1 #![feature(box_patterns)]
2 #![feature(control_flow_enum)]
3 #![feature(in_band_lifetimes)]
6 #![feature(rustc_private)]
7 #![recursion_limit = "512"]
8 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
9 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
10 // warn on the same lints as `clippy_lints`
11 #![warn(trivial_casts, trivial_numeric_casts)]
12 // warn on lints, that are included in `rust-lang/rust`s bootstrap
13 #![warn(rust_2018_idioms, unused_lifetimes)]
14 // warn on rustc internal lints
15 #![warn(rustc::internal)]
17 // FIXME: switch to something more ergonomic here, once available.
18 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
19 extern crate rustc_ast;
20 extern crate rustc_ast_pretty;
21 extern crate rustc_attr;
22 extern crate rustc_data_structures;
23 extern crate rustc_errors;
24 extern crate rustc_hir;
25 extern crate rustc_infer;
26 extern crate rustc_lexer;
27 extern crate rustc_lint;
28 extern crate rustc_middle;
29 extern crate rustc_session;
30 extern crate rustc_span;
31 extern crate rustc_target;
32 extern crate rustc_trait_selection;
33 extern crate rustc_typeck;
38 #[allow(clippy::module_name_repetitions)]
44 pub mod eager_or_lazy;
48 pub mod numeric_literal;
51 pub mod qualify_min_const_fn;
59 pub use self::attrs::*;
60 pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, SpanlessHash};
62 use std::collections::hash_map::Entry;
63 use std::hash::BuildHasherDefault;
64 use std::lazy::SyncOnceCell;
65 use std::sync::{Mutex, MutexGuard};
67 use if_chain::if_chain;
68 use rustc_ast::ast::{self, Attribute, LitKind};
69 use rustc_data_structures::fx::FxHashMap;
70 use rustc_data_structures::unhash::UnhashMap;
72 use rustc_hir::def::{DefKind, Res};
73 use rustc_hir::def_id::DefId;
74 use rustc_hir::hir_id::{HirIdMap, HirIdSet};
75 use rustc_hir::intravisit::{walk_expr, ErasedMap, FnKind, NestedVisitorMap, Visitor};
76 use rustc_hir::itemlikevisit::ItemLikeVisitor;
77 use rustc_hir::LangItem::{OptionNone, ResultErr, ResultOk};
79 def, Arm, BindingAnnotation, Block, BlockCheckMode, Body, Constness, Destination, Expr, ExprKind, FnDecl,
80 ForeignItem, GenericArgs, HirId, Impl, ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem, Local,
81 MatchSource, Mutability, Node, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, TraitItem,
82 TraitItemKind, TraitRef, TyKind, UnOp, ArrayLen
84 use rustc_lint::{LateContext, Level, Lint, LintContext};
85 use rustc_middle::hir::exports::Export;
86 use rustc_middle::hir::map::Map;
87 use rustc_middle::hir::place::PlaceBase;
88 use rustc_middle::ty as rustc_ty;
89 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
90 use rustc_middle::ty::binding::BindingMode;
91 use rustc_middle::ty::{layout::IntegerExt, BorrowKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeFoldable, UpvarCapture};
92 use rustc_semver::RustcVersion;
93 use rustc_session::Session;
94 use rustc_span::def_id::LocalDefId;
95 use rustc_span::hygiene::{ExpnKind, MacroKind};
96 use rustc_span::source_map::original_sp;
98 use rustc_span::symbol::{kw, Symbol};
99 use rustc_span::{Span, DUMMY_SP};
100 use rustc_target::abi::Integer;
102 use crate::consts::{constant, Constant};
103 use crate::ty::{can_partially_move_ty, is_copy, is_recursively_primitive_type};
104 use crate::visitors::expr_visitor_no_bodies;
106 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
107 if let Ok(version) = RustcVersion::parse(msrv) {
108 return Some(version);
109 } else if let Some(sess) = sess {
110 if let Some(span) = span {
111 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
117 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
118 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
122 macro_rules! extract_msrv_attr {
124 extract_msrv_attr!(@LateContext, ());
127 extract_msrv_attr!(@EarlyContext);
129 (@$context:ident$(, $call:tt)?) => {
130 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
131 use $crate::get_unique_inner_attr;
132 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
134 if let Some(msrv) = msrv_attr.value_str() {
135 self.msrv = $crate::parse_msrv(
137 Some(cx.sess$($call)?),
138 Some(msrv_attr.span),
141 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
150 /// Returns `true` if the span comes from a macro expansion, no matter if from a
151 /// macro by example or from a procedural macro
153 pub fn in_macro(span: Span) -> bool {
154 span.from_expansion() && !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
157 /// Returns `true` if the two spans come from differing expansions (i.e., one is
158 /// from a macro and one isn't).
160 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
161 rhs.ctxt() != lhs.ctxt()
164 /// If the given expression is a local binding, find the initializer expression.
165 /// If that initializer expression is another local binding, find its initializer again.
166 /// This process repeats as long as possible (but usually no more than once). Initializer
167 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
180 /// let def = abc + 2;
181 /// // ^^^^^^^ output
185 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
186 while let Some(init) = path_to_local(expr)
187 .and_then(|id| find_binding_init(cx, id))
188 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
195 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
196 /// By only considering immutable bindings, we guarantee that the returned expression represents the
197 /// value of the binding wherever it is referenced.
199 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
200 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
201 /// canonical binding `HirId`.
202 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
203 let hir = cx.tcx.hir();
205 if let Some(Node::Binding(pat)) = hir.find(hir_id);
206 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
207 let parent = hir.get_parent_node(hir_id);
208 if let Some(Node::Local(local)) = hir.find(parent);
216 /// Returns `true` if the given `NodeId` is inside a constant context
221 /// if in_constant(cx, expr.hir_id) {
225 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
226 let parent_id = cx.tcx.hir().get_parent_item(id);
227 match cx.tcx.hir().get(parent_id) {
229 kind: ItemKind::Const(..) | ItemKind::Static(..),
232 | Node::TraitItem(&TraitItem {
233 kind: TraitItemKind::Const(..),
236 | Node::ImplItem(&ImplItem {
237 kind: ImplItemKind::Const(..),
240 | Node::AnonConst(_) => true,
242 kind: ItemKind::Fn(ref sig, ..),
245 | Node::ImplItem(&ImplItem {
246 kind: ImplItemKind::Fn(ref sig, _),
248 }) => sig.header.constness == Constness::Const,
253 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
254 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
255 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
256 if let QPath::Resolved(_, path) = qpath {
257 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
258 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
259 return cx.tcx.parent(ctor_id) == Some(item_id);
266 pub fn is_unit_expr(expr: &Expr<'_>) -> bool {
276 ) | ExprKind::Tup([])
280 /// Checks if given pattern is a wildcard (`_`)
281 pub fn is_wild(pat: &Pat<'_>) -> bool {
282 matches!(pat.kind, PatKind::Wild)
285 /// Checks if the first type parameter is a lang item.
286 pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
287 let ty = get_qpath_generic_tys(qpath).next()?;
289 if let TyKind::Path(qpath) = &ty.kind {
290 cx.qpath_res(qpath, ty.hir_id)
292 .map_or(false, |id| {
293 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
301 /// Checks if the first type parameter is a diagnostic item.
302 pub fn is_ty_param_diagnostic_item(
303 cx: &LateContext<'_>,
306 ) -> Option<&'tcx hir::Ty<'tcx>> {
307 let ty = get_qpath_generic_tys(qpath).next()?;
309 if let TyKind::Path(qpath) = &ty.kind {
310 cx.qpath_res(qpath, ty.hir_id)
312 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
319 /// Checks if the method call given in `expr` belongs to the given trait.
320 /// This is a deprecated function, consider using [`is_trait_method`].
321 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
322 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
323 let trt_id = cx.tcx.trait_of_item(def_id);
324 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
327 /// Checks if a method is defined in an impl of a diagnostic item
328 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
329 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
330 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
331 return cx.tcx.is_diagnostic_item(diag_item, adt.did);
337 /// Checks if a method is in a diagnostic item trait
338 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
339 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
340 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
345 /// Checks if the method call given in `expr` belongs to the given trait.
346 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
348 .type_dependent_def_id(expr.hir_id)
349 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
352 /// Checks if the given expression is a path referring an item on the trait
353 /// that is marked with the given diagnostic item.
355 /// For checking method call expressions instead of path expressions, use
356 /// [`is_trait_method`].
358 /// For example, this can be used to find if an expression like `u64::default`
359 /// refers to an item of the trait `Default`, which is associated with the
360 /// `diag_item` of `sym::Default`.
361 pub fn is_trait_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
362 if let hir::ExprKind::Path(ref qpath) = expr.kind {
363 cx.qpath_res(qpath, expr.hir_id)
365 .map_or(false, |def_id| is_diag_trait_item(cx, def_id, diag_item))
371 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
373 QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
374 QPath::TypeRelative(_, seg) => seg,
375 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
379 pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
381 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
382 QPath::TypeRelative(_, s) => s.args,
383 QPath::LangItem(..) => None,
387 pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
388 get_qpath_generics(path)
389 .map_or([].as_ref(), |a| a.args)
392 if let hir::GenericArg::Type(ty) = a {
400 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
402 QPath::Resolved(_, path) => path.segments.get(0),
403 QPath::TypeRelative(_, seg) => Some(seg),
404 QPath::LangItem(..) => None,
408 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
409 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
410 /// `QPath::Resolved.1.res.opt_def_id()`.
412 /// Matches a `QPath` against a slice of segment string literals.
414 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
415 /// `rustc_hir::QPath`.
419 /// match_qpath(path, &["std", "rt", "begin_unwind"])
421 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
423 QPath::Resolved(_, path) => match_path(path, segments),
424 QPath::TypeRelative(ty, segment) => match ty.kind {
425 TyKind::Path(ref inner_path) => {
426 if let [prefix @ .., end] = segments {
427 if match_qpath(inner_path, prefix) {
428 return segment.ident.name.as_str() == *end;
435 QPath::LangItem(..) => false,
439 /// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
440 pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
441 if let ExprKind::Path(p) = &expr.kind {
442 cx.qpath_res(p, expr.hir_id)
448 /// Resolves the path to a `DefId` and checks if it matches the given path.
449 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
450 cx.qpath_res(path, hir_id)
452 .map_or(false, |id| match_def_path(cx, id, segments))
455 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
457 /// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
458 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
459 expr_path_res(cx, expr)
461 .map_or(false, |id| match_def_path(cx, id, segments))
464 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
466 pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
467 expr_path_res(cx, expr)
469 .map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
472 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
473 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
474 /// `QPath::Resolved.1.res.opt_def_id()`.
476 /// Matches a `Path` against a slice of segment string literals.
478 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
479 /// `rustc_hir::Path`.
484 /// if match_path(&trait_ref.path, &paths::HASH) {
485 /// // This is the `std::hash::Hash` trait.
488 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
489 /// // This is a `rustc_middle::lint::Lint`.
492 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
496 .zip(segments.iter().rev())
497 .all(|(a, b)| a.ident.name.as_str() == *b)
500 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
501 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
502 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
503 if let Res::Local(id) = path.res {
510 /// Returns true if the expression is a path to a local with the specified `HirId`.
511 /// Use this function to see if an expression matches a function argument or a match binding.
512 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
513 path_to_local(expr) == Some(id)
516 /// Gets the definition associated to a path.
517 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
518 macro_rules! try_res {
522 None => return Res::Err,
526 fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export> {
527 tcx.item_children(def_id)
529 .find(|item| item.ident.name.as_str() == name)
532 let (krate, first, path) = match *path {
533 [krate, first, ref path @ ..] => (krate, first, path),
535 return PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy);
537 _ => return Res::Err,
540 let crates = tcx.crates(());
541 let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
542 let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
546 // `get_def_path` seems to generate these empty segments for extern blocks.
547 // We can just ignore them.
548 .filter(|segment| !segment.is_empty())
549 // for each segment, find the child item
550 .try_fold(first, |item, segment| {
551 let def_id = item.res.def_id();
552 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
554 } else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
555 // it is not a child item so check inherent impl items
556 tcx.inherent_impls(def_id)
558 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
563 try_res!(last).res.expect_non_local()
566 /// Convenience function to get the `DefId` of a trait by path.
567 /// It could be a trait or trait alias.
568 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
569 match path_to_res(cx, path) {
570 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
575 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
577 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
580 /// struct Point(isize, isize);
582 /// impl std::ops::Add for Point {
583 /// type Output = Self;
585 /// fn add(self, other: Self) -> Self {
590 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
591 // Get the implemented trait for the current function
592 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
594 if parent_impl != hir::CRATE_HIR_ID;
595 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
596 if let hir::ItemKind::Impl(impl_) = &item.kind;
597 then { return impl_.of_trait.as_ref(); }
602 /// This method will return tuple of projection stack and root of the expression,
603 /// used in `can_mut_borrow_both`.
605 /// For example, if `e` represents the `v[0].a.b[x]`
606 /// this method will return a tuple, composed of a `Vec`
607 /// containing the `Expr`s for `v[0], v[0].a, v[0].a.b, v[0].a.b[x]`
608 /// and an `Expr` for root of them, `v`
609 fn projection_stack<'a, 'hir>(mut e: &'a Expr<'hir>) -> (Vec<&'a Expr<'hir>>, &'a Expr<'hir>) {
610 let mut result = vec![];
613 ExprKind::Index(ep, _) | ExprKind::Field(ep, _) => {
624 /// Checks if two expressions can be mutably borrowed simultaneously
625 /// and they aren't dependent on borrowing same thing twice
626 pub fn can_mut_borrow_both(cx: &LateContext<'_>, e1: &Expr<'_>, e2: &Expr<'_>) -> bool {
627 let (s1, r1) = projection_stack(e1);
628 let (s2, r2) = projection_stack(e2);
629 if !eq_expr_value(cx, r1, r2) {
632 for (x1, x2) in s1.iter().zip(s2.iter()) {
633 match (&x1.kind, &x2.kind) {
634 (ExprKind::Field(_, i1), ExprKind::Field(_, i2)) => {
639 (ExprKind::Index(_, i1), ExprKind::Index(_, i2)) => {
640 if !eq_expr_value(cx, i1, i2) {
650 /// Returns true if the `def_id` associated with the `path` is recognized as a "default-equivalent"
651 /// constructor from the std library
652 fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<'_>) -> bool {
653 let std_types_symbols = &[
665 if let QPath::TypeRelative(_, method) = path {
666 if method.ident.name == sym::new {
667 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
668 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
669 return std_types_symbols
671 .any(|&symbol| cx.tcx.is_diagnostic_item(symbol, adt.did));
679 /// Return true if the expr is equal to `Default::default` when evaluated.
680 pub fn is_default_equivalent_call(cx: &LateContext<'_>, repl_func: &Expr<'_>) -> bool {
682 if let hir::ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
683 if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
684 if is_diag_trait_item(cx, repl_def_id, sym::Default)
685 || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
695 /// Returns true if the expr is equal to `Default::default()` of it's type when evaluated.
696 /// It doesn't cover all cases, for example indirect function calls (some of std
697 /// functions are supported) but it is the best we have.
698 pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
700 ExprKind::Lit(lit) => match lit.node {
701 LitKind::Bool(false) | LitKind::Int(0, _) => true,
702 LitKind::Str(s, _) => s.is_empty(),
705 ExprKind::Tup(items) | ExprKind::Array(items) => items.iter().all(|x| is_default_equivalent(cx, x)),
706 ExprKind::Repeat(x, len) => if_chain! {
707 if let ArrayLen::Body(len) = len;
708 if let ExprKind::Lit(ref const_lit) = cx.tcx.hir().body(len.body).value.kind;
709 if let LitKind::Int(v, _) = const_lit.node;
710 if v <= 32 && is_default_equivalent(cx, x);
718 ExprKind::Call(repl_func, _) => is_default_equivalent_call(cx, repl_func),
719 ExprKind::Path(qpath) => is_lang_ctor(cx, qpath, OptionNone),
720 ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
725 /// Checks if the top level expression can be moved into a closure as is.
726 /// Currently checks for:
727 /// * Break/Continue outside the given loop HIR ids.
728 /// * Yield/Return statements.
729 /// * Inline assembly.
730 /// * Usages of a field of a local where the type of the local can be partially moved.
732 /// For example, given the following function:
735 /// fn f<'a>(iter: &mut impl Iterator<Item = (usize, &'a mut String)>) {
736 /// for item in iter {
747 /// When called on the expression `item.0` this will return false unless the local `item` is in the
748 /// `ignore_locals` set. The type `(usize, &mut String)` can have the second element moved, so it
749 /// isn't always safe to move into a closure when only a single field is needed.
751 /// When called on the `continue` expression this will return false unless the outer loop expression
752 /// is in the `loop_ids` set.
754 /// Note that this check is not recursive, so passing the `if` expression will always return true
755 /// even though sub-expressions might return false.
756 pub fn can_move_expr_to_closure_no_visit(
757 cx: &LateContext<'tcx>,
758 expr: &'tcx Expr<'_>,
760 ignore_locals: &HirIdSet,
763 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
764 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
765 if loop_ids.contains(&id) =>
770 | ExprKind::Continue(_)
772 | ExprKind::Yield(..)
773 | ExprKind::InlineAsm(_)
774 | ExprKind::LlvmInlineAsm(_) => false,
775 // Accessing a field of a local value can only be done if the type isn't
781 ExprKind::Path(QPath::Resolved(
784 res: Res::Local(local_id),
791 ) if !ignore_locals.contains(local_id) && can_partially_move_ty(cx, cx.typeck_results().node_type(hir_id)) => {
792 // TODO: check if the local has been partially moved. Assume it has for now.
799 /// How a local is captured by a closure
800 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
801 pub enum CaptureKind {
806 pub fn is_imm_ref(self) -> bool {
807 self == Self::Ref(Mutability::Not)
810 impl std::ops::BitOr for CaptureKind {
812 fn bitor(self, rhs: Self) -> Self::Output {
814 (CaptureKind::Value, _) | (_, CaptureKind::Value) => CaptureKind::Value,
815 (CaptureKind::Ref(Mutability::Mut), CaptureKind::Ref(_))
816 | (CaptureKind::Ref(_), CaptureKind::Ref(Mutability::Mut)) => CaptureKind::Ref(Mutability::Mut),
817 (CaptureKind::Ref(Mutability::Not), CaptureKind::Ref(Mutability::Not)) => CaptureKind::Ref(Mutability::Not),
821 impl std::ops::BitOrAssign for CaptureKind {
822 fn bitor_assign(&mut self, rhs: Self) {
827 /// Given an expression referencing a local, determines how it would be captured in a closure.
828 /// Note as this will walk up to parent expressions until the capture can be determined it should
829 /// only be used while making a closure somewhere a value is consumed. e.g. a block, match arm, or
830 /// function argument (other than a receiver).
831 pub fn capture_local_usage(cx: &LateContext<'tcx>, e: &Expr<'_>) -> CaptureKind {
832 fn pat_capture_kind(cx: &LateContext<'_>, pat: &Pat<'_>) -> CaptureKind {
833 let mut capture = CaptureKind::Ref(Mutability::Not);
834 pat.each_binding_or_first(&mut |_, id, span, _| match cx
836 .extract_binding_mode(cx.sess(), id, span)
839 BindingMode::BindByValue(_) if !is_copy(cx, cx.typeck_results().node_type(id)) => {
840 capture = CaptureKind::Value;
842 BindingMode::BindByReference(Mutability::Mut) if capture != CaptureKind::Value => {
843 capture = CaptureKind::Ref(Mutability::Mut);
850 debug_assert!(matches!(
852 ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(_), .. }))
855 let mut child_id = e.hir_id;
856 let mut capture = CaptureKind::Value;
857 let mut capture_expr_ty = e;
859 for (parent_id, parent) in cx.tcx.hir().parent_iter(e.hir_id) {
862 kind: Adjust::Deref(_) | Adjust::Borrow(AutoBorrow::Ref(..)),
870 .map_or(&[][..], |x| &**x)
872 if let rustc_ty::RawPtr(TypeAndMut { mutbl: mutability, .. }) | rustc_ty::Ref(_, _, mutability) =
873 *adjust.last().map_or(target, |a| a.target).kind()
875 return CaptureKind::Ref(mutability);
880 Node::Expr(e) => match e.kind {
881 ExprKind::AddrOf(_, mutability, _) => return CaptureKind::Ref(mutability),
882 ExprKind::Index(..) | ExprKind::Unary(UnOp::Deref, _) => capture = CaptureKind::Ref(Mutability::Not),
883 ExprKind::Assign(lhs, ..) | ExprKind::Assign(_, lhs, _) if lhs.hir_id == child_id => {
884 return CaptureKind::Ref(Mutability::Mut);
886 ExprKind::Field(..) => {
887 if capture == CaptureKind::Value {
891 ExprKind::Let(let_expr) => {
892 let mutability = match pat_capture_kind(cx, let_expr.pat) {
893 CaptureKind::Value => Mutability::Not,
894 CaptureKind::Ref(m) => m,
896 return CaptureKind::Ref(mutability);
898 ExprKind::Match(_, arms, _) => {
899 let mut mutability = Mutability::Not;
900 for capture in arms.iter().map(|arm| pat_capture_kind(cx, arm.pat)) {
902 CaptureKind::Value => break,
903 CaptureKind::Ref(Mutability::Mut) => mutability = Mutability::Mut,
904 CaptureKind::Ref(Mutability::Not) => (),
907 return CaptureKind::Ref(mutability);
911 Node::Local(l) => match pat_capture_kind(cx, l.pat) {
912 CaptureKind::Value => break,
913 capture @ CaptureKind::Ref(_) => return capture,
918 child_id = parent_id;
921 if capture == CaptureKind::Value && is_copy(cx, cx.typeck_results().expr_ty(capture_expr_ty)) {
922 // Copy types are never automatically captured by value.
923 CaptureKind::Ref(Mutability::Not)
929 /// Checks if the expression can be moved into a closure as is. This will return a list of captures
930 /// if so, otherwise, `None`.
931 pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<HirIdMap<CaptureKind>> {
932 struct V<'cx, 'tcx> {
933 cx: &'cx LateContext<'tcx>,
934 // Stack of potential break targets contained in the expression.
936 /// Local variables created in the expression. These don't need to be captured.
938 /// Whether this expression can be turned into a closure.
940 /// Locals which need to be captured, and whether they need to be by value, reference, or
941 /// mutable reference.
942 captures: HirIdMap<CaptureKind>,
944 impl Visitor<'tcx> for V<'_, 'tcx> {
945 type Map = ErasedMap<'tcx>;
946 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
947 NestedVisitorMap::None
950 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
951 if !self.allow_closure {
956 ExprKind::Path(QPath::Resolved(None, &Path { res: Res::Local(l), .. })) => {
957 if !self.locals.contains(&l) {
958 let cap = capture_local_usage(self.cx, e);
959 self.captures.entry(l).and_modify(|e| *e |= cap).or_insert(cap);
962 ExprKind::Closure(..) => {
963 let closure_id = self.cx.tcx.hir().local_def_id(e.hir_id).to_def_id();
964 for capture in self.cx.typeck_results().closure_min_captures_flattened(closure_id) {
965 let local_id = match capture.place.base {
966 PlaceBase::Local(id) => id,
967 PlaceBase::Upvar(var) => var.var_path.hir_id,
970 if !self.locals.contains(&local_id) {
971 let capture = match capture.info.capture_kind {
972 UpvarCapture::ByValue(_) => CaptureKind::Value,
973 UpvarCapture::ByRef(borrow) => match borrow.kind {
974 BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
975 BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
976 CaptureKind::Ref(Mutability::Mut)
982 .and_modify(|e| *e |= capture)
987 ExprKind::Loop(b, ..) => {
988 self.loops.push(e.hir_id);
993 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops, &self.locals);
999 fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) {
1000 p.each_binding_or_first(&mut |_, id, _, _| {
1001 self.locals.insert(id);
1008 allow_closure: true,
1010 locals: HirIdSet::default(),
1011 captures: HirIdMap::default(),
1014 v.allow_closure.then(|| v.captures)
1017 /// Returns the method names and argument list of nested method call expressions that make up
1018 /// `expr`. method/span lists are sorted with the most recent call first.
1019 pub fn method_calls<'tcx>(
1020 expr: &'tcx Expr<'tcx>,
1022 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
1023 let mut method_names = Vec::with_capacity(max_depth);
1024 let mut arg_lists = Vec::with_capacity(max_depth);
1025 let mut spans = Vec::with_capacity(max_depth);
1027 let mut current = expr;
1028 for _ in 0..max_depth {
1029 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
1030 if args.iter().any(|e| e.span.from_expansion()) {
1033 method_names.push(path.ident.name);
1034 arg_lists.push(&**args);
1042 (method_names, arg_lists, spans)
1045 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
1047 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
1048 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
1049 /// containing the `Expr`s for
1050 /// `.bar()` and `.baz()`
1051 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
1052 let mut current = expr;
1053 let mut matched = Vec::with_capacity(methods.len());
1054 for method_name in methods.iter().rev() {
1055 // method chains are stored last -> first
1056 if let ExprKind::MethodCall(path, _, args, _) = current.kind {
1057 if path.ident.name.as_str() == *method_name {
1058 if args.iter().any(|e| e.span.from_expansion()) {
1061 matched.push(args); // build up `matched` backwards
1062 current = &args[0]; // go to parent expression
1070 // Reverse `matched` so that it is in the same order as `methods`.
1075 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
1076 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
1079 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
1082 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
1083 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1084 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
1085 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
1086 Some(def_id) == cx.tcx.lang_items().panic_impl()
1089 /// Gets the name of the item the expression is in, if available.
1090 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
1091 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
1092 match cx.tcx.hir().find(parent_id) {
1094 Node::Item(Item { ident, .. })
1095 | Node::TraitItem(TraitItem { ident, .. })
1096 | Node::ImplItem(ImplItem { ident, .. }),
1097 ) => Some(ident.name),
1102 pub struct ContainsName {
1107 impl<'tcx> Visitor<'tcx> for ContainsName {
1108 type Map = Map<'tcx>;
1110 fn visit_name(&mut self, _: Span, name: Symbol) {
1111 if self.name == name {
1115 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
1116 NestedVisitorMap::None
1120 /// Checks if an `Expr` contains a certain name.
1121 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
1122 let mut cn = ContainsName { name, result: false };
1123 cn.visit_expr(expr);
1127 /// Returns `true` if `expr` contains a return expression
1128 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
1129 let mut found = false;
1130 expr_visitor_no_bodies(|expr| {
1132 if let hir::ExprKind::Ret(..) = &expr.kind {
1142 /// Finds calls of the specified macros in a function body.
1143 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
1144 let mut result = Vec::new();
1145 expr_visitor_no_bodies(|expr| {
1146 if names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
1147 result.push(expr.span);
1151 .visit_expr(&body.value);
1155 /// Extends the span to the beginning of the spans line, incl. whitespaces.
1160 /// // will be converted to
1162 /// // ^^^^^^^^^^^^^^
1164 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
1165 let span = original_sp(span, DUMMY_SP);
1166 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
1167 let line_no = source_map_and_line.line;
1168 let line_start = source_map_and_line.sf.lines[line_no];
1169 span.with_lo(line_start)
1172 /// Gets the parent node, if any.
1173 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
1174 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
1177 /// Gets the parent expression, if any –- this is useful to constrain a lint.
1178 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1179 get_parent_expr_for_hir(cx, e.hir_id)
1182 /// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
1183 /// constraint lints
1184 pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
1185 match get_parent_node(cx.tcx, hir_id) {
1186 Some(Node::Expr(parent)) => Some(parent),
1191 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
1192 let map = &cx.tcx.hir();
1193 let enclosing_node = map
1194 .get_enclosing_scope(hir_id)
1195 .and_then(|enclosing_id| map.find(enclosing_id));
1196 enclosing_node.and_then(|node| match node {
1197 Node::Block(block) => Some(block),
1199 kind: ItemKind::Fn(_, _, eid),
1202 | Node::ImplItem(&ImplItem {
1203 kind: ImplItemKind::Fn(_, eid),
1205 }) => match cx.tcx.hir().body(eid).value.kind {
1206 ExprKind::Block(block, _) => Some(block),
1213 /// Gets the loop or closure enclosing the given expression, if any.
1214 pub fn get_enclosing_loop_or_closure(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1215 for (_, node) in tcx.hir().parent_iter(expr.hir_id) {
1219 kind: ExprKind::Loop(..) | ExprKind::Closure(..),
1222 ) => return Some(e),
1223 Node::Expr(_) | Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
1230 /// Gets the parent node if it's an impl block.
1231 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
1232 match tcx.hir().parent_iter(id).next() {
1236 kind: ItemKind::Impl(imp),
1244 /// Removes blocks around an expression, only if the block contains just one expression
1245 /// and no statements. Unsafe blocks are not removed.
1249 /// * `{ x }` -> `x`
1250 /// * `{{ x }}` -> `x`
1251 /// * `{ x; }` -> `{ x; }`
1252 /// * `{ x; y }` -> `{ x; y }`
1253 /// * `{ unsafe { x } }` -> `unsafe { x }`
1254 pub fn peel_blocks<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1255 while let ExprKind::Block(
1259 rules: BlockCheckMode::DefaultBlock,
1270 /// Removes blocks around an expression, only if the block contains just one expression
1271 /// or just one expression statement with a semicolon. Unsafe blocks are not removed.
1275 /// * `{ x }` -> `x`
1276 /// * `{ x; }` -> `x`
1277 /// * `{{ x; }}` -> `x`
1278 /// * `{ x; y }` -> `{ x; y }`
1279 /// * `{ unsafe { x } }` -> `unsafe { x }`
1280 pub fn peel_blocks_with_stmt<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1281 while let ExprKind::Block(
1285 rules: BlockCheckMode::DefaultBlock,
1292 kind: StmtKind::Expr(inner) | StmtKind::Semi(inner),
1297 rules: BlockCheckMode::DefaultBlock,
1308 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
1309 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1310 let mut iter = tcx.hir().parent_iter(expr.hir_id);
1315 kind: ExprKind::If(_, _, Some(else_expr)),
1318 )) => else_expr.hir_id == expr.hir_id,
1323 /// Checks whether the given expression is a constant integer of the given value.
1324 /// unlike `is_integer_literal`, this version does const folding
1325 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
1326 if is_integer_literal(e, value) {
1329 let enclosing_body = cx.tcx.hir().local_def_id(cx.tcx.hir().enclosing_body_owner(e.hir_id));
1330 if let Some((Constant::Int(v), _)) = constant(cx, cx.tcx.typeck(enclosing_body), e) {
1336 /// Checks whether the given expression is a constant literal of the given value.
1337 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
1338 // FIXME: use constant folding
1339 if let ExprKind::Lit(ref spanned) = expr.kind {
1340 if let LitKind::Int(v, _) = spanned.node {
1347 /// Returns `true` if the given `Expr` has been coerced before.
1349 /// Examples of coercions can be found in the Nomicon at
1350 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
1352 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
1353 /// information on adjustments and coercions.
1354 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1355 cx.typeck_results().adjustments().get(e.hir_id).is_some()
1358 /// Returns the pre-expansion span if this comes from an expansion of the
1360 /// See also [`is_direct_expn_of`].
1362 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
1364 if span.from_expansion() {
1365 let data = span.ctxt().outer_expn_data();
1366 let new_span = data.call_site;
1368 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1369 if mac_name.as_str() == name {
1370 return Some(new_span);
1381 /// Returns the pre-expansion span if the span directly comes from an expansion
1382 /// of the macro `name`.
1383 /// The difference with [`is_expn_of`] is that in
1385 /// # macro_rules! foo { ($name:tt!$args:tt) => { $name!$args } }
1386 /// # macro_rules! bar { ($e:expr) => { $e } }
1389 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1390 /// from `bar!` by `is_direct_expn_of`.
1392 pub fn is_direct_expn_of(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);
1407 /// Convenience function to get the return type of a function.
1408 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1409 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1410 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1411 cx.tcx.erase_late_bound_regions(ret_ty)
1414 /// Convenience function to get the nth argument type of a function.
1415 pub fn nth_arg<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId, nth: usize) -> Ty<'tcx> {
1416 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1417 let arg = cx.tcx.fn_sig(fn_def_id).input(nth);
1418 cx.tcx.erase_late_bound_regions(arg)
1421 /// Checks if an expression is constructing a tuple-like enum variant or struct
1422 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1423 if let ExprKind::Call(fun, _) = expr.kind {
1424 if let ExprKind::Path(ref qp) = fun.kind {
1425 let res = cx.qpath_res(qp, fun.hir_id);
1427 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1428 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1436 /// Returns `true` if a pattern is refutable.
1437 // TODO: should be implemented using rustc/mir_build/thir machinery
1438 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1439 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1441 cx.qpath_res(qpath, id),
1442 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1446 fn are_refutable<'a, I: IntoIterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, i: I) -> bool {
1447 i.into_iter().any(|pat| is_refutable(cx, pat))
1451 PatKind::Wild => false,
1452 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1453 PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
1454 PatKind::Lit(..) | PatKind::Range(..) => true,
1455 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1456 PatKind::Or(pats) => {
1457 // TODO: should be the honest check, that pats is exhaustive set
1458 are_refutable(cx, pats)
1460 PatKind::Tuple(pats, _) => are_refutable(cx, pats),
1461 PatKind::Struct(ref qpath, fields, _) => {
1462 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1464 PatKind::TupleStruct(ref qpath, pats, _) => is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats),
1465 PatKind::Slice(head, middle, tail) => {
1466 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1467 rustc_ty::Slice(..) => {
1468 // [..] is the only irrefutable slice pattern.
1469 !head.is_empty() || middle.is_none() || !tail.is_empty()
1471 rustc_ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter())),
1481 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1482 /// the function once on the given pattern.
1483 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1484 if let PatKind::Or(pats) = pat.kind {
1485 pats.iter().for_each(f);
1491 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1492 /// implementations have.
1493 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1494 has_attr(attrs, sym::automatically_derived)
1497 pub fn is_self(slf: &Param<'_>) -> bool {
1498 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1499 name.name == kw::SelfLower
1505 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1506 if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind {
1507 if let Res::SelfTy(..) = path.res {
1514 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1515 (0..decl.inputs.len()).map(move |i| &body.params[i])
1518 /// Checks if a given expression is a match expression expanded from the `?`
1519 /// operator or the `try` macro.
1520 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1521 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1523 if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
1524 if is_lang_ctor(cx, path, ResultOk);
1525 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1526 if path_to_local_id(arm.body, hir_id);
1534 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1535 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1536 is_lang_ctor(cx, path, ResultErr)
1542 if let ExprKind::Match(_, arms, ref source) = expr.kind {
1543 // desugared from a `?` operator
1544 if *source == MatchSource::TryDesugar {
1550 if arms[0].guard.is_none();
1551 if arms[1].guard.is_none();
1552 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) ||
1553 (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1563 /// Returns `true` if the lint is allowed in the current context
1565 /// Useful for skipping long running code when it's unnecessary
1566 pub fn is_lint_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1567 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1570 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1571 while let PatKind::Ref(subpat, _) = pat.kind {
1577 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1578 Integer::from_int_ty(&tcx, ity).size().bits()
1581 #[allow(clippy::cast_possible_wrap)]
1582 /// Turn a constant int byte representation into an i128
1583 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1584 let amt = 128 - int_bits(tcx, ity);
1585 ((u as i128) << amt) >> amt
1588 #[allow(clippy::cast_sign_loss)]
1589 /// clip unused bytes
1590 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1591 let amt = 128 - int_bits(tcx, ity);
1592 ((u as u128) << amt) >> amt
1595 /// clip unused bytes
1596 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1597 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1598 let amt = 128 - bits;
1602 pub fn has_attr(attrs: &[ast::Attribute], symbol: Symbol) -> bool {
1603 attrs.iter().any(|attr| attr.has_name(symbol))
1606 pub fn any_parent_has_attr(tcx: TyCtxt<'_>, node: HirId, symbol: Symbol) -> bool {
1607 let map = &tcx.hir();
1608 let mut prev_enclosing_node = None;
1609 let mut enclosing_node = node;
1610 while Some(enclosing_node) != prev_enclosing_node {
1611 if has_attr(map.attrs(enclosing_node), symbol) {
1614 prev_enclosing_node = Some(enclosing_node);
1615 enclosing_node = map.get_parent_item(enclosing_node);
1621 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1622 any_parent_has_attr(tcx, node, sym::automatically_derived)
1625 /// Matches a function call with the given path and returns the arguments.
1630 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1632 pub fn match_function_call<'tcx>(
1633 cx: &LateContext<'tcx>,
1634 expr: &'tcx Expr<'_>,
1636 ) -> Option<&'tcx [Expr<'tcx>]> {
1638 if let ExprKind::Call(fun, args) = expr.kind;
1639 if let ExprKind::Path(ref qpath) = fun.kind;
1640 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1641 if match_def_path(cx, fun_def_id, path);
1649 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1652 /// Please use `match_any_diagnostic_items` if the targets are all diagnostic items.
1653 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1654 let search_path = cx.get_def_path(did);
1657 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1660 /// Checks if the given `DefId` matches any of provided diagnostic items. Returns the index of
1661 /// matching path, if any.
1662 pub fn match_any_diagnostic_items(cx: &LateContext<'_>, def_id: DefId, diag_items: &[Symbol]) -> Option<usize> {
1665 .position(|item| cx.tcx.is_diagnostic_item(*item, def_id))
1668 /// Checks if the given `DefId` matches the path.
1669 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1670 // We should probably move to Symbols in Clippy as well rather than interning every time.
1671 let path = cx.get_def_path(did);
1672 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1675 /// Checks if the given `DefId` matches the `libc` item.
1676 pub fn match_libc_symbol(cx: &LateContext<'_>, did: DefId, name: &str) -> bool {
1677 let path = cx.get_def_path(did);
1678 // libc is meant to be used as a flat list of names, but they're all actually defined in different
1679 // modules based on the target platform. Ignore everything but crate name and the item name.
1680 path.first().map_or(false, |s| s.as_str() == "libc") && path.last().map_or(false, |s| s.as_str() == name)
1683 pub fn match_panic_call(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1684 if let ExprKind::Call(func, [arg]) = expr.kind {
1685 expr_path_res(cx, func)
1687 .map_or(false, |id| match_panic_def_id(cx, id))
1694 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1695 match_any_def_paths(
1699 &paths::BEGIN_PANIC,
1701 &paths::PANICKING_PANIC,
1702 &paths::PANICKING_PANIC_FMT,
1703 &paths::PANICKING_PANIC_STR,
1709 /// Returns the list of condition expressions and the list of blocks in a
1710 /// sequence of `if/else`.
1711 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1712 /// `if a { c } else if b { d } else { e }`.
1713 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1714 let mut conds = Vec::new();
1715 let mut blocks: Vec<&Block<'_>> = Vec::new();
1717 while let Some(higher::IfOrIfLet { cond, then, r#else }) = higher::IfOrIfLet::hir(expr) {
1719 if let ExprKind::Block(block, _) = then.kind {
1722 panic!("ExprKind::If node is not an ExprKind::Block");
1725 if let Some(else_expr) = r#else {
1732 // final `else {..}`
1733 if !blocks.is_empty() {
1734 if let ExprKind::Block(block, _) = expr.kind {
1742 /// Checks if the given function kind is an async function.
1743 pub fn is_async_fn(kind: FnKind<'_>) -> bool {
1744 matches!(kind, FnKind::ItemFn(_, _, header, _) if header.asyncness == IsAsync::Async)
1747 /// Peels away all the compiler generated code surrounding the body of an async function,
1748 pub fn get_async_fn_body(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
1749 if let ExprKind::Call(
1753 kind: ExprKind::Closure(_, _, body, _, _),
1759 if let ExprKind::Block(
1764 kind: ExprKind::DropTemps(expr),
1770 ) = tcx.hir().body(body).value.kind
1778 // Finds the `#[must_use]` attribute, if any
1779 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1780 attrs.iter().find(|a| a.has_name(sym::must_use))
1783 // check if expr is calling method or function with #[must_use] attribute
1784 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1785 let did = match expr.kind {
1786 ExprKind::Call(path, _) => if_chain! {
1787 if let ExprKind::Path(ref qpath) = path.kind;
1788 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1795 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1799 did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
1802 /// Checks if an expression represents the identity function
1803 /// Only examines closures and `std::convert::identity`
1804 pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1805 /// Checks if a function's body represents the identity function. Looks for bodies of the form:
1807 /// * `|x| return x`
1808 /// * `|x| { return x }`
1809 /// * `|x| { return x; }`
1810 fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
1811 let id = if_chain! {
1812 if let [param] = func.params;
1813 if let PatKind::Binding(_, id, _, _) = param.pat.kind;
1821 let mut expr = &func.value;
1825 ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
1826 | ExprKind::Ret(Some(e)) => expr = e,
1828 ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
1830 if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
1831 if let ExprKind::Ret(Some(ret_val)) = e.kind;
1839 _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
1845 ExprKind::Closure(_, _, body_id, _, _) => is_body_identity_function(cx, cx.tcx.hir().body(body_id)),
1846 ExprKind::Path(ref path) => is_qpath_def_path(cx, path, expr.hir_id, &paths::CONVERT_IDENTITY),
1851 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1852 pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
1853 let mut child_id = expr.hir_id;
1854 let mut iter = tcx.hir().parent_iter(child_id);
1858 Some((id, Node::Block(_))) => child_id = id,
1859 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1860 Some((_, Node::Expr(expr))) => match expr.kind {
1861 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1862 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1863 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1864 _ => break Some(Node::Expr(expr)),
1866 Some((_, node)) => break Some(node),
1871 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1872 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1874 get_expr_use_or_unification_node(tcx, expr),
1875 None | Some(Node::Stmt(Stmt {
1876 kind: StmtKind::Expr(_)
1878 | StmtKind::Local(Local {
1880 kind: PatKind::Wild,
1890 /// Checks if the expression is the final expression returned from a block.
1891 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1892 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1895 pub fn std_or_core(cx: &LateContext<'_>) -> Option<&'static str> {
1896 if !is_no_std_crate(cx) {
1898 } else if !is_no_core_crate(cx) {
1905 pub fn is_no_std_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_std
1915 pub fn is_no_core_crate(cx: &LateContext<'_>) -> bool {
1916 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1917 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1918 attr.path == sym::no_core
1925 /// Check if parent of a hir node is a trait implementation block.
1926 /// For example, `f` in
1929 /// # trait Trait { fn f(); }
1930 /// impl Trait for S {
1934 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1935 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1936 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1942 /// Check if it's even possible to satisfy the `where` clause for the item.
1944 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1947 /// fn foo() where i32: Iterator {
1948 /// for _ in 2i32 {}
1951 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1952 use rustc_trait_selection::traits;
1958 .filter_map(|(p, _)| if p.is_global(cx.tcx) { Some(*p) } else { None });
1959 traits::impossible_predicates(
1961 traits::elaborate_predicates(cx.tcx, predicates)
1962 .map(|o| o.predicate)
1963 .collect::<Vec<_>>(),
1967 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1968 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1970 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1973 kind: ExprKind::Path(qpath),
1974 hir_id: path_hir_id,
1978 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_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(cx.tcx).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(cx.tcx).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(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
2059 fn peel(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(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(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 /// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
2109 /// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
2110 pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
2113 ExprKind::AddrOf(_, _, e) => expr = e,
2114 ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
2122 macro_rules! unwrap_cargo_metadata {
2123 ($cx: ident, $lint: ident, $deps: expr) => {{
2124 let mut command = cargo_metadata::MetadataCommand::new();
2129 match command.exec() {
2130 Ok(metadata) => metadata,
2132 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
2139 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
2140 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2141 if let Res::Def(_, def_id) = path.res {
2142 return cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr);
2148 struct TestItemNamesVisitor<'tcx> {
2153 impl<'hir> ItemLikeVisitor<'hir> for TestItemNamesVisitor<'hir> {
2154 fn visit_item(&mut self, item: &Item<'_>) {
2155 if let ItemKind::Const(ty, _body) = item.kind {
2156 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2157 // We could also check for the type name `test::TestDescAndFn`
2158 if let Res::Def(DefKind::Struct, _) = path.res {
2159 let has_test_marker = self
2162 .attrs(item.hir_id())
2164 .any(|a| a.has_name(sym::rustc_test_marker));
2165 if has_test_marker {
2166 self.names.push(item.ident.name);
2172 fn visit_trait_item(&mut self, _: &TraitItem<'_>) {}
2173 fn visit_impl_item(&mut self, _: &ImplItem<'_>) {}
2174 fn visit_foreign_item(&mut self, _: &ForeignItem<'_>) {}
2177 static TEST_ITEM_NAMES_CACHE: SyncOnceCell<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = SyncOnceCell::new();
2179 fn with_test_item_names(tcx: TyCtxt<'tcx>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
2180 let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
2181 let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
2182 match map.entry(module) {
2183 Entry::Occupied(entry) => f(entry.get()),
2184 Entry::Vacant(entry) => {
2185 let mut visitor = TestItemNamesVisitor { tcx, names: Vec::new() };
2186 tcx.hir().visit_item_likes_in_module(module, &mut visitor);
2187 visitor.names.sort_unstable();
2188 f(&*entry.insert(visitor.names))
2193 /// Checks if the function containing the given `HirId` is a `#[test]` function
2195 /// Note: If you use this function, please add a `#[test]` case in `tests/ui_test`.
2196 pub fn is_in_test_function(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2197 with_test_item_names(tcx, tcx.parent_module(id), |names| {
2200 // Since you can nest functions we need to collect all until we leave
2202 .any(|(_id, node)| {
2203 if let Node::Item(item) = node {
2204 if let ItemKind::Fn(_, _, _) = item.kind {
2205 // Note that we have sorted the item names in the visitor,
2206 // so the binary_search gets the same as `contains`, but faster.
2207 return names.binary_search(&item.ident.name).is_ok();
2215 /// Checks whether item either has `test` attribute applied, or
2216 /// is a module with `test` in its name.
2218 /// Note: If you use this function, please add a `#[test]` case in `tests/ui_test`.
2219 pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
2220 is_in_test_function(tcx, item.hir_id())
2221 || matches!(item.kind, ItemKind::Mod(..))
2222 && item.ident.name.as_str().split('_').any(|a| a == "test" || a == "tests")
2225 macro_rules! op_utils {
2226 ($($name:ident $assign:ident)*) => {
2227 /// Binary operation traits like `LangItem::Add`
2228 pub static BINOP_TRAITS: &[LangItem] = &[$(LangItem::$name,)*];
2230 /// Operator-Assign traits like `LangItem::AddAssign`
2231 pub static OP_ASSIGN_TRAITS: &[LangItem] = &[$(LangItem::$assign,)*];
2233 /// Converts `BinOpKind::Add` to `(LangItem::Add, LangItem::AddAssign)`, for example
2234 pub fn binop_traits(kind: hir::BinOpKind) -> Option<(LangItem, LangItem)> {
2236 $(hir::BinOpKind::$name => Some((LangItem::$name, LangItem::$assign)),)*