1 #![feature(box_patterns)]
2 #![feature(control_flow_enum)]
5 #![feature(rustc_private)]
6 #![recursion_limit = "512"]
7 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
8 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
9 // warn on the same lints as `clippy_lints`
10 #![warn(trivial_casts, trivial_numeric_casts)]
11 // warn on lints, that are included in `rust-lang/rust`s bootstrap
12 #![warn(rust_2018_idioms, unused_lifetimes)]
13 // warn on rustc internal lints
14 #![warn(rustc::internal)]
16 // FIXME: switch to something more ergonomic here, once available.
17 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
18 extern crate rustc_ast;
19 extern crate rustc_ast_pretty;
20 extern crate rustc_attr;
21 extern crate rustc_data_structures;
22 extern crate rustc_errors;
23 extern crate rustc_hir;
24 extern crate rustc_infer;
25 extern crate rustc_lexer;
26 extern crate rustc_lint;
27 extern crate rustc_middle;
28 extern crate rustc_session;
29 extern crate rustc_span;
30 extern crate rustc_target;
31 extern crate rustc_trait_selection;
32 extern crate rustc_typeck;
37 #[allow(clippy::module_name_repetitions)]
43 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::{CrateNum, DefId, LocalDefId, CRATE_DEF_ID};
74 use rustc_hir::hir_id::{HirIdMap, HirIdSet};
75 use rustc_hir::intravisit::{walk_expr, FnKind, Visitor};
76 use rustc_hir::itemlikevisit::ItemLikeVisitor;
77 use rustc_hir::LangItem::{OptionNone, ResultErr, ResultOk};
79 def, lang_items, Arm, ArrayLen, BindingAnnotation, Block, BlockCheckMode, Body, Constness, Destination, Expr,
80 ExprKind, FnDecl, ForeignItem, GenericArgs, HirId, Impl, ImplItem, ImplItemKind, IsAsync, Item, ItemKind, LangItem,
81 Local, MatchSource, Mutability, Node, Param, Pat, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind,
82 Target, TraitItem, TraitItemKind, TraitRef, TyKind, UnOp,
84 use rustc_lint::{LateContext, Level, Lint, LintContext};
85 use rustc_middle::hir::place::PlaceBase;
86 use rustc_middle::ty as rustc_ty;
87 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow};
88 use rustc_middle::ty::binding::BindingMode;
89 use rustc_middle::ty::{layout::IntegerExt, BorrowKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeFoldable, UpvarCapture};
90 use rustc_semver::RustcVersion;
91 use rustc_session::Session;
92 use rustc_span::hygiene::{ExpnKind, MacroKind};
93 use rustc_span::source_map::original_sp;
95 use rustc_span::symbol::{kw, Symbol};
96 use rustc_span::{Span, DUMMY_SP};
97 use rustc_target::abi::Integer;
99 use crate::consts::{constant, Constant};
100 use crate::ty::{can_partially_move_ty, is_copy, is_recursively_primitive_type};
101 use crate::visitors::expr_visitor_no_bodies;
103 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
104 if let Ok(version) = RustcVersion::parse(msrv) {
105 return Some(version);
106 } else if let Some(sess) = sess {
107 if let Some(span) = span {
108 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
114 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
115 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
119 macro_rules! extract_msrv_attr {
121 extract_msrv_attr!(@LateContext, ());
124 extract_msrv_attr!(@EarlyContext);
126 (@$context:ident$(, $call:tt)?) => {
127 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'_>, attrs: &[rustc_ast::ast::Attribute]) {
128 use $crate::get_unique_inner_attr;
129 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
131 if let Some(msrv) = msrv_attr.value_str() {
132 self.msrv = $crate::parse_msrv(
134 Some(cx.sess$($call)?),
135 Some(msrv_attr.span),
138 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
147 /// Returns `true` if the two spans come from differing expansions (i.e., one is
148 /// from a macro and one isn't).
150 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
151 rhs.ctxt() != lhs.ctxt()
154 /// If the given expression is a local binding, find the initializer expression.
155 /// If that initializer expression is another local binding, find its initializer again.
156 /// This process repeats as long as possible (but usually no more than once). Initializer
157 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
170 /// let def = abc + 2;
171 /// // ^^^^^^^ output
175 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
176 while let Some(init) = path_to_local(expr)
177 .and_then(|id| find_binding_init(cx, id))
178 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
185 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
186 /// By only considering immutable bindings, we guarantee that the returned expression represents the
187 /// value of the binding wherever it is referenced.
189 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
190 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
191 /// canonical binding `HirId`.
192 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
193 let hir = cx.tcx.hir();
195 if let Some(Node::Binding(pat)) = hir.find(hir_id);
196 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
197 let parent = hir.get_parent_node(hir_id);
198 if let Some(Node::Local(local)) = hir.find(parent);
206 /// Returns `true` if the given `NodeId` is inside a constant context
211 /// if in_constant(cx, expr.hir_id) {
215 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
216 let parent_id = cx.tcx.hir().get_parent_item(id);
217 match cx.tcx.hir().get_by_def_id(parent_id) {
219 kind: ItemKind::Const(..) | ItemKind::Static(..),
222 | Node::TraitItem(&TraitItem {
223 kind: TraitItemKind::Const(..),
226 | Node::ImplItem(&ImplItem {
227 kind: ImplItemKind::Const(..),
230 | Node::AnonConst(_) => true,
232 kind: ItemKind::Fn(ref sig, ..),
235 | Node::ImplItem(&ImplItem {
236 kind: ImplItemKind::Fn(ref sig, _),
238 }) => sig.header.constness == Constness::Const,
243 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
244 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
245 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
246 if let QPath::Resolved(_, path) = qpath {
247 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
248 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
249 return cx.tcx.parent(ctor_id) == Some(item_id);
256 pub fn is_unit_expr(expr: &Expr<'_>) -> bool {
266 ) | ExprKind::Tup([])
270 /// Checks if given pattern is a wildcard (`_`)
271 pub fn is_wild(pat: &Pat<'_>) -> bool {
272 matches!(pat.kind, PatKind::Wild)
275 /// Checks if the first type parameter is a lang item.
276 pub fn is_ty_param_lang_item<'tcx>(
277 cx: &LateContext<'_>,
280 ) -> Option<&'tcx hir::Ty<'tcx>> {
281 let ty = get_qpath_generic_tys(qpath).next()?;
283 if let TyKind::Path(qpath) = &ty.kind {
284 cx.qpath_res(qpath, ty.hir_id)
286 .map_or(false, |id| {
287 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
295 /// Checks if the first type parameter is a diagnostic item.
296 pub fn is_ty_param_diagnostic_item<'tcx>(
297 cx: &LateContext<'_>,
300 ) -> Option<&'tcx hir::Ty<'tcx>> {
301 let ty = get_qpath_generic_tys(qpath).next()?;
303 if let TyKind::Path(qpath) = &ty.kind {
304 cx.qpath_res(qpath, ty.hir_id)
306 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
313 /// Checks if the method call given in `expr` belongs to the given trait.
314 /// This is a deprecated function, consider using [`is_trait_method`].
315 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
316 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
317 let trt_id = cx.tcx.trait_of_item(def_id);
318 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
321 /// Checks if a method is defined in an impl of a diagnostic item
322 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
323 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
324 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
325 return cx.tcx.is_diagnostic_item(diag_item, adt.did);
331 /// Checks if a method is in a diagnostic item trait
332 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
333 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
334 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
339 /// Checks if the method call given in `expr` belongs to the given trait.
340 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
342 .type_dependent_def_id(expr.hir_id)
343 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
346 /// Checks if the given expression is a path referring an item on the trait
347 /// that is marked with the given diagnostic item.
349 /// For checking method call expressions instead of path expressions, use
350 /// [`is_trait_method`].
352 /// For example, this can be used to find if an expression like `u64::default`
353 /// refers to an item of the trait `Default`, which is associated with the
354 /// `diag_item` of `sym::Default`.
355 pub fn is_trait_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
356 if let hir::ExprKind::Path(ref qpath) = expr.kind {
357 cx.qpath_res(qpath, expr.hir_id)
359 .map_or(false, |def_id| is_diag_trait_item(cx, def_id, diag_item))
365 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
367 QPath::Resolved(_, path) => path.segments.last().expect("A path must have at least one segment"),
368 QPath::TypeRelative(_, seg) => seg,
369 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
373 pub fn get_qpath_generics<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
375 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
376 QPath::TypeRelative(_, s) => s.args,
377 QPath::LangItem(..) => None,
381 pub fn get_qpath_generic_tys<'tcx>(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
382 get_qpath_generics(path)
383 .map_or([].as_ref(), |a| a.args)
386 if let hir::GenericArg::Type(ty) = a {
394 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
396 QPath::Resolved(_, path) => path.segments.get(0),
397 QPath::TypeRelative(_, seg) => Some(seg),
398 QPath::LangItem(..) => None,
402 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
403 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
404 /// `QPath::Resolved.1.res.opt_def_id()`.
406 /// Matches a `QPath` against a slice of segment string literals.
408 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
409 /// `rustc_hir::QPath`.
413 /// match_qpath(path, &["std", "rt", "begin_unwind"])
415 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
417 QPath::Resolved(_, path) => match_path(path, segments),
418 QPath::TypeRelative(ty, segment) => match ty.kind {
419 TyKind::Path(ref inner_path) => {
420 if let [prefix @ .., end] = segments {
421 if match_qpath(inner_path, prefix) {
422 return segment.ident.name.as_str() == *end;
429 QPath::LangItem(..) => false,
433 /// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
434 pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
435 if let ExprKind::Path(p) = &expr.kind {
436 cx.qpath_res(p, expr.hir_id)
442 /// Resolves the path to a `DefId` and checks if it matches the given path.
443 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
444 cx.qpath_res(path, hir_id)
446 .map_or(false, |id| match_def_path(cx, id, segments))
449 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
451 /// Please use `is_expr_diagnostic_item` if the target is a diagnostic item.
452 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
453 expr_path_res(cx, expr)
455 .map_or(false, |id| match_def_path(cx, id, segments))
458 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given
460 pub fn is_expr_diagnostic_item(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
461 expr_path_res(cx, expr)
463 .map_or(false, |id| cx.tcx.is_diagnostic_item(diag_item, id))
466 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
467 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
468 /// `QPath::Resolved.1.res.opt_def_id()`.
470 /// Matches a `Path` against a slice of segment string literals.
472 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
473 /// `rustc_hir::Path`.
478 /// if match_path(&trait_ref.path, &paths::HASH) {
479 /// // This is the `std::hash::Hash` trait.
482 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
483 /// // This is a `rustc_middle::lint::Lint`.
486 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
490 .zip(segments.iter().rev())
491 .all(|(a, b)| a.ident.name.as_str() == *b)
494 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
495 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
496 if let ExprKind::Path(QPath::Resolved(None, path)) = expr.kind {
497 if let Res::Local(id) = path.res {
504 /// Returns true if the expression is a path to a local with the specified `HirId`.
505 /// Use this function to see if an expression matches a function argument or a match binding.
506 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
507 path_to_local(expr) == Some(id)
510 /// Gets the definition associated to a path.
511 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
512 macro_rules! try_res {
516 None => return Res::Err,
520 fn item_child_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: &str) -> Option<Res> {
521 match tcx.def_kind(def_id) {
522 DefKind::Mod | DefKind::Enum | DefKind::Trait => tcx
523 .module_children(def_id)
525 .find(|item| item.ident.name.as_str() == name)
526 .map(|child| child.res.expect_non_local()),
528 .associated_item_def_ids(def_id)
531 .find(|assoc_def_id| tcx.item_name(*assoc_def_id).as_str() == name)
532 .map(|assoc_def_id| Res::Def(tcx.def_kind(assoc_def_id), assoc_def_id)),
536 fn find_primitive(tcx: TyCtxt<'_>, name: &str) -> Option<DefId> {
537 if let Some(&(index, Target::Impl)) = lang_items::ITEM_REFS.get(&Symbol::intern(name)) {
538 tcx.lang_items().items()[index]
543 fn find_crate(tcx: TyCtxt<'_>, name: &str) -> Option<DefId> {
546 .find(|&&num| tcx.crate_name(num).as_str() == name)
547 .map(CrateNum::as_def_id)
550 let (base, first, path) = match *path {
551 [base, first, ref path @ ..] => (base, first, path),
553 return PrimTy::from_name(Symbol::intern(primitive)).map_or(Res::Err, Res::PrimTy);
555 _ => return Res::Err,
558 let first = try_res!(
559 find_primitive(tcx, base)
560 .or_else(|| find_crate(tcx, base))
561 .and_then(|id| item_child_by_name(tcx, id, first))
567 // for each segment, find the child item
568 .try_fold(first, |res, segment| {
569 let def_id = res.def_id();
570 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
572 } else if matches!(res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
573 // it is not a child item so check inherent impl items
574 tcx.inherent_impls(def_id)
576 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
581 try_res!(last).expect_non_local()
584 /// Convenience function to get the `DefId` of a trait by path.
585 /// It could be a trait or trait alias.
586 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
587 match path_to_res(cx, path) {
588 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
593 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
595 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
598 /// struct Point(isize, isize);
600 /// impl std::ops::Add for Point {
601 /// type Output = Self;
603 /// fn add(self, other: Self) -> Self {
608 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, def_id: LocalDefId) -> Option<&'tcx TraitRef<'tcx>> {
609 // Get the implemented trait for the current function
610 let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
611 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
613 if parent_impl != CRATE_DEF_ID;
614 if let hir::Node::Item(item) = cx.tcx.hir().get_by_def_id(parent_impl);
615 if let hir::ItemKind::Impl(impl_) = &item.kind;
616 then { return impl_.of_trait.as_ref(); }
621 /// This method will return tuple of projection stack and root of the expression,
622 /// used in `can_mut_borrow_both`.
624 /// For example, if `e` represents the `v[0].a.b[x]`
625 /// this method will return a tuple, composed of a `Vec`
626 /// containing the `Expr`s for `v[0], v[0].a, v[0].a.b, v[0].a.b[x]`
627 /// and an `Expr` for root of them, `v`
628 fn projection_stack<'a, 'hir>(mut e: &'a Expr<'hir>) -> (Vec<&'a Expr<'hir>>, &'a Expr<'hir>) {
629 let mut result = vec![];
632 ExprKind::Index(ep, _) | ExprKind::Field(ep, _) => {
643 /// Gets the mutability of the custom deref adjustment, if any.
644 pub fn expr_custom_deref_adjustment(cx: &LateContext<'_>, e: &Expr<'_>) -> Option<Mutability> {
648 .find_map(|a| match a.kind {
649 Adjust::Deref(Some(d)) => Some(Some(d.mutbl)),
650 Adjust::Deref(None) => None,
656 /// Checks if two expressions can be mutably borrowed simultaneously
657 /// and they aren't dependent on borrowing same thing twice
658 pub fn can_mut_borrow_both(cx: &LateContext<'_>, e1: &Expr<'_>, e2: &Expr<'_>) -> bool {
659 let (s1, r1) = projection_stack(e1);
660 let (s2, r2) = projection_stack(e2);
661 if !eq_expr_value(cx, r1, r2) {
664 if expr_custom_deref_adjustment(cx, r1).is_some() || expr_custom_deref_adjustment(cx, r2).is_some() {
668 for (x1, x2) in s1.iter().zip(s2.iter()) {
669 if expr_custom_deref_adjustment(cx, x1).is_some() || expr_custom_deref_adjustment(cx, x2).is_some() {
673 match (&x1.kind, &x2.kind) {
674 (ExprKind::Field(_, i1), ExprKind::Field(_, i2)) => {
679 (ExprKind::Index(_, i1), ExprKind::Index(_, i2)) => {
680 if !eq_expr_value(cx, i1, i2) {
690 /// Returns true if the `def_id` associated with the `path` is recognized as a "default-equivalent"
691 /// constructor from the std library
692 fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<'_>) -> bool {
693 let std_types_symbols = &[
705 if let QPath::TypeRelative(_, method) = path {
706 if method.ident.name == sym::new {
707 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
708 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
709 return std_types_symbols
711 .any(|&symbol| cx.tcx.is_diagnostic_item(symbol, adt.did));
719 /// Return true if the expr is equal to `Default::default` when evaluated.
720 pub fn is_default_equivalent_call(cx: &LateContext<'_>, repl_func: &Expr<'_>) -> bool {
722 if let hir::ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
723 if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
724 if is_diag_trait_item(cx, repl_def_id, sym::Default)
725 || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
735 /// Returns true if the expr is equal to `Default::default()` of it's type when evaluated.
736 /// It doesn't cover all cases, for example indirect function calls (some of std
737 /// functions are supported) but it is the best we have.
738 pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
740 ExprKind::Lit(lit) => match lit.node {
741 LitKind::Bool(false) | LitKind::Int(0, _) => true,
742 LitKind::Str(s, _) => s.is_empty(),
745 ExprKind::Tup(items) | ExprKind::Array(items) => items.iter().all(|x| is_default_equivalent(cx, x)),
746 ExprKind::Repeat(x, ArrayLen::Body(len)) => if_chain! {
747 if let ExprKind::Lit(ref const_lit) = cx.tcx.hir().body(len.body).value.kind;
748 if let LitKind::Int(v, _) = const_lit.node;
749 if v <= 32 && is_default_equivalent(cx, x);
757 ExprKind::Call(repl_func, _) => is_default_equivalent_call(cx, repl_func),
758 ExprKind::Path(qpath) => is_lang_ctor(cx, qpath, OptionNone),
759 ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
764 /// Checks if the top level expression can be moved into a closure as is.
765 /// Currently checks for:
766 /// * Break/Continue outside the given loop HIR ids.
767 /// * Yield/Return statements.
768 /// * Inline assembly.
769 /// * Usages of a field of a local where the type of the local can be partially moved.
771 /// For example, given the following function:
774 /// fn f<'a>(iter: &mut impl Iterator<Item = (usize, &'a mut String)>) {
775 /// for item in iter {
786 /// When called on the expression `item.0` this will return false unless the local `item` is in the
787 /// `ignore_locals` set. The type `(usize, &mut String)` can have the second element moved, so it
788 /// isn't always safe to move into a closure when only a single field is needed.
790 /// When called on the `continue` expression this will return false unless the outer loop expression
791 /// is in the `loop_ids` set.
793 /// Note that this check is not recursive, so passing the `if` expression will always return true
794 /// even though sub-expressions might return false.
795 pub fn can_move_expr_to_closure_no_visit<'tcx>(
796 cx: &LateContext<'tcx>,
797 expr: &'tcx Expr<'_>,
799 ignore_locals: &HirIdSet,
802 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
803 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
804 if loop_ids.contains(&id) =>
809 | ExprKind::Continue(_)
811 | ExprKind::Yield(..)
812 | ExprKind::InlineAsm(_) => false,
813 // Accessing a field of a local value can only be done if the type isn't
819 ExprKind::Path(QPath::Resolved(
822 res: Res::Local(local_id),
829 ) if !ignore_locals.contains(local_id) && can_partially_move_ty(cx, cx.typeck_results().node_type(hir_id)) => {
830 // TODO: check if the local has been partially moved. Assume it has for now.
837 /// How a local is captured by a closure
838 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
839 pub enum CaptureKind {
844 pub fn is_imm_ref(self) -> bool {
845 self == Self::Ref(Mutability::Not)
848 impl std::ops::BitOr for CaptureKind {
850 fn bitor(self, rhs: Self) -> Self::Output {
852 (CaptureKind::Value, _) | (_, CaptureKind::Value) => CaptureKind::Value,
853 (CaptureKind::Ref(Mutability::Mut), CaptureKind::Ref(_))
854 | (CaptureKind::Ref(_), CaptureKind::Ref(Mutability::Mut)) => CaptureKind::Ref(Mutability::Mut),
855 (CaptureKind::Ref(Mutability::Not), CaptureKind::Ref(Mutability::Not)) => CaptureKind::Ref(Mutability::Not),
859 impl std::ops::BitOrAssign for CaptureKind {
860 fn bitor_assign(&mut self, rhs: Self) {
865 /// Given an expression referencing a local, determines how it would be captured in a closure.
866 /// Note as this will walk up to parent expressions until the capture can be determined it should
867 /// only be used while making a closure somewhere a value is consumed. e.g. a block, match arm, or
868 /// function argument (other than a receiver).
869 pub fn capture_local_usage<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> CaptureKind {
870 fn pat_capture_kind(cx: &LateContext<'_>, pat: &Pat<'_>) -> CaptureKind {
871 let mut capture = CaptureKind::Ref(Mutability::Not);
872 pat.each_binding_or_first(&mut |_, id, span, _| match cx
874 .extract_binding_mode(cx.sess(), id, span)
877 BindingMode::BindByValue(_) if !is_copy(cx, cx.typeck_results().node_type(id)) => {
878 capture = CaptureKind::Value;
880 BindingMode::BindByReference(Mutability::Mut) if capture != CaptureKind::Value => {
881 capture = CaptureKind::Ref(Mutability::Mut);
888 debug_assert!(matches!(
890 ExprKind::Path(QPath::Resolved(None, Path { res: Res::Local(_), .. }))
893 let mut child_id = e.hir_id;
894 let mut capture = CaptureKind::Value;
895 let mut capture_expr_ty = e;
897 for (parent_id, parent) in cx.tcx.hir().parent_iter(e.hir_id) {
900 kind: Adjust::Deref(_) | Adjust::Borrow(AutoBorrow::Ref(..)),
908 .map_or(&[][..], |x| &**x)
910 if let rustc_ty::RawPtr(TypeAndMut { mutbl: mutability, .. }) | rustc_ty::Ref(_, _, mutability) =
911 *adjust.last().map_or(target, |a| a.target).kind()
913 return CaptureKind::Ref(mutability);
918 Node::Expr(e) => match e.kind {
919 ExprKind::AddrOf(_, mutability, _) => return CaptureKind::Ref(mutability),
920 ExprKind::Index(..) | ExprKind::Unary(UnOp::Deref, _) => capture = CaptureKind::Ref(Mutability::Not),
921 ExprKind::Assign(lhs, ..) | ExprKind::Assign(_, lhs, _) if lhs.hir_id == child_id => {
922 return CaptureKind::Ref(Mutability::Mut);
924 ExprKind::Field(..) => {
925 if capture == CaptureKind::Value {
929 ExprKind::Let(let_expr) => {
930 let mutability = match pat_capture_kind(cx, let_expr.pat) {
931 CaptureKind::Value => Mutability::Not,
932 CaptureKind::Ref(m) => m,
934 return CaptureKind::Ref(mutability);
936 ExprKind::Match(_, arms, _) => {
937 let mut mutability = Mutability::Not;
938 for capture in arms.iter().map(|arm| pat_capture_kind(cx, arm.pat)) {
940 CaptureKind::Value => break,
941 CaptureKind::Ref(Mutability::Mut) => mutability = Mutability::Mut,
942 CaptureKind::Ref(Mutability::Not) => (),
945 return CaptureKind::Ref(mutability);
949 Node::Local(l) => match pat_capture_kind(cx, l.pat) {
950 CaptureKind::Value => break,
951 capture @ CaptureKind::Ref(_) => return capture,
956 child_id = parent_id;
959 if capture == CaptureKind::Value && is_copy(cx, cx.typeck_results().expr_ty(capture_expr_ty)) {
960 // Copy types are never automatically captured by value.
961 CaptureKind::Ref(Mutability::Not)
967 /// Checks if the expression can be moved into a closure as is. This will return a list of captures
968 /// if so, otherwise, `None`.
969 pub fn can_move_expr_to_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<HirIdMap<CaptureKind>> {
970 struct V<'cx, 'tcx> {
971 cx: &'cx LateContext<'tcx>,
972 // Stack of potential break targets contained in the expression.
974 /// Local variables created in the expression. These don't need to be captured.
976 /// Whether this expression can be turned into a closure.
978 /// Locals which need to be captured, and whether they need to be by value, reference, or
979 /// mutable reference.
980 captures: HirIdMap<CaptureKind>,
982 impl<'tcx> Visitor<'tcx> for V<'_, 'tcx> {
983 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
984 if !self.allow_closure {
989 ExprKind::Path(QPath::Resolved(None, &Path { res: Res::Local(l), .. })) => {
990 if !self.locals.contains(&l) {
991 let cap = capture_local_usage(self.cx, e);
992 self.captures.entry(l).and_modify(|e| *e |= cap).or_insert(cap);
995 ExprKind::Closure(..) => {
996 let closure_id = self.cx.tcx.hir().local_def_id(e.hir_id).to_def_id();
997 for capture in self.cx.typeck_results().closure_min_captures_flattened(closure_id) {
998 let local_id = match capture.place.base {
999 PlaceBase::Local(id) => id,
1000 PlaceBase::Upvar(var) => var.var_path.hir_id,
1003 if !self.locals.contains(&local_id) {
1004 let capture = match capture.info.capture_kind {
1005 UpvarCapture::ByValue => CaptureKind::Value,
1006 UpvarCapture::ByRef(kind) => match kind {
1007 BorrowKind::ImmBorrow => CaptureKind::Ref(Mutability::Not),
1008 BorrowKind::UniqueImmBorrow | BorrowKind::MutBorrow => {
1009 CaptureKind::Ref(Mutability::Mut)
1015 .and_modify(|e| *e |= capture)
1016 .or_insert(capture);
1020 ExprKind::Loop(b, ..) => {
1021 self.loops.push(e.hir_id);
1022 self.visit_block(b);
1026 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops, &self.locals);
1032 fn visit_pat(&mut self, p: &'tcx Pat<'tcx>) {
1033 p.each_binding_or_first(&mut |_, id, _, _| {
1034 self.locals.insert(id);
1041 allow_closure: true,
1043 locals: HirIdSet::default(),
1044 captures: HirIdMap::default(),
1047 v.allow_closure.then(|| v.captures)
1050 /// Returns the method names and argument list of nested method call expressions that make up
1051 /// `expr`. method/span lists are sorted with the most recent call first.
1052 pub fn method_calls<'tcx>(
1053 expr: &'tcx Expr<'tcx>,
1055 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
1056 let mut method_names = Vec::with_capacity(max_depth);
1057 let mut arg_lists = Vec::with_capacity(max_depth);
1058 let mut spans = Vec::with_capacity(max_depth);
1060 let mut current = expr;
1061 for _ in 0..max_depth {
1062 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
1063 if args.iter().any(|e| e.span.from_expansion()) {
1066 method_names.push(path.ident.name);
1067 arg_lists.push(&**args);
1075 (method_names, arg_lists, spans)
1078 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
1080 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
1081 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
1082 /// containing the `Expr`s for
1083 /// `.bar()` and `.baz()`
1084 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
1085 let mut current = expr;
1086 let mut matched = Vec::with_capacity(methods.len());
1087 for method_name in methods.iter().rev() {
1088 // method chains are stored last -> first
1089 if let ExprKind::MethodCall(path, _, args, _) = current.kind {
1090 if path.ident.name.as_str() == *method_name {
1091 if args.iter().any(|e| e.span.from_expansion()) {
1094 matched.push(args); // build up `matched` backwards
1095 current = &args[0]; // go to parent expression
1103 // Reverse `matched` so that it is in the same order as `methods`.
1108 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
1109 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
1112 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id)
1115 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
1116 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1117 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
1118 Some(parent.to_def_id()) == cx.tcx.lang_items().panic_impl()
1121 /// Gets the name of the item the expression is in, if available.
1122 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
1123 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
1124 match cx.tcx.hir().find_by_def_id(parent_id) {
1126 Node::Item(Item { ident, .. })
1127 | Node::TraitItem(TraitItem { ident, .. })
1128 | Node::ImplItem(ImplItem { ident, .. }),
1129 ) => Some(ident.name),
1134 pub struct ContainsName {
1139 impl<'tcx> Visitor<'tcx> for ContainsName {
1140 fn visit_name(&mut self, _: Span, name: Symbol) {
1141 if self.name == name {
1147 /// Checks if an `Expr` contains a certain name.
1148 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
1149 let mut cn = ContainsName { name, result: false };
1150 cn.visit_expr(expr);
1154 /// Returns `true` if `expr` contains a return expression
1155 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
1156 let mut found = false;
1157 expr_visitor_no_bodies(|expr| {
1159 if let hir::ExprKind::Ret(..) = &expr.kind {
1169 /// Extends the span to the beginning of the spans line, incl. whitespaces.
1174 /// // will be converted to
1176 /// // ^^^^^^^^^^^^^^
1178 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
1179 let span = original_sp(span, DUMMY_SP);
1180 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
1181 let line_no = source_map_and_line.line;
1182 let line_start = source_map_and_line.sf.lines[line_no];
1183 span.with_lo(line_start)
1186 /// Gets the parent node, if any.
1187 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
1188 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
1191 /// Gets the parent expression, if any –- this is useful to constrain a lint.
1192 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1193 get_parent_expr_for_hir(cx, e.hir_id)
1196 /// This retrieves the parent for the given `HirId` if it's an expression. This is useful for
1197 /// constraint lints
1198 pub fn get_parent_expr_for_hir<'tcx>(cx: &LateContext<'tcx>, hir_id: hir::HirId) -> Option<&'tcx Expr<'tcx>> {
1199 match get_parent_node(cx.tcx, hir_id) {
1200 Some(Node::Expr(parent)) => Some(parent),
1205 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
1206 let map = &cx.tcx.hir();
1207 let enclosing_node = map
1208 .get_enclosing_scope(hir_id)
1209 .and_then(|enclosing_id| map.find(enclosing_id));
1210 enclosing_node.and_then(|node| match node {
1211 Node::Block(block) => Some(block),
1213 kind: ItemKind::Fn(_, _, eid),
1216 | Node::ImplItem(&ImplItem {
1217 kind: ImplItemKind::Fn(_, eid),
1219 }) => match cx.tcx.hir().body(eid).value.kind {
1220 ExprKind::Block(block, _) => Some(block),
1227 /// Gets the loop or closure enclosing the given expression, if any.
1228 pub fn get_enclosing_loop_or_closure<'tcx>(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1229 for (_, node) in tcx.hir().parent_iter(expr.hir_id) {
1233 kind: ExprKind::Loop(..) | ExprKind::Closure(..),
1236 ) => return Some(e),
1237 Node::Expr(_) | Node::Stmt(_) | Node::Block(_) | Node::Local(_) | Node::Arm(_) => (),
1244 /// Gets the parent node if it's an impl block.
1245 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
1246 match tcx.hir().parent_iter(id).next() {
1250 kind: ItemKind::Impl(imp),
1258 /// Removes blocks around an expression, only if the block contains just one expression
1259 /// and no statements. Unsafe blocks are not removed.
1263 /// * `{ x }` -> `x`
1264 /// * `{{ x }}` -> `x`
1265 /// * `{ x; }` -> `{ x; }`
1266 /// * `{ x; y }` -> `{ x; y }`
1267 /// * `{ unsafe { x } }` -> `unsafe { x }`
1268 pub fn peel_blocks<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1269 while let ExprKind::Block(
1273 rules: BlockCheckMode::DefaultBlock,
1284 /// Removes blocks around an expression, only if the block contains just one expression
1285 /// or just one expression statement with a semicolon. Unsafe blocks are not removed.
1289 /// * `{ x }` -> `x`
1290 /// * `{ x; }` -> `x`
1291 /// * `{{ x; }}` -> `x`
1292 /// * `{ x; y }` -> `{ x; y }`
1293 /// * `{ unsafe { x } }` -> `unsafe { x }`
1294 pub fn peel_blocks_with_stmt<'a>(mut expr: &'a Expr<'a>) -> &'a Expr<'a> {
1295 while let ExprKind::Block(
1299 rules: BlockCheckMode::DefaultBlock,
1306 kind: StmtKind::Expr(inner) | StmtKind::Semi(inner),
1311 rules: BlockCheckMode::DefaultBlock,
1322 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
1323 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1324 let mut iter = tcx.hir().parent_iter(expr.hir_id);
1329 kind: ExprKind::If(_, _, Some(else_expr)),
1332 )) => else_expr.hir_id == expr.hir_id,
1337 /// Checks whether the given expression is a constant integer of the given value.
1338 /// unlike `is_integer_literal`, this version does const folding
1339 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
1340 if is_integer_literal(e, value) {
1343 let enclosing_body = cx.tcx.hir().local_def_id(cx.tcx.hir().enclosing_body_owner(e.hir_id));
1344 if let Some((Constant::Int(v), _)) = constant(cx, cx.tcx.typeck(enclosing_body), e) {
1350 /// Checks whether the given expression is a constant literal of the given value.
1351 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
1352 // FIXME: use constant folding
1353 if let ExprKind::Lit(ref spanned) = expr.kind {
1354 if let LitKind::Int(v, _) = spanned.node {
1361 /// Returns `true` if the given `Expr` has been coerced before.
1363 /// Examples of coercions can be found in the Nomicon at
1364 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
1366 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
1367 /// information on adjustments and coercions.
1368 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
1369 cx.typeck_results().adjustments().get(e.hir_id).is_some()
1372 /// Returns the pre-expansion span if this comes from an expansion of the
1374 /// See also [`is_direct_expn_of`].
1376 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
1378 if span.from_expansion() {
1379 let data = span.ctxt().outer_expn_data();
1380 let new_span = data.call_site;
1382 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1383 if mac_name.as_str() == name {
1384 return Some(new_span);
1395 /// Returns the pre-expansion span if the span directly comes from an expansion
1396 /// of the macro `name`.
1397 /// The difference with [`is_expn_of`] is that in
1399 /// # macro_rules! foo { ($name:tt!$args:tt) => { $name!$args } }
1400 /// # macro_rules! bar { ($e:expr) => { $e } }
1403 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1404 /// from `bar!` by `is_direct_expn_of`.
1406 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1407 if span.from_expansion() {
1408 let data = span.ctxt().outer_expn_data();
1409 let new_span = data.call_site;
1411 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1412 if mac_name.as_str() == name {
1413 return Some(new_span);
1421 /// Convenience function to get the return type of a function.
1422 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1423 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1424 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1425 cx.tcx.erase_late_bound_regions(ret_ty)
1428 /// Convenience function to get the nth argument type of a function.
1429 pub fn nth_arg<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId, nth: usize) -> Ty<'tcx> {
1430 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1431 let arg = cx.tcx.fn_sig(fn_def_id).input(nth);
1432 cx.tcx.erase_late_bound_regions(arg)
1435 /// Checks if an expression is constructing a tuple-like enum variant or struct
1436 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1437 if let ExprKind::Call(fun, _) = expr.kind {
1438 if let ExprKind::Path(ref qp) = fun.kind {
1439 let res = cx.qpath_res(qp, fun.hir_id);
1441 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1442 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1450 /// Returns `true` if a pattern is refutable.
1451 // TODO: should be implemented using rustc/mir_build/thir machinery
1452 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1453 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1455 cx.qpath_res(qpath, id),
1456 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1460 fn are_refutable<'a, I: IntoIterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, i: I) -> bool {
1461 i.into_iter().any(|pat| is_refutable(cx, pat))
1465 PatKind::Wild => false,
1466 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1467 PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
1468 PatKind::Lit(..) | PatKind::Range(..) => true,
1469 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1470 PatKind::Or(pats) => {
1471 // TODO: should be the honest check, that pats is exhaustive set
1472 are_refutable(cx, pats)
1474 PatKind::Tuple(pats, _) => are_refutable(cx, pats),
1475 PatKind::Struct(ref qpath, fields, _) => {
1476 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1478 PatKind::TupleStruct(ref qpath, pats, _) => is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats),
1479 PatKind::Slice(head, middle, tail) => {
1480 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1481 rustc_ty::Slice(..) => {
1482 // [..] is the only irrefutable slice pattern.
1483 !head.is_empty() || middle.is_none() || !tail.is_empty()
1485 rustc_ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter())),
1495 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1496 /// the function once on the given pattern.
1497 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1498 if let PatKind::Or(pats) = pat.kind {
1499 pats.iter().for_each(f);
1505 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1506 /// implementations have.
1507 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1508 has_attr(attrs, sym::automatically_derived)
1511 pub fn is_self(slf: &Param<'_>) -> bool {
1512 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1513 name.name == kw::SelfLower
1519 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1520 if let TyKind::Path(QPath::Resolved(None, path)) = slf.kind {
1521 if let Res::SelfTy(..) = path.res {
1528 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1529 (0..decl.inputs.len()).map(move |i| &body.params[i])
1532 /// Checks if a given expression is a match expression expanded from the `?`
1533 /// operator or the `try` macro.
1534 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1535 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1537 if let PatKind::TupleStruct(ref path, pat, None) = arm.pat.kind;
1538 if is_lang_ctor(cx, path, ResultOk);
1539 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1540 if path_to_local_id(arm.body, hir_id);
1548 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1549 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1550 is_lang_ctor(cx, path, ResultErr)
1556 if let ExprKind::Match(_, arms, ref source) = expr.kind {
1557 // desugared from a `?` operator
1558 if *source == MatchSource::TryDesugar {
1564 if arms[0].guard.is_none();
1565 if arms[1].guard.is_none();
1566 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) ||
1567 (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1577 /// Returns `true` if the lint is allowed in the current context
1579 /// Useful for skipping long running code when it's unnecessary
1580 pub fn is_lint_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1581 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1584 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1585 while let PatKind::Ref(subpat, _) = pat.kind {
1591 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1592 Integer::from_int_ty(&tcx, ity).size().bits()
1595 #[allow(clippy::cast_possible_wrap)]
1596 /// Turn a constant int byte representation into an i128
1597 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1598 let amt = 128 - int_bits(tcx, ity);
1599 ((u as i128) << amt) >> amt
1602 #[allow(clippy::cast_sign_loss)]
1603 /// clip unused bytes
1604 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1605 let amt = 128 - int_bits(tcx, ity);
1606 ((u as u128) << amt) >> amt
1609 /// clip unused bytes
1610 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1611 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1612 let amt = 128 - bits;
1616 pub fn has_attr(attrs: &[ast::Attribute], symbol: Symbol) -> bool {
1617 attrs.iter().any(|attr| attr.has_name(symbol))
1620 pub fn any_parent_has_attr(tcx: TyCtxt<'_>, node: HirId, symbol: Symbol) -> bool {
1621 let map = &tcx.hir();
1622 let mut prev_enclosing_node = None;
1623 let mut enclosing_node = node;
1624 while Some(enclosing_node) != prev_enclosing_node {
1625 if has_attr(map.attrs(enclosing_node), symbol) {
1628 prev_enclosing_node = Some(enclosing_node);
1629 enclosing_node = map.local_def_id_to_hir_id(map.get_parent_item(enclosing_node));
1635 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1636 any_parent_has_attr(tcx, node, sym::automatically_derived)
1639 /// Matches a function call with the given path and returns the arguments.
1644 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1646 pub fn match_function_call<'tcx>(
1647 cx: &LateContext<'tcx>,
1648 expr: &'tcx Expr<'_>,
1650 ) -> Option<&'tcx [Expr<'tcx>]> {
1652 if let ExprKind::Call(fun, args) = expr.kind;
1653 if let ExprKind::Path(ref qpath) = fun.kind;
1654 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1655 if match_def_path(cx, fun_def_id, path);
1663 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1666 /// Please use `match_any_diagnostic_items` if the targets are all diagnostic items.
1667 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1668 let search_path = cx.get_def_path(did);
1671 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1674 /// Checks if the given `DefId` matches any of provided diagnostic items. Returns the index of
1675 /// matching path, if any.
1676 pub fn match_any_diagnostic_items(cx: &LateContext<'_>, def_id: DefId, diag_items: &[Symbol]) -> Option<usize> {
1679 .position(|item| cx.tcx.is_diagnostic_item(*item, def_id))
1682 /// Checks if the given `DefId` matches the path.
1683 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1684 // We should probably move to Symbols in Clippy as well rather than interning every time.
1685 let path = cx.get_def_path(did);
1686 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1689 /// Checks if the given `DefId` matches the `libc` item.
1690 pub fn match_libc_symbol(cx: &LateContext<'_>, did: DefId, name: &str) -> bool {
1691 let path = cx.get_def_path(did);
1692 // libc is meant to be used as a flat list of names, but they're all actually defined in different
1693 // modules based on the target platform. Ignore everything but crate name and the item name.
1694 path.first().map_or(false, |s| s.as_str() == "libc") && path.last().map_or(false, |s| s.as_str() == name)
1697 /// Returns the list of condition expressions and the list of blocks in a
1698 /// sequence of `if/else`.
1699 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1700 /// `if a { c } else if b { d } else { e }`.
1701 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1702 let mut conds = Vec::new();
1703 let mut blocks: Vec<&Block<'_>> = Vec::new();
1705 while let Some(higher::IfOrIfLet { cond, then, r#else }) = higher::IfOrIfLet::hir(expr) {
1707 if let ExprKind::Block(block, _) = then.kind {
1710 panic!("ExprKind::If node is not an ExprKind::Block");
1713 if let Some(else_expr) = r#else {
1720 // final `else {..}`
1721 if !blocks.is_empty() {
1722 if let ExprKind::Block(block, _) = expr.kind {
1730 /// Checks if the given function kind is an async function.
1731 pub fn is_async_fn(kind: FnKind<'_>) -> bool {
1732 matches!(kind, FnKind::ItemFn(_, _, header, _) if header.asyncness == IsAsync::Async)
1735 /// Peels away all the compiler generated code surrounding the body of an async function,
1736 pub fn get_async_fn_body<'tcx>(tcx: TyCtxt<'tcx>, body: &Body<'_>) -> Option<&'tcx Expr<'tcx>> {
1737 if let ExprKind::Call(
1741 kind: ExprKind::Closure(_, _, body, _, _),
1747 if let ExprKind::Block(
1752 kind: ExprKind::DropTemps(expr),
1758 ) = tcx.hir().body(body).value.kind
1766 // Finds the `#[must_use]` attribute, if any
1767 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1768 attrs.iter().find(|a| a.has_name(sym::must_use))
1771 // check if expr is calling method or function with #[must_use] attribute
1772 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1773 let did = match expr.kind {
1774 ExprKind::Call(path, _) => if_chain! {
1775 if let ExprKind::Path(ref qpath) = path.kind;
1776 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1783 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1787 did.map_or(false, |did| must_use_attr(cx.tcx.get_attrs(did)).is_some())
1790 /// Checks if an expression represents the identity function
1791 /// Only examines closures and `std::convert::identity`
1792 pub fn is_expr_identity_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1793 /// Checks if a function's body represents the identity function. Looks for bodies of the form:
1795 /// * `|x| return x`
1796 /// * `|x| { return x }`
1797 /// * `|x| { return x; }`
1798 fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
1799 let id = if_chain! {
1800 if let [param] = func.params;
1801 if let PatKind::Binding(_, id, _, _) = param.pat.kind;
1809 let mut expr = &func.value;
1813 ExprKind::Block(&Block { stmts: [], expr: Some(e), .. }, _, )
1814 | ExprKind::Ret(Some(e)) => expr = e,
1816 ExprKind::Block(&Block { stmts: [stmt], expr: None, .. }, _) => {
1818 if let StmtKind::Semi(e) | StmtKind::Expr(e) = stmt.kind;
1819 if let ExprKind::Ret(Some(ret_val)) = e.kind;
1827 _ => return path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty(),
1833 ExprKind::Closure(_, _, body_id, _, _) => is_body_identity_function(cx, cx.tcx.hir().body(body_id)),
1834 ExprKind::Path(ref path) => is_qpath_def_path(cx, path, expr.hir_id, &paths::CONVERT_IDENTITY),
1839 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1840 pub fn get_expr_use_or_unification_node<'tcx>(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
1841 let mut child_id = expr.hir_id;
1842 let mut iter = tcx.hir().parent_iter(child_id);
1846 Some((id, Node::Block(_))) => child_id = id,
1847 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1848 Some((_, Node::Expr(expr))) => match expr.kind {
1849 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1850 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1851 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1852 _ => break Some(Node::Expr(expr)),
1854 Some((_, node)) => break Some(node),
1859 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1860 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1862 get_expr_use_or_unification_node(tcx, expr),
1863 None | Some(Node::Stmt(Stmt {
1864 kind: StmtKind::Expr(_)
1866 | StmtKind::Local(Local {
1868 kind: PatKind::Wild,
1878 /// Checks if the expression is the final expression returned from a block.
1879 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1880 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1883 pub fn std_or_core(cx: &LateContext<'_>) -> Option<&'static str> {
1884 if !is_no_std_crate(cx) {
1886 } else if !is_no_core_crate(cx) {
1893 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1894 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1895 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1896 attr.path == sym::no_std
1903 pub fn is_no_core_crate(cx: &LateContext<'_>) -> bool {
1904 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1905 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1906 attr.path == sym::no_core
1913 /// Check if parent of a hir node is a trait implementation block.
1914 /// For example, `f` in
1917 /// # trait Trait { fn f(); }
1918 /// impl Trait for S {
1922 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1923 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1924 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1930 /// Check if it's even possible to satisfy the `where` clause for the item.
1932 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1935 /// fn foo() where i32: Iterator {
1936 /// for _ in 2i32 {}
1939 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1940 use rustc_trait_selection::traits;
1946 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1947 traits::impossible_predicates(
1949 traits::elaborate_predicates(cx.tcx, predicates)
1950 .map(|o| o.predicate)
1951 .collect::<Vec<_>>(),
1955 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1956 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1958 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1961 kind: ExprKind::Path(qpath),
1962 hir_id: path_hir_id,
1966 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
1971 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1972 /// slice iff the given expression is a slice of primitives (as defined in the
1973 /// `is_recursively_primitive_type` function) and None otherwise.
1974 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1975 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1976 let expr_kind = expr_type.kind();
1977 let is_primitive = match expr_kind {
1978 rustc_ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1979 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1980 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1981 is_recursively_primitive_type(element_type)
1990 // if we have wrappers like Array, Slice or Tuple, print these
1991 // and get the type enclosed in the slice ref
1992 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1993 rustc_ty::Slice(..) => return Some("slice".into()),
1994 rustc_ty::Array(..) => return Some("array".into()),
1995 rustc_ty::Tuple(..) => return Some("tuple".into()),
1997 // is_recursively_primitive_type() should have taken care
1998 // of the rest and we can rely on the type that is found
1999 let refs_peeled = expr_type.peel_refs();
2000 return Some(refs_peeled.walk().last().unwrap().to_string());
2007 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
2008 /// `hash` must be comformed with `eq`
2009 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
2011 Hash: Fn(&T) -> u64,
2012 Eq: Fn(&T, &T) -> bool,
2015 [a, b] if eq(a, b) => return vec![(a, b)],
2016 _ if exprs.len() <= 2 => return vec![],
2020 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
2022 let mut map: UnhashMap<u64, Vec<&_>> =
2023 UnhashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
2026 match map.entry(hash(expr)) {
2027 Entry::Occupied(mut o) => {
2030 match_expr_list.push((o, expr));
2033 o.get_mut().push(expr);
2035 Entry::Vacant(v) => {
2036 v.insert(vec![expr]);
2044 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
2045 /// references removed.
2046 pub fn peel_hir_pat_refs<'a>(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
2047 fn peel<'a>(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
2048 if let PatKind::Ref(pat, _) = pat.kind {
2049 peel(pat, count + 1)
2057 /// Peels of expressions while the given closure returns `Some`.
2058 pub fn peel_hir_expr_while<'tcx>(
2059 mut expr: &'tcx Expr<'tcx>,
2060 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
2061 ) -> &'tcx Expr<'tcx> {
2062 while let Some(e) = f(expr) {
2068 /// Peels off up to the given number of references on the expression. Returns the underlying
2069 /// expression and the number of references removed.
2070 pub fn peel_n_hir_expr_refs<'a>(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
2071 let mut remaining = count;
2072 let e = peel_hir_expr_while(expr, |e| match e.kind {
2073 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) if remaining != 0 => {
2079 (e, count - remaining)
2082 /// Peels off all references on the expression. Returns the underlying expression and the number of
2083 /// references removed.
2084 pub fn peel_hir_expr_refs<'a>(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
2086 let e = peel_hir_expr_while(expr, |e| match e.kind {
2087 ExprKind::AddrOf(ast::BorrowKind::Ref, _, e) => {
2096 /// Removes `AddrOf` operators (`&`) or deref operators (`*`), but only if a reference type is
2097 /// dereferenced. An overloaded deref such as `Vec` to slice would not be removed.
2098 pub fn peel_ref_operators<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
2101 ExprKind::AddrOf(_, _, e) => expr = e,
2102 ExprKind::Unary(UnOp::Deref, e) if cx.typeck_results().expr_ty(e).is_ref() => expr = e,
2110 macro_rules! unwrap_cargo_metadata {
2111 ($cx: ident, $lint: ident, $deps: expr) => {{
2112 let mut command = cargo_metadata::MetadataCommand::new();
2117 match command.exec() {
2118 Ok(metadata) => metadata,
2120 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
2127 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
2128 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2129 if let Res::Def(_, def_id) = path.res {
2130 return cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr);
2136 struct TestItemNamesVisitor<'tcx> {
2141 impl<'hir> ItemLikeVisitor<'hir> for TestItemNamesVisitor<'hir> {
2142 fn visit_item(&mut self, item: &Item<'_>) {
2143 if let ItemKind::Const(ty, _body) = item.kind {
2144 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
2145 // We could also check for the type name `test::TestDescAndFn`
2146 if let Res::Def(DefKind::Struct, _) = path.res {
2147 let has_test_marker = self
2150 .attrs(item.hir_id())
2152 .any(|a| a.has_name(sym::rustc_test_marker));
2153 if has_test_marker {
2154 self.names.push(item.ident.name);
2160 fn visit_trait_item(&mut self, _: &TraitItem<'_>) {}
2161 fn visit_impl_item(&mut self, _: &ImplItem<'_>) {}
2162 fn visit_foreign_item(&mut self, _: &ForeignItem<'_>) {}
2165 static TEST_ITEM_NAMES_CACHE: SyncOnceCell<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = SyncOnceCell::new();
2167 fn with_test_item_names<'tcx>(tcx: TyCtxt<'tcx>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
2168 let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
2169 let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
2170 match map.entry(module) {
2171 Entry::Occupied(entry) => f(entry.get()),
2172 Entry::Vacant(entry) => {
2173 let mut visitor = TestItemNamesVisitor { tcx, names: Vec::new() };
2174 tcx.hir().visit_item_likes_in_module(module, &mut visitor);
2175 visitor.names.sort_unstable();
2176 f(&*entry.insert(visitor.names))
2181 /// Checks if the function containing the given `HirId` is a `#[test]` function
2183 /// Note: If you use this function, please add a `#[test]` case in `tests/ui_test`.
2184 pub fn is_in_test_function(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
2185 with_test_item_names(tcx, tcx.parent_module(id), |names| {
2188 // Since you can nest functions we need to collect all until we leave
2190 .any(|(_id, node)| {
2191 if let Node::Item(item) = node {
2192 if let ItemKind::Fn(_, _, _) = item.kind {
2193 // Note that we have sorted the item names in the visitor,
2194 // so the binary_search gets the same as `contains`, but faster.
2195 return names.binary_search(&item.ident.name).is_ok();
2203 /// Checks whether item either has `test` attribute applied, or
2204 /// is a module with `test` in its name.
2206 /// Note: If you use this function, please add a `#[test]` case in `tests/ui_test`.
2207 pub fn is_test_module_or_function(tcx: TyCtxt<'_>, item: &Item<'_>) -> bool {
2208 is_in_test_function(tcx, item.hir_id())
2209 || matches!(item.kind, ItemKind::Mod(..))
2210 && item.ident.name.as_str().split('_').any(|a| a == "test" || a == "tests")
2213 macro_rules! op_utils {
2214 ($($name:ident $assign:ident)*) => {
2215 /// Binary operation traits like `LangItem::Add`
2216 pub static BINOP_TRAITS: &[LangItem] = &[$(LangItem::$name,)*];
2218 /// Operator-Assign traits like `LangItem::AddAssign`
2219 pub static OP_ASSIGN_TRAITS: &[LangItem] = &[$(LangItem::$assign,)*];
2221 /// Converts `BinOpKind::Add` to `(LangItem::Add, LangItem::AddAssign)`, for example
2222 pub fn binop_traits(kind: hir::BinOpKind) -> Option<(LangItem, LangItem)> {
2224 $(hir::BinOpKind::$name => Some((LangItem::$name, LangItem::$assign)),)*