1 #![feature(array_chunks)]
2 #![feature(box_patterns)]
3 #![feature(control_flow_enum)]
4 #![feature(let_chains)]
5 #![feature(lint_reasons)]
7 #![feature(rustc_private)]
8 #![recursion_limit = "512"]
9 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
10 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
11 // warn on the same lints as `clippy_lints`
12 #![warn(trivial_casts, trivial_numeric_casts)]
13 // warn on lints, that are included in `rust-lang/rust`s bootstrap
14 #![warn(rust_2018_idioms, unused_lifetimes)]
15 // warn on rustc internal lints
16 #![warn(rustc::internal)]
18 // FIXME: switch to something more ergonomic here, once available.
19 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
20 extern crate rustc_ast;
21 extern crate rustc_ast_pretty;
22 extern crate rustc_attr;
23 extern crate rustc_data_structures;
24 extern crate rustc_errors;
25 extern crate rustc_hir;
26 extern crate rustc_infer;
27 extern crate rustc_lexer;
28 extern crate rustc_lint;
29 extern crate rustc_middle;
30 extern crate rustc_parse_format;
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_hir_analysis;
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};
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_lexer::{tokenize, TokenKind};
91 use rustc_lint::{LateContext, Level, Lint, LintContext};
92 use rustc_middle::hir::place::PlaceBase;
93 use rustc_middle::ty as rustc_ty;
94 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
95 use rustc_middle::ty::binding::BindingMode;
96 use rustc_middle::ty::fast_reject::SimplifiedTypeGen::{
97 ArraySimplifiedType, BoolSimplifiedType, CharSimplifiedType, FloatSimplifiedType, IntSimplifiedType,
98 PtrSimplifiedType, SliceSimplifiedType, StrSimplifiedType, UintSimplifiedType,
100 use rustc_middle::ty::{
101 layout::IntegerExt, BorrowKind, ClosureKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeVisitable, UpvarCapture,
103 use rustc_middle::ty::{FloatTy, IntTy, UintTy};
104 use rustc_semver::RustcVersion;
105 use rustc_session::Session;
106 use rustc_span::hygiene::{ExpnKind, MacroKind};
107 use rustc_span::source_map::original_sp;
108 use rustc_span::source_map::SourceMap;
110 use rustc_span::symbol::{kw, Symbol};
111 use rustc_span::{Span, DUMMY_SP};
112 use rustc_target::abi::Integer;
114 use crate::consts::{constant, Constant};
115 use crate::ty::{can_partially_move_ty, expr_sig, is_copy, is_recursively_primitive_type, ty_is_fn_once_param};
116 use crate::visitors::expr_visitor_no_bodies;
118 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
119 if let Ok(version) = RustcVersion::parse(msrv) {
120 return Some(version);
121 } else if let Some(sess) = sess {
122 if let Some(span) = span {
123 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
129 pub fn meets_msrv(msrv: Option<RustcVersion>, lint_msrv: RustcVersion) -> bool {
130 msrv.map_or(true, |msrv| msrv.meets(lint_msrv))
134 macro_rules! extract_msrv_attr {
135 ($context:ident) => {
136 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'_>, attrs: &[rustc_ast::ast::Attribute]) {
137 let sess = rustc_lint::LintContext::sess(cx);
138 match $crate::get_unique_inner_attr(sess, attrs, "msrv") {
140 if let Some(msrv) = msrv_attr.value_str() {
141 self.msrv = $crate::parse_msrv(&msrv.to_string(), Some(sess), Some(msrv_attr.span));
143 sess.span_err(msrv_attr.span, "bad clippy attribute");
152 /// If the given expression is a local binding, find the initializer expression.
153 /// If that initializer expression is another local binding, find its initializer again.
154 /// This process repeats as long as possible (but usually no more than once). Initializer
155 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
168 /// let def = abc + 2;
169 /// // ^^^^^^^ output
173 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
174 while let Some(init) = path_to_local(expr)
175 .and_then(|id| find_binding_init(cx, id))
176 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
183 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
184 /// By only considering immutable bindings, we guarantee that the returned expression represents the
185 /// value of the binding wherever it is referenced.
187 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
188 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
189 /// canonical binding `HirId`.
190 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
191 let hir = cx.tcx.hir();
193 if let Some(Node::Pat(pat)) = hir.find(hir_id);
194 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::NONE, ..));
195 let parent = hir.get_parent_node(hir_id);
196 if let Some(Node::Local(local)) = hir.find(parent);
204 /// Returns `true` if the given `NodeId` is inside a constant context
209 /// if in_constant(cx, expr.hir_id) {
213 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
214 let parent_id = cx.tcx.hir().get_parent_item(id).def_id;
215 match cx.tcx.hir().get_by_def_id(parent_id) {
217 kind: ItemKind::Const(..) | ItemKind::Static(..),
220 | Node::TraitItem(&TraitItem {
221 kind: TraitItemKind::Const(..),
224 | Node::ImplItem(&ImplItem {
225 kind: ImplItemKind::Const(..),
228 | Node::AnonConst(_) => true,
230 kind: ItemKind::Fn(ref sig, ..),
233 | Node::ImplItem(&ImplItem {
234 kind: ImplItemKind::Fn(ref sig, _),
236 }) => sig.header.constness == Constness::Const,
241 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
242 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
243 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
244 if let QPath::Resolved(_, path) = qpath {
245 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
246 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
247 return cx.tcx.parent(ctor_id) == item_id;
254 pub fn is_unit_expr(expr: &Expr<'_>) -> bool {
264 ) | ExprKind::Tup([])
268 /// Checks if given pattern is a wildcard (`_`)
269 pub fn is_wild(pat: &Pat<'_>) -> bool {
270 matches!(pat.kind, PatKind::Wild)
273 /// Checks if the method call given in `expr` belongs to the given trait.
274 /// This is a deprecated function, consider using [`is_trait_method`].
275 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
276 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
277 let trt_id = cx.tcx.trait_of_item(def_id);
278 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
281 /// Checks if a method is defined in an impl of a diagnostic item
282 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
283 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
284 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
285 return cx.tcx.is_diagnostic_item(diag_item, adt.did());
291 /// Checks if a method is in a diagnostic item trait
292 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
293 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
294 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
299 /// Checks if the method call given in `expr` belongs to the given trait.
300 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
302 .type_dependent_def_id(expr.hir_id)
303 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
306 /// Checks if the given expression is a path referring an item on the trait
307 /// that is marked with the given diagnostic item.
309 /// For checking method call expressions instead of path expressions, use
310 /// [`is_trait_method`].
312 /// For example, this can be used to find if an expression like `u64::default`
313 /// refers to an item of the trait `Default`, which is associated with the
314 /// `diag_item` of `sym::Default`.
315 pub fn is_trait_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
316 if let hir::ExprKind::Path(ref qpath) = expr.kind {
317 cx.qpath_res(qpath, expr.hir_id)
319 .map_or(false, |def_id| is_diag_trait_item(cx, def_id, diag_item))
325 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
327 QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
328 QPath::TypeRelative(_, seg) => seg,
329 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
333 pub fn qpath_generic_tys<'tcx>(qpath: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
334 last_path_segment(qpath)
336 .map_or(&[][..], |a| a.args)
338 .filter_map(|a| match a {
339 hir::GenericArg::Type(ty) => Some(*ty),
344 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
345 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
346 /// `QPath::Resolved.1.res.opt_def_id()`.
348 /// Matches a `QPath` against a slice of segment string literals.
350 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
351 /// `rustc_hir::QPath`.
355 /// match_qpath(path, &["std", "rt", "begin_unwind"])
357 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
359 QPath::Resolved(_, path) => match_path(path, segments),
360 QPath::TypeRelative(ty, segment) => match ty.kind {
361 TyKind::Path(ref inner_path) => {
362 if let [prefix @ .., end] = segments {
363 if match_qpath(inner_path, prefix) {
364 return segment.ident.name.as_str() == *end;
371 QPath::LangItem(..) => false,
375 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
377 /// Please use `is_path_diagnostic_item` if the target is a diagnostic item.
378 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
379 path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, segments))
382 /// If `maybe_path` is a path node which resolves to an item, resolves it to a `DefId` and checks if
383 /// it matches the given diagnostic item.
384 pub fn is_path_diagnostic_item<'tcx>(
385 cx: &LateContext<'_>,
386 maybe_path: &impl MaybePath<'tcx>,
389 path_def_id(cx, maybe_path).map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
392 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
393 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
394 /// `QPath::Resolved.1.res.opt_def_id()`.
396 /// Matches a `Path` against a slice of segment string literals.
398 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
399 /// `rustc_hir::Path`.
404 /// if match_path(&trait_ref.path, &paths::HASH) {
405 /// // This is the `std::hash::Hash` trait.
408 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
409 /// // This is a `rustc_middle::lint::Lint`.
412 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
416 .zip(segments.iter().rev())
417 .all(|(a, b)| a.ident.name.as_str() == *b)
420 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
421 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
422 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
423 if let Res::Local(id) = path.res {
430 /// Returns true if the expression is a path to a local with the specified `HirId`.
431 /// Use this function to see if an expression matches a function argument or a match binding.
432 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
433 path_to_local(expr) == Some(id)
436 pub trait MaybePath<'hir> {
437 fn hir_id(&self) -> HirId;
438 fn qpath_opt(&self) -> Option<&QPath<'hir>>;
441 macro_rules! maybe_path {
442 ($ty:ident, $kind:ident) => {
443 impl<'hir> MaybePath<'hir> for hir::$ty<'hir> {
444 fn hir_id(&self) -> HirId {
447 fn qpath_opt(&self) -> Option<&QPath<'hir>> {
449 hir::$kind::Path(qpath) => Some(qpath),
456 maybe_path!(Expr, ExprKind);
457 maybe_path!(Pat, PatKind);
458 maybe_path!(Ty, TyKind);
460 /// If `maybe_path` is a path node, resolves it, otherwise returns `Res::Err`
461 pub fn path_res<'tcx>(cx: &LateContext<'_>, maybe_path: &impl MaybePath<'tcx>) -> Res {
462 match maybe_path.qpath_opt() {
464 Some(qpath) => cx.qpath_res(qpath, maybe_path.hir_id()),
468 /// If `maybe_path` is a path node which resolves to an item, retrieves the item ID
469 pub fn path_def_id<'tcx>(cx: &LateContext<'_>, maybe_path: &impl MaybePath<'tcx>) -> Option<DefId> {
470 path_res(cx, maybe_path).opt_def_id()
473 /// Resolves a def path like `std::vec::Vec`.
474 /// This function is expensive and should be used sparingly.
475 pub fn def_path_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
476 fn item_child_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Option<Res> {
477 match tcx.def_kind(def_id) {
478 DefKind::Mod | DefKind::Enum | DefKind::Trait => tcx
479 .module_children(def_id)
481 .find(|item| item.ident.name.as_str() == name)
482 .map(|child| child.res.expect_non_local()),
484 .associated_item_def_ids(def_id)
487 .find(|assoc_def_id| tcx.item_name(*assoc_def_id).as_str() == name)
488 .map(|assoc_def_id| Res::Def(tcx.def_kind(assoc_def_id), assoc_def_id)),
492 fn find_primitive<'tcx>(tcx: TyCtxt<'tcx>, name: &str) -> impl Iterator<Item = DefId> + 'tcx {
493 let single = |ty| tcx.incoherent_impls(ty).iter().copied();
494 let empty = || [].iter().copied();
496 "bool" => single(BoolSimplifiedType),
497 "char" => single(CharSimplifiedType),
498 "str" => single(StrSimplifiedType),
499 "array" => single(ArraySimplifiedType),
500 "slice" => single(SliceSimplifiedType),
501 // FIXME: rustdoc documents these two using just `pointer`.
503 // Maybe this is something we should do here too.
504 "const_ptr" => single(PtrSimplifiedType(Mutability::Not)),
505 "mut_ptr" => single(PtrSimplifiedType(Mutability::Mut)),
506 "isize" => single(IntSimplifiedType(IntTy::Isize)),
507 "i8" => single(IntSimplifiedType(IntTy::I8)),
508 "i16" => single(IntSimplifiedType(IntTy::I16)),
509 "i32" => single(IntSimplifiedType(IntTy::I32)),
510 "i64" => single(IntSimplifiedType(IntTy::I64)),
511 "i128" => single(IntSimplifiedType(IntTy::I128)),
512 "usize" => single(UintSimplifiedType(UintTy::Usize)),
513 "u8" => single(UintSimplifiedType(UintTy::U8)),
514 "u16" => single(UintSimplifiedType(UintTy::U16)),
515 "u32" => single(UintSimplifiedType(UintTy::U32)),
516 "u64" => single(UintSimplifiedType(UintTy::U64)),
517 "u128" => single(UintSimplifiedType(UintTy::U128)),
518 "f32" => single(FloatSimplifiedType(FloatTy::F32)),
519 "f64" => single(FloatSimplifiedType(FloatTy::F64)),
523 fn find_crate(tcx: TyCtxt<'_>, name: &str) -> Option<DefId> {
527 .find(|&num| tcx.crate_name(num).as_str() == name)
528 .map(CrateNum::as_def_id)
531 let (base, first, path) = match *path {
532 [base, first, ref path @ ..] => (base, first, path),
534 return PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy);
536 _ => return Res::Err,
539 let starts = find_primitive(tcx, base)
540 .chain(find_crate(tcx, base))
541 .filter_map(|id| item_child_by_name(tcx, id, first));
543 for first in starts {
547 // for each segment, find the child item
548 .try_fold(first, |res, segment| {
549 let def_id = res.def_id();
550 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
552 } else if matches!(res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
553 // it is not a child item so check inherent impl items
554 tcx.inherent_impls(def_id)
556 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
562 if let Some(last) = last {
570 /// Convenience function to get the `DefId` of a trait by path.
571 /// It could be a trait or trait alias.
572 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
573 match def_path_res(cx, path) {
574 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
579 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
581 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
584 /// struct Point(isize, isize);
586 /// impl std::ops::Add for Point {
587 /// type Output = Self;
589 /// fn add(self, other: Self) -> Self {
594 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, def_id: LocalDefId) -> Option<&'tcx TraitRef<'tcx>> {
595 // Get the implemented trait for the current function
596 let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
597 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
599 if parent_impl != hir::CRATE_OWNER_ID;
600 if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent_impl.def_id);
601 if let hir::ItemKind::Impl(impl_) = &item.kind;
603 return impl_.of_trait.as_ref();
609 /// This method will return tuple of projection stack and root of the expression,
610 /// used in `can_mut_borrow_both`.
612 /// For example, if `e` represents the `v[0].a.b[x]`
613 /// this method will return a tuple, composed of a `Vec`
614 /// containing the `Expr`s for `v[0], v[0].a, v[0].a.b, v[0].a.b[x]`
615 /// and an `Expr` for root of them, `v`
616 fn projection_stack<'a, 'hir>(mut e: &'a Expr<'hir>) -> (Vec<&'a Expr<'hir>>, &'a Expr<'hir>) {
617 let mut result = vec![];
620 ExprKind::Index(ep, _) | ExprKind::Field(ep, _) => {
631 /// Gets the mutability of the custom deref adjustment, if any.
632 pub fn expr_custom_deref_adjustment(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<Mutability> {
636 .find_map(|a| match a.kind {
637 Adjust::Deref(Some(d)) => Some(Some(d.mutbl)),
638 Adjust::Deref(None) => None,
644 /// Checks if two expressions can be mutably borrowed simultaneously
645 /// and they aren't dependent on borrowing same thing twice
646 pub fn can_mut_borrow_both(cx: &LateContext<'_>, e1: &Expr<'_>, e2: &Expr<'_>) -> bool {
647 let (s1, r1) = projection_stack(e1);
648 let (s2, r2) = projection_stack(e2);
649 if !eq_expr_value(cx, r1, r2) {
652 if expr_custom_deref_adjustment(cx, r1).is_some() || expr_custom_deref_adjustment(cx, r2).is_some() {
656 for (x1, x2) in s1.iter().zip(s2.iter()) {
657 if expr_custom_deref_adjustment(cx, x1).is_some() || expr_custom_deref_adjustment(cx, x2).is_some() {
661 match (&x1.kind, &x2.kind) {
662 (ExprKind::Field(_, i1), ExprKind::Field(_, i2)) => {
667 (ExprKind::Index(_, i1), ExprKind::Index(_, i2)) => {
668 if !eq_expr_value(cx, i1, i2) {
678 /// Returns true if the `def_id` associated with the `path` is recognized as a "default-equivalent"
679 /// constructor from the std library
680 fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<'_>) -> bool {
681 let std_types_symbols = &[
693 if let QPath::TypeRelative(_, method) = path {
694 if method.ident.name == sym::new {
695 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
696 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
697 return std_types_symbols
699 .any(|&symbol| cx.tcx.is_diagnostic_item(symbol, adt.did()));
707 /// Return true if the expr is equal to `Default::default` when evaluated.
708 pub fn is_default_equivalent_call(cx: &LateContext<'_>, repl_func: &Expr<'_>) -> bool {
710 if let hir::ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
711 if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
712 if is_diag_trait_item(cx, repl_def_id, sym::Default)
713 || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
714 then { true } else { false }
718 /// Returns true if the expr is equal to `Default::default()` of it's type when evaluated.
719 /// It doesn't cover all cases, for example indirect function calls (some of std
720 /// functions are supported) but it is the best we have.
721 pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
723 ExprKind::Lit(lit) => match lit.node {
724 LitKind::Bool(false) | LitKind::Int(0, _) => true,
725 LitKind::Str(s, _) => s.is_empty(),
728 ExprKind::Tup(items) | ExprKind::Array(items) => items.iter().all(|x| is_default_equivalent(cx, x)),
729 ExprKind::Repeat(x, ArrayLen::Body(len)) => if_chain! {
730 if let ExprKind::Lit(ref const_lit) = cx.tcx.hir().body(len.body).value.kind;
731 if let LitKind::Int(v, _) = const_lit.node;
732 if v <= 32 && is_default_equivalent(cx, x);
740 ExprKind::Call(repl_func, _) => is_default_equivalent_call(cx, repl_func),
741 ExprKind::Path(qpath) => is_lang_ctor(cx, qpath, OptionNone),
742 ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
747 /// Checks if the top level expression can be moved into a closure as is.
748 /// Currently checks for:
749 /// * Break/Continue outside the given loop HIR ids.
750 /// * Yield/Return statements.
751 /// * Inline assembly.
752 /// * Usages of a field of a local where the type of the local can be partially moved.
754 /// For example, given the following function:
757 /// fn f<'a>(iter: &mut impl Iterator<Item = (usize, &'a mut String)>) {
758 /// for item in iter {
769 /// When called on the expression `item.0` this will return false unless the local `item` is in the
770 /// `ignore_locals` set. The type `(usize, &mut String)` can have the second element moved, so it
771 /// isn't always safe to move into a closure when only a single field is needed.
773 /// When called on the `continue` expression this will return false unless the outer loop expression
774 /// is in the `loop_ids` set.
776 /// Note that this check is not recursive, so passing the `if` expression will always return true
777 /// even though sub-expressions might return false.
778 pub fn can_move_expr_to_closure_no_visit<'tcx>(
779 cx: &LateContext<'tcx>,
780 expr: &'tcx Expr<'_>,
782 ignore_locals: &HirIdSet,
785 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
786 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
787 if loop_ids.contains(&id) =>
792 | ExprKind::Continue(_)
794 | ExprKind::Yield(..)
795 | ExprKind::InlineAsm(_) => false,
796 // Accessing a field of a local value can only be done if the type isn't
802 ExprKind::Path(QPath::Resolved(
805 res: Res::Local(local_id),
812 ) if !ignore_locals.contains(local_id) && can_partially_move_ty(cx, cx.typeck_results().node_type(hir_id)) => {
813 // TODO: check if the local has been partially moved. Assume it has for now.
820 /// How a local is captured by a closure
821 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
822 pub enum CaptureKind {
827 pub fn is_imm_ref(self) -> bool {
828 self == Self::Ref(Mutability::Not)
831 impl std::ops::BitOr for CaptureKind {
833 fn bitor(self, rhs: Self) -> Self::Output {
835 (CaptureKind::Value, _) | (_, CaptureKind::Value) => CaptureKind::Value,
836 (CaptureKind::Ref(Mutability::Mut), CaptureKind::Ref(_))
837 | (CaptureKind::Ref(_), CaptureKind::Ref(Mutability::Mut)) => CaptureKind::Ref(Mutability::Mut),
838 (CaptureKind::Ref(Mutability::Not), CaptureKind::Ref(Mutability::Not)) => CaptureKind::Ref(Mutability::Not),
842 impl std::ops::BitOrAssign for CaptureKind {
843 fn bitor_assign(&mut self, rhs: Self) {
848 /// Given an expression referencing a local, determines how it would be captured in a closure.
849 /// Note as this will walk up to parent expressions until the capture can be determined it should
850 /// only be used while making a closure somewhere a value is consumed. e.g. a block, match arm, or
851 /// function argument (other than a receiver).
852 pub fn capture_local_usage<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> CaptureKind {
853 fn pat_capture_kind(cx: &LateContext<'_>, pat: &Pat<'_>) -> CaptureKind {
854 let mut capture = CaptureKind::Ref(Mutability::Not);
855 pat.each_binding_or_first(&mut |_, id, span, _| match cx
857 .extract_binding_mode(cx.sess(), id, span)
860 BindingMode::BindByValue(_) if !is_copy(cx, cx.typeck_results().node_type(id)) => {
861 capture = CaptureKind::Value;
863 BindingMode::BindByReference(Mutability::Mut) if capture != CaptureKind::Value => {
864 capture = CaptureKind::Ref(Mutability::Mut);
871 debug_assert!(matches!(
873 ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(_), .. }))
876 let mut child_id = e.hir_id;
877 let mut capture = CaptureKind::Value;
878 let mut capture_expr_ty = e;
880 for (parent_id, parent) in cx.tcx.hir().parent_iter(e.hir_id) {
883 kind: Adjust::Deref(_) | Adjust::Borrow(AutoBorrow::Ref(..)),
891 .map_or(&[][..], |x| &**x)
893 if let rustc_ty::RawPtr(TypeAndMut { mutbl: mutability, .. }) | rustc_ty::Ref(_, _, mutability) =
894 *adjust.last().map_or(target, |a| a.target).kind()
896 return CaptureKind::Ref(mutability);
901 Node::Expr(e) => match e.kind {
902 ExprKind::AddrOf(_, mutability, _) => return CaptureKind::Ref(mutability),
903 ExprKind::Index(..) | ExprKind::Unary(UnOp::Deref, _) => capture = CaptureKind::Ref(Mutability::Not),
904 ExprKind::Assign(lhs, ..) | ExprKind::AssignOp(_, lhs, _) if lhs.hir_id == child_id => {
905 return CaptureKind::Ref(Mutability::Mut);
907 ExprKind::Field(..) => {
908 if capture == CaptureKind::Value {
912 ExprKind::Let(let_expr) => {
913 let mutability = match pat_capture_kind(cx, let_expr.pat) {
914 CaptureKind::Value => Mutability::Not,
915 CaptureKind::Ref(m) => m,
917 return CaptureKind::Ref(mutability);
919 ExprKind::Match(_, arms, _) => {
920 let mut mutability = Mutability::Not;
921 for capture in arms.iter().map(|arm| pat_capture_kind(cx, arm.pat)) {
923 CaptureKind::Value => break,
924 CaptureKind::Ref(Mutability::Mut) => mutability = Mutability::Mut,
925 CaptureKind::Ref(Mutability::Not) => (),
928 return CaptureKind::Ref(mutability);
932 Node::Local(l) => match pat_capture_kind(cx, l.pat) {
933 CaptureKind::Value => break,
934 capture @ CaptureKind::Ref(_) => return capture,
939 child_id = parent_id;
942 if capture == CaptureKind::Value && is_copy(cx, cx.typeck_results().expr_ty(capture_expr_ty)) {
943 // Copy types are never automatically captured by value.
944 CaptureKind::Ref(Mutability::Not)
950 /// Checks if the expression can be moved into a closure as is. This will return a list of captures
951 /// if so, otherwise, `None`.
952 pub fn can_move_expr_to_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<HirIdMap<CaptureKind>> {
953 struct V<'cx, 'tcx> {
954 cx: &'cx LateContext<'tcx>,
955 // Stack of potential break targets contained in the expression.
957 /// Local variables created in the expression. These don't need to be captured.
959 /// Whether this expression can be turned into a closure.
961 /// Locals which need to be captured, and whether they need to be by value, reference, or
962 /// mutable reference.
963 captures: HirIdMap<CaptureKind>,
965 impl<'tcx> Visitor<'tcx> for V<'_, 'tcx> {
966 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
967 if !self.allow_closure {
972 ExprKind::Path(QPath::Resolved(None, &Path { res: Res::Local(l), .. })) => {
973 if !self.locals.contains(&l) {
974 let cap = capture_local_usage(self.cx, e);
975 self.captures.entry(l).and_modify(|e| *e |= cap).or_insert(cap);
978 ExprKind::Closure { .. } => {
979 let closure_id = self.cx.tcx.hir().local_def_id(e.hir_id);
980 for capture in self.cx.typeck_results().closure_min_captures_flattened(closure_id) {
981 let local_id = match capture.place.base {
982 PlaceBase::Local(id) => id,
983 PlaceBase::Upvar(var) => var.var_path.hir_id,
986 if !self.locals.contains(&local_id) {
987 let capture = match capture.info.capture_kind {
988 UpvarCapture::ByValue => CaptureKind::Value,
989 UpvarCapture::ByRef(kind) => match kind {
990 BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
991 BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
992 CaptureKind::Ref(Mutability::Mut)
998 .and_modify(|e| *e |= capture)
1003 ExprKind::Loop(b, ..) => {
1004 self.loops.push(e.hir_id);
1005 self.visit_block(b);
1009 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops, &self.locals);
1015 fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) {
1016 p.each_binding_or_first(&mut |_, id, _, _| {
1017 self.locals.insert(id);
1024 allow_closure: true,
1026 locals: HirIdSet::default(),
1027 captures: HirIdMap::default(),
1030 v.allow_closure.then_some(v.captures)
1033 /// Arguments of a method: the receiver and all the additional arguments.
1034 pub type MethodArguments<'tcx> = Vec<(&'tcx Expr<'tcx>, &'tcx [Expr<'tcx>])>;
1036 /// Returns the method names and argument list of nested method call expressions that make up
1037 /// `expr`. method/span lists are sorted with the most recent call first.
1038 pub fn method_calls<'tcx>(expr: &'tcx Expr<'tcx>, max_depth: usize) -> (Vec<Symbol>, MethodArguments<'tcx>, Vec<Span>) {
1039 let mut method_names = Vec::with_capacity(max_depth);
1040 let mut arg_lists = Vec::with_capacity(max_depth);
1041 let mut spans = Vec::with_capacity(max_depth);
1043 let mut current = expr;
1044 for _ in 0..max_depth {
1045 if let ExprKind::MethodCall(path, receiver, args, _) = ¤t.kind {
1046 if receiver.span.from_expansion() || args.iter().any(|e| e.span.from_expansion()) {
1049 method_names.push(path.ident.name);
1050 arg_lists.push((*receiver, &**args));
1051 spans.push(path.ident.span);
1058 (method_names, arg_lists, spans)
1061 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
1063 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
1064 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
1065 /// containing the `Expr`s for
1066 /// `.bar()` and `.baz()`
1067 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<(&'a Expr<'a>, &'a [Expr<'a>])>> {
1068 let mut current = expr;
1069 let mut matched = Vec::with_capacity(methods.len());
1070 for method_name in methods.iter().rev() {
1071 // method chains are stored last -> first
1072 if let ExprKind::MethodCall(path, receiver, args, _) = current.kind {
1073 if path.ident.name.as_str() == *method_name {
1074 if receiver.span.from_expansion() || args.iter().any(|e| e.span.from_expansion()) {
1077 matched.push((receiver, args)); // build up `matched` backwards
1078 current = receiver; // go to parent expression
1086 // Reverse `matched` so that it is in the same order as `methods`.
1091 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
1092 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
1095 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
1098 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
1099 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1100 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
1101 Some(parent.to_def_id()) == cx.tcx.lang_items().panic_impl()
1104 /// Gets the name of the item the expression is in, if available.
1105 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
1106 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id).def_id;
1107 match cx.tcx.hir().find_by_def_id(parent_id) {
1109 Node::Item(Item { ident, .. })
1110 | Node::TraitItem(TraitItem { ident, .. })
1111 | Node::ImplItem(ImplItem { ident, .. }),
1112 ) => Some(ident.name),
1117 pub struct ContainsName {
1122 impl<'tcx> Visitor<'tcx> for ContainsName {
1123 fn visit_name(&mut self, name: Symbol) {
1124 if self.name == name {
1130 /// Checks if an `Expr` contains a certain name.
1131 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
1132 let mut cn = ContainsName { name, result: false };
1133 cn.visit_expr(expr);
1137 /// Returns `true` if `expr` contains a return expression
1138 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
1139 let mut found = false;
1140 expr_visitor_no_bodies(|expr| {
1142 if let hir::ExprKind::Ret(..) = &expr.kind {
1152 /// Extends the span to the beginning of the spans line, incl. whitespaces.
1157 /// // will be converted to
1159 /// // ^^^^^^^^^^^^^^
1161 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
1162 let span = original_sp(span, DUMMY_SP);
1163 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
1164 let line_no = source_map_and_line.line;
1165 let line_start = source_map_and_line.sf.lines(|lines| lines[line_no]);
1166 span.with_lo(line_start)
1169 /// Gets the parent node, if any.
1170 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
1171 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
1174 /// Gets the parent expression, if any –- this is useful to constrain a lint.
1175 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1176 get_parent_expr_for_hir(cx, e.hir_id)
1179 /// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
1180 /// constraint lints
1181 pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
1182 match get_parent_node(cx.tcx, hir_id) {
1183 Some(Node::Expr(parent)) => Some(parent),
1188 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
1189 let map = &cx.tcx.hir();
1190 let enclosing_node = map
1191 .get_enclosing_scope(hir_id)
1192 .and_then(|enclosing_id| map.find(enclosing_id));
1193 enclosing_node.and_then(|node| match node {
1194 Node::Block(block) => Some(block),
1196 kind: ItemKind::Fn(_, _, eid),
1199 | Node::ImplItem(&ImplItem {
1200 kind: ImplItemKind::Fn(_, eid),
1202 }) => match cx.tcx.hir().body(eid).value.kind {
1203 ExprKind::Block(block, _) => Some(block),
1210 /// Gets the loop or closure enclosing the given expression, if any.
1211 pub fn get_enclosing_loop_or_multi_call_closure<'tcx>(
1212 cx: &LateContext<'tcx>,
1214 ) -> Option<&'tcx Expr<'tcx>> {
1215 for (_, node) in cx.tcx.hir().parent_iter(expr.hir_id) {
1217 Node::Expr(e) => match e.kind {
1218 ExprKind::Closure { .. } => {
1219 if let rustc_ty::Closure(_, subs) = cx.typeck_results().expr_ty(e).kind()
1220 && subs.as_closure().kind() == ClosureKind::FnOnce
1224 let is_once = walk_to_expr_usage(cx, e, |node, id| {
1225 let Node::Expr(e) = node else {
1229 ExprKind::Call(f, _) if f.hir_id == id => Some(()),
1230 ExprKind::Call(f, args) => {
1231 let i = args.iter().position(|arg| arg.hir_id == id)?;
1232 let sig = expr_sig(cx, f)?;
1233 let predicates = sig
1235 .map_or(cx.param_env, |id| cx.tcx.param_env(id))
1237 sig.input(i).and_then(|ty| {
1238 ty_is_fn_once_param(cx.tcx, ty.skip_binder(), predicates).then_some(())
1241 ExprKind::MethodCall(_, receiver, args, _) => {
1242 let i = std::iter::once(receiver)
1244 .position(|arg| arg.hir_id == id)?;
1245 let id = cx.typeck_results().type_dependent_def_id(e.hir_id)?;
1246 let ty = cx.tcx.fn_sig(id).skip_binder().inputs()[i];
1247 ty_is_fn_once_param(cx.tcx, ty, cx.tcx.param_env(id).caller_bounds()).then_some(())
1257 ExprKind::Loop(..) => return Some(e),
1260 Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
1267 /// Gets the parent node if it's an impl block.
1268 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
1269 match tcx.hir().parent_iter(id).next() {
1273 kind: ItemKind::Impl(imp),
1281 /// Removes blocks around an expression, only if the block contains just one expression
1282 /// and no statements. Unsafe blocks are not removed.
1286 /// * `{ x }` -> `x`
1287 /// * `{{ x }}` -> `x`
1288 /// * `{ x; }` -> `{ x; }`
1289 /// * `{ x; y }` -> `{ x; y }`
1290 /// * `{ unsafe { x } }` -> `unsafe { x }`
1291 pub fn peel_blocks<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1292 while let ExprKind::Block(
1296 rules: BlockCheckMode::DefaultBlock,
1307 /// Removes blocks around an expression, only if the block contains just one expression
1308 /// or just one expression statement with a semicolon. Unsafe blocks are not removed.
1312 /// * `{ x }` -> `x`
1313 /// * `{ x; }` -> `x`
1314 /// * `{{ x; }}` -> `x`
1315 /// * `{ x; y }` -> `{ x; y }`
1316 /// * `{ unsafe { x } }` -> `unsafe { x }`
1317 pub fn peel_blocks_with_stmt<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1318 while let ExprKind::Block(
1322 rules: BlockCheckMode::DefaultBlock,
1329 kind: StmtKind::Expr(inner) | StmtKind::Semi(inner),
1334 rules: BlockCheckMode::DefaultBlock,
1345 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
1346 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1347 let mut iter = tcx.hir().parent_iter(expr.hir_id);
1352 kind: ExprKind::If(_, _, Some(else_expr)),
1355 )) => else_expr.hir_id == expr.hir_id,
1360 /// Checks whether the given expression is a constant integer of the given value.
1361 /// unlike `is_integer_literal`, this version does const folding
1362 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
1363 if is_integer_literal(e, value) {
1366 let enclosing_body = cx.tcx.hir().enclosing_body_owner(e.hir_id);
1367 if let Some((Constant::Int(v), _)) = constant(cx, cx.tcx.typeck(enclosing_body), e) {
1373 /// Checks whether the given expression is a constant literal of the given value.
1374 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
1375 // FIXME: use constant folding
1376 if let ExprKind::Lit(ref spanned) = expr.kind {
1377 if let LitKind::Int(v, _) = spanned.node {
1384 /// Returns `true` if the given `Expr` has been coerced before.
1386 /// Examples of coercions can be found in the Nomicon at
1387 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
1389 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_hir_analysis::check::coercion` for more
1390 /// information on adjustments and coercions.
1391 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1392 cx.typeck_results().adjustments().get(e.hir_id).is_some()
1395 /// Returns the pre-expansion span if this comes from an expansion of the
1397 /// See also [`is_direct_expn_of`].
1399 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
1401 if span.from_expansion() {
1402 let data = span.ctxt().outer_expn_data();
1403 let new_span = data.call_site;
1405 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1406 if mac_name.as_str() == name {
1407 return Some(new_span);
1418 /// Returns the pre-expansion span if the span directly comes from an expansion
1419 /// of the macro `name`.
1420 /// The difference with [`is_expn_of`] is that in
1422 /// # macro_rules! foo { ($name:tt!$args:tt) => { $name!$args } }
1423 /// # macro_rules! bar { ($e:expr) => { $e } }
1426 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1427 /// from `bar!` by `is_direct_expn_of`.
1429 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1430 if span.from_expansion() {
1431 let data = span.ctxt().outer_expn_data();
1432 let new_span = data.call_site;
1434 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1435 if mac_name.as_str() == name {
1436 return Some(new_span);
1444 /// Convenience function to get the return type of a function.
1445 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1446 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1447 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1448 cx.tcx.erase_late_bound_regions(ret_ty)
1451 /// Convenience function to get the nth argument type of a function.
1452 pub fn nth_arg<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId, nth: usize) -> Ty<'tcx> {
1453 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1454 let arg = cx.tcx.fn_sig(fn_def_id).input(nth);
1455 cx.tcx.erase_late_bound_regions(arg)
1458 /// Checks if an expression is constructing a tuple-like enum variant or struct
1459 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1460 if let ExprKind::Call(fun, _) = expr.kind {
1461 if let ExprKind::Path(ref qp) = fun.kind {
1462 let res = cx.qpath_res(qp, fun.hir_id);
1464 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1465 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1473 /// Returns `true` if a pattern is refutable.
1474 // TODO: should be implemented using rustc/mir_build/thir machinery
1475 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1476 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1478 cx.qpath_res(qpath, id),
1479 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1483 fn are_refutable<'a, I: IntoIterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, i: I) -> bool {
1484 i.into_iter().any(|pat| is_refutable(cx, pat))
1488 PatKind::Wild => false,
1489 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1490 PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
1491 PatKind::Lit(..) | PatKind::Range(..) => true,
1492 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1493 PatKind::Or(pats) => {
1494 // TODO: should be the honest check, that pats is exhaustive set
1495 are_refutable(cx, pats)
1497 PatKind::Tuple(pats, _) => are_refutable(cx, pats),
1498 PatKind::Struct(ref qpath, fields, _) => {
1499 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| field.pat))
1501 PatKind::TupleStruct(ref qpath, pats, _) => is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats),
1502 PatKind::Slice(head, middle, tail) => {
1503 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1504 rustc_ty::Slice(..) => {
1505 // [..] is the only irrefutable slice pattern.
1506 !head.is_empty() || middle.is_none() || !tail.is_empty()
1508 rustc_ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter())),
1518 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1519 /// the function once on the given pattern.
1520 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1521 if let PatKind::Or(pats) = pat.kind {
1522 pats.iter().for_each(f);
1528 pub fn is_self(slf: &Param<'_>) -> bool {
1529 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1530 name.name == kw::SelfLower
1536 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1537 if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind {
1538 if let Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } = path.res {
1545 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1546 (0..decl.inputs.len()).map(move |i| &body.params[i])
1549 /// Checks if a given expression is a match expression expanded from the `?`
1550 /// operator or the `try` macro.
1551 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1552 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1554 if let PatKind::TupleStruct(ref path, pat, ddpos) = arm.pat.kind;
1555 if ddpos.as_opt_usize().is_none();
1556 if is_lang_ctor(cx, path, ResultOk);
1557 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1558 if path_to_local_id(arm.body, hir_id);
1566 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1567 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1568 is_lang_ctor(cx, path, ResultErr)
1574 if let ExprKind::Match(_, arms, ref source) = expr.kind {
1575 // desugared from a `?` operator
1576 if *source == MatchSource::TryDesugar {
1582 if arms[0].guard.is_none();
1583 if arms[1].guard.is_none();
1584 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) || (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1594 /// Returns `true` if the lint is allowed in the current context. This is useful for
1595 /// skipping long running code when it's unnecessary
1597 /// This function should check the lint level for the same node, that the lint will
1598 /// be emitted at. If the information is buffered to be emitted at a later point, please
1599 /// make sure to use `span_lint_hir` functions to emit the lint. This ensures that
1600 /// expectations at the checked nodes will be fulfilled.
1601 pub fn is_lint_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1602 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1605 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1606 while let PatKind::Ref(subpat, _) = pat.kind {
1612 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1613 Integer::from_int_ty(&tcx, ity).size().bits()
1616 #[expect(clippy::cast_possible_wrap)]
1617 /// Turn a constant int byte representation into an i128
1618 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1619 let amt = 128 - int_bits(tcx, ity);
1620 ((u as i128) << amt) >> amt
1623 #[expect(clippy::cast_sign_loss)]
1624 /// clip unused bytes
1625 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1626 let amt = 128 - int_bits(tcx, ity);
1627 ((u as u128) << amt) >> amt
1630 /// clip unused bytes
1631 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1632 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1633 let amt = 128 - bits;
1637 pub fn has_attr(attrs: &[ast::Attribute], symbol: Symbol) -> bool {
1638 attrs.iter().any(|attr| attr.has_name(symbol))
1641 pub fn any_parent_has_attr(tcx: TyCtxt<'_>, node: HirId, symbol: Symbol) -> bool {
1642 let map = &tcx.hir();
1643 let mut prev_enclosing_node = None;
1644 let mut enclosing_node = node;
1645 while Some(enclosing_node) != prev_enclosing_node {
1646 if has_attr(map.attrs(enclosing_node), symbol) {
1649 prev_enclosing_node = Some(enclosing_node);
1650 enclosing_node = map.get_parent_item(enclosing_node).into();
1656 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1657 any_parent_has_attr(tcx, node, sym::automatically_derived)
1660 /// Matches a function call with the given path and returns the arguments.
1665 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1667 pub fn match_function_call<'tcx>(
1668 cx: &LateContext<'tcx>,
1669 expr: &'tcx Expr<'_>,
1671 ) -> Option<&'tcx [Expr<'tcx>]> {
1673 if let ExprKind::Call(fun, args) = expr.kind;
1674 if let ExprKind::Path(ref qpath) = fun.kind;
1675 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1676 if match_def_path(cx, fun_def_id, path);
1684 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1687 /// Please use `tcx.get_diagnostic_name` if the targets are all diagnostic items.
1688 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1689 let search_path = cx.get_def_path(did);
1692 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1695 /// Checks if the given `DefId` matches the path.
1696 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1697 // We should probably move to Symbols in Clippy as well rather than interning every time.
1698 let path = cx.get_def_path(did);
1699 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1702 /// Checks if the given `DefId` matches the `libc` item.
1703 pub fn match_libc_symbol(cx: &LateContext<'_>, did: DefId, name: &str) -> bool {
1704 let path = cx.get_def_path(did);
1705 // libc is meant to be used as a flat list of names, but they're all actually defined in different
1706 // modules based on the target platform. Ignore everything but crate name and the item name.
1707 path.first().map_or(false, |s| s.as_str() == "libc") && path.last().map_or(false, |s| s.as_str() == name)
1710 /// Returns the list of condition expressions and the list of blocks in a
1711 /// sequence of `if/else`.
1712 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1713 /// `if a { c } else if b { d } else { e }`.
1714 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1715 let mut conds = Vec::new();
1716 let mut blocks: Vec<&Block<'_>> = Vec::new();
1718 while let Some(higher::IfOrIfLet { cond, then, r#else }) = higher::IfOrIfLet::hir(expr) {
1720 if let ExprKind::Block(block, _) = then.kind {
1723 panic!("ExprKind::If node is not an ExprKind::Block");
1726 if let Some(else_expr) = r#else {
1733 // final `else {..}`
1734 if !blocks.is_empty() {
1735 if let ExprKind::Block(block, _) = expr.kind {
1743 /// Checks if the given function kind is an async function.
1744 pub fn is_async_fn(kind: FnKind<'_>) -> bool {
1745 matches!(kind, FnKind::ItemFn(_, _, header) if header.asyncness == IsAsync::Async)
1748 /// Peels away all the compiler generated code surrounding the body of an async function,
1749 pub fn get_async_fn_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
1750 if let ExprKind::Call(
1754 kind: ExprKind::Closure(&Closure { body, .. }),
1760 if let ExprKind::Block(
1765 kind: ExprKind::DropTemps(expr),
1771 ) = tcx.hir().body(body).value.kind
1779 // check if expr is calling method or function with #[must_use] attribute
1780 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1781 let did = match expr.kind {
1782 ExprKind::Call(path, _) => if_chain! {
1783 if let ExprKind::Path(ref qpath) = path.kind;
1784 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1791 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1795 did.map_or(false, |did| cx.tcx.has_attr(did, sym::must_use))
1798 /// Checks if an expression represents the identity function
1799 /// Only examines closures and `std::convert::identity`
1800 pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1801 /// Checks if a function's body represents the identity function. Looks for bodies of the form:
1803 /// * `|x| return x`
1804 /// * `|x| { return x }`
1805 /// * `|x| { return x; }`
1806 fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
1807 let id = if_chain! {
1808 if let [param] = func.params;
1809 if let PatKind::Binding(_, id, _, _) = param.pat.kind;
1817 let mut expr = func.value;
1821 ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
1822 | ExprKind::Ret(Some(e)) => expr = e,
1824 ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
1826 if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
1827 if let ExprKind::Ret(Some(ret_val)) = e.kind;
1835 _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
1841 ExprKind::Closure(&Closure { body, .. }) => is_body_identity_function(cx, cx.tcx.hir().body(body)),
1842 _ => path_def_id(cx, expr).map_or(false, |id| match_def_path(cx, id, &paths::CONVERT_IDENTITY)),
1846 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1847 /// Returns both the node and the `HirId` of the closest child node.
1848 pub fn get_expr_use_or_unification_node<'tcx>(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<(Node<'tcx>, HirId)> {
1849 let mut child_id = expr.hir_id;
1850 let mut iter = tcx.hir().parent_iter(child_id);
1854 Some((id, Node::Block(_))) => child_id = id,
1855 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1856 Some((_, Node::Expr(expr))) => match expr.kind {
1857 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1858 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1859 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1860 _ => break Some((Node::Expr(expr), child_id)),
1862 Some((_, node)) => break Some((node, child_id)),
1867 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1868 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1870 get_expr_use_or_unification_node(tcx, expr),
1873 kind: StmtKind::Expr(_)
1875 | StmtKind::Local(Local {
1877 kind: PatKind::Wild,
1889 /// Checks if the expression is the final expression returned from a block.
1890 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1891 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1894 pub fn std_or_core(cx: &LateContext<'_>) -> Option<&'static str> {
1895 if !is_no_std_crate(cx) {
1897 } else if !is_no_core_crate(cx) {
1904 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1905 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1906 if let ast::AttrKind::Normal(ref normal) = attr.kind {
1907 normal.item.path == sym::no_std
1914 pub fn is_no_core_crate(cx: &LateContext<'_>) -> bool {
1915 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1916 if let ast::AttrKind::Normal(ref normal) = attr.kind {
1917 normal.item.path == sym::no_core
1924 /// Check if parent of a hir node is a trait implementation block.
1925 /// For example, `f` in
1928 /// # trait Trait { fn f(); }
1929 /// impl Trait for S {
1933 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1934 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1935 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1941 /// Check if it's even possible to satisfy the `where` clause for the item.
1943 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1946 /// fn foo() where i32: Iterator {
1947 /// for _ in 2i32 {}
1950 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1951 use rustc_trait_selection::traits;
1957 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1958 traits::impossible_predicates(
1960 traits::elaborate_predicates(cx.tcx, predicates)
1961 .map(|o| o.predicate)
1962 .collect::<Vec<_>>(),
1966 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1967 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1969 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1972 kind: ExprKind::Path(qpath),
1973 hir_id: path_hir_id,
1978 // Only return Fn-like DefIds, not the DefIds of statics/consts/etc that contain or
1979 // deref to fn pointers, dyn Fn, impl Fn - #8850
1980 if let Res::Def(DefKind::Fn | DefKind::Ctor(..) | DefKind::AssocFn, id) =
1981 cx.typeck_results().qpath_res(qpath, *path_hir_id)
1992 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1993 /// slice iff the given expression is a slice of primitives (as defined in the
1994 /// `is_recursively_primitive_type` function) and None otherwise.
1995 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1996 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1997 let expr_kind = expr_type.kind();
1998 let is_primitive = match expr_kind {
1999 rustc_ty::Slice(element_type) => is_recursively_primitive_type(*element_type),
2000 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
2001 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
2002 is_recursively_primitive_type(*element_type)
2011 // if we have wrappers like Array, Slice or Tuple, print these
2012 // and get the type enclosed in the slice ref
2013 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
2014 rustc_ty::Slice(..) => return Some("slice".into()),
2015 rustc_ty::Array(..) => return Some("array".into()),
2016 rustc_ty::Tuple(..) => return Some("tuple".into()),
2018 // is_recursively_primitive_type() should have taken care
2019 // of the rest and we can rely on the type that is found
2020 let refs_peeled = expr_type.peel_refs();
2021 return Some(refs_peeled.walk().last().unwrap().to_string());
2028 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
2029 /// `hash` must be comformed with `eq`
2030 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
2032 Hash: Fn(&T) -> u64,
2033 Eq: Fn(&T, &T) -> bool,
2036 [a, b] if eq(a, b) => return vec![(a, b)],
2037 _ if exprs.len() <= 2 => return vec![],
2041 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
2043 let mut map: UnhashMap<u64, Vec<&_>> =
2044 UnhashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
2047 match map.entry(hash(expr)) {
2048 Entry::Occupied(mut o) => {
2051 match_expr_list.push((o, expr));
2054 o.get_mut().push(expr);
2056 Entry::Vacant(v) => {
2057 v.insert(vec![expr]);
2065 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
2066 /// references removed.
2067 pub fn peel_hir_pat_refs<'a>(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
2068 fn peel<'a>(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
2069 if let PatKind::Ref(pat, _) = pat.kind {
2070 peel(pat, count + 1)
2078 /// Peels of expressions while the given closure returns `Some`.
2079 pub fn peel_hir_expr_while<'tcx>(
2080 mut expr: &'tcx Expr<'tcx>,
2081 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
2082 ) -> &'tcx Expr<'tcx> {
2083 while let Some(e) = f(expr) {
2089 /// Peels off up to the given number of references on the expression. Returns the underlying
2090 /// expression and the number of references removed.
2091 pub fn peel_n_hir_expr_refs<'a>(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
2092 let mut remaining = count;
2093 let e = peel_hir_expr_while(expr, |e| match e.kind {
2094 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) if remaining != 0 => {
2100 (e, count - remaining)
2103 /// Peels off all references on the expression. Returns the underlying expression and the number of
2104 /// references removed.
2105 pub fn peel_hir_expr_refs<'a>(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
2107 let e = peel_hir_expr_while(expr, |e| match e.kind {
2108 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) => {
2117 /// Peels off all references on the type. Returns the underlying type and the number of references
2119 pub fn peel_hir_ty_refs<'a>(mut ty: &'a hir::Ty<'a>) -> (&'a hir::Ty<'a>, usize) {
2123 TyKind::Rptr(_, ref_ty) => {
2127 _ => break (ty, count),
2132 /// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
2133 /// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
2134 pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
2137 ExprKind::AddrOf(_, _, e) => expr = e,
2138 ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
2145 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
2146 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2147 if let Res::Def(_, def_id) = path.res {
2148 return cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr);
2154 static TEST_ITEM_NAMES_CACHE: OnceLock<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = OnceLock::new();
2156 fn with_test_item_names(tcx: TyCtxt<'_>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
2157 let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
2158 let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
2159 let value = map.entry(module);
2161 Entry::Occupied(entry) => f(entry.get()),
2162 Entry::Vacant(entry) => {
2163 let mut names = Vec::new();
2164 for id in tcx.hir().module_items(module) {
2165 if matches!(tcx.def_kind(id.def_id), DefKind::Const)
2166 && let item = tcx.hir().item(id)
2167 && let ItemKind::Const(ty, _body) = item.kind {
2168 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2169 // We could also check for the type name `test::TestDescAndFn`
2170 if let Res::Def(DefKind::Struct, _) = path.res {
2171 let has_test_marker = tcx
2173 .attrs(item.hir_id())
2175 .any(|a| a.has_name(sym::rustc_test_marker));
2176 if has_test_marker {
2177 names.push(item.ident.name);
2183 names.sort_unstable();
2184 f(entry.insert(names))
2189 /// Checks if the function containing the given `HirId` is a `#[test]` function
2191 /// Note: Add `// compile-flags: --test` to UI tests with a `#[test]` function
2192 pub fn is_in_test_function(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2193 with_test_item_names(tcx, tcx.parent_module(id), |names| {
2196 // Since you can nest functions we need to collect all until we leave
2198 .any(|(_id, node)| {
2199 if let Node::Item(item) = node {
2200 if let ItemKind::Fn(_, _, _) = item.kind {
2201 // Note that we have sorted the item names in the visitor,
2202 // so the binary_search gets the same as `contains`, but faster.
2203 return names.binary_search(&item.ident.name).is_ok();
2211 /// Checks if the item containing the given `HirId` has `#[cfg(test)]` attribute applied
2213 /// Note: Add `// compile-flags: --test` to UI tests with a `#[cfg(test)]` function
2214 pub fn is_in_cfg_test(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2215 fn is_cfg_test(attr: &Attribute) -> bool {
2216 if attr.has_name(sym::cfg)
2217 && let Some(items) = attr.meta_item_list()
2218 && let [item] = &*items
2219 && item.has_name(sym::test)
2228 .flat_map(|(parent_id, _)| tcx.hir().attrs(parent_id))
2232 /// Checks whether item either has `test` attribute applied, or
2233 /// is a module with `test` in its name.
2235 /// Note: Add `// compile-flags: --test` to UI tests with a `#[test]` function
2236 pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
2237 is_in_test_function(tcx, item.hir_id())
2238 || matches!(item.kind, ItemKind::Mod(..))
2239 && item.ident.name.as_str().split('_').any(|a| a == "test" || a == "tests")
2242 /// Walks the HIR tree from the given expression, up to the node where the value produced by the
2243 /// expression is consumed. Calls the function for every node encountered this way until it returns
2246 /// This allows walking through `if`, `match`, `break`, block expressions to find where the value
2247 /// produced by the expression is consumed.
2248 pub fn walk_to_expr_usage<'tcx, T>(
2249 cx: &LateContext<'tcx>,
2251 mut f: impl FnMut(Node<'tcx>, HirId) -> Option<T>,
2253 let map = cx.tcx.hir();
2254 let mut iter = map.parent_iter(e.hir_id);
2255 let mut child_id = e.hir_id;
2257 while let Some((parent_id, parent)) = iter.next() {
2258 if let Some(x) = f(parent, child_id) {
2261 let parent = match parent {
2263 Node::Block(Block { expr: Some(body), .. }) | Node::Arm(Arm { body, .. }) if body.hir_id == child_id => {
2264 child_id = parent_id;
2267 Node::Arm(a) if a.body.hir_id == child_id => {
2268 child_id = parent_id;
2274 ExprKind::If(child, ..) | ExprKind::Match(child, ..) if child.hir_id != child_id => child_id = parent_id,
2275 ExprKind::Break(Destination { target_id: Ok(id), .. }, _) => {
2277 iter = map.parent_iter(id);
2279 ExprKind::Block(..) => child_id = parent_id,
2286 /// Checks whether a given span has any comment token
2287 /// This checks for all types of comment: line "//", block "/**", doc "///" "//!"
2288 pub fn span_contains_comment(sm: &SourceMap, span: Span) -> bool {
2289 let Ok(snippet) = sm.span_to_snippet(span) else { return false };
2290 return tokenize(&snippet).any(|token| {
2293 TokenKind::BlockComment { .. } | TokenKind::LineComment { .. }
2298 macro_rules! op_utils {
2299 ($($name:ident $assign:ident)*) => {
2300 /// Binary operation traits like `LangItem::Add`
2301 pub static BINOP_TRAITS: &[LangItem] = &[$(LangItem::$name,)*];
2303 /// Operator-Assign traits like `LangItem::AddAssign`
2304 pub static OP_ASSIGN_TRAITS: &[LangItem] = &[$(LangItem::$assign,)*];
2306 /// Converts `BinOpKind::Add` to `(LangItem::Add, LangItem::AddAssign)`, for example
2307 pub fn binop_traits(kind: hir::BinOpKind) -> Option<(LangItem, LangItem)> {
2309 $(hir::BinOpKind::$name => Some((LangItem::$name, LangItem::$assign)),)*