Entry;
69 use std::hash::BuildHasherDefault;
70 use std::sync::OnceLock;
71 use std::sync::{Mutex, MutexGuard};
73 use if_chain::if_chain;
74 use rustc_ast::ast::{self, LitKind};
75 use rustc_ast::Attribute;
76 use rustc_data_structures::fx::FxHashMap;
77 use rustc_data_structures::unhash::UnhashMap;
79 use rustc_hir::def::{DefKind, Res};
80 use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_ID};
81 use rustc_hir::hir_id::{HirIdMap, HirIdSet};
82 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
83 use rustc_hir::LangItem::{OptionNone, ResultErr, ResultOk};
85 def, Arm, ArrayLen, BindingAnnotation, Block, BlockCheckMode, Body, Closure, Constness, Destination, Expr,
86 ExprKind, FnDecl, HirId, Impl, ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local, MatchSource,
87 Mutability, Node, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem, TraitItemKind,
88 TraitRef, TyKind, UnOp,
90 use rustc_lint::{LateContext, Level, Lint, LintContext};
91 use rustc_middle::hir::place::PlaceBase;
92 use rustc_middle::ty as rustc_ty;
93 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
94 use rustc_middle::ty::binding::BindingMode;
95 use rustc_middle::ty::fast_reject::SimplifiedTypeGen::{
96 ArraySimplifiedType, BoolSimplifiedType, CharSimplifiedType, FloatSimplifiedType, IntSimplifiedType,
97 PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
99 use rustc_middle::ty::{
100 layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitable, UpvarCapture,
102 use rustc_middle::ty::{FloatTy, IntTy, UintTy};
103 use rustc_semver::RustcVersion;
104 use rustc_session::Session;
105 use rustc_span::hygiene::{ExpnKind, MacroKind};
106 use rustc_span::source_map::original_sp;
108 use rustc_span::symbol::{kw, Symbol};
109 use rustc_span::{Span, DUMMY_SP};
110 use rustc_target::abi::Integer;
112 use crate::consts::{constant, Constant};
113 use crate::ty::{can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type, ty_is_fn_once_param};
114 use crate::visitors::expr_visitor_no_bodies;
116 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
117 if let Ok(version) = RustcVersion::parse(msrv) {
118 return Some(version);
119 } else if let Some(sess) = sess {
120 if let Some(span) = span {
121 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
127 pub fn meets_msrv(msrv: Option<RustcVersion>, lint_msrv: RustcVersion) -> bool {
128 msrv.map_or(true, |msrv| msrv.meets(lint_msrv))
132 macro_rules! extract_msrv_attr {
133 ($context:ident) => {
134 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'_>, attrs: &[rustc_ast::ast::Attribute]) {
135 let sess = rustc_lint::LintContext::sess(cx);
136 match $crate::get_unique_inner_attr(sess, attrs, "msrv") {
138 if let Some(msrv) = msrv_attr.value_str() {
139 self.msrv = $crate::parse_msrv(&msrv.to_string(), Some(sess), Some(msrv_attr.span));
141 sess.span_err(msrv_attr.span, "bad clippy attribute");
150 /// If the given expression is a local binding, find the initializer expression.
151 /// If that initializer expression is another local binding, find its initializer again.
152 /// This process repeats as long as possible (but usually no more than once). Initializer
153 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
166 /// let def = abc + 2;
167 /// // ^^^^^^^ output
171 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
172 while let Some(init) = path_to_local(expr)
173 .and_then(|id| find_binding_init(cx, id))
174 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
181 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
182 /// By only considering immutable bindings, we guarantee that the returned expression represents the
183 /// value of the binding wherever it is referenced.
185 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
186 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
187 /// canonical binding `HirId`.
188 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
189 let hir = cx.tcx.hir();
191 if let Some(Node::Pat(pat)) = hir.find(hir_id);
192 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
193 let parent = hir.get_parent_node(hir_id);
194 if let Some(Node::Local(local)) = hir.find(parent);
202 /// Returns `true` if the given `NodeId` is inside a constant context
207 /// if in_constant(cx, expr.hir_id) {
211 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
212 let parent_id = cx.tcx.hir().get_parent_item(id);
213 match cx.tcx.hir().get_by_def_id(parent_id) {
215 kind: ItemKind::Const(..) | ItemKind::Static(..),
218 | Node::TraitItem(&TraitItem {
219 kind: TraitItemKind::Const(..),
222 | Node::ImplItem(&ImplItem {
223 kind: ImplItemKind::Const(..),
226 | Node::AnonConst(_) => true,
228 kind: ItemKind::Fn(ref sig, ..),
231 | Node::ImplItem(&ImplItem {
232 kind: ImplItemKind::Fn(ref sig, _),
234 }) => sig.header.constness == Constness::Const,
239 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
240 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
241 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
242 if let QPath::Resolved(_, path) = qpath {
243 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
244 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
245 return cx.tcx.parent(ctor_id) == item_id;
252 pub fn is_unit_expr(expr: &Expr<'_>) -> bool {
262 ) | ExprKind::Tup([])
266 /// Checks if given pattern is a wildcard (`_`)
267 pub fn is_wild(pat: &Pat<'_>) -> bool {
268 matches!(pat.kind, PatKind::Wild)
271 /// Checks if the method call given in `expr` belongs to the given trait.
272 /// This is a deprecated function, consider using [`is_trait_method`].
273 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
274 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
275 let trt_id = cx.tcx.trait_of_item(def_id);
276 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
279 /// Checks if a method is defined in an impl of a diagnostic item
280 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
281 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
282 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
283 return cx.tcx.is_diagnostic_item(diag_item, adt.did());
289 /// Checks if a method is in a diagnostic item trait
290 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
291 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
292 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
297 /// Checks if the method call given in `expr` belongs to the given trait.
298 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
300 .type_dependent_def_id(expr.hir_id)
301 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
304 /// Checks if the given expression is a path referring an item on the trait
305 /// that is marked with the given diagnostic item.
307 /// For checking method call expressions instead of path expressions, use
308 /// [`is_trait_method`].
310 /// For example, this can be used to find if an expression like `u64::default`
311 /// refers to an item of the trait `Default`, which is associated with the
312 /// `diag_item` of `sym::Default`.
313 pub fn is_trait_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
314 if let hir::ExprKind::Path(ref qpath) = expr.kind {
315 cx.qpath_res(qpath, expr.hir_id)
317 .map_or(false, |def_id| is_diag_trait_item(cx, def_id, diag_item))
323 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
325 QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
326 QPath::TypeRelative(_, seg) => seg,
327 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
331 pub fn qpath_generic_tys<'tcx>(qpath: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
332 last_path_segment(qpath)
334 .map_or(&[][..], |a| a.args)
336 .filter_map(|a| match a {
337 hir::GenericArg::Type(ty) => Some(ty),
342 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
343 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
344 /// `QPath::Resolved.1.res.opt_def_id()`.
346 /// Matches a `QPath` against a slice of segment string literals.
348 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
349 /// `rustc_hir::QPath`.
353 /// match_qpath(path, &["std", "rt", "begin_unwind"])
355 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
357 QPath::Resolved(_, path) => match_path(path, segments),
358 QPath::TypeRelative(ty, segment) => match ty.kind {
359 TyKind::Path(ref inner_path) => {
360 if let [prefix @ .., end] = segments {
361 if match_qpath(inner_path, prefix) {
362 return segment.ident.name.as_str() == *end;
369 QPath::LangItem(..) => false,
373 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
375 /// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
376 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
377 path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, segments))
380 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
382 pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
383 path_def_id(cx, expr).map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
386 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
387 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
388 /// `QPath::Resolved.1.res.opt_def_id()`.
390 /// Matches a `Path` against a slice of segment string literals.
392 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
393 /// `rustc_hir::Path`.
398 /// if match_path(&trait_ref.path, &paths::HASH) {
399 /// // This is the `std::hash::Hash` trait.
402 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
403 /// // This is a `rustc_middle::lint::Lint`.
406 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
410 .zip(segments.iter().rev())
411 .all(|(a, b)| a.ident.name.as_str() == *b)
414 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
415 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
416 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
417 if let Res::Local(id) = path.res {
424 /// Returns true if the expression is a path to a local with the specified `HirId`.
425 /// Use this function to see if an expression matches a function argument or a match binding.
426 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
427 path_to_local(expr) == Some(id)
430 pub trait MaybePath<'hir> {
431 fn hir_id(&self) -> HirId;
432 fn qpath_opt(&self) -> Option<&QPath<'hir>>;
435 macro_rules! maybe_path {
436 ($ty:ident, $kind:ident) => {
437 impl<'hir> MaybePath<'hir> for hir::$ty<'hir> {
438 fn hir_id(&self) -> HirId {
441 fn qpath_opt(&self) -> Option<&QPath<'hir>> {
443 hir::$kind::Path(qpath) => Some(qpath),
450 maybe_path!(Expr, ExprKind);
451 maybe_path!(Pat, PatKind);
452 maybe_path!(Ty, TyKind);
454 /// If `maybe_path` is a path node, resolves it, otherwise returns `Res::Err`
455 pub fn path_res<'tcx>(cx: &LateContext<'_>, maybe_path: &impl MaybePath<'tcx>) -> Res {
456 match maybe_path.qpath_opt() {
458 Some(qpath) => cx.qpath_res(qpath, maybe_path.hir_id()),
462 /// If `maybe_path` is a path node which resolves to an item, retrieves the item ID
463 pub fn path_def_id<'tcx>(cx: &LateContext<'_>, maybe_path: &impl MaybePath<'tcx>) -> Option<DefId> {
464 path_res(cx, maybe_path).opt_def_id()
467 /// Resolves a def path like `std::vec::Vec`.
468 /// This function is expensive and should be used sparingly.
469 pub fn def_path_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
470 fn item_child_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Option<Res> {
471 match tcx.def_kind(def_id) {
472 DefKind::Mod | DefKind::Enum | DefKind::Trait => tcx
473 .module_children(def_id)
475 .find(|item| item.ident.name.as_str() == name)
476 .map(|child| child.res.expect_non_local()),
478 .associated_item_def_ids(def_id)
481 .find(|assoc_def_id| tcx.item_name(*assoc_def_id).as_str() == name)
482 .map(|assoc_def_id| Res::Def(tcx.def_kind(assoc_def_id), assoc_def_id)),
486 fn find_primitive<'tcx>(tcx: TyCtxt<'tcx>, name: &str) -> impl Iterator<Item = DefId> + 'tcx {
487 let single = |ty| tcx.incoherent_impls(ty).iter().copied();
488 let empty = || [].iter().copied();
490 "bool" => single(BoolSimplifiedType),
491 "char" => single(CharSimplifiedType),
492 "str" => single(StrSimplifiedType),
493 "array" => single(ArraySimplifiedType),
494 "slice" => single(SliceSimplifiedType),
495 // FIXME: rustdoc documents these two using just `pointer`.
497 // Maybe this is something we should do here too.
498 "const_ptr" => single(PtrSimplifiedType(Mutability::Not)),
499 "mut_ptr" => single(PtrSimplifiedType(Mutability::Mut)),
500 "isize" => single(IntSimplifiedType(IntTy::Isize)),
501 "i8" => single(IntSimplifiedType(IntTy::I8)),
502 "i16" => single(IntSimplifiedType(IntTy::I16)),
503 "i32" => single(IntSimplifiedType(IntTy::I32)),
504 "i64" => single(IntSimplifiedType(IntTy::I64)),
505 "i128" => single(IntSimplifiedType(IntTy::I128)),
506 "usize" => single(UintSimplifiedType(UintTy::Usize)),
507 "u8" => single(UintSimplifiedType(UintTy::U8)),
508 "u16" => single(UintSimplifiedType(UintTy::U16)),
509 "u32" => single(UintSimplifiedType(UintTy::U32)),
510 "u64" => single(UintSimplifiedType(UintTy::U64)),
511 "u128" => single(UintSimplifiedType(UintTy::U128)),
512 "f32" => single(FloatSimplifiedType(FloatTy::F32)),
513 "f64" => single(FloatSimplifiedType(FloatTy::F64)),
517 fn find_crate(tcx: TyCtxt<'_>, name: &str) -> Option<DefId> {
521 .find(|&num| tcx.crate_name(num).as_str() == name)
522 .map(CrateNum::as_def_id)
525 let (base, first, path) = match *path {
526 [base, first, ref path @ ..] => (base, first, path),
528 return PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy);
530 _ => return Res::Err,
533 let starts = find_primitive(tcx, base)
534 .chain(find_crate(tcx, base))
535 .filter_map(|id| item_child_by_name(tcx, id, first));
537 for first in starts {
541 // for each segment, find the child item
542 .try_fold(first, |res, segment| {
543 let def_id = res.def_id();
544 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
546 } else if matches!(res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
547 // it is not a child item so check inherent impl items
548 tcx.inherent_impls(def_id)
550 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
556 if let Some(last) = last {
564 /// Convenience function to get the `DefId` of a trait by path.
565 /// It could be a trait or trait alias.
566 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
567 match def_path_res(cx, path) {
568 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
573 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
575 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
578 /// struct Point(isize, isize);
580 /// impl std::ops::Add for Point {
581 /// type Output = Self;
583 /// fn add(self, other: Self) -> Self {
588 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, def_id: LocalDefId) -> Option<&'tcx TraitRef<'tcx>> {
589 // Get the implemented trait for the current function
590 let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
591 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
593 if parent_impl != CRATE_DEF_ID;
594 if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent_impl);
595 if let hir::ItemKind::Impl(impl_) = &item.kind;
597 return impl_.of_trait.as_ref();
603 /// This method will return tuple of projection stack and root of the expression,
604 /// used in `can_mut_borrow_both`.
606 /// For example, if `e` represents the `v[0].a.b[x]`
607 /// this method will return a tuple, composed of a `Vec`
608 /// containing the `Expr`s for `v[0], v[0].a, v[0].a.b, v[0].a.b[x]`
609 /// and an `Expr` for root of them, `v`
610 fn projection_stack<'a, 'hir>(mut e: &'a Expr<'hir>) -> (Vec<&'a Expr<'hir>>, &'a Expr<'hir>) {
611 let mut result = vec![];
614 ExprKind::Index(ep, _) | ExprKind::Field(ep, _) => {
625 /// Gets the mutability of the custom deref adjustment, if any.
626 pub fn expr_custom_deref_adjustment(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<Mutability> {
630 .find_map(|a| match a.kind {
631 Adjust::Deref(Some(d)) => Some(Some(d.mutbl)),
632 Adjust::Deref(None) => None,
638 /// Checks if two expressions can be mutably borrowed simultaneously
639 /// and they aren't dependent on borrowing same thing twice
640 pub fn can_mut_borrow_both(cx: &LateContext<'_>, e1: &Expr<'_>, e2: &Expr<'_>) -> bool {
641 let (s1, r1) = projection_stack(e1);
642 let (s2, r2) = projection_stack(e2);
643 if !eq_expr_value(cx, r1, r2) {
646 if expr_custom_deref_adjustment(cx, r1).is_some() || expr_custom_deref_adjustment(cx, r2).is_some() {
650 for (x1, x2) in s1.iter().zip(s2.iter()) {
651 if expr_custom_deref_adjustment(cx, x1).is_some() || expr_custom_deref_adjustment(cx, x2).is_some() {
655 match (&x1.kind, &x2.kind) {
656 (ExprKind::Field(_, i1), ExprKind::Field(_, i2)) => {
661 (ExprKind::Index(_, i1), ExprKind::Index(_, i2)) => {
662 if !eq_expr_value(cx, i1, i2) {
672 /// Returns true if the `def_id` associated with the `path` is recognized as a "default-equivalent"
673 /// constructor from the std library
674 fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<'_>) -> bool {
675 let std_types_symbols = &[
687 if let QPath::TypeRelative(_, method) = path {
688 if method.ident.name == sym::new {
689 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
690 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
691 return std_types_symbols
693 .any(|&symbol| cx.tcx.is_diagnostic_item(symbol, adt.did()));
701 /// Return true if the expr is equal to `Default::default` when evaluated.
702 pub fn is_default_equivalent_call(cx: &LateContext<'_>, repl_func: &Expr<'_>) -> bool {
704 if let hir::ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
705 if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
706 if is_diag_trait_item(cx, repl_def_id, sym::Default)
707 || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
708 then { true } else { false }
712 /// Returns true if the expr is equal to `Default::default()` of it's type when evaluated.
713 /// It doesn't cover all cases, for example indirect function calls (some of std
714 /// functions are supported) but it is the best we have.
715 pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
717 ExprKind::Lit(lit) => match lit.node {
718 LitKind::Bool(false) | LitKind::Int(0, _) => true,
719 LitKind::Str(s, _) => s.is_empty(),
722 ExprKind::Tup(items) | ExprKind::Array(items) => items.iter().all(|x| is_default_equivalent(cx, x)),
723 ExprKind::Repeat(x, ArrayLen::Body(len)) => if_chain! {
724 if let ExprKind::Lit(ref const_lit) = cx.tcx.hir().body(len.body).value.kind;
725 if let LitKind::Int(v, _) = const_lit.node;
726 if v <= 32 && is_default_equivalent(cx, x);
734 ExprKind::Call(repl_func, _) => is_default_equivalent_call(cx, repl_func),
735 ExprKind::Path(qpath) => is_lang_ctor(cx, qpath, OptionNone),
736 ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
741 /// Checks if the top level expression can be moved into a closure as is.
742 /// Currently checks for:
743 /// * Break/Continue outside the given loop HIR ids.
744 /// * Yield/Return statements.
745 /// * Inline assembly.
746 /// * Usages of a field of a local where the type of the local can be partially moved.
748 /// For example, given the following function:
751 /// fn f<'a>(iter: &mut impl Iterator<Item = (usize, &'a mut String)>) {
752 /// for item in iter {
763 /// When called on the expression `item.0` this will return false unless the local `item` is in the
764 /// `ignore_locals` set. The type `(usize, &mut String)` can have the second element moved, so it
765 /// isn't always safe to move into a closure when only a single field is needed.
767 /// When called on the `continue` expression this will return false unless the outer loop expression
768 /// is in the `loop_ids` set.
770 /// Note that this check is not recursive, so passing the `if` expression will always return true
771 /// even though sub-expressions might return false.
772 pub fn can_move_expr_to_closure_no_visit<'tcx>(
773 cx: &LateContext<'tcx>,
774 expr: &'tcx Expr<'_>,
776 ignore_locals: &HirIdSet,
779 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
780 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
781 if loop_ids.contains(&id) =>
786 | ExprKind::Continue(_)
788 | ExprKind::Yield(..)
789 | ExprKind::InlineAsm(_) => false,
790 // Accessing a field of a local value can only be done if the type isn't
796 ExprKind::Path(QPath::Resolved(
799 res: Res::Local(local_id),
806 ) if !ignore_locals.contains(local_id) && can_partially_move_ty(cx, cx.typeck_results().node_type(hir_id)) => {
807 // TODO: check if the local has been partially moved. Assume it has for now.
814 /// How a local is captured by a closure
815 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
816 pub enum CaptureKind {
821 pub fn is_imm_ref(self) -> bool {
822 self == Self::Ref(Mutability::Not)
825 impl std::ops::BitOr for CaptureKind {
827 fn bitor(self, rhs: Self) -> Self::Output {
829 (CaptureKind::Value, _) | (_, CaptureKind::Value) => CaptureKind::Value,
830 (CaptureKind::Ref(Mutability::Mut), CaptureKind::Ref(_))
831 | (CaptureKind::Ref(_), CaptureKind::Ref(Mutability::Mut)) => CaptureKind::Ref(Mutability::Mut),
832 (CaptureKind::Ref(Mutability::Not), CaptureKind::Ref(Mutability::Not)) => CaptureKind::Ref(Mutability::Not),
836 impl std::ops::BitOrAssign for CaptureKind {
837 fn bitor_assign(&mut self, rhs: Self) {
842 /// Given an expression referencing a local, determines how it would be captured in a closure.
843 /// Note as this will walk up to parent expressions until the capture can be determined it should
844 /// only be used while making a closure somewhere a value is consumed. e.g. a block, match arm, or
845 /// function argument (other than a receiver).
846 pub fn capture_local_usage<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> CaptureKind {
847 fn pat_capture_kind(cx: &LateContext<'_>, pat: &Pat<'_>) -> CaptureKind {
848 let mut capture = CaptureKind::Ref(Mutability::Not);
849 pat.each_binding_or_first(&mut |_, id, span, _| match cx
851 .extract_binding_mode(cx.sess(), id, span)
854 BindingMode::BindByValue(_) if !is_copy(cx, cx.typeck_results().node_type(id)) => {
855 capture = CaptureKind::Value;
857 BindingMode::BindByReference(Mutability::Mut) if capture != CaptureKind::Value => {
858 capture = CaptureKind::Ref(Mutability::Mut);
865 debug_assert!(matches!(
867 ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(_), .. }))
870 let mut child_id = e.hir_id;
871 let mut capture = CaptureKind::Value;
872 let mut capture_expr_ty = e;
874 for (parent_id, parent) in cx.tcx.hir().parent_iter(e.hir_id) {
877 kind: Adjust::Deref(_) | Adjust::Borrow(AutoBorrow::Ref(..)),
885 .map_or(&[][..], |x| &**x)
887 if let rustc_ty::RawPtr(TypeAndMut { mutbl: mutability, .. }) | rustc_ty::Ref(_, _, mutability) =
888 *adjust.last().map_or(target, |a| a.target).kind()
890 return CaptureKind::Ref(mutability);
895 Node::Expr(e) => match e.kind {
896 ExprKind::AddrOf(_, mutability, _) => return CaptureKind::Ref(mutability),
897 ExprKind::Index(..) | ExprKind::Unary(UnOp::Deref, _) => capture = CaptureKind::Ref(Mutability::Not),
898 ExprKind::Assign(lhs, ..) | ExprKind::AssignOp(_, lhs, _) if lhs.hir_id == child_id => {
899 return CaptureKind::Ref(Mutability::Mut);
901 ExprKind::Field(..) => {
902 if capture == CaptureKind::Value {
906 ExprKind::Let(let_expr) => {
907 let mutability = match pat_capture_kind(cx, let_expr.pat) {
908 CaptureKind::Value => Mutability::Not,
909 CaptureKind::Ref(m) => m,
911 return CaptureKind::Ref(mutability);
913 ExprKind::Match(_, arms, _) => {
914 let mut mutability = Mutability::Not;
915 for capture in arms.iter().map(|arm| pat_capture_kind(cx, arm.pat)) {
917 CaptureKind::Value => break,
918 CaptureKind::Ref(Mutability::Mut) => mutability = Mutability::Mut,
919 CaptureKind::Ref(Mutability::Not) => (),
922 return CaptureKind::Ref(mutability);
926 Node::Local(l) => match pat_capture_kind(cx, l.pat) {
927 CaptureKind::Value => break,
928 capture @ CaptureKind::Ref(_) => return capture,
933 child_id = parent_id;
936 if capture == CaptureKind::Value && is_copy(cx, cx.typeck_results().expr_ty(capture_expr_ty)) {
937 // Copy types are never automatically captured by value.
938 CaptureKind::Ref(Mutability::Not)
944 /// Checks if the expression can be moved into a closure as is. This will return a list of captures
945 /// if so, otherwise, `None`.
946 pub fn can_move_expr_to_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<HirIdMap<CaptureKind>> {
947 struct V<'cx, 'tcx> {
948 cx: &'cx LateContext<'tcx>,
949 // Stack of potential break targets contained in the expression.
951 /// Local variables created in the expression. These don't need to be captured.
953 /// Whether this expression can be turned into a closure.
955 /// Locals which need to be captured, and whether they need to be by value, reference, or
956 /// mutable reference.
957 captures: HirIdMap<CaptureKind>,
959 impl<'tcx> Visitor<'tcx> for V<'_, 'tcx> {
960 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
961 if !self.allow_closure {
966 ExprKind::Path(QPath::Resolved(None, &Path { res: Res::Local(l), .. })) => {
967 if !self.locals.contains(&l) {
968 let cap = capture_local_usage(self.cx, e);
969 self.captures.entry(l).and_modify(|e| *e |= cap).or_insert(cap);
972 ExprKind::Closure { .. } => {
973 let closure_id = self.cx.tcx.hir().local_def_id(e.hir_id);
974 for capture in self.cx.typeck_results().closure_min_captures_flattened(closure_id) {
975 let local_id = match capture.place.base {
976 PlaceBase::Local(id) => id,
977 PlaceBase::Upvar(var) => var.var_path.hir_id,
980 if !self.locals.contains(&local_id) {
981 let capture = match capture.info.capture_kind {
982 UpvarCapture::ByValue => CaptureKind::Value,
983 UpvarCapture::ByRef(kind) => match kind {
984 BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
985 BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
986 CaptureKind::Ref(Mutability::Mut)
992 .and_modify(|e| *e |= capture)
997 ExprKind::Loop(b, ..) => {
998 self.loops.push(e.hir_id);
1003 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops, &self.locals);
1009 fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) {
1010 p.each_binding_or_first(&mut |_, id, _, _| {
1011 self.locals.insert(id);
1018 allow_closure: true,
1020 locals: HirIdSet::default(),
1021 captures: HirIdMap::default(),
1024 v.allow_closure.then_some(v.captures)
1027 /// Returns the method names and argument list of nested method call expressions that make up
1028 /// `expr`. method/span lists are sorted with the most recent call first.
1029 pub fn method_calls<'tcx>(
1030 expr: &'tcx Expr<'tcx>,
1032 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
1033 let mut method_names = Vec::with_capacity(max_depth);
1034 let mut arg_lists = Vec::with_capacity(max_depth);
1035 let mut spans = Vec::with_capacity(max_depth);
1037 let mut current = expr;
1038 for _ in 0..max_depth {
1039 if let ExprKind::MethodCall(path, args, _) = ¤t.kind {
1040 if args.iter().any(|e| e.span.from_expansion()) {
1043 method_names.push(path.ident.name);
1044 arg_lists.push(&**args);
1045 spans.push(path.ident.span);
1052 (method_names, arg_lists, spans)
1055 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
1057 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
1058 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
1059 /// containing the `Expr`s for
1060 /// `.bar()` and `.baz()`
1061 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
1062 let mut current = expr;
1063 let mut matched = Vec::with_capacity(methods.len());
1064 for method_name in methods.iter().rev() {
1065 // method chains are stored last -> first
1066 if let ExprKind::MethodCall(path, args, _) = current.kind {
1067 if path.ident.name.as_str() == *method_name {
1068 if args.iter().any(|e| e.span.from_expansion()) {
1071 matched.push(args); // build up `matched` backwards
1072 current = &args[0]; // go to parent expression
1080 // Reverse `matched` so that it is in the same order as `methods`.
1085 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
1086 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
1089 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
1092 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
1093 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1094 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
1095 Some(parent.to_def_id()) == cx.tcx.lang_items().panic_impl()
1098 /// Gets the name of the item the expression is in, if available.
1099 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
1100 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
1101 match cx.tcx.hir().find_by_def_id(parent_id) {
1103 Node::Item(Item { ident, .. })
1104 | Node::TraitItem(TraitItem { ident, .. })
1105 | Node::ImplItem(ImplItem { ident, .. }),
1106 ) => Some(ident.name),
1111 pub struct ContainsName {
1116 impl<'tcx> Visitor<'tcx> for ContainsName {
1117 fn visit_name(&mut self, _: Span, name: Symbol) {
1118 if self.name == name {
1124 /// Checks if an `Expr` contains a certain name.
1125 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
1126 let mut cn = ContainsName { name, result: false };
1127 cn.visit_expr(expr);
1131 /// Returns `true` if `expr` contains a return expression
1132 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
1133 let mut found = false;
1134 expr_visitor_no_bodies(|expr| {
1136 if let hir::ExprKind::Ret(..) = &expr.kind {
1146 /// Extends the span to the beginning of the spans line, incl. whitespaces.
1151 /// // will be converted to
1153 /// // ^^^^^^^^^^^^^^
1155 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
1156 let span = original_sp(span, DUMMY_SP);
1157 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
1158 let line_no = source_map_and_line.line;
1159 let line_start = source_map_and_line.sf.lines(|lines| lines[line_no]);
1160 span.with_lo(line_start)
1163 /// Gets the parent node, if any.
1164 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
1165 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
1168 /// Gets the parent expression, if any –- this is useful to constrain a lint.
1169 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1170 get_parent_expr_for_hir(cx, e.hir_id)
1173 /// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
1174 /// constraint lints
1175 pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
1176 match get_parent_node(cx.tcx, hir_id) {
1177 Some(Node::Expr(parent)) => Some(parent),
1182 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
1183 let map = &cx.tcx.hir();
1184 let enclosing_node = map
1185 .get_enclosing_scope(hir_id)
1186 .and_then(|enclosing_id| map.find(enclosing_id));
1187 enclosing_node.and_then(|node| match node {
1188 Node::Block(block) => Some(block),
1190 kind: ItemKind::Fn(_, _, eid),
1193 | Node::ImplItem(&ImplItem {
1194 kind: ImplItemKind::Fn(_, eid),
1196 }) => match cx.tcx.hir().body(eid).value.kind {
1197 ExprKind::Block(block, _) => Some(block),
1204 /// Gets the loop or closure enclosing the given expression, if any.
1205 pub fn get_enclosing_loop_or_multi_call_closure<'tcx>(
1206 cx: &LateContext<'tcx>,
1208 ) -> Option<&'tcx Expr<'tcx>> {
1209 for (_, node) in cx.tcx.hir().parent_iter(expr.hir_id) {
1211 Node::Expr(e) => match e.kind {
1212 ExprKind::Closure { .. } => {
1213 if let rustc_ty::Closure(_, subs) = cx.typeck_results().expr_ty(e).kind()
1214 && subs.as_closure().kind() == ClosureKind::FnOnce
1218 let is_once = walk_to_expr_usage(cx, e, |node, id| {
1219 let Node::Expr(e) = node else {
1223 ExprKind::Call(f, _) if f.hir_id == id => Some(()),
1224 ExprKind::Call(f, args) => {
1225 let i = args.iter().position(|arg| arg.hir_id == id)?;
1226 let sig = expr_sig(cx, f)?;
1227 let predicates = sig
1229 .map_or(cx.param_env, |id| cx.tcx.param_env(id))
1231 sig.input(i).and_then(|ty| {
1232 ty_is_fn_once_param(cx.tcx, ty.skip_binder(), predicates).then_some(())
1235 ExprKind::MethodCall(_, args, _) => {
1236 let i = args.iter().position(|arg| arg.hir_id == id)?;
1237 let id = cx.typeck_results().type_dependent_def_id(e.hir_id)?;
1238 let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i];
1239 ty_is_fn_once_param(cx.tcx, ty, cx.tcx.param_env(id).caller_bounds()).then_some(())
1249 ExprKind::Loop(..) => return Some(e),
1252 Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
1259 /// Gets the parent node if it's an impl block.
1260 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
1261 match tcx.hir().parent_iter(id).next() {
1265 kind: ItemKind::Impl(imp),
1273 /// Removes blocks around an expression, only if the block contains just one expression
1274 /// and no statements. Unsafe blocks are not removed.
1278 /// * `{ x }` -> `x`
1279 /// * `{{ x }}` -> `x`
1280 /// * `{ x; }` -> `{ x; }`
1281 /// * `{ x; y }` -> `{ x; y }`
1282 /// * `{ unsafe { x } }` -> `unsafe { x }`
1283 pub fn peel_blocks<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1284 while let ExprKind::Block(
1288 rules: BlockCheckMode::DefaultBlock,
1299 /// Removes blocks around an expression, only if the block contains just one expression
1300 /// or just one expression statement with a semicolon. Unsafe blocks are not removed.
1304 /// * `{ x }` -> `x`
1305 /// * `{ x; }` -> `x`
1306 /// * `{{ x; }}` -> `x`
1307 /// * `{ x; y }` -> `{ x; y }`
1308 /// * `{ unsafe { x } }` -> `unsafe { x }`
1309 pub fn peel_blocks_with_stmt<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1310 while let ExprKind::Block(
1314 rules: BlockCheckMode::DefaultBlock,
1321 kind: StmtKind::Expr(inner) | StmtKind::Semi(inner),
1326 rules: BlockCheckMode::DefaultBlock,
1337 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
1338 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1339 let mut iter = tcx.hir().parent_iter(expr.hir_id);
1344 kind: ExprKind::If(_, _, Some(else_expr)),
1347 )) => else_expr.hir_id == expr.hir_id,
1352 /// Checks whether the given expression is a constant integer of the given value.
1353 /// unlike `is_integer_literal`, this version does const folding
1354 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
1355 if is_integer_literal(e, value) {
1358 let enclosing_body = cx.tcx.hir().enclosing_body_owner(e.hir_id);
1359 if let Some((Constant::Int(v), _)) = constant(cx, cx.tcx.typeck(enclosing_body), e) {
1365 /// Checks whether the given expression is a constant literal of the given value.
1366 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
1367 // FIXME: use constant folding
1368 if let ExprKind::Lit(ref spanned) = expr.kind {
1369 if let LitKind::Int(v, _) = spanned.node {
1376 /// Returns `true` if the given `Expr` has been coerced before.
1378 /// Examples of coercions can be found in the Nomicon at
1379 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
1381 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
1382 /// information on adjustments and coercions.
1383 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1384 cx.typeck_results().adjustments().get(e.hir_id).is_some()
1387 /// Returns the pre-expansion span if this comes from an expansion of the
1389 /// See also [`is_direct_expn_of`].
1391 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
1393 if span.from_expansion() {
1394 let data = span.ctxt().outer_expn_data();
1395 let new_span = data.call_site;
1397 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1398 if mac_name.as_str() == name {
1399 return Some(new_span);
1410 /// Returns the pre-expansion span if the span directly comes from an expansion
1411 /// of the macro `name`.
1412 /// The difference with [`is_expn_of`] is that in
1414 /// # macro_rules! foo { ($name:tt!$args:tt) => { $name!$args } }
1415 /// # macro_rules! bar { ($e:expr) => { $e } }
1418 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1419 /// from `bar!` by `is_direct_expn_of`.
1421 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1422 if span.from_expansion() {
1423 let data = span.ctxt().outer_expn_data();
1424 let new_span = data.call_site;
1426 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1427 if mac_name.as_str() == name {
1428 return Some(new_span);
1436 /// Convenience function to get the return type of a function.
1437 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1438 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1439 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1440 cx.tcx.erase_late_bound_regions(ret_ty)
1443 /// Convenience function to get the nth argument type of a function.
1444 pub fn nth_arg<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId, nth: usize) -> Ty<'tcx> {
1445 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1446 let arg = cx.tcx.fn_sig(fn_def_id).input(nth);
1447 cx.tcx.erase_late_bound_regions(arg)
1450 /// Checks if an expression is constructing a tuple-like enum variant or struct
1451 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1452 if let ExprKind::Call(fun, _) = expr.kind {
1453 if let ExprKind::Path(ref qp) = fun.kind {
1454 let res = cx.qpath_res(qp, fun.hir_id);
1456 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1457 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1465 /// Returns `true` if a pattern is refutable.
1466 // TODO: should be implemented using rustc/mir_build/thir machinery
1467 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1468 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1470 cx.qpath_res(qpath, id),
1471 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1475 fn are_refutable<'a, I: IntoIterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, i: I) -> bool {
1476 i.into_iter().any(|pat| is_refutable(cx, pat))
1480 PatKind::Wild => false,
1481 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1482 PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
1483 PatKind::Lit(..) | PatKind::Range(..) => true,
1484 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1485 PatKind::Or(pats) => {
1486 // TODO: should be the honest check, that pats is exhaustive set
1487 are_refutable(cx, pats)
1489 PatKind::Tuple(pats, _) => are_refutable(cx, pats),
1490 PatKind::Struct(ref qpath, fields, _) => {
1491 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| field.pat))
1493 PatKind::TupleStruct(ref qpath, pats, _) => is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats),
1494 PatKind::Slice(head, middle, tail) => {
1495 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1496 rustc_ty::Slice(..) => {
1497 // [..] is the only irrefutable slice pattern.
1498 !head.is_empty() || middle.is_none() || !tail.is_empty()
1500 rustc_ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter())),
1510 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1511 /// the function once on the given pattern.
1512 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1513 if let PatKind::Or(pats) = pat.kind {
1514 pats.iter().for_each(f);
1520 pub fn is_self(slf: &Param<'_>) -> bool {
1521 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1522 name.name == kw::SelfLower
1528 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1529 if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind {
1530 if let Res::SelfTy { .. } = path.res {
1537 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1538 (0..decl.inputs.len()).map(move |i| &body.params[i])
1541 /// Checks if a given expression is a match expression expanded from the `?`
1542 /// operator or the `try` macro.
1543 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1544 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1546 if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
1547 if is_lang_ctor(cx, path, ResultOk);
1548 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1549 if path_to_local_id(arm.body, hir_id);
1557 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1558 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1559 is_lang_ctor(cx, path, ResultErr)
1565 if let ExprKind::Match(_, arms, ref source) = expr.kind {
1566 // desugared from a `?` operator
1567 if *source == MatchSource::TryDesugar {
1573 if arms[0].guard.is_none();
1574 if arms[1].guard.is_none();
1575 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) || (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1585 /// Returns `true` if the lint is allowed in the current context. This is useful for
1586 /// skipping long running code when it's unnecessary
1588 /// This function should check the lint level for the same node, that the lint will
1589 /// be emitted at. If the information is buffered to be emitted at a later point, please
1590 /// make sure to use `span_lint_hir` functions to emit the lint. This ensures that
1591 /// expectations at the checked nodes will be fulfilled.
1592 pub fn is_lint_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1593 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1596 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1597 while let PatKind::Ref(subpat, _) = pat.kind {
1603 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1604 Integer::from_int_ty(&tcx, ity).size().bits()
1607 #[expect(clippy::cast_possible_wrap)]
1608 /// Turn a constant int byte representation into an i128
1609 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1610 let amt = 128 - int_bits(tcx, ity);
1611 ((u as i128) << amt) >> amt
1614 #[expect(clippy::cast_sign_loss)]
1615 /// clip unused bytes
1616 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1617 let amt = 128 - int_bits(tcx, ity);
1618 ((u as u128) << amt) >> amt
1621 /// clip unused bytes
1622 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1623 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1624 let amt = 128 - bits;
1628 pub fn has_attr(attrs: &[ast::Attribute], symbol: Symbol) -> bool {
1629 attrs.iter().any(|attr| attr.has_name(symbol))
1632 pub fn any_parent_has_attr(tcx: TyCtxt<'_>, node: HirId, symbol: Symbol) -> bool {
1633 let map = &tcx.hir();
1634 let mut prev_enclosing_node = None;
1635 let mut enclosing_node = node;
1636 while Some(enclosing_node) != prev_enclosing_node {
1637 if has_attr(map.attrs(enclosing_node), symbol) {
1640 prev_enclosing_node = Some(enclosing_node);
1641 enclosing_node = map.local_def_id_to_hir_id(map.get_parent_item(enclosing_node));
1647 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1648 any_parent_has_attr(tcx, node, sym::automatically_derived)
1651 /// Matches a function call with the given path and returns the arguments.
1656 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1658 pub fn match_function_call<'tcx>(
1659 cx: &LateContext<'tcx>,
1660 expr: &'tcx Expr<'_>,
1662 ) -> Option<&'tcx [Expr<'tcx>]> {
1664 if let ExprKind::Call(fun, args) = expr.kind;
1665 if let ExprKind::Path(ref qpath) = fun.kind;
1666 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1667 if match_def_path(cx, fun_def_id, path);
1675 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1678 /// Please use `tcx.get_diagnostic_name` if the targets are all diagnostic items.
1679 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1680 let search_path = cx.get_def_path(did);
1683 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1686 /// Checks if the given `DefId` matches the path.
1687 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1688 // We should probably move to Symbols in Clippy as well rather than interning every time.
1689 let path = cx.get_def_path(did);
1690 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1693 /// Checks if the given `DefId` matches the `libc` item.
1694 pub fn match_libc_symbol(cx: &LateContext<'_>, did: DefId, name: &str) -> bool {
1695 let path = cx.get_def_path(did);
1696 // libc is meant to be used as a flat list of names, but they're all actually defined in different
1697 // modules based on the target platform. Ignore everything but crate name and the item name.
1698 path.first().map_or(false, |s| s.as_str() == "libc") && path.last().map_or(false, |s| s.as_str() == name)
1701 /// Returns the list of condition expressions and the list of blocks in a
1702 /// sequence of `if/else`.
1703 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1704 /// `if a { c } else if b { d } else { e }`.
1705 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1706 let mut conds = Vec::new();
1707 let mut blocks: Vec<&Block<'_>> = Vec::new();
1709 while let Some(higher::IfOrIfLet { cond, then, r#else }) = higher::IfOrIfLet::hir(expr) {
1711 if let ExprKind::Block(block, _) = then.kind {
1714 panic!("ExprKind::If node is not an ExprKind::Block");
1717 if let Some(else_expr) = r#else {
1724 // final `else {..}`
1725 if !blocks.is_empty() {
1726 if let ExprKind::Block(block, _) = expr.kind {
1734 /// Checks if the given function kind is an async function.
1735 pub fn is_async_fn(kind: FnKind<'_>) -> bool {
1736 matches!(kind, FnKind::ItemFn(_, _, header) if header.asyncness == IsAsync::Async)
1739 /// Peels away all the compiler generated code surrounding the body of an async function,
1740 pub fn get_async_fn_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
1741 if let ExprKind::Call(
1745 kind: ExprKind::Closure(&Closure { body, .. }),
1751 if let ExprKind::Block(
1756 kind: ExprKind::DropTemps(expr),
1762 ) = tcx.hir().body(body).value.kind
1770 // check if expr is calling method or function with #[must_use] attribute
1771 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1772 let did = match expr.kind {
1773 ExprKind::Call(path, _) => if_chain! {
1774 if let ExprKind::Path(ref qpath) = path.kind;
1775 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1782 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1786 did.map_or(false, |did| cx.tcx.has_attr(did, sym::must_use))
1789 /// Checks if an expression represents the identity function
1790 /// Only examines closures and `std::convert::identity`
1791 pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1792 /// Checks if a function's body represents the identity function. Looks for bodies of the form:
1794 /// * `|x| return x`
1795 /// * `|x| { return x }`
1796 /// * `|x| { return x; }`
1797 fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
1798 let id = if_chain! {
1799 if let [param] = func.params;
1800 if let PatKind::Binding(_, id, _, _) = param.pat.kind;
1808 let mut expr = &func.value;
1812 ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
1813 | ExprKind::Ret(Some(e)) => expr = e,
1815 ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
1817 if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
1818 if let ExprKind::Ret(Some(ret_val)) = e.kind;
1826 _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
1832 ExprKind::Closure(&Closure { body, .. }) => is_body_identity_function(cx, cx.tcx.hir().body(body)),
1833 _ => path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, &paths::CONVERT_IDENTITY)),
1837 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1838 /// Returns both the node and the `HirId` of the closest child node.
1839 pub fn get_expr_use_or_unification_node<'tcx>(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<(Node<'tcx>, HirId)> {
1840 let mut child_id = expr.hir_id;
1841 let mut iter = tcx.hir().parent_iter(child_id);
1845 Some((id, Node::Block(_))) => child_id = id,
1846 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1847 Some((_, Node::Expr(expr))) => match expr.kind {
1848 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1849 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1850 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1851 _ => break Some((Node::Expr(expr), child_id)),
1853 Some((_, node)) => break Some((node, child_id)),
1858 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1859 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1861 get_expr_use_or_unification_node(tcx, expr),
1864 kind: StmtKind::Expr(_)
1866 | StmtKind::Local(Local {
1868 kind: PatKind::Wild,
1880 /// Checks if the expression is the final expression returned from a block.
1881 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1882 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1885 pub fn std_or_core(cx: &LateContext<'_>) -> Option<&'static str> {
1886 if !is_no_std_crate(cx) {
1888 } else if !is_no_core_crate(cx) {
1895 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1896 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1897 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1898 attr.path == sym::no_std
1905 pub fn is_no_core_crate(cx: &LateContext<'_>) -> bool {
1906 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1907 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1908 attr.path == sym::no_core
1915 /// Check if parent of a hir node is a trait implementation block.
1916 /// For example, `f` in
1919 /// # trait Trait { fn f(); }
1920 /// impl Trait for S {
1924 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1925 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1926 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1932 /// Check if it's even possible to satisfy the `where` clause for the item.
1934 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1937 /// fn foo() where i32: Iterator {
1938 /// for _ in 2i32 {}
1941 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1942 use rustc_trait_selection::traits;
1948 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1949 traits::impossible_predicates(
1951 traits::elaborate_predicates(cx.tcx, predicates)
1952 .map(|o| o.predicate)
1953 .collect::<Vec<_>>(),
1957 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1958 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1960 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1963 kind: ExprKind::Path(qpath),
1964 hir_id: path_hir_id,
1969 // Only return Fn-like DefIds, not the DefIds of statics/consts/etc that contain or
1970 // deref to fn pointers, dyn Fn, impl Fn - #8850
1971 if let Res::Def(DefKind::Fn | DefKind::Ctor(..) | DefKind::AssocFn, id) =
1972 cx.typeck_results().qpath_res(qpath, *path_hir_id)
1983 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1984 /// slice iff the given expression is a slice of primitives (as defined in the
1985 /// `is_recursively_primitive_type` function) and None otherwise.
1986 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1987 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1988 let expr_kind = expr_type.kind();
1989 let is_primitive = match expr_kind {
1990 rustc_ty::Slice(element_type) => is_recursively_primitive_type(*element_type),
1991 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1992 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1993 is_recursively_primitive_type(*element_type)
2002 // if we have wrappers like Array, Slice or Tuple, print these
2003 // and get the type enclosed in the slice ref
2004 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
2005 rustc_ty::Slice(..) => return Some("slice".into()),
2006 rustc_ty::Array(..) => return Some("array".into()),
2007 rustc_ty::Tuple(..) => return Some("tuple".into()),
2009 // is_recursively_primitive_type() should have taken care
2010 // of the rest and we can rely on the type that is found
2011 let refs_peeled = expr_type.peel_refs();
2012 return Some(refs_peeled.walk().last().unwrap().to_string());
2019 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
2020 /// `hash` must be comformed with `eq`
2021 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
2023 Hash: Fn(&T) -> u64,
2024 Eq: Fn(&T, &T) -> bool,
2027 [a, b] if eq(a, b) => return vec![(a, b)],
2028 _ if exprs.len() <= 2 => return vec![],
2032 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
2034 let mut map: UnhashMap<u64, Vec<&_>> =
2035 UnhashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
2038 match map.entry(hash(expr)) {
2039 Entry::Occupied(mut o) => {
2042 match_expr_list.push((o, expr));
2045 o.get_mut().push(expr);
2047 Entry::Vacant(v) => {
2048 v.insert(vec![expr]);
2056 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
2057 /// references removed.
2058 pub fn peel_hir_pat_refs<'a>(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
2059 fn peel<'a>(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
2060 if let PatKind::Ref(pat, _) = pat.kind {
2061 peel(pat, count + 1)
2069 /// Peels of expressions while the given closure returns `Some`.
2070 pub fn peel_hir_expr_while<'tcx>(
2071 mut expr: &'tcx Expr<'tcx>,
2072 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
2073 ) -> &'tcx Expr<'tcx> {
2074 while let Some(e) = f(expr) {
2080 /// Peels off up to the given number of references on the expression. Returns the underlying
2081 /// expression and the number of references removed.
2082 pub fn peel_n_hir_expr_refs<'a>(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
2083 let mut remaining = count;
2084 let e = peel_hir_expr_while(expr, |e| match e.kind {
2085 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) if remaining != 0 => {
2091 (e, count - remaining)
2094 /// Peels off all references on the expression. Returns the underlying expression and the number of
2095 /// references removed.
2096 pub fn peel_hir_expr_refs<'a>(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
2098 let e = peel_hir_expr_while(expr, |e| match e.kind {
2099 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) => {
2108 /// Peels off all references on the type. Returns the underlying type and the number of references
2110 pub fn peel_hir_ty_refs<'a>(mut ty: &'a hir::Ty<'a>) -> (&'a hir::Ty<'a>, usize) {
2114 TyKind::Rptr(_, ref_ty) => {
2118 _ => break (ty, count),
2123 /// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
2124 /// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
2125 pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
2128 ExprKind::AddrOf(_, _, e) => expr = e,
2129 ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
2136 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
2137 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2138 if let Res::Def(_, def_id) = path.res {
2139 return cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr);
2145 static TEST_ITEM_NAMES_CACHE: OnceLock<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = OnceLock::new();
2147 fn with_test_item_names(tcx: TyCtxt<'_>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
2148 let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
2149 let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
2150 let value = map.entry(module);
2152 Entry::Occupied(entry) => f(entry.get()),
2153 Entry::Vacant(entry) => {
2154 let mut names = Vec::new();
2155 for id in tcx.hir().module_items(module) {
2156 if matches!(tcx.def_kind(id.def_id), DefKind::Const)
2157 && let item = tcx.hir().item(id)
2158 && let ItemKind::Const(ty, _body) = item.kind {
2159 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2160 // We could also check for the type name `test::TestDescAndFn`
2161 if let Res::Def(DefKind::Struct, _) = path.res {
2162 let has_test_marker = tcx
2164 .attrs(item.hir_id())
2166 .any(|a| a.has_name(sym::rustc_test_marker));
2167 if has_test_marker {
2168 names.push(item.ident.name);
2174 names.sort_unstable();
2175 f(entry.insert(names))
2180 /// Checks if the function containing the given `HirId` is a `#[test]` function
2182 /// Note: Add `// compile-flags: --test` to UI tests with a `#[test]` function
2183 pub fn is_in_test_function(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2184 with_test_item_names(tcx, tcx.parent_module(id), |names| {
2187 // Since you can nest functions we need to collect all until we leave
2189 .any(|(_id, node)| {
2190 if let Node::Item(item) = node {
2191 if let ItemKind::Fn(_, _, _) = item.kind {
2192 // Note that we have sorted the item names in the visitor,
2193 // so the binary_search gets the same as `contains`, but faster.
2194 return names.binary_search(&item.ident.name).is_ok();
2202 /// Checks if the item containing the given `HirId` has `#[cfg(test)]` attribute applied
2204 /// Note: Add `// compile-flags: --test` to UI tests with a `#[cfg(test)]` function
2205 pub fn is_in_cfg_test(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2206 fn is_cfg_test(attr: &Attribute) -> bool {
2207 if attr.has_name(sym::cfg)
2208 && let Some(items) = attr.meta_item_list()
2209 && let [item] = &*items
2210 && item.has_name(sym::test)
2219 .flat_map(|(parent_id, _)| tcx.hir().attrs(parent_id))
2223 /// Checks whether item either has `test` attribute applied, or
2224 /// is a module with `test` in its name.
2226 /// Note: Add `// compile-flags: --test` to UI tests with a `#[test]` function
2227 pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
2228 is_in_test_function(tcx, item.hir_id())
2229 || matches!(item.kind, ItemKind::Mod(..))
2230 && item.ident.name.as_str().split('_').any(|a| a == "test" || a == "tests")
2233 /// Walks the HIR tree from the given expression, up to the node where the value produced by the
2234 /// expression is consumed. Calls the function for every node encountered this way until it returns
2237 /// This allows walking through `if`, `match`, `break`, block expressions to find where the value
2238 /// produced by the expression is consumed.
2239 pub fn walk_to_expr_usage<'tcx, T>(
2240 cx: &LateContext<'tcx>,
2242 mut f: impl FnMut(Node<'tcx>, HirId) -> Option<T>,
2244 let map = cx.tcx.hir();
2245 let mut iter = map.parent_iter(e.hir_id);
2246 let mut child_id = e.hir_id;
2248 while let Some((parent_id, parent)) = iter.next() {
2249 if let Some(x) = f(parent, child_id) {
2252 let parent = match parent {
2254 Node::Block(Block { expr: Some(body), .. }) | Node::Arm(Arm { body, .. }) if body.hir_id == child_id => {
2255 child_id = parent_id;
2258 Node::Arm(a) if a.body.hir_id == child_id => {
2259 child_id = parent_id;
2265 ExprKind::If(child, ..) | ExprKind::Match(child, ..) if child.hir_id != child_id => child_id = parent_id,
2266 ExprKind::Break(Destination { target_id: Ok(id), .. }, _) => {
2268 iter = map.parent_iter(id);
2270 ExprKind::Block(..) => child_id = parent_id,
2277 macro_rules! op_utils {
2278 ($($name:ident $assign:ident)*) => {
2279 /// Binary operation traits like `LangItem::Add`
2280 pub static BINOP_TRAITS: &[LangItem] = &[$(LangItem::$name,)*];
2282 /// Operator-Assign traits like `LangItem::AddAssign`
2283 pub static OP_ASSIGN_TRAITS: &[LangItem] = &[$(LangItem::$assign,)*];
2285 /// Converts `BinOpKind::Add` to `(LangItem::Add, LangItem::AddAssign)`, for example
2286 pub fn binop_traits(kind: hir::BinOpKind) -> Option<(LangItem, LangItem)> {
2288 $(hir::BinOpKind::$name => Some((LangItem::$name, LangItem::$assign)),)*