4 #[allow(clippy::module_name_repetitions)]
13 pub mod eager_or_lazy;
17 #[cfg(feature = "internal-lints")]
18 pub mod internal_lints;
19 pub mod numeric_literal;
22 pub mod qualify_min_const_fn;
27 pub use self::attrs::*;
28 pub use self::diagnostics::*;
29 pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash};
32 use std::collections::hash_map::Entry;
33 use std::hash::BuildHasherDefault;
36 use if_chain::if_chain;
37 use rustc_ast::ast::{self, Attribute, LitKind};
38 use rustc_attr as attr;
39 use rustc_data_structures::fx::FxHashMap;
40 use rustc_errors::Applicability;
42 use rustc_hir::def::{DefKind, Res};
43 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
44 use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
47 def, Arm, Block, Body, Constness, Crate, Expr, ExprKind, FnDecl, HirId, ImplItem, ImplItemKind, Item, ItemKind,
48 MatchSource, Param, Pat, PatKind, Path, PathSegment, QPath, TraitItem, TraitItemKind, TraitRef, TyKind, Unsafety,
50 use rustc_infer::infer::TyCtxtInferExt;
51 use rustc_lint::{LateContext, Level, Lint, LintContext};
52 use rustc_middle::hir::map::Map;
53 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
54 use rustc_middle::ty::{self, layout::IntegerExt, Ty, TyCtxt, TypeFoldable};
55 use rustc_semver::RustcVersion;
56 use rustc_session::Session;
57 use rustc_span::hygiene::{ExpnKind, MacroKind};
58 use rustc_span::source_map::original_sp;
59 use rustc_span::sym as rustc_sym;
60 use rustc_span::symbol::{self, kw, Symbol};
61 use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
62 use rustc_target::abi::Integer;
63 use rustc_trait_selection::traits::query::normalize::AtExt;
64 use smallvec::SmallVec;
66 use crate::consts::{constant, Constant};
68 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
69 if let Ok(version) = RustcVersion::parse(msrv) {
71 } else if let Some(sess) = sess {
72 if let Some(span) = span {
73 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
79 pub fn meets_msrv(msrv: Option<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
80 msrv.map_or(true, |msrv| msrv.meets(*lint_msrv))
83 macro_rules! extract_msrv_attr {
85 extract_msrv_attr!(@LateContext, ());
88 extract_msrv_attr!(@EarlyContext);
90 (@$context:ident$(, $call:tt)?) => {
91 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
92 use $crate::utils::get_unique_inner_attr;
93 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
95 if let Some(msrv) = msrv_attr.value_str() {
96 self.msrv = $crate::utils::parse_msrv(
98 Some(cx.sess$($call)?),
102 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
111 /// Returns `true` if the two spans come from differing expansions (i.e., one is
112 /// from a macro and one isn't).
114 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
115 rhs.ctxt() != lhs.ctxt()
118 /// Returns `true` if the given `NodeId` is inside a constant context
123 /// if in_constant(cx, expr.hir_id) {
127 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
128 let parent_id = cx.tcx.hir().get_parent_item(id);
129 match cx.tcx.hir().get(parent_id) {
131 kind: ItemKind::Const(..) | ItemKind::Static(..),
134 | Node::TraitItem(&TraitItem {
135 kind: TraitItemKind::Const(..),
138 | Node::ImplItem(&ImplItem {
139 kind: ImplItemKind::Const(..),
142 | Node::AnonConst(_) => true,
144 kind: ItemKind::Fn(ref sig, ..),
147 | Node::ImplItem(&ImplItem {
148 kind: ImplItemKind::Fn(ref sig, _),
150 }) => sig.header.constness == Constness::Const,
155 /// Returns `true` if this `span` was expanded by any macro.
157 pub fn in_macro(span: Span) -> bool {
158 if span.from_expansion() {
159 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
165 // If the snippet is empty, it's an attribute that was inserted during macro
166 // expansion and we want to ignore those, because they could come from external
167 // sources that the user has no control over.
168 // For some reason these attributes don't have any expansion info on them, so
169 // we have to check it this way until there is a better way.
170 pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
171 if let Some(snippet) = snippet_opt(cx, span) {
172 if snippet.is_empty() {
179 /// Checks if given pattern is a wildcard (`_`)
180 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
181 matches!(pat.kind, PatKind::Wild)
184 /// Checks if type is struct, enum or union type with the given def path.
186 /// If the type is a diagnostic item, use `is_type_diagnostic_item` instead.
187 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
188 pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
190 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
195 /// Checks if the type is equal to a diagnostic item
197 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
198 pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
200 ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
205 /// Checks if the type is equal to a lang item
206 pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
208 ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
213 /// Checks if the method call given in `expr` belongs to the given trait.
214 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
215 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
216 let trt_id = cx.tcx.trait_of_item(def_id);
217 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
220 /// Checks if an expression references a variable of the given name.
221 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
222 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
223 if let [p] = path.segments {
224 return p.ident.name == var;
230 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
232 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
233 QPath::TypeRelative(_, ref seg) => seg,
234 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
238 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
240 QPath::Resolved(_, ref path) => path.segments.get(0),
241 QPath::TypeRelative(_, ref seg) => Some(seg),
242 QPath::LangItem(..) => None,
246 /// Matches a `QPath` against a slice of segment string literals.
248 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
249 /// `rustc_hir::QPath`.
253 /// match_qpath(path, &["std", "rt", "begin_unwind"])
255 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
257 QPath::Resolved(_, ref path) => match_path(path, segments),
258 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
259 TyKind::Path(ref inner_path) => {
260 if let [prefix @ .., end] = segments {
261 if match_qpath(inner_path, prefix) {
262 return segment.ident.name.as_str() == *end;
269 QPath::LangItem(..) => false,
273 /// Matches a `Path` against a slice of segment string literals.
275 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
276 /// `rustc_hir::Path`.
281 /// if match_path(&trait_ref.path, &paths::HASH) {
282 /// // This is the `std::hash::Hash` trait.
285 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
286 /// // This is a `rustc_middle::lint::Lint`.
289 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
293 .zip(segments.iter().rev())
294 .all(|(a, b)| a.ident.name.as_str() == *b)
297 /// Matches a `Path` against a slice of segment string literals, e.g.
301 /// match_path_ast(path, &["std", "rt", "begin_unwind"])
303 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
307 .zip(segments.iter().rev())
308 .all(|(a, b)| a.ident.name.as_str() == *b)
311 /// Gets the definition associated to a path.
312 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Option<def::Res> {
313 let crates = cx.tcx.crates();
316 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
317 if let Some(krate) = krate {
320 index: CRATE_DEF_INDEX,
322 let mut current_item = None;
323 let mut items = cx.tcx.item_children(krate);
324 let mut path_it = path.iter().skip(1).peekable();
327 let segment = match path_it.next() {
328 Some(segment) => segment,
332 // `get_def_path` seems to generate these empty segments for extern blocks.
333 // We can just ignore them.
334 if segment.is_empty() {
338 let result = SmallVec::<[_; 8]>::new();
339 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
340 if item.ident.name.as_str() == *segment {
341 if path_it.peek().is_none() {
342 return Some(item.res);
345 current_item = Some(item);
346 items = cx.tcx.item_children(item.res.def_id());
351 // The segment isn't a child_item.
352 // Try to find it under an inherent impl.
354 if path_it.peek().is_none();
355 if let Some(current_item) = current_item;
356 let item_def_id = current_item.res.def_id();
357 if cx.tcx.def_kind(item_def_id) == DefKind::Struct;
359 // Bad `find_map` suggestion. See #4193.
360 #[allow(clippy::find_map)]
361 return cx.tcx.inherent_impls(item_def_id).iter()
362 .flat_map(|&impl_def_id| cx.tcx.item_children(impl_def_id))
363 .find(|item| item.ident.name.as_str() == *segment)
364 .map(|item| item.res);
373 pub fn qpath_res(cx: &LateContext<'_>, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
375 hir::QPath::Resolved(_, path) => path.res,
376 hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => {
377 if cx.tcx.has_typeck_results(id.owner.to_def_id()) {
378 cx.tcx.typeck(id.owner).qpath_res(qpath, id)
386 /// Convenience function to get the `DefId` of a trait by path.
387 /// It could be a trait or trait alias.
388 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
389 let res = match path_to_res(cx, path) {
395 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
396 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
401 /// Checks whether a type implements a trait.
402 /// See also `get_trait_def_id`.
403 pub fn implements_trait<'tcx>(
404 cx: &LateContext<'tcx>,
407 ty_params: &[GenericArg<'tcx>],
409 // Do not check on infer_types to avoid panic in evaluate_obligation.
410 if ty.has_infer_types() {
413 let ty = cx.tcx.erase_regions(ty);
414 if ty.has_escaping_bound_vars() {
417 let ty_params = cx.tcx.mk_substs(ty_params.iter());
418 cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
421 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
423 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
426 /// struct Point(isize, isize);
428 /// impl std::ops::Add for Point {
429 /// type Output = Self;
431 /// fn add(self, other: Self) -> Self {
436 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
437 // Get the implemented trait for the current function
438 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
440 if parent_impl != hir::CRATE_HIR_ID;
441 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
442 if let hir::ItemKind::Impl{ of_trait: trait_ref, .. } = &item.kind;
443 then { return trait_ref.as_ref(); }
448 /// Checks whether this type implements `Drop`.
449 pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
450 match ty.ty_adt_def() {
451 Some(def) => def.has_dtor(cx.tcx),
456 /// Returns the method names and argument list of nested method call expressions that make up
457 /// `expr`. method/span lists are sorted with the most recent call first.
458 pub fn method_calls<'tcx>(
459 expr: &'tcx Expr<'tcx>,
461 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
462 let mut method_names = Vec::with_capacity(max_depth);
463 let mut arg_lists = Vec::with_capacity(max_depth);
464 let mut spans = Vec::with_capacity(max_depth);
466 let mut current = expr;
467 for _ in 0..max_depth {
468 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
469 if args.iter().any(|e| e.span.from_expansion()) {
472 method_names.push(path.ident.name);
473 arg_lists.push(&**args);
481 (method_names, arg_lists, spans)
484 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
486 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
487 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
488 /// containing the `Expr`s for
489 /// `.bar()` and `.baz()`
490 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
491 let mut current = expr;
492 let mut matched = Vec::with_capacity(methods.len());
493 for method_name in methods.iter().rev() {
494 // method chains are stored last -> first
495 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
496 if path.ident.name.as_str() == *method_name {
497 if args.iter().any(|e| e.span.from_expansion()) {
500 matched.push(&**args); // build up `matched` backwards
501 current = &args[0] // go to parent expression
509 // Reverse `matched` so that it is in the same order as `methods`.
514 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
515 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
517 .entry_fn(LOCAL_CRATE)
518 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
521 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
522 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
523 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
524 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
525 Some(def_id) == cx.tcx.lang_items().panic_impl()
528 /// Gets the name of the item the expression is in, if available.
529 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
530 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
531 match cx.tcx.hir().find(parent_id) {
533 Node::Item(Item { ident, .. })
534 | Node::TraitItem(TraitItem { ident, .. })
535 | Node::ImplItem(ImplItem { ident, .. }),
536 ) => Some(ident.name),
541 /// Gets the name of a `Pat`, if any.
542 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
544 PatKind::Binding(.., ref spname, _) => Some(spname.name),
545 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
546 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
551 struct ContainsName {
556 impl<'tcx> Visitor<'tcx> for ContainsName {
557 type Map = Map<'tcx>;
559 fn visit_name(&mut self, _: Span, name: Symbol) {
560 if self.name == name {
564 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
565 NestedVisitorMap::None
569 /// Checks if an `Expr` contains a certain name.
570 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
571 let mut cn = ContainsName { name, result: false };
576 /// Returns `true` if `expr` contains a return expression
577 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
578 struct RetCallFinder {
582 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
583 type Map = Map<'tcx>;
585 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
589 if let hir::ExprKind::Ret(..) = &expr.kind {
592 hir::intravisit::walk_expr(self, expr);
596 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
597 hir::intravisit::NestedVisitorMap::None
601 let mut visitor = RetCallFinder { found: false };
602 visitor.visit_expr(expr);
606 struct FindMacroCalls<'a, 'b> {
607 names: &'a [&'b str],
611 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
612 type Map = Map<'tcx>;
614 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
615 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
616 self.result.push(expr.span);
618 // and check sub-expressions
619 intravisit::walk_expr(self, expr);
622 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
623 NestedVisitorMap::None
627 /// Finds calls of the specified macros in a function body.
628 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
629 let mut fmc = FindMacroCalls {
633 fmc.visit_expr(&body.value);
637 /// Converts a span to a code snippet if available, otherwise use default.
639 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
640 /// to convert a given `Span` to a `str`.
644 /// snippet(cx, expr.span, "..")
646 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
647 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
650 /// Same as `snippet`, but it adapts the applicability level by following rules:
652 /// - Applicability level `Unspecified` will never be changed.
653 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
654 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
655 /// `HasPlaceholders`
656 pub fn snippet_with_applicability<'a, T: LintContext>(
660 applicability: &mut Applicability,
662 if *applicability != Applicability::Unspecified && span.from_expansion() {
663 *applicability = Applicability::MaybeIncorrect;
665 snippet_opt(cx, span).map_or_else(
667 if *applicability == Applicability::MachineApplicable {
668 *applicability = Applicability::HasPlaceholders;
670 Cow::Borrowed(default)
676 /// Same as `snippet`, but should only be used when it's clear that the input span is
677 /// not a macro argument.
678 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
679 snippet(cx, span.source_callsite(), default)
682 /// Converts a span to a code snippet. Returns `None` if not available.
683 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
684 cx.sess().source_map().span_to_snippet(span).ok()
687 /// Converts a span (from a block) to a code snippet if available, otherwise use default.
689 /// This trims the code of indentation, except for the first line. Use it for blocks or block-like
690 /// things which need to be printed as such.
692 /// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
693 /// resulting snippet of the given span.
698 /// snippet_block(cx, block.span, "..", None)
699 /// // where, `block` is the block of the if expr
703 /// // will return the snippet
710 /// snippet_block(cx, block.span, "..", Some(if_expr.span))
711 /// // where, `block` is the block of the if expr
715 /// // will return the snippet
718 /// } // aligned with `if`
720 /// Note that the first line of the snippet always has 0 indentation.
721 pub fn snippet_block<'a, T: LintContext>(
725 indent_relative_to: Option<Span>,
727 let snip = snippet(cx, span, default);
728 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
729 reindent_multiline(snip, true, indent)
732 /// Same as `snippet_block`, but adapts the applicability level by the rules of
733 /// `snippet_with_applicability`.
734 pub fn snippet_block_with_applicability<'a, T: LintContext>(
738 indent_relative_to: Option<Span>,
739 applicability: &mut Applicability,
741 let snip = snippet_with_applicability(cx, span, default, applicability);
742 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
743 reindent_multiline(snip, true, indent)
746 /// Returns a new Span that extends the original Span to the first non-whitespace char of the first
752 /// // will be converted to
756 pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
757 first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
760 fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
761 let line_span = line_span(cx, span);
762 snippet_opt(cx, line_span).and_then(|snip| {
763 snip.find(|c: char| !c.is_whitespace())
764 .map(|pos| line_span.lo() + BytePos::from_usize(pos))
768 /// Returns the indentation of the line of a span
772 /// // ^^ -- will return 0
774 /// // ^^ -- will return 4
776 pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
777 snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
780 /// Returns the positon just before rarrow
783 /// fn into(self) -> () {}
785 /// // in case of unformatted code
786 /// fn into2(self)-> () {}
788 /// fn into3(self) -> () {}
791 #[allow(clippy::needless_pass_by_value)]
792 pub fn position_before_rarrow(s: String) -> Option<usize> {
793 s.rfind("->").map(|rpos| {
795 let chars: Vec<char> = s.chars().collect();
797 if let Some(c) = chars.get(rpos - 1) {
798 if c.is_whitespace() {
809 /// Extends the span to the beginning of the spans line, incl. whitespaces.
814 /// // will be converted to
816 /// // ^^^^^^^^^^^^^^
818 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
819 let span = original_sp(span, DUMMY_SP);
820 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
821 let line_no = source_map_and_line.line;
822 let line_start = source_map_and_line.sf.lines[line_no];
823 Span::new(line_start, span.hi(), span.ctxt())
826 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
827 /// Also takes an `Option<String>` which can be put inside the braces.
828 pub fn expr_block<'a, T: LintContext>(
831 option: Option<String>,
833 indent_relative_to: Option<Span>,
835 let code = snippet_block(cx, expr.span, default, indent_relative_to);
836 let string = option.unwrap_or_default();
837 if expr.span.from_expansion() {
838 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
839 } else if let ExprKind::Block(_, _) = expr.kind {
840 Cow::Owned(format!("{}{}", code, string))
841 } else if string.is_empty() {
842 Cow::Owned(format!("{{ {} }}", code))
844 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
848 /// Reindent a multiline string with possibility of ignoring the first line.
849 #[allow(clippy::needless_pass_by_value)]
850 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
851 let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
852 let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
853 reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
856 fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
859 .skip(ignore_first as usize)
864 // ignore empty lines
865 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
870 let indent = indent.unwrap_or(0);
874 if (ignore_first && i == 0) || l.is_empty() {
876 } else if x > indent {
877 l.split_at(x - indent).1.to_owned()
879 " ".repeat(indent - x) + l
882 .collect::<Vec<String>>()
886 /// Gets the parent expression, if any –- this is useful to constrain a lint.
887 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
888 let map = &cx.tcx.hir();
889 let hir_id = e.hir_id;
890 let parent_id = map.get_parent_node(hir_id);
891 if hir_id == parent_id {
894 map.find(parent_id).and_then(|node| {
895 if let Node::Expr(parent) = node {
903 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
904 let map = &cx.tcx.hir();
905 let enclosing_node = map
906 .get_enclosing_scope(hir_id)
907 .and_then(|enclosing_id| map.find(enclosing_id));
908 enclosing_node.and_then(|node| match node {
909 Node::Block(block) => Some(block),
911 kind: ItemKind::Fn(_, _, eid),
914 | Node::ImplItem(&ImplItem {
915 kind: ImplItemKind::Fn(_, eid),
917 }) => match cx.tcx.hir().body(eid).value.kind {
918 ExprKind::Block(ref block, _) => Some(block),
925 /// Returns the base type for HIR references and pointers.
926 pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
928 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
933 /// Returns the base type for references and raw pointers, and count reference
935 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
936 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
938 ty::Ref(_, ty, _) => inner(ty, depth + 1),
945 /// Checks whether the given expression is a constant integer of the given value.
946 /// unlike `is_integer_literal`, this version does const folding
947 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
948 if is_integer_literal(e, value) {
951 let map = cx.tcx.hir();
952 let parent_item = map.get_parent_item(e.hir_id);
953 if let Some((Constant::Int(v), _)) = map
954 .maybe_body_owned_by(parent_item)
955 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
963 /// Checks whether the given expression is a constant literal of the given value.
964 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
965 // FIXME: use constant folding
966 if let ExprKind::Lit(ref spanned) = expr.kind {
967 if let LitKind::Int(v, _) = spanned.node {
974 /// Returns `true` if the given `Expr` has been coerced before.
976 /// Examples of coercions can be found in the Nomicon at
977 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
979 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
980 /// information on adjustments and coercions.
981 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
982 cx.typeck_results().adjustments().get(e.hir_id).is_some()
985 /// Returns the pre-expansion span if is this comes from an expansion of the
987 /// See also `is_direct_expn_of`.
989 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
991 if span.from_expansion() {
992 let data = span.ctxt().outer_expn_data();
993 let new_span = data.call_site;
995 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
996 if mac_name.as_str() == name {
997 return Some(new_span);
1008 /// Returns the pre-expansion span if the span directly comes from an expansion
1009 /// of the macro `name`.
1010 /// The difference with `is_expn_of` is that in
1014 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1016 /// `is_direct_expn_of`.
1018 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1019 if span.from_expansion() {
1020 let data = span.ctxt().outer_expn_data();
1021 let new_span = data.call_site;
1023 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1024 if mac_name.as_str() == name {
1025 return Some(new_span);
1033 /// Convenience function to get the return type of a function.
1034 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1035 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1036 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1037 cx.tcx.erase_late_bound_regions(ret_ty)
1040 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
1041 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
1042 ty.walk().any(|inner| match inner.unpack() {
1043 GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
1044 GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
1048 /// Returns `true` if the given type is an `unsafe` function.
1049 pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1051 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
1056 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1057 ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
1060 /// Checks if an expression is constructing a tuple-like enum variant or struct
1061 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1062 if let ExprKind::Call(ref fun, _) = expr.kind {
1063 if let ExprKind::Path(ref qp) = fun.kind {
1064 let res = cx.qpath_res(qp, fun.hir_id);
1066 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1067 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1075 /// Returns `true` if a pattern is refutable.
1076 // TODO: should be implemented using rustc/mir_build/thir machinery
1077 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1078 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1080 cx.qpath_res(qpath, id),
1081 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1085 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1086 i.any(|pat| is_refutable(cx, pat))
1090 PatKind::Wild => false,
1091 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1092 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1093 PatKind::Lit(..) | PatKind::Range(..) => true,
1094 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1095 PatKind::Or(ref pats) => {
1096 // TODO: should be the honest check, that pats is exhaustive set
1097 are_refutable(cx, pats.iter().map(|pat| &**pat))
1099 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1100 PatKind::Struct(ref qpath, ref fields, _) => {
1101 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1103 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1104 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1106 PatKind::Slice(ref head, ref middle, ref tail) => {
1107 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1109 // [..] is the only irrefutable slice pattern.
1110 !head.is_empty() || middle.is_none() || !tail.is_empty()
1112 ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
1122 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1123 /// implementations have.
1124 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1125 attrs.iter().any(|attr| attr.has_name(rustc_sym::automatically_derived))
1128 /// Remove blocks around an expression.
1130 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1132 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1133 while let ExprKind::Block(ref block, ..) = expr.kind {
1134 match (block.stmts.is_empty(), block.expr.as_ref()) {
1135 (true, Some(e)) => expr = e,
1142 pub fn is_self(slf: &Param<'_>) -> bool {
1143 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1144 name.name == kw::SelfLower
1150 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1152 if let TyKind::Path(ref qp) = slf.kind;
1153 if let QPath::Resolved(None, ref path) = *qp;
1154 if let Res::SelfTy(..) = path.res;
1162 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1163 (0..decl.inputs.len()).map(move |i| &body.params[i])
1166 /// Checks if a given expression is a match expression expanded from the `?`
1167 /// operator or the `try` macro.
1168 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1169 fn is_ok(arm: &Arm<'_>) -> bool {
1171 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1172 if match_qpath(path, &paths::RESULT_OK[1..]);
1173 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1174 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.kind;
1175 if let Res::Local(lid) = path.res;
1184 fn is_err(arm: &Arm<'_>) -> bool {
1185 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1186 match_qpath(path, &paths::RESULT_ERR[1..])
1192 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1193 // desugared from a `?` operator
1194 if let MatchSource::TryDesugar = *source {
1200 if arms[0].guard.is_none();
1201 if arms[1].guard.is_none();
1202 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1203 (is_ok(&arms[1]) && is_err(&arms[0]));
1213 /// Returns `true` if the lint is allowed in the current context
1215 /// Useful for skipping long running code when it's unnecessary
1216 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1217 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1220 pub fn get_arg_name(pat: &Pat<'_>) -> Option<Symbol> {
1222 PatKind::Binding(.., ident, None) => Some(ident.name),
1223 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1228 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
1229 Integer::from_attr(&tcx, attr::IntType::SignedInt(ity)).size().bits()
1232 #[allow(clippy::cast_possible_wrap)]
1233 /// Turn a constant int byte representation into an i128
1234 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
1235 let amt = 128 - int_bits(tcx, ity);
1236 ((u as i128) << amt) >> amt
1239 #[allow(clippy::cast_sign_loss)]
1240 /// clip unused bytes
1241 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
1242 let amt = 128 - int_bits(tcx, ity);
1243 ((u as u128) << amt) >> amt
1246 /// clip unused bytes
1247 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
1248 let bits = Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity)).size().bits();
1249 let amt = 128 - bits;
1253 /// Removes block comments from the given `Vec` of lines.
1258 /// without_block_comments(vec!["/*", "foo", "*/"]);
1261 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1262 /// // => vec!["bar"]
1264 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1265 let mut without = vec![];
1267 let mut nest_level = 0;
1270 if line.contains("/*") {
1273 } else if line.contains("*/") {
1278 if nest_level == 0 {
1286 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1287 let map = &tcx.hir();
1288 let mut prev_enclosing_node = None;
1289 let mut enclosing_node = node;
1290 while Some(enclosing_node) != prev_enclosing_node {
1291 if is_automatically_derived(map.attrs(enclosing_node)) {
1294 prev_enclosing_node = Some(enclosing_node);
1295 enclosing_node = map.get_parent_item(enclosing_node);
1300 /// Returns true if ty has `iter` or `iter_mut` methods
1301 pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1302 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1303 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1304 // so we can't use its `lookup_method` method.
1305 let into_iter_collections: [&[&str]; 13] = [
1312 &paths::LINKED_LIST,
1313 &paths::BINARY_HEAP,
1321 let ty_to_check = match probably_ref_ty.kind() {
1322 ty::Ref(_, ty_to_check, _) => ty_to_check,
1323 _ => probably_ref_ty,
1326 let def_id = match ty_to_check.kind() {
1327 ty::Array(..) => return Some("array"),
1328 ty::Slice(..) => return Some("slice"),
1329 ty::Adt(adt, _) => adt.did,
1333 for path in &into_iter_collections {
1334 if match_def_path(cx, def_id, path) {
1335 return Some(*path.last().unwrap());
1341 /// Matches a function call with the given path and returns the arguments.
1346 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1348 pub fn match_function_call<'tcx>(
1349 cx: &LateContext<'tcx>,
1350 expr: &'tcx Expr<'_>,
1352 ) -> Option<&'tcx [Expr<'tcx>]> {
1354 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1355 if let ExprKind::Path(ref qpath) = fun.kind;
1356 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1357 if match_def_path(cx, fun_def_id, path);
1365 /// Checks if `Ty` is normalizable. This function is useful
1366 /// to avoid crashes on `layout_of`.
1367 pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
1368 cx.tcx.infer_ctxt().enter(|infcx| {
1369 let cause = rustc_middle::traits::ObligationCause::dummy();
1370 infcx.at(&cause, param_env).normalize(ty).is_ok()
1374 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1375 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1376 // accepts only that. We should probably move to Symbols in Clippy as well.
1377 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1378 cx.match_def_path(did, &syms)
1381 pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
1382 match_function_call(cx, expr, &paths::BEGIN_PANIC)
1383 .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
1384 .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
1385 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
1386 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
1387 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
1390 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1391 match_def_path(cx, did, &paths::BEGIN_PANIC)
1392 || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
1393 || match_def_path(cx, did, &paths::PANIC_ANY)
1394 || match_def_path(cx, did, &paths::PANICKING_PANIC)
1395 || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
1396 || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
1399 /// Returns the list of condition expressions and the list of blocks in a
1400 /// sequence of `if/else`.
1401 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1402 /// `if a { c } else if b { d } else { e }`.
1403 pub fn if_sequence<'tcx>(
1404 mut expr: &'tcx Expr<'tcx>,
1405 ) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
1406 let mut conds = SmallVec::new();
1407 let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
1409 while let Some((ref cond, ref then_expr, ref else_expr)) = higher::if_block(&expr) {
1410 conds.push(&**cond);
1411 if let ExprKind::Block(ref block, _) = then_expr.kind {
1414 panic!("ExprKind::If node is not an ExprKind::Block");
1417 if let Some(ref else_expr) = *else_expr {
1424 // final `else {..}`
1425 if !blocks.is_empty() {
1426 if let ExprKind::Block(ref block, _) = expr.kind {
1427 blocks.push(&**block);
1434 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1435 let map = cx.tcx.hir();
1436 let parent_id = map.get_parent_node(expr.hir_id);
1437 let parent_node = map.get(parent_id);
1440 Node::Expr(e) => higher::if_block(&e).is_some(),
1441 Node::Arm(e) => higher::if_block(&e.body).is_some(),
1446 // Finds the attribute with the given name, if any
1447 pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
1450 .find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
1453 // Finds the `#[must_use]` attribute, if any
1454 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1455 attr_by_name(attrs, "must_use")
1458 // Returns whether the type has #[must_use] attribute
1459 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1461 ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
1462 ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
1464 | ty::Array(ref ty, _)
1465 | ty::RawPtr(ty::TypeAndMut { ref ty, .. })
1466 | ty::Ref(_, ref ty, _) => {
1467 // for the Array case we don't need to care for the len == 0 case
1468 // because we don't want to lint functions returning empty arrays
1469 is_must_use_ty(cx, *ty)
1471 ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
1472 ty::Opaque(ref def_id, _) => {
1473 for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
1474 if let ty::PredicateAtom::Trait(trait_predicate, _) = predicate.skip_binders() {
1475 if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
1482 ty::Dynamic(binder, _) => {
1483 for predicate in binder.iter() {
1484 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
1485 if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
1496 // check if expr is calling method or function with #[must_use] attribute
1497 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1498 let did = match expr.kind {
1499 ExprKind::Call(ref path, _) => if_chain! {
1500 if let ExprKind::Path(ref qpath) = path.kind;
1501 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1508 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1512 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1515 pub fn is_no_std_crate(krate: &Crate<'_>) -> bool {
1516 krate.item.attrs.iter().any(|attr| {
1517 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1518 attr.path == symbol::sym::no_std
1525 /// Check if parent of a hir node is a trait implementation block.
1526 /// For example, `f` in
1528 /// impl Trait for S {
1532 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1533 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1534 matches!(item.kind, ItemKind::Impl { of_trait: Some(_), .. })
1540 /// Check if it's even possible to satisfy the `where` clause for the item.
1542 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1545 /// fn foo() where i32: Iterator {
1546 /// for _ in 2i32 {}
1549 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1550 use rustc_trait_selection::traits;
1556 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1557 traits::impossible_predicates(
1559 traits::elaborate_predicates(cx.tcx, predicates)
1560 .map(|o| o.predicate)
1561 .collect::<Vec<_>>(),
1565 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1566 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1568 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1571 kind: ExprKind::Path(qpath),
1575 ) => cx.typeck_results().qpath_res(qpath, expr.hir_id).opt_def_id(),
1580 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1581 lints.iter().any(|lint| {
1583 cx.tcx.lint_level_at_node(lint, id),
1584 (Level::Forbid | Level::Deny | Level::Warn, _)
1589 /// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
1590 /// number type, a str, or an array, slice, or tuple of those types).
1591 pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
1593 ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
1594 ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
1595 ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
1596 ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
1601 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1602 /// slice iff the given expression is a slice of primitives (as defined in the
1603 /// `is_recursively_primitive_type` function) and None otherwise.
1604 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1605 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1606 let expr_kind = expr_type.kind();
1607 let is_primitive = match expr_kind {
1608 ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1609 ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
1610 if let ty::Slice(element_type) = inner_ty.kind() {
1611 is_recursively_primitive_type(element_type)
1620 // if we have wrappers like Array, Slice or Tuple, print these
1621 // and get the type enclosed in the slice ref
1622 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1623 ty::Slice(..) => return Some("slice".into()),
1624 ty::Array(..) => return Some("array".into()),
1625 ty::Tuple(..) => return Some("tuple".into()),
1627 // is_recursively_primitive_type() should have taken care
1628 // of the rest and we can rely on the type that is found
1629 let refs_peeled = expr_type.peel_refs();
1630 return Some(refs_peeled.walk().last().unwrap().to_string());
1637 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1638 /// `hash` must be comformed with `eq`
1639 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1641 Hash: Fn(&T) -> u64,
1642 Eq: Fn(&T, &T) -> bool,
1644 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1645 return vec![(&exprs[0], &exprs[1])];
1648 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1650 let mut map: FxHashMap<_, Vec<&_>> =
1651 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1654 match map.entry(hash(expr)) {
1655 Entry::Occupied(mut o) => {
1658 match_expr_list.push((o, expr));
1661 o.get_mut().push(expr);
1663 Entry::Vacant(v) => {
1664 v.insert(vec![expr]);
1673 macro_rules! unwrap_cargo_metadata {
1674 ($cx: ident, $lint: ident, $deps: expr) => {{
1675 let mut command = cargo_metadata::MetadataCommand::new();
1680 match command.exec() {
1681 Ok(metadata) => metadata,
1683 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1692 use super::{reindent_multiline, without_block_comments};
1695 fn test_reindent_multiline_single_line() {
1696 assert_eq!("", reindent_multiline("".into(), false, None));
1697 assert_eq!("...", reindent_multiline("...".into(), false, None));
1698 assert_eq!("...", reindent_multiline(" ...".into(), false, None));
1699 assert_eq!("...", reindent_multiline("\t...".into(), false, None));
1700 assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
1705 fn test_reindent_multiline_block() {
1711 }", reindent_multiline(" if x {
1715 }".into(), false, None));
1721 }", reindent_multiline(" if x {
1725 }".into(), false, None));
1730 fn test_reindent_multiline_empty_line() {
1737 }", reindent_multiline(" if x {
1742 }".into(), false, None));
1747 fn test_reindent_multiline_lines_deeper() {
1753 }", reindent_multiline("\
1758 }".into(), true, Some(8)));
1762 fn test_without_block_comments_lines_without_block_comments() {
1763 let result = without_block_comments(vec!["/*", "", "*/"]);
1764 println!("result: {:?}", result);
1765 assert!(result.is_empty());
1767 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1768 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1770 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1771 assert!(result.is_empty());
1773 let result = without_block_comments(vec!["/* one-line comment */"]);
1774 assert!(result.is_empty());
1776 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1777 assert!(result.is_empty());
1779 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1780 assert!(result.is_empty());
1782 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1783 assert_eq!(result, vec!["foo", "bar", "baz"]);