1 #![feature(box_patterns)]
2 #![feature(in_band_lifetimes)]
4 #![feature(rustc_private)]
5 #![recursion_limit = "512"]
6 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
8 // FIXME: switch to something more ergonomic here, once available.
9 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
10 extern crate rustc_ast;
11 extern crate rustc_ast_pretty;
12 extern crate rustc_attr;
13 extern crate rustc_data_structures;
14 extern crate rustc_errors;
15 extern crate rustc_hir;
16 extern crate rustc_hir_pretty;
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;
41 pub mod numeric_literal;
44 pub mod qualify_min_const_fn;
51 pub use self::attrs::*;
52 pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, SpanlessHash};
54 use std::collections::hash_map::Entry;
55 use std::hash::BuildHasherDefault;
57 use if_chain::if_chain;
58 use rustc_ast::ast::{self, Attribute, BorrowKind, LitKind};
59 use rustc_data_structures::fx::FxHashMap;
61 use rustc_hir::def::{DefKind, Res};
62 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
63 use rustc_hir::intravisit::{self, walk_expr, ErasedMap, NestedVisitorMap, Visitor};
64 use rustc_hir::LangItem::{ResultErr, ResultOk};
66 def, Arm, BindingAnnotation, Block, Body, Constness, Destination, Expr, ExprKind, FnDecl, GenericArgs, HirId, Impl,
67 ImplItem, ImplItemKind, Item, ItemKind, LangItem, Local, MatchSource, Node, Param, Pat, PatKind, Path, PathSegment,
68 QPath, Stmt, StmtKind, TraitItem, TraitItemKind, TraitRef, TyKind,
70 use rustc_lint::{LateContext, Level, Lint, LintContext};
71 use rustc_middle::hir::exports::Export;
72 use rustc_middle::hir::map::Map;
73 use rustc_middle::ty as rustc_ty;
74 use rustc_middle::ty::{layout::IntegerExt, DefIdTree, Ty, TyCtxt, TypeFoldable};
75 use rustc_semver::RustcVersion;
76 use rustc_session::Session;
77 use rustc_span::hygiene::{ExpnKind, MacroKind};
78 use rustc_span::source_map::original_sp;
80 use rustc_span::symbol::{kw, Symbol};
81 use rustc_span::{Span, DUMMY_SP};
82 use rustc_target::abi::Integer;
84 use crate::consts::{constant, Constant};
85 use crate::ty::{can_partially_move_ty, is_recursively_primitive_type};
87 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
88 if let Ok(version) = RustcVersion::parse(msrv) {
90 } else if let Some(sess) = sess {
91 if let Some(span) = span {
92 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
98 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
99 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
103 macro_rules! extract_msrv_attr {
105 extract_msrv_attr!(@LateContext, ());
108 extract_msrv_attr!(@EarlyContext);
110 (@$context:ident$(, $call:tt)?) => {
111 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
112 use $crate::get_unique_inner_attr;
113 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
115 if let Some(msrv) = msrv_attr.value_str() {
116 self.msrv = $crate::parse_msrv(
118 Some(cx.sess$($call)?),
119 Some(msrv_attr.span),
122 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
131 /// Returns `true` if the two spans come from differing expansions (i.e., one is
132 /// from a macro and one isn't).
134 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
135 rhs.ctxt() != lhs.ctxt()
138 /// If the given expression is a local binding, find the initializer expression.
139 /// If that initializer expression is another local binding, find its initializer again.
140 /// This process repeats as long as possible (but usually no more than once). Initializer
141 /// expressions with adjustments are ignored. If this is not desired, use [`find_binding_init`]
154 /// let def = abc + 2;
155 /// // ^^^^^^^ output
159 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
160 while let Some(init) = path_to_local(expr)
161 .and_then(|id| find_binding_init(cx, id))
162 .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
169 /// Finds the initializer expression for a local binding. Returns `None` if the binding is mutable.
170 /// By only considering immutable bindings, we guarantee that the returned expression represents the
171 /// value of the binding wherever it is referenced.
173 /// Example: For `let x = 1`, if the `HirId` of `x` is provided, the `Expr` `1` is returned.
174 /// Note: If you have an expression that references a binding `x`, use `path_to_local` to get the
175 /// canonical binding `HirId`.
176 pub fn find_binding_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
177 let hir = cx.tcx.hir();
179 if let Some(Node::Binding(pat)) = hir.find(hir_id);
180 if matches!(pat.kind, PatKind::Binding(BindingAnnotation::Unannotated, ..));
181 let parent = hir.get_parent_node(hir_id);
182 if let Some(Node::Local(local)) = hir.find(parent);
190 /// Returns `true` if the given `NodeId` is inside a constant context
195 /// if in_constant(cx, expr.hir_id) {
199 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
200 let parent_id = cx.tcx.hir().get_parent_item(id);
201 match cx.tcx.hir().get(parent_id) {
203 kind: ItemKind::Const(..) | ItemKind::Static(..),
206 | Node::TraitItem(&TraitItem {
207 kind: TraitItemKind::Const(..),
210 | Node::ImplItem(&ImplItem {
211 kind: ImplItemKind::Const(..),
214 | Node::AnonConst(_) => true,
216 kind: ItemKind::Fn(ref sig, ..),
219 | Node::ImplItem(&ImplItem {
220 kind: ImplItemKind::Fn(ref sig, _),
222 }) => sig.header.constness == Constness::Const,
227 /// Checks if a `QPath` resolves to a constructor of a `LangItem`.
228 /// For example, use this to check whether a function call or a pattern is `Some(..)`.
229 pub fn is_lang_ctor(cx: &LateContext<'_>, qpath: &QPath<'_>, lang_item: LangItem) -> bool {
230 if let QPath::Resolved(_, path) = qpath {
231 if let Res::Def(DefKind::Ctor(..), ctor_id) = path.res {
232 if let Ok(item_id) = cx.tcx.lang_items().require(lang_item) {
233 return cx.tcx.parent(ctor_id) == Some(item_id);
240 /// Returns `true` if this `span` was expanded by any macro.
242 pub fn in_macro(span: Span) -> bool {
243 if span.from_expansion() {
244 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
250 /// Checks if given pattern is a wildcard (`_`)
251 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
252 matches!(pat.kind, PatKind::Wild)
255 /// Checks if the first type parameter is a lang item.
256 pub fn is_ty_param_lang_item(cx: &LateContext<'_>, qpath: &QPath<'tcx>, item: LangItem) -> Option<&'tcx hir::Ty<'tcx>> {
257 let ty = get_qpath_generic_tys(qpath).next()?;
259 if let TyKind::Path(qpath) = &ty.kind {
260 cx.qpath_res(qpath, ty.hir_id)
262 .map_or(false, |id| {
263 cx.tcx.lang_items().require(item).map_or(false, |lang_id| id == lang_id)
271 /// Checks if the first type parameter is a diagnostic item.
272 pub fn is_ty_param_diagnostic_item(
273 cx: &LateContext<'_>,
276 ) -> Option<&'tcx hir::Ty<'tcx>> {
277 let ty = get_qpath_generic_tys(qpath).next()?;
279 if let TyKind::Path(qpath) = &ty.kind {
280 cx.qpath_res(qpath, ty.hir_id)
282 .map_or(false, |id| cx.tcx.is_diagnostic_item(item, id))
289 /// Checks if the method call given in `expr` belongs to the given trait.
290 /// This is a deprecated function, consider using [`is_trait_method`].
291 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
292 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
293 let trt_id = cx.tcx.trait_of_item(def_id);
294 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
297 /// Checks if a method is defined in an impl of a diagnostic item
298 pub fn is_diag_item_method(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
299 if let Some(impl_did) = cx.tcx.impl_of_method(def_id) {
300 if let Some(adt) = cx.tcx.type_of(impl_did).ty_adt_def() {
301 return cx.tcx.is_diagnostic_item(diag_item, adt.did);
307 /// Checks if a method is in a diagnostic item trait
308 pub fn is_diag_trait_item(cx: &LateContext<'_>, def_id: DefId, diag_item: Symbol) -> bool {
309 if let Some(trait_did) = cx.tcx.trait_of_item(def_id) {
310 return cx.tcx.is_diagnostic_item(diag_item, trait_did);
315 /// Checks if the method call given in `expr` belongs to the given trait.
316 pub fn is_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, diag_item: Symbol) -> bool {
318 .type_dependent_def_id(expr.hir_id)
319 .map_or(false, |did| is_diag_trait_item(cx, did, diag_item))
322 /// Checks if an expression references a variable of the given name.
323 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
324 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
325 if let [p] = path.segments {
326 return p.ident.name == var;
332 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
334 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
335 QPath::TypeRelative(_, ref seg) => seg,
336 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
340 pub fn get_qpath_generics(path: &QPath<'tcx>) -> Option<&'tcx GenericArgs<'tcx>> {
342 QPath::Resolved(_, p) => p.segments.last().and_then(|s| s.args),
343 QPath::TypeRelative(_, s) => s.args,
344 QPath::LangItem(..) => None,
348 pub fn get_qpath_generic_tys(path: &QPath<'tcx>) -> impl Iterator<Item = &'tcx hir::Ty<'tcx>> {
349 get_qpath_generics(path)
350 .map_or([].as_ref(), |a| a.args)
353 if let hir::GenericArg::Type(ty) = a {
361 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
363 QPath::Resolved(_, ref path) => path.segments.get(0),
364 QPath::TypeRelative(_, ref seg) => Some(seg),
365 QPath::LangItem(..) => None,
369 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
370 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
371 /// `QPath::Resolved.1.res.opt_def_id()`.
373 /// Matches a `QPath` against a slice of segment string literals.
375 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
376 /// `rustc_hir::QPath`.
380 /// match_qpath(path, &["std", "rt", "begin_unwind"])
382 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
384 QPath::Resolved(_, ref path) => match_path(path, segments),
385 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
386 TyKind::Path(ref inner_path) => {
387 if let [prefix @ .., end] = segments {
388 if match_qpath(inner_path, prefix) {
389 return segment.ident.name.as_str() == *end;
396 QPath::LangItem(..) => false,
400 /// If the expression is a path, resolve it. Otherwise, return `Res::Err`.
401 pub fn expr_path_res(cx: &LateContext<'_>, expr: &Expr<'_>) -> Res {
402 if let ExprKind::Path(p) = &expr.kind {
403 cx.qpath_res(p, expr.hir_id)
409 /// Resolves the path to a `DefId` and checks if it matches the given path.
410 pub fn is_qpath_def_path(cx: &LateContext<'_>, path: &QPath<'_>, hir_id: HirId, segments: &[&str]) -> bool {
411 cx.qpath_res(path, hir_id)
413 .map_or(false, |id| match_def_path(cx, id, segments))
416 /// If the expression is a path, resolves it to a `DefId` and checks if it matches the given path.
417 pub fn is_expr_path_def_path(cx: &LateContext<'_>, expr: &Expr<'_>, segments: &[&str]) -> bool {
418 expr_path_res(cx, expr)
420 .map_or(false, |id| match_def_path(cx, id, segments))
423 /// THIS METHOD IS DEPRECATED and will eventually be removed since it does not match against the
424 /// entire path or resolved `DefId`. Prefer using `match_def_path`. Consider getting a `DefId` from
425 /// `QPath::Resolved.1.res.opt_def_id()`.
427 /// Matches a `Path` against a slice of segment string literals.
429 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
430 /// `rustc_hir::Path`.
435 /// if match_path(&trait_ref.path, &paths::HASH) {
436 /// // This is the `std::hash::Hash` trait.
439 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
440 /// // This is a `rustc_middle::lint::Lint`.
443 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
447 .zip(segments.iter().rev())
448 .all(|(a, b)| a.ident.name.as_str() == *b)
451 /// If the expression is a path to a local, returns the canonical `HirId` of the local.
452 pub fn path_to_local(expr: &Expr<'_>) -> Option<HirId> {
453 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
454 if let Res::Local(id) = path.res {
461 /// Returns true if the expression is a path to a local with the specified `HirId`.
462 /// Use this function to see if an expression matches a function argument or a match binding.
463 pub fn path_to_local_id(expr: &Expr<'_>, id: HirId) -> bool {
464 path_to_local(expr) == Some(id)
467 /// Gets the definition associated to a path.
468 #[allow(clippy::shadow_unrelated)] // false positive #6563
469 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Res {
470 macro_rules! try_res {
474 None => return Res::Err,
478 fn item_child_by_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, name: &str) -> Option<&'tcx Export<HirId>> {
479 tcx.item_children(def_id)
481 .find(|item| item.ident.name.as_str() == name)
484 let (krate, first, path) = match *path {
485 [krate, first, ref path @ ..] => (krate, first, path),
486 _ => return Res::Err,
489 let crates = tcx.crates();
490 let krate = try_res!(crates.iter().find(|&&num| tcx.crate_name(num).as_str() == krate));
491 let first = try_res!(item_child_by_name(tcx, krate.as_def_id(), first));
495 // `get_def_path` seems to generate these empty segments for extern blocks.
496 // We can just ignore them.
497 .filter(|segment| !segment.is_empty())
498 // for each segment, find the child item
499 .try_fold(first, |item, segment| {
500 let def_id = item.res.def_id();
501 if let Some(item) = item_child_by_name(tcx, def_id, segment) {
503 } else if matches!(item.res, Res::Def(DefKind::Enum | DefKind::Struct, _)) {
504 // it is not a child item so check inherent impl items
505 tcx.inherent_impls(def_id)
507 .find_map(|&impl_def_id| item_child_by_name(tcx, impl_def_id, segment))
515 /// Convenience function to get the `DefId` of a trait by path.
516 /// It could be a trait or trait alias.
517 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
518 match path_to_res(cx, path) {
519 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
524 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
526 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
529 /// struct Point(isize, isize);
531 /// impl std::ops::Add for Point {
532 /// type Output = Self;
534 /// fn add(self, other: Self) -> Self {
539 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
540 // Get the implemented trait for the current function
541 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
543 if parent_impl != hir::CRATE_HIR_ID;
544 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
545 if let hir::ItemKind::Impl(impl_) = &item.kind;
546 then { return impl_.of_trait.as_ref(); }
551 /// Checks if the top level expression can be moved into a closure as is.
552 pub fn can_move_expr_to_closure_no_visit(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, jump_targets: &[HirId]) -> bool {
554 ExprKind::Break(Destination { target_id: Ok(id), .. }, _)
555 | ExprKind::Continue(Destination { target_id: Ok(id), .. })
556 if jump_targets.contains(&id) =>
561 | ExprKind::Continue(_)
563 | ExprKind::Yield(..)
564 | ExprKind::InlineAsm(_)
565 | ExprKind::LlvmInlineAsm(_) => false,
566 // Accessing a field of a local value can only be done if the type isn't
568 ExprKind::Field(base_expr, _)
571 ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
572 ) && can_partially_move_ty(cx, cx.typeck_results().expr_ty(base_expr)) =>
574 // TODO: check if the local has been partially moved. Assume it has for now.
581 /// Checks if the expression can be moved into a closure as is.
582 pub fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
583 struct V<'cx, 'tcx> {
584 cx: &'cx LateContext<'tcx>,
588 impl Visitor<'tcx> for V<'_, 'tcx> {
589 type Map = ErasedMap<'tcx>;
590 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
591 NestedVisitorMap::None
594 fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
595 if !self.allow_closure {
598 if let ExprKind::Loop(b, ..) = e.kind {
599 self.loops.push(e.hir_id);
603 self.allow_closure &= can_move_expr_to_closure_no_visit(self.cx, e, &self.loops);
618 /// Returns the method names and argument list of nested method call expressions that make up
619 /// `expr`. method/span lists are sorted with the most recent call first.
620 pub fn method_calls<'tcx>(
621 expr: &'tcx Expr<'tcx>,
623 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
624 let mut method_names = Vec::with_capacity(max_depth);
625 let mut arg_lists = Vec::with_capacity(max_depth);
626 let mut spans = Vec::with_capacity(max_depth);
628 let mut current = expr;
629 for _ in 0..max_depth {
630 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
631 if args.iter().any(|e| e.span.from_expansion()) {
634 method_names.push(path.ident.name);
635 arg_lists.push(&**args);
643 (method_names, arg_lists, spans)
646 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
648 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
649 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
650 /// containing the `Expr`s for
651 /// `.bar()` and `.baz()`
652 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
653 let mut current = expr;
654 let mut matched = Vec::with_capacity(methods.len());
655 for method_name in methods.iter().rev() {
656 // method chains are stored last -> first
657 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
658 if path.ident.name.as_str() == *method_name {
659 if args.iter().any(|e| e.span.from_expansion()) {
662 matched.push(&**args); // build up `matched` backwards
663 current = &args[0] // go to parent expression
671 // Reverse `matched` so that it is in the same order as `methods`.
676 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
677 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
679 .entry_fn(LOCAL_CRATE)
680 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
683 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
684 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
685 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
686 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
687 Some(def_id) == cx.tcx.lang_items().panic_impl()
690 /// Gets the name of the item the expression is in, if available.
691 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
692 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
693 match cx.tcx.hir().find(parent_id) {
695 Node::Item(Item { ident, .. })
696 | Node::TraitItem(TraitItem { ident, .. })
697 | Node::ImplItem(ImplItem { ident, .. }),
698 ) => Some(ident.name),
703 /// Gets the name of a `Pat`, if any.
704 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
706 PatKind::Binding(.., ref spname, _) => Some(spname.name),
707 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
708 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
713 pub struct ContainsName {
718 impl<'tcx> Visitor<'tcx> for ContainsName {
719 type Map = Map<'tcx>;
721 fn visit_name(&mut self, _: Span, name: Symbol) {
722 if self.name == name {
726 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
727 NestedVisitorMap::None
731 /// Checks if an `Expr` contains a certain name.
732 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
733 let mut cn = ContainsName { name, result: false };
738 /// Returns `true` if `expr` contains a return expression
739 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
740 struct RetCallFinder {
744 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
745 type Map = Map<'tcx>;
747 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
751 if let hir::ExprKind::Ret(..) = &expr.kind {
754 hir::intravisit::walk_expr(self, expr);
758 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
759 hir::intravisit::NestedVisitorMap::None
763 let mut visitor = RetCallFinder { found: false };
764 visitor.visit_expr(expr);
768 struct FindMacroCalls<'a, 'b> {
769 names: &'a [&'b str],
773 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
774 type Map = Map<'tcx>;
776 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
777 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
778 self.result.push(expr.span);
780 // and check sub-expressions
781 intravisit::walk_expr(self, expr);
784 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
785 NestedVisitorMap::None
789 /// Finds calls of the specified macros in a function body.
790 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
791 let mut fmc = FindMacroCalls {
795 fmc.visit_expr(&body.value);
799 /// Extends the span to the beginning of the spans line, incl. whitespaces.
804 /// // will be converted to
806 /// // ^^^^^^^^^^^^^^
808 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
809 let span = original_sp(span, DUMMY_SP);
810 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
811 let line_no = source_map_and_line.line;
812 let line_start = source_map_and_line.sf.lines[line_no];
813 Span::new(line_start, span.hi(), span.ctxt())
816 /// Gets the parent node, if any.
817 pub fn get_parent_node(tcx: TyCtxt<'_>, id: HirId) -> Option<Node<'_>> {
818 tcx.hir().parent_iter(id).next().map(|(_, node)| node)
821 /// Gets the parent expression, if any –- this is useful to constrain a lint.
822 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
823 match get_parent_node(cx.tcx, e.hir_id) {
824 Some(Node::Expr(parent)) => Some(parent),
829 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
830 let map = &cx.tcx.hir();
831 let enclosing_node = map
832 .get_enclosing_scope(hir_id)
833 .and_then(|enclosing_id| map.find(enclosing_id));
834 enclosing_node.and_then(|node| match node {
835 Node::Block(block) => Some(block),
837 kind: ItemKind::Fn(_, _, eid),
840 | Node::ImplItem(&ImplItem {
841 kind: ImplItemKind::Fn(_, eid),
843 }) => match cx.tcx.hir().body(eid).value.kind {
844 ExprKind::Block(ref block, _) => Some(block),
851 /// Gets the parent node if it's an impl block.
852 pub fn get_parent_as_impl(tcx: TyCtxt<'_>, id: HirId) -> Option<&Impl<'_>> {
854 match map.parent_iter(id).next() {
858 kind: ItemKind::Impl(imp),
866 /// Checks if the given expression is the else clause of either an `if` or `if let` expression.
867 pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
869 let mut iter = map.parent_iter(expr.hir_id);
871 Some((arm_id, Node::Arm(..))) => matches!(
876 kind: ExprKind::Match(_, [_, else_arm], MatchSource::IfLetDesugar { .. }),
880 if else_arm.hir_id == arm_id
885 kind: ExprKind::If(_, _, Some(else_expr)),
888 )) => else_expr.hir_id == expr.hir_id,
893 /// Checks whether the given expression is a constant integer of the given value.
894 /// unlike `is_integer_literal`, this version does const folding
895 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
896 if is_integer_literal(e, value) {
899 let map = cx.tcx.hir();
900 let parent_item = map.get_parent_item(e.hir_id);
901 if let Some((Constant::Int(v), _)) = map
902 .maybe_body_owned_by(parent_item)
903 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
911 /// Checks whether the given expression is a constant literal of the given value.
912 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
913 // FIXME: use constant folding
914 if let ExprKind::Lit(ref spanned) = expr.kind {
915 if let LitKind::Int(v, _) = spanned.node {
922 /// Returns `true` if the given `Expr` has been coerced before.
924 /// Examples of coercions can be found in the Nomicon at
925 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
927 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
928 /// information on adjustments and coercions.
929 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
930 cx.typeck_results().adjustments().get(e.hir_id).is_some()
933 /// Returns the pre-expansion span if is this comes from an expansion of the
935 /// See also `is_direct_expn_of`.
937 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
939 if span.from_expansion() {
940 let data = span.ctxt().outer_expn_data();
941 let new_span = data.call_site;
943 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
944 if mac_name.as_str() == name {
945 return Some(new_span);
956 /// Returns the pre-expansion span if the span directly comes from an expansion
957 /// of the macro `name`.
958 /// The difference with `is_expn_of` is that in
962 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
964 /// `is_direct_expn_of`.
966 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
967 if span.from_expansion() {
968 let data = span.ctxt().outer_expn_data();
969 let new_span = data.call_site;
971 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
972 if mac_name.as_str() == name {
973 return Some(new_span);
981 /// Convenience function to get the return type of a function.
982 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
983 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
984 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
985 cx.tcx.erase_late_bound_regions(ret_ty)
988 /// Checks if an expression is constructing a tuple-like enum variant or struct
989 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
990 if let ExprKind::Call(ref fun, _) = expr.kind {
991 if let ExprKind::Path(ref qp) = fun.kind {
992 let res = cx.qpath_res(qp, fun.hir_id);
994 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
995 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1003 /// Returns `true` if a pattern is refutable.
1004 // TODO: should be implemented using rustc/mir_build/thir machinery
1005 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1006 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1008 cx.qpath_res(qpath, id),
1009 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1013 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1014 i.any(|pat| is_refutable(cx, pat))
1018 PatKind::Wild => false,
1019 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1020 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1021 PatKind::Lit(..) | PatKind::Range(..) => true,
1022 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1023 PatKind::Or(ref pats) => {
1024 // TODO: should be the honest check, that pats is exhaustive set
1025 are_refutable(cx, pats.iter().map(|pat| &**pat))
1027 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1028 PatKind::Struct(ref qpath, ref fields, _) => {
1029 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1031 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1032 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1034 PatKind::Slice(ref head, ref middle, ref tail) => {
1035 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1036 rustc_ty::Slice(..) => {
1037 // [..] is the only irrefutable slice pattern.
1038 !head.is_empty() || middle.is_none() || !tail.is_empty()
1040 rustc_ty::Array(..) => {
1041 are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat))
1052 /// If the pattern is an `or` pattern, call the function once for each sub pattern. Otherwise, call
1053 /// the function once on the given pattern.
1054 pub fn recurse_or_patterns<'tcx, F: FnMut(&'tcx Pat<'tcx>)>(pat: &'tcx Pat<'tcx>, mut f: F) {
1055 if let PatKind::Or(pats) = pat.kind {
1056 pats.iter().copied().for_each(f)
1062 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1063 /// implementations have.
1064 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1065 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
1068 /// Remove blocks around an expression.
1070 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1072 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1073 while let ExprKind::Block(ref block, ..) = expr.kind {
1074 match (block.stmts.is_empty(), block.expr.as_ref()) {
1075 (true, Some(e)) => expr = e,
1082 pub fn is_self(slf: &Param<'_>) -> bool {
1083 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1084 name.name == kw::SelfLower
1090 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1092 if let TyKind::Path(QPath::Resolved(None, ref path)) = slf.kind;
1093 if let Res::SelfTy(..) = path.res;
1101 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1102 (0..decl.inputs.len()).map(move |i| &body.params[i])
1105 /// Checks if a given expression is a match expression expanded from the `?`
1106 /// operator or the `try` macro.
1107 pub fn is_try<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1108 fn is_ok(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1110 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1111 if is_lang_ctor(cx, path, ResultOk);
1112 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1113 if path_to_local_id(arm.body, hir_id);
1121 fn is_err(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
1122 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1123 is_lang_ctor(cx, path, ResultErr)
1129 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1130 // desugared from a `?` operator
1131 if let MatchSource::TryDesugar = *source {
1137 if arms[0].guard.is_none();
1138 if arms[1].guard.is_none();
1139 if (is_ok(cx, &arms[0]) && is_err(cx, &arms[1])) ||
1140 (is_ok(cx, &arms[1]) && is_err(cx, &arms[0]));
1150 /// Returns `true` if the lint is allowed in the current context
1152 /// Useful for skipping long running code when it's unnecessary
1153 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1154 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1157 pub fn strip_pat_refs<'hir>(mut pat: &'hir Pat<'hir>) -> &'hir Pat<'hir> {
1158 while let PatKind::Ref(subpat, _) = pat.kind {
1164 pub fn int_bits(tcx: TyCtxt<'_>, ity: rustc_ty::IntTy) -> u64 {
1165 Integer::from_int_ty(&tcx, ity).size().bits()
1168 #[allow(clippy::cast_possible_wrap)]
1169 /// Turn a constant int byte representation into an i128
1170 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::IntTy) -> i128 {
1171 let amt = 128 - int_bits(tcx, ity);
1172 ((u as i128) << amt) >> amt
1175 #[allow(clippy::cast_sign_loss)]
1176 /// clip unused bytes
1177 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: rustc_ty::IntTy) -> u128 {
1178 let amt = 128 - int_bits(tcx, ity);
1179 ((u as u128) << amt) >> amt
1182 /// clip unused bytes
1183 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: rustc_ty::UintTy) -> u128 {
1184 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1185 let amt = 128 - bits;
1189 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1190 let map = &tcx.hir();
1191 let mut prev_enclosing_node = None;
1192 let mut enclosing_node = node;
1193 while Some(enclosing_node) != prev_enclosing_node {
1194 if is_automatically_derived(map.attrs(enclosing_node)) {
1197 prev_enclosing_node = Some(enclosing_node);
1198 enclosing_node = map.get_parent_item(enclosing_node);
1203 /// Matches a function call with the given path and returns the arguments.
1208 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1210 pub fn match_function_call<'tcx>(
1211 cx: &LateContext<'tcx>,
1212 expr: &'tcx Expr<'_>,
1214 ) -> Option<&'tcx [Expr<'tcx>]> {
1216 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1217 if let ExprKind::Path(ref qpath) = fun.kind;
1218 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1219 if match_def_path(cx, fun_def_id, path);
1227 /// Checks if the given `DefId` matches any of the paths. Returns the index of matching path, if
1229 pub fn match_any_def_paths(cx: &LateContext<'_>, did: DefId, paths: &[&[&str]]) -> Option<usize> {
1230 let search_path = cx.get_def_path(did);
1233 .position(|p| p.iter().map(|x| Symbol::intern(x)).eq(search_path.iter().copied()))
1236 /// Checks if the given `DefId` matches the path.
1237 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1238 // We should probably move to Symbols in Clippy as well rather than interning every time.
1239 let path = cx.get_def_path(did);
1240 syms.iter().map(|x| Symbol::intern(x)).eq(path.iter().copied())
1243 pub fn match_panic_call(cx: &LateContext<'_>, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
1244 if let ExprKind::Call(func, [arg]) = expr.kind {
1245 expr_path_res(cx, func)
1247 .map_or(false, |id| match_panic_def_id(cx, id))
1254 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1255 match_any_def_paths(
1259 &paths::BEGIN_PANIC,
1260 &paths::BEGIN_PANIC_FMT,
1262 &paths::PANICKING_PANIC,
1263 &paths::PANICKING_PANIC_FMT,
1264 &paths::PANICKING_PANIC_STR,
1270 /// Returns the list of condition expressions and the list of blocks in a
1271 /// sequence of `if/else`.
1272 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1273 /// `if a { c } else if b { d } else { e }`.
1274 pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>, Vec<&'tcx Block<'tcx>>) {
1275 let mut conds = Vec::new();
1276 let mut blocks: Vec<&Block<'_>> = Vec::new();
1278 while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
1279 conds.push(&**cond);
1280 if let ExprKind::Block(ref block, _) = then_expr.kind {
1283 panic!("ExprKind::If node is not an ExprKind::Block");
1286 if let Some(ref else_expr) = *else_expr {
1293 // final `else {..}`
1294 if !blocks.is_empty() {
1295 if let ExprKind::Block(ref block, _) = expr.kind {
1296 blocks.push(&**block);
1303 // Finds the `#[must_use]` attribute, if any
1304 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1305 attrs.iter().find(|a| a.has_name(sym::must_use))
1308 // check if expr is calling method or function with #[must_use] attribute
1309 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1310 let did = match expr.kind {
1311 ExprKind::Call(ref path, _) => if_chain! {
1312 if let ExprKind::Path(ref qpath) = path.kind;
1313 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1320 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1324 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1327 /// Gets the node where an expression is either used, or it's type is unified with another branch.
1328 pub fn get_expr_use_or_unification_node(tcx: TyCtxt<'tcx>, expr: &Expr<'_>) -> Option<Node<'tcx>> {
1329 let map = tcx.hir();
1330 let mut child_id = expr.hir_id;
1331 let mut iter = map.parent_iter(child_id);
1335 Some((id, Node::Block(_))) => child_id = id,
1336 Some((id, Node::Arm(arm))) if arm.body.hir_id == child_id => child_id = id,
1337 Some((_, Node::Expr(expr))) => match expr.kind {
1338 ExprKind::Match(_, [arm], _) if arm.hir_id == child_id => child_id = expr.hir_id,
1339 ExprKind::Block(..) | ExprKind::DropTemps(_) => child_id = expr.hir_id,
1340 ExprKind::If(_, then_expr, None) if then_expr.hir_id == child_id => break None,
1341 _ => break Some(Node::Expr(expr)),
1343 Some((_, node)) => break Some(node),
1348 /// Checks if the result of an expression is used, or it's type is unified with another branch.
1349 pub fn is_expr_used_or_unified(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1351 get_expr_use_or_unification_node(tcx, expr),
1352 None | Some(Node::Stmt(Stmt {
1353 kind: StmtKind::Expr(_)
1355 | StmtKind::Local(Local {
1357 kind: PatKind::Wild,
1367 /// Checks if the expression is the final expression returned from a block.
1368 pub fn is_expr_final_block_expr(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
1369 matches!(get_parent_node(tcx, expr.hir_id), Some(Node::Block(..)))
1372 pub fn is_no_std_crate(cx: &LateContext<'_>) -> bool {
1373 cx.tcx.hir().attrs(hir::CRATE_HIR_ID).iter().any(|attr| {
1374 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1375 attr.path == sym::no_std
1382 /// Check if parent of a hir node is a trait implementation block.
1383 /// For example, `f` in
1385 /// impl Trait for S {
1389 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1390 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1391 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1397 /// Check if it's even possible to satisfy the `where` clause for the item.
1399 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1402 /// fn foo() where i32: Iterator {
1403 /// for _ in 2i32 {}
1406 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1407 use rustc_trait_selection::traits;
1413 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1414 traits::impossible_predicates(
1416 traits::elaborate_predicates(cx.tcx, predicates)
1417 .map(|o| o.predicate)
1418 .collect::<Vec<_>>(),
1422 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1423 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1425 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1428 kind: ExprKind::Path(qpath),
1429 hir_id: path_hir_id,
1433 ) => cx.typeck_results().qpath_res(qpath, *path_hir_id).opt_def_id(),
1438 /// This function checks if any of the lints in the slice is enabled for the provided `HirId`.
1439 /// A lint counts as enabled with any of the levels: `Level::Forbid` | `Level::Deny` | `Level::Warn`
1442 /// #[deny(clippy::YOUR_AWESOME_LINT)]
1443 /// println!("Hello, World!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == true
1445 /// #[allow(clippy::YOUR_AWESOME_LINT)]
1446 /// println!("See you soon!"); // <- Clippy code: run_lints(cx, &[YOUR_AWESOME_LINT], id) == false
1448 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1449 lints.iter().any(|lint| {
1451 cx.tcx.lint_level_at_node(lint, id),
1452 (Level::Forbid | Level::Deny | Level::Warn, _)
1457 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1458 /// slice iff the given expression is a slice of primitives (as defined in the
1459 /// `is_recursively_primitive_type` function) and None otherwise.
1460 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1461 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1462 let expr_kind = expr_type.kind();
1463 let is_primitive = match expr_kind {
1464 rustc_ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1465 rustc_ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &rustc_ty::Slice(_)) => {
1466 if let rustc_ty::Slice(element_type) = inner_ty.kind() {
1467 is_recursively_primitive_type(element_type)
1476 // if we have wrappers like Array, Slice or Tuple, print these
1477 // and get the type enclosed in the slice ref
1478 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1479 rustc_ty::Slice(..) => return Some("slice".into()),
1480 rustc_ty::Array(..) => return Some("array".into()),
1481 rustc_ty::Tuple(..) => return Some("tuple".into()),
1483 // is_recursively_primitive_type() should have taken care
1484 // of the rest and we can rely on the type that is found
1485 let refs_peeled = expr_type.peel_refs();
1486 return Some(refs_peeled.walk().last().unwrap().to_string());
1493 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1494 /// `hash` must be comformed with `eq`
1495 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1497 Hash: Fn(&T) -> u64,
1498 Eq: Fn(&T, &T) -> bool,
1500 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1501 return vec![(&exprs[0], &exprs[1])];
1504 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1506 let mut map: FxHashMap<_, Vec<&_>> =
1507 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1510 match map.entry(hash(expr)) {
1511 Entry::Occupied(mut o) => {
1514 match_expr_list.push((o, expr));
1517 o.get_mut().push(expr);
1519 Entry::Vacant(v) => {
1520 v.insert(vec![expr]);
1528 /// Peels off all references on the pattern. Returns the underlying pattern and the number of
1529 /// references removed.
1530 pub fn peel_hir_pat_refs(pat: &'a Pat<'a>) -> (&'a Pat<'a>, usize) {
1531 fn peel(pat: &'a Pat<'a>, count: usize) -> (&'a Pat<'a>, usize) {
1532 if let PatKind::Ref(pat, _) = pat.kind {
1533 peel(pat, count + 1)
1541 /// Peels of expressions while the given closure returns `Some`.
1542 pub fn peel_hir_expr_while<'tcx>(
1543 mut expr: &'tcx Expr<'tcx>,
1544 mut f: impl FnMut(&'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>>,
1545 ) -> &'tcx Expr<'tcx> {
1546 while let Some(e) = f(expr) {
1552 /// Peels off up to the given number of references on the expression. Returns the underlying
1553 /// expression and the number of references removed.
1554 pub fn peel_n_hir_expr_refs(expr: &'a Expr<'a>, count: usize) -> (&'a Expr<'a>, usize) {
1555 let mut remaining = count;
1556 let e = peel_hir_expr_while(expr, |e| match e.kind {
1557 ExprKind::AddrOf(BorrowKind::Ref, _, e) if remaining != 0 => {
1563 (e, count - remaining)
1566 /// Peels off all references on the expression. Returns the underlying expression and the number of
1567 /// references removed.
1568 pub fn peel_hir_expr_refs(expr: &'a Expr<'a>) -> (&'a Expr<'a>, usize) {
1570 let e = peel_hir_expr_while(expr, |e| match e.kind {
1571 ExprKind::AddrOf(BorrowKind::Ref, _, e) => {
1581 macro_rules! unwrap_cargo_metadata {
1582 ($cx: ident, $lint: ident, $deps: expr) => {{
1583 let mut command = cargo_metadata::MetadataCommand::new();
1588 match command.exec() {
1589 Ok(metadata) => metadata,
1591 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1598 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1600 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1601 if let Res::Def(_, def_id) = path.res;
1603 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)