1 #![feature(box_patterns)]
2 #![feature(in_band_lifetimes)]
4 #![cfg_attr(bootstrap, feature(or_patterns))]
5 #![feature(rustc_private)]
6 #![recursion_limit = "512"]
7 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
9 // FIXME: switch to something more ergonomic here, once available.
10 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
11 extern crate rustc_ast;
12 extern crate rustc_ast_pretty;
13 extern crate rustc_attr;
14 extern crate rustc_data_structures;
15 extern crate rustc_errors;
16 extern crate rustc_hir;
17 extern crate rustc_infer;
18 extern crate rustc_lexer;
19 extern crate rustc_lint;
20 extern crate rustc_middle;
21 extern crate rustc_mir;
22 extern crate rustc_session;
23 extern crate rustc_span;
24 extern crate rustc_target;
25 extern crate rustc_trait_selection;
26 extern crate rustc_typeck;
31 #[allow(clippy::module_name_repetitions)]
38 pub mod eager_or_lazy;
42 pub mod numeric_literal;
45 pub mod qualify_min_const_fn;
52 pub use self::attrs::*;
53 pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, SpanlessHash};
55 use std::collections::hash_map::Entry;
56 use std::hash::BuildHasherDefault;
58 use if_chain::if_chain;
59 use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
60 use rustc_data_structures::fx::FxHashMap;
62 use rustc_hir::def::{DefKind, Res};
63 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
64 use rustc_hir::intravisit::{self, walk_expr, ErasedMap, NestedVisitorMap, Visitor};
65 use rustc_hir::LangItem::{ResultErr, ResultOk};
67 def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
68 ImplItem, ImplItemKind, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path, PathSegment,
69 QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
71 use rustc_lint::{LateContext, Level, Lint, LintContext};
72 use rustc_middle::hir::exports::Export;
73 use rustc_middle::hir::map::Map;
74 use rustc_middle::ty as rustc_ty;
75 use rustc_middle::ty::{layout::IntegerExt, DefIdTree, Ty, TyCtxt, TypeFoldable};
76 use rustc_semver::RustcVersion;
77 use rustc_session::Session;
78 use rustc_span::hygiene::{ExpnKind, MacroKind};
79 use rustc_span::source_map::original_sp;
81 use rustc_span::symbol::{kw, Symbol};
82 use rustc_span::{Span, DUMMY_SP};
83 use rustc_target::abi::Integer;
85 use crate::consts::{constant, Constant};
86 use crate::ty::{can_partially_move_ty, is_recursively_primitive_type};
88 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
89 if let Ok(version) = RustcVersion::parse(msrv) {
91 } else if let Some(sess) = sess {
92 if let Some(span) = span {
93 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
99 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
100 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
104 macro_rules! extract_msrv_attr {
106 extract_msrv_attr!(@LateContext, ());
109 extract_msrv_attr!(@EarlyContext);
111 (@$context:ident$(, $call:tt)?) => {
112 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
113 use $crate::get_unique_inner_attr;
114 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
116 if let Some(msrv) = msrv_attr.value_str() {
117 self.msrv = $crate::parse_msrv(
119 Some(cx.sess$($call)?),
120 Some(msrv_attr.span),
123 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
132 /// Returns `true` if the two spans come from differing expansions (i.e., one is
133 /// from a macro and one isn't).
135 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
136 rhs.ctxt() != lhs.ctxt()
139 /// If the given expression is a local binding, find the initializer expression.
140 /// If that initializer expression is another local binding, find its initializer again.
141 /// This process repeats as long as possible (but usually no more than once). Initializer
142 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
155 /// let def = abc + 2;
156 /// // ^^^^^^^ output
160 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
161 while let Some(init) = path_to_local(expr)
162 .and_then(|id| find_binding_init(cx, id))
163 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
170 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
171 /// By only considering immutable bindings, we guarantee that the returned expression represents the
172 /// value of the binding wherever it is referenced.
174 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
175 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
176 /// canonical binding `HirId`.
177 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
178 let hir = cx.tcx.hir();
180 if let Some(Node::Binding(pat)) = hir.find(hir_id);
181 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
182 let parent = hir.get_parent_node(hir_id);
183 if let Some(Node::Local(local)) = hir.find(parent);
191 /// Returns `true` if the given `NodeId` is inside a constant context
196 /// if in_constant(cx, expr.hir_id) {
200 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
201 let parent_id = cx.tcx.hir().get_parent_item(id);
202 match cx.tcx.hir().get(parent_id) {
204 kind: ItemKind::Const(..) | ItemKind::Static(..),
207 | Node::TraitItem(&TraitItem {
208 kind: TraitItemKind::Const(..),
211 | Node::ImplItem(&ImplItem {
212 kind: ImplItemKind::Const(..),
215 | Node::AnonConst(_) => true,
217 kind: ItemKind::Fn(ref sig, ..),
220 | Node::ImplItem(&ImplItem {
221 kind: ImplItemKind::Fn(ref sig, _),
223 }) => sig.header.constness == Constness::Const,
228 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
229 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
230 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
231 if let QPath::Resolved(_, path) = qpath {
232 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
233 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
234 return cx.tcx.parent(ctor_id) == Some(item_id);
241 /// Returns `true` if this `span` was expanded by any macro.
243 pub fn in_macro(span: Span) -> bool {
244 if span.from_expansion() {
245 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
251 /// Checks if given pattern is a wildcard (`_`)
252 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
253 matches!(pat.kind, PatKind::Wild)
256 /// Checks if the first type parameter is a lang item.
257 pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
258 let ty = get_qpath_generic_tys(qpath).next()?;
260 if let TyKind::Path(qpath) = &ty.kind {
261 cx.qpath_res(qpath, ty.hir_id)
263 .map_or(false, |id| {
264 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
272 /// Checks if the first type parameter is a diagnostic item.
273 pub fn is_ty_param_diagnostic_item(
274 cx: &LateContext<'_>,
277 ) -> Option<&'tcx hir::Ty<'tcx>> {
278 let ty = get_qpath_generic_tys(qpath).next()?;
280 if let TyKind::Path(qpath) = &ty.kind {
281 cx.qpath_res(qpath, ty.hir_id)
283 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
290 /// Checks if the method call given in `expr` belongs to the given trait.
291 /// This is a deprecated function, consider using [`is_trait_method`].
292 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
293 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
294 let trt_id = cx.tcx.trait_of_item(def_id);
295 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
298 /// Checks if a method is defined in an impl of a diagnostic item
299 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
300 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
301 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
302 return cx.tcx.is_diagnostic_item(diag_item, adt.did);
308 /// Checks if a method is in a diagnostic item trait
309 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
310 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
311 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
316 /// Checks if the method call given in `expr` belongs to the given trait.
317 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
319 .type_dependent_def_id(expr.hir_id)
320 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
323 /// Checks if an expression references a variable of the given name.
324 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
325 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
326 if let [p] = path.segments {
327 return p.ident.name == var;
333 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
335 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
336 QPath::TypeRelative(_, ref seg) => seg,
337 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
341 pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
343 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
344 QPath::TypeRelative(_, s) => s.args,
345 QPath::LangItem(..) => None,
349 pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
350 get_qpath_generics(path)
351 .map_or([].as_ref(), |a| a.args)
354 if let hir::GenericArg::Type(ty) = a {
362 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
364 QPath::Resolved(_, ref path) => path.segments.get(0),
365 QPath::TypeRelative(_, ref seg) => Some(seg),
366 QPath::LangItem(..) => None,
370 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
371 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
372 /// `QPath::Resolved.1.res.opt_def_id()`.
374 /// Matches a `QPath` against a slice of segment string literals.
376 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
377 /// `rustc_hir::QPath`.
381 /// match_qpath(path, &["std", "rt", "begin_unwind"])
383 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
385 QPath::Resolved(_, ref path) => match_path(path, segments),
386 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
387 TyKind::Path(ref inner_path) => {
388 if let [prefix @ .., end] = segments {
389 if match_qpath(inner_path, prefix) {
390 return segment.ident.name.as_str() == *end;
397 QPath::LangItem(..) => false,
401 /// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
402 pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
403 if let ExprKind::Path(p) = &expr.kind {
404 cx.qpath_res(p, expr.hir_id)
410 /// Resolves the path to a `DefId` and checks if it matches the given path.
411 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
412 cx.qpath_res(path, hir_id)
414 .map_or(false, |id| match_def_path(cx, id, segments))
417 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
418 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
419 expr_path_res(cx, expr)
421 .map_or(false, |id| match_def_path(cx, id, segments))
424 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
425 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
426 /// `QPath::Resolved.1.res.opt_def_id()`.
428 /// Matches a `Path` against a slice of segment string literals.
430 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
431 /// `rustc_hir::Path`.
436 /// if match_path(&trait_ref.path, &paths::HASH) {
437 /// // This is the `std::hash::Hash` trait.
440 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
441 /// // This is a `rustc_middle::lint::Lint`.
444 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
448 .zip(segments.iter().rev())
449 .all(|(a, b)| a.ident.name.as_str() == *b)
452 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
453 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
454 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
455 if let Res::Local(id) = path.res {
462 /// Returns true if the expression is a path to a local with the specified `HirId`.
463 /// Use this function to see if an expression matches a function argument or a match binding.
464 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
465 path_to_local(expr) == Some(id)
468 /// Gets the definition associated to a path.
469 #[allow(clippy::shadow_unrelated)] // false positive #6563
470 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
471 macro_rules! try_res {
475 None => return Res::Err,
479 fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export<HirId>> {
480 tcx.item_children(def_id)
482 .find(|item| item.ident.name.as_str() == name)
485 let (krate, first, path) = match *path {
486 [krate, first, ref path @ ..] => (krate, first, path),
487 _ => return Res::Err,
490 let crates = tcx.crates();
491 let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
492 let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
496 // `get_def_path` seems to generate these empty segments for extern blocks.
497 // We can just ignore them.
498 .filter(|segment| !segment.is_empty())
499 // for each segment, find the child item
500 .try_fold(first, |item, segment| {
501 let def_id = item.res.def_id();
502 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
504 } else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
505 // it is not a child item so check inherent impl items
506 tcx.inherent_impls(def_id)
508 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
516 /// Convenience function to get the `DefId` of a trait by path.
517 /// It could be a trait or trait alias.
518 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
519 match path_to_res(cx, path) {
520 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
525 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
527 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
530 /// struct Point(isize, isize);
532 /// impl std::ops::Add for Point {
533 /// type Output = Self;
535 /// fn add(self, other: Self) -> Self {
540 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
541 // Get the implemented trait for the current function
542 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
544 if parent_impl != hir::CRATE_HIR_ID;
545 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
546 if let hir::ItemKind::Impl(impl_) = &item.kind;
547 then { return impl_.of_trait.as_ref(); }
552 /// Checks if the top level expression can be moved into a closure as is.
553 pub fn can_move_expr_to_closure_no_visit(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, jump_targets: &[HirId]) -> bool {
555 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
556 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
557 if jump_targets.contains(&id) =>
562 | ExprKind::Continue(_)
564 | ExprKind::Yield(..)
565 | ExprKind::InlineAsm(_)
566 | ExprKind::LlvmInlineAsm(_) => false,
567 // Accessing a field of a local value can only be done if the type isn't
569 ExprKind::Field(base_expr, _)
572 ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
573 ) && can_partially_move_ty(cx, cx.typeck_results().expr_ty(base_expr)) =>
575 // TODO: check if the local has been partially moved. Assume it has for now.
582 /// Checks if the expression can be moved into a closure as is.
583 pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
584 struct V<'cx, 'tcx> {
585 cx: &'cx LateContext<'tcx>,
589 impl Visitor<'tcx> for V<'_, 'tcx> {
590 type Map = ErasedMap<'tcx>;
591 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
592 NestedVisitorMap::None
595 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
596 if !self.allow_closure {
599 if let ExprKind::Loop(b, ..) = e.kind {
600 self.loops.push(e.hir_id);
604 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops);
619 /// Returns the method names and argument list of nested method call expressions that make up
620 /// `expr`. method/span lists are sorted with the most recent call first.
621 pub fn method_calls<'tcx>(
622 expr: &'tcx Expr<'tcx>,
624 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
625 let mut method_names = Vec::with_capacity(max_depth);
626 let mut arg_lists = Vec::with_capacity(max_depth);
627 let mut spans = Vec::with_capacity(max_depth);
629 let mut current = expr;
630 for _ in 0..max_depth {
631 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
632 if args.iter().any(|e| e.span.from_expansion()) {
635 method_names.push(path.ident.name);
636 arg_lists.push(&**args);
644 (method_names, arg_lists, spans)
647 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
649 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
650 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
651 /// containing the `Expr`s for
652 /// `.bar()` and `.baz()`
653 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
654 let mut current = expr;
655 let mut matched = Vec::with_capacity(methods.len());
656 for method_name in methods.iter().rev() {
657 // method chains are stored last -> first
658 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
659 if path.ident.name.as_str() == *method_name {
660 if args.iter().any(|e| e.span.from_expansion()) {
663 matched.push(&**args); // build up `matched` backwards
664 current = &args[0] // go to parent expression
672 // Reverse `matched` so that it is in the same order as `methods`.
677 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
678 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
680 .entry_fn(LOCAL_CRATE)
681 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
684 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
685 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
686 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
687 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
688 Some(def_id) == cx.tcx.lang_items().panic_impl()
691 /// Gets the name of the item the expression is in, if available.
692 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
693 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
694 match cx.tcx.hir().find(parent_id) {
696 Node::Item(Item { ident, .. })
697 | Node::TraitItem(TraitItem { ident, .. })
698 | Node::ImplItem(ImplItem { ident, .. }),
699 ) => Some(ident.name),
704 /// Gets the name of a `Pat`, if any.
705 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
707 PatKind::Binding(.., ref spname, _) => Some(spname.name),
708 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
709 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
714 pub struct ContainsName {
719 impl<'tcx> Visitor<'tcx> for ContainsName {
720 type Map = Map<'tcx>;
722 fn visit_name(&mut self, _: Span, name: Symbol) {
723 if self.name == name {
727 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
728 NestedVisitorMap::None
732 /// Checks if an `Expr` contains a certain name.
733 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
734 let mut cn = ContainsName { name, result: false };
739 /// Returns `true` if `expr` contains a return expression
740 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
741 struct RetCallFinder {
745 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
746 type Map = Map<'tcx>;
748 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
752 if let hir::ExprKind::Ret(..) = &expr.kind {
755 hir::intravisit::walk_expr(self, expr);
759 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
760 hir::intravisit::NestedVisitorMap::None
764 let mut visitor = RetCallFinder { found: false };
765 visitor.visit_expr(expr);
769 struct FindMacroCalls<'a, 'b> {
770 names: &'a [&'b str],
774 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
775 type Map = Map<'tcx>;
777 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
778 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
779 self.result.push(expr.span);
781 // and check sub-expressions
782 intravisit::walk_expr(self, expr);
785 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
786 NestedVisitorMap::None
790 /// Finds calls of the specified macros in a function body.
791 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
792 let mut fmc = FindMacroCalls {
796 fmc.visit_expr(&body.value);
800 /// Extends the span to the beginning of the spans line, incl. whitespaces.
805 /// // will be converted to
807 /// // ^^^^^^^^^^^^^^
809 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
810 let span = original_sp(span, DUMMY_SP);
811 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
812 let line_no = source_map_and_line.line;
813 let line_start = source_map_and_line.sf.lines[line_no];
814 Span::new(line_start, span.hi(), span.ctxt())
817 /// Gets the parent node, if any.
818 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
819 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
822 /// Gets the parent expression, if any –- this is useful to constrain a lint.
823 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
824 match get_parent_node(cx.tcx, e.hir_id) {
825 Some(Node::Expr(parent)) => Some(parent),
830 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
831 let map = &cx.tcx.hir();
832 let enclosing_node = map
833 .get_enclosing_scope(hir_id)
834 .and_then(|enclosing_id| map.find(enclosing_id));
835 enclosing_node.and_then(|node| match node {
836 Node::Block(block) => Some(block),
838 kind: ItemKind::Fn(_, _, eid),
841 | Node::ImplItem(&ImplItem {
842 kind: ImplItemKind::Fn(_, eid),
844 }) => match cx.tcx.hir().body(eid).value.kind {
845 ExprKind::Block(ref block, _) => Some(block),
852 /// Gets the parent node if it's an impl block.
853 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
855 match map.parent_iter(id).next() {
859 kind: ItemKind::Impl(imp),
867 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
868 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
870 let mut iter = map.parent_iter(expr.hir_id);
872 Some((arm_id, Node::Arm(..))) => matches!(
877 kind: ExprKind::Match(_, [_, else_arm], MatchSource::IfLetDesugar { .. }),
881 if else_arm.hir_id == arm_id
886 kind: ExprKind::If(_, _, Some(else_expr)),
889 )) => else_expr.hir_id == expr.hir_id,
894 /// Checks whether the given expression is a constant integer of the given value.
895 /// unlike `is_integer_literal`, this version does const folding
896 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
897 if is_integer_literal(e, value) {
900 let map = cx.tcx.hir();
901 let parent_item = map.get_parent_item(e.hir_id);
902 if let Some((Constant::Int(v), _)) = map
903 .maybe_body_owned_by(parent_item)
904 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
912 /// Checks whether the given expression is a constant literal of the given value.
913 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
914 // FIXME: use constant folding
915 if let ExprKind::Lit(ref spanned) = expr.kind {
916 if let LitKind::Int(v, _) = spanned.node {
923 /// Returns `true` if the given `Expr` has been coerced before.
925 /// Examples of coercions can be found in the Nomicon at
926 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
928 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
929 /// information on adjustments and coercions.
930 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
931 cx.typeck_results().adjustments().get(e.hir_id).is_some()
934 /// Returns the pre-expansion span if is this comes from an expansion of the
936 /// See also `is_direct_expn_of`.
938 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
940 if span.from_expansion() {
941 let data = span.ctxt().outer_expn_data();
942 let new_span = data.call_site;
944 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
945 if mac_name.as_str() == name {
946 return Some(new_span);
957 /// Returns the pre-expansion span if the span directly comes from an expansion
958 /// of the macro `name`.
959 /// The difference with `is_expn_of` is that in
963 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
965 /// `is_direct_expn_of`.
967 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
968 if span.from_expansion() {
969 let data = span.ctxt().outer_expn_data();
970 let new_span = data.call_site;
972 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
973 if mac_name.as_str() == name {
974 return Some(new_span);
982 /// Convenience function to get the return type of a function.
983 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
984 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
985 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
986 cx.tcx.erase_late_bound_regions(ret_ty)
989 /// Checks if an expression is constructing a tuple-like enum variant or struct
990 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
991 if let ExprKind::Call(ref fun, _) = expr.kind {
992 if let ExprKind::Path(ref qp) = fun.kind {
993 let res = cx.qpath_res(qp, fun.hir_id);
995 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
996 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1004 /// Returns `true` if a pattern is refutable.
1005 // TODO: should be implemented using rustc/mir_build/thir machinery
1006 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1007 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1009 cx.qpath_res(qpath, id),
1010 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1014 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1015 i.any(|pat| is_refutable(cx, pat))
1019 PatKind::Wild => false,
1020 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1021 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1022 PatKind::Lit(..) | PatKind::Range(..) => true,
1023 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1024 PatKind::Or(ref pats) => {
1025 // TODO: should be the honest check, that pats is exhaustive set
1026 are_refutable(cx, pats.iter().map(|pat| &**pat))
1028 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1029 PatKind::Struct(ref qpath, ref fields, _) => {
1030 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1032 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1033 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1035 PatKind::Slice(ref head, ref middle, ref tail) => {
1036 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1037 rustc_ty::Slice(..) => {
1038 // [..] is the only irrefutable slice pattern.
1039 !head.is_empty() || middle.is_none() || !tail.is_empty()
1041 rustc_ty::Array(..) => {
1042 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
1053 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1054 /// the function once on the given pattern.
1055 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1056 if let PatKind::Or(pats) = pat.kind {
1057 pats.iter().copied().for_each(f)
1063 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1064 /// implementations have.
1065 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1066 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
1069 /// Remove blocks around an expression.
1071 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1073 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1074 while let ExprKind::Block(ref block, ..) = expr.kind {
1075 match (block.stmts.is_empty(), block.expr.as_ref()) {
1076 (true, Some(e)) => expr = e,
1083 pub fn is_self(slf: &Param<'_>) -> bool {
1084 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1085 name.name == kw::SelfLower
1091 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1093 if let TyKind::Path(QPath::Resolved(None, ref path)) = slf.kind;
1094 if let Res::SelfTy(..) = path.res;
1102 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1103 (0..decl.inputs.len()).map(move |i| &body.params[i])
1106 /// Checks if a given expression is a match expression expanded from the `?`
1107 /// operator or the `try` macro.
1108 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1109 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1111 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1112 if is_lang_ctor(cx, path, ResultOk);
1113 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1114 if path_to_local_id(arm.body, hir_id);
1122 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1123 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1124 is_lang_ctor(cx, path, ResultErr)
1130 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1131 // desugared from a `?` operator
1132 if let MatchSource::TryDesugar = *source {
1138 if arms[0].guard.is_none();
1139 if arms[1].guard.is_none();
1140 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) ||
1141 (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1151 /// Returns `true` if the lint is allowed in the current context
1153 /// Useful for skipping long running code when it's unnecessary
1154 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1155 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1158 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1159 while let PatKind::Ref(subpat, _) = pat.kind {
1165 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1166 Integer::from_int_ty(&tcx, ity).size().bits()
1169 #[allow(clippy::cast_possible_wrap)]
1170 /// Turn a constant int byte representation into an i128
1171 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1172 let amt = 128 - int_bits(tcx, ity);
1173 ((u as i128) << amt) >> amt
1176 #[allow(clippy::cast_sign_loss)]
1177 /// clip unused bytes
1178 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1179 let amt = 128 - int_bits(tcx, ity);
1180 ((u as u128) << amt) >> amt
1183 /// clip unused bytes
1184 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1185 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1186 let amt = 128 - bits;
1190 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1191 let map = &tcx.hir();
1192 let mut prev_enclosing_node = None;
1193 let mut enclosing_node = node;
1194 while Some(enclosing_node) != prev_enclosing_node {
1195 if is_automatically_derived(map.attrs(enclosing_node)) {
1198 prev_enclosing_node = Some(enclosing_node);
1199 enclosing_node = map.get_parent_item(enclosing_node);
1204 /// Matches a function call with the given path and returns the arguments.
1209 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1211 pub fn match_function_call<'tcx>(
1212 cx: &LateContext<'tcx>,
1213 expr: &'tcx Expr<'_>,
1215 ) -> Option<&'tcx [Expr<'tcx>]> {
1217 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1218 if let ExprKind::Path(ref qpath) = fun.kind;
1219 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1220 if match_def_path(cx, fun_def_id, path);
1228 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1230 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1231 let search_path = cx.get_def_path(did);
1234 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1237 /// Checks if the given `DefId` matches the path.
1238 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1239 // We should probably move to Symbols in Clippy as well rather than interning every time.
1240 let path = cx.get_def_path(did);
1241 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1244 pub fn match_panic_call(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1245 if let ExprKind::Call(func, [arg]) = expr.kind {
1246 expr_path_res(cx, func)
1248 .map_or(false, |id| match_panic_def_id(cx, id))
1255 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1256 match_any_def_paths(
1260 &paths::BEGIN_PANIC,
1261 &paths::BEGIN_PANIC_FMT,
1263 &paths::PANICKING_PANIC,
1264 &paths::PANICKING_PANIC_FMT,
1265 &paths::PANICKING_PANIC_STR,
1271 /// Returns the list of condition expressions and the list of blocks in a
1272 /// sequence of `if/else`.
1273 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1274 /// `if a { c } else if b { d } else { e }`.
1275 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1276 let mut conds = Vec::new();
1277 let mut blocks: Vec<&Block<'_>> = Vec::new();
1279 while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
1280 conds.push(&**cond);
1281 if let ExprKind::Block(ref block, _) = then_expr.kind {
1284 panic!("ExprKind::If node is not an ExprKind::Block");
1287 if let Some(ref else_expr) = *else_expr {
1294 // final `else {..}`
1295 if !blocks.is_empty() {
1296 if let ExprKind::Block(ref block, _) = expr.kind {
1297 blocks.push(&**block);
1304 // Finds the `#[must_use]` attribute, if any
1305 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1306 attrs.iter().find(|a| a.has_name(sym::must_use))
1309 // check if expr is calling method or function with #[must_use] attribute
1310 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1311 let did = match expr.kind {
1312 ExprKind::Call(ref path, _) => if_chain! {
1313 if let ExprKind::Path(ref qpath) = path.kind;
1314 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1321 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1325 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1328 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1329 pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
1330 let map = tcx.hir();
1331 let mut child_id = expr.hir_id;
1332 let mut iter = map.parent_iter(child_id);
1336 Some((id, Node::Block(_))) => child_id = id,
1337 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1338 Some((_, Node::Expr(expr))) => match expr.kind {
1339 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1340 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1341 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1342 _ => break Some(Node::Expr(expr)),
1344 Some((_, node)) => break Some(node),
1349 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1350 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1352 get_expr_use_or_unification_node(tcx, expr),
1353 None | Some(Node::Stmt(Stmt {
1354 kind: StmtKind::Expr(_)
1356 | StmtKind::Local(Local {
1358 kind: PatKind::Wild,
1368 /// Checks if the expression is the final expression returned from a block.
1369 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1370 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1373 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1374 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1375 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1376 attr.path == sym::no_std
1383 /// Check if parent of a hir node is a trait implementation block.
1384 /// For example, `f` in
1386 /// impl Trait for S {
1390 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1391 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1392 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1398 /// Check if it's even possible to satisfy the `where` clause for the item.
1400 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1403 /// fn foo() where i32: Iterator {
1404 /// for _ in 2i32 {}
1407 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1408 use rustc_trait_selection::traits;
1414 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1415 traits::impossible_predicates(
1417 traits::elaborate_predicates(cx.tcx, predicates)
1418 .map(|o| o.predicate)
1419 .collect::<Vec<_>>(),
1423 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1424 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1426 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1429 kind: ExprKind::Path(qpath),
1430 hir_id: path_hir_id,
1434 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
1439 /// This function checks if any of the lints in the slice is enabled for the provided `HirId`.
1440 /// A lint counts as enabled with any of the levels: `Level::Forbid` | `Level::Deny` | `Level::Warn`
1443 /// #[deny(clippy::YOUR_AWESOME_LINT)]
1444 /// println!("Hello, World!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == true
1446 /// #[allow(clippy::YOUR_AWESOME_LINT)]
1447 /// println!("See you soon!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == false
1449 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1450 lints.iter().any(|lint| {
1452 cx.tcx.lint_level_at_node(lint, id),
1453 (Level::Forbid | Level::Deny | Level::Warn, _)
1458 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1459 /// slice iff the given expression is a slice of primitives (as defined in the
1460 /// `is_recursively_primitive_type` function) and None otherwise.
1461 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1462 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1463 let expr_kind = expr_type.kind();
1464 let is_primitive = match expr_kind {
1465 rustc_ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1466 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1467 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1468 is_recursively_primitive_type(element_type)
1477 // if we have wrappers like Array, Slice or Tuple, print these
1478 // and get the type enclosed in the slice ref
1479 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1480 rustc_ty::Slice(..) => return Some("slice".into()),
1481 rustc_ty::Array(..) => return Some("array".into()),
1482 rustc_ty::Tuple(..) => return Some("tuple".into()),
1484 // is_recursively_primitive_type() should have taken care
1485 // of the rest and we can rely on the type that is found
1486 let refs_peeled = expr_type.peel_refs();
1487 return Some(refs_peeled.walk().last().unwrap().to_string());
1494 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1495 /// `hash` must be comformed with `eq`
1496 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1498 Hash: Fn(&T) -> u64,
1499 Eq: Fn(&T, &T) -> bool,
1501 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1502 return vec![(&exprs[0], &exprs[1])];
1505 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1507 let mut map: FxHashMap<_, Vec<&_>> =
1508 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1511 match map.entry(hash(expr)) {
1512 Entry::Occupied(mut o) => {
1515 match_expr_list.push((o, expr));
1518 o.get_mut().push(expr);
1520 Entry::Vacant(v) => {
1521 v.insert(vec![expr]);
1529 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
1530 /// references removed.
1531 pub fn peel_hir_pat_refs(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
1532 fn peel(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
1533 if let PatKind::Ref(pat, _) = pat.kind {
1534 peel(pat, count + 1)
1542 /// Peels of expressions while the given closure returns `Some`.
1543 pub fn peel_hir_expr_while<'tcx>(
1544 mut expr: &'tcx Expr<'tcx>,
1545 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
1546 ) -> &'tcx Expr<'tcx> {
1547 while let Some(e) = f(expr) {
1553 /// Peels off up to the given number of references on the expression. Returns the underlying
1554 /// expression and the number of references removed.
1555 pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
1556 let mut remaining = count;
1557 let e = peel_hir_expr_while(expr, |e| match e.kind {
1558 ExprKind::AddrOf(BorrowKind::Ref, _, e) if remaining != 0 => {
1564 (e, count - remaining)
1567 /// Peels off all references on the expression. Returns the underlying expression and the number of
1568 /// references removed.
1569 pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
1571 let e = peel_hir_expr_while(expr, |e| match e.kind {
1572 ExprKind::AddrOf(BorrowKind::Ref, _, e) => {
1582 macro_rules! unwrap_cargo_metadata {
1583 ($cx: ident, $lint: ident, $deps: expr) => {{
1584 let mut command = cargo_metadata::MetadataCommand::new();
1589 match command.exec() {
1590 Ok(metadata) => metadata,
1592 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1599 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1601 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1602 if let Res::Def(_, def_id) = path.res;
1604 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)