4 #[allow(clippy::module_name_repetitions)]
13 pub mod eager_or_lazy;
17 pub mod internal_lints;
18 pub mod numeric_literal;
21 pub mod qualify_min_const_fn;
26 pub use self::attrs::*;
27 pub use self::diagnostics::*;
28 pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash};
31 use std::collections::hash_map::Entry;
32 use std::hash::BuildHasherDefault;
35 use if_chain::if_chain;
36 use rustc_ast::ast::{self, Attribute, LitKind};
37 use rustc_attr as attr;
38 use rustc_data_structures::fx::FxHashMap;
39 use rustc_errors::Applicability;
41 use rustc_hir::def::{DefKind, Res};
42 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
43 use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
46 def, Arm, Block, Body, Constness, Crate, Expr, ExprKind, FnDecl, HirId, ImplItem, ImplItemKind, Item, ItemKind,
47 MatchSource, Param, Pat, PatKind, Path, PathSegment, QPath, TraitItem, TraitItemKind, TraitRef, TyKind, Unsafety,
49 use rustc_infer::infer::TyCtxtInferExt;
50 use rustc_lint::{LateContext, Level, Lint, LintContext};
51 use rustc_middle::hir::map::Map;
52 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
53 use rustc_middle::ty::{self, layout::IntegerExt, Ty, TyCtxt, TypeFoldable};
54 use rustc_session::Session;
55 use rustc_span::hygiene::{ExpnKind, MacroKind};
56 use rustc_span::source_map::original_sp;
57 use rustc_span::sym as rustc_sym;
58 use rustc_span::symbol::{self, kw, Symbol};
59 use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
60 use rustc_target::abi::Integer;
61 use rustc_trait_selection::traits::query::normalize::AtExt;
62 use semver::{Version, VersionReq};
63 use smallvec::SmallVec;
65 use crate::consts::{constant, Constant};
67 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<VersionReq> {
68 if let Ok(version) = VersionReq::parse(msrv) {
70 } else if let Some(sess) = sess {
71 if let Some(span) = span {
72 sess.span_err(span, &format!("`{}` is not a valid Rust version", msrv));
78 pub fn meets_msrv(msrv: Option<&VersionReq>, lint_msrv: &Version) -> bool {
79 msrv.map_or(true, |msrv| !msrv.matches(lint_msrv))
82 macro_rules! extract_msrv_attr {
84 extract_msrv_attr!(@LateContext, ());
87 extract_msrv_attr!(@EarlyContext);
89 (@$context:ident$(, $call:tt)?) => {
90 fn enter_lint_attrs(&mut self, cx: &rustc_lint::$context<'tcx>, attrs: &'tcx [rustc_ast::ast::Attribute]) {
91 use $crate::utils::get_unique_inner_attr;
92 match get_unique_inner_attr(cx.sess$($call)?, attrs, "msrv") {
94 if let Some(msrv) = msrv_attr.value_str() {
95 self.msrv = $crate::utils::parse_msrv(
97 Some(cx.sess$($call)?),
101 cx.sess$($call)?.span_err(msrv_attr.span, "bad clippy attribute");
110 /// Returns `true` if the two spans come from differing expansions (i.e., one is
111 /// from a macro and one isn't).
113 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
114 rhs.ctxt() != lhs.ctxt()
117 /// Returns `true` if the given `NodeId` is inside a constant context
122 /// if in_constant(cx, expr.hir_id) {
126 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
127 let parent_id = cx.tcx.hir().get_parent_item(id);
128 match cx.tcx.hir().get(parent_id) {
130 kind: ItemKind::Const(..) | ItemKind::Static(..),
133 | Node::TraitItem(&TraitItem {
134 kind: TraitItemKind::Const(..),
137 | Node::ImplItem(&ImplItem {
138 kind: ImplItemKind::Const(..),
141 | Node::AnonConst(_) => true,
143 kind: ItemKind::Fn(ref sig, ..),
146 | Node::ImplItem(&ImplItem {
147 kind: ImplItemKind::Fn(ref sig, _),
149 }) => sig.header.constness == Constness::Const,
154 /// Returns `true` if this `span` was expanded by any macro.
156 pub fn in_macro(span: Span) -> bool {
157 if span.from_expansion() {
158 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
164 // If the snippet is empty, it's an attribute that was inserted during macro
165 // expansion and we want to ignore those, because they could come from external
166 // sources that the user has no control over.
167 // For some reason these attributes don't have any expansion info on them, so
168 // we have to check it this way until there is a better way.
169 pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
170 if let Some(snippet) = snippet_opt(cx, span) {
171 if snippet.is_empty() {
178 /// Checks if given pattern is a wildcard (`_`)
179 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
180 matches!(pat.kind, PatKind::Wild)
183 /// Checks if type is struct, enum or union type with the given def path.
185 /// If the type is a diagnostic item, use `is_type_diagnostic_item` instead.
186 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
187 pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
189 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
194 /// Checks if the type is equal to a diagnostic item
196 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
197 pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
199 ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
204 /// Checks if the type is equal to a lang item
205 pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
207 ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
212 /// Checks if the method call given in `expr` belongs to the given trait.
213 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
214 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
215 let trt_id = cx.tcx.trait_of_item(def_id);
216 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
219 /// Checks if an expression references a variable of the given name.
220 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
221 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
222 if let [p] = path.segments {
223 return p.ident.name == var;
229 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
231 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
232 QPath::TypeRelative(_, ref seg) => seg,
233 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
237 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
239 QPath::Resolved(_, ref path) => path.segments.get(0),
240 QPath::TypeRelative(_, ref seg) => Some(seg),
241 QPath::LangItem(..) => None,
245 /// Matches a `QPath` against a slice of segment string literals.
247 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
248 /// `rustc_hir::QPath`.
252 /// match_qpath(path, &["std", "rt", "begin_unwind"])
254 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
256 QPath::Resolved(_, ref path) => match_path(path, segments),
257 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
258 TyKind::Path(ref inner_path) => {
259 if let [prefix @ .., end] = segments {
260 if match_qpath(inner_path, prefix) {
261 return segment.ident.name.as_str() == *end;
268 QPath::LangItem(..) => false,
272 /// Matches a `Path` against a slice of segment string literals.
274 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
275 /// `rustc_hir::Path`.
280 /// if match_path(&trait_ref.path, &paths::HASH) {
281 /// // This is the `std::hash::Hash` trait.
284 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
285 /// // This is a `rustc_middle::lint::Lint`.
288 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
292 .zip(segments.iter().rev())
293 .all(|(a, b)| a.ident.name.as_str() == *b)
296 /// Matches a `Path` against a slice of segment string literals, e.g.
300 /// match_path_ast(path, &["std", "rt", "begin_unwind"])
302 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
306 .zip(segments.iter().rev())
307 .all(|(a, b)| a.ident.name.as_str() == *b)
310 /// Gets the definition associated to a path.
311 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Option<def::Res> {
312 let crates = cx.tcx.crates();
315 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
316 if let Some(krate) = krate {
319 index: CRATE_DEF_INDEX,
321 let mut current_item = None;
322 let mut items = cx.tcx.item_children(krate);
323 let mut path_it = path.iter().skip(1).peekable();
326 let segment = match path_it.next() {
327 Some(segment) => segment,
331 // `get_def_path` seems to generate these empty segments for extern blocks.
332 // We can just ignore them.
333 if segment.is_empty() {
337 let result = SmallVec::<[_; 8]>::new();
338 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
339 if item.ident.name.as_str() == *segment {
340 if path_it.peek().is_none() {
341 return Some(item.res);
344 current_item = Some(item);
345 items = cx.tcx.item_children(item.res.def_id());
350 // The segment isn't a child_item.
351 // Try to find it under an inherent impl.
353 if path_it.peek().is_none();
354 if let Some(current_item) = current_item;
355 let item_def_id = current_item.res.def_id();
356 if cx.tcx.def_kind(item_def_id) == DefKind::Struct;
358 // Bad `find_map` suggestion. See #4193.
359 #[allow(clippy::find_map)]
360 return cx.tcx.inherent_impls(item_def_id).iter()
361 .flat_map(|&impl_def_id| cx.tcx.item_children(impl_def_id))
362 .find(|item| item.ident.name.as_str() == *segment)
363 .map(|item| item.res);
372 pub fn qpath_res(cx: &LateContext<'_>, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
374 hir::QPath::Resolved(_, path) => path.res,
375 hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => {
376 if cx.tcx.has_typeck_results(id.owner.to_def_id()) {
377 cx.tcx.typeck(id.owner).qpath_res(qpath, id)
385 /// Convenience function to get the `DefId` of a trait by path.
386 /// It could be a trait or trait alias.
387 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
388 let res = match path_to_res(cx, path) {
394 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
395 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
400 /// Checks whether a type implements a trait.
401 /// See also `get_trait_def_id`.
402 pub fn implements_trait<'tcx>(
403 cx: &LateContext<'tcx>,
406 ty_params: &[GenericArg<'tcx>],
408 // Do not check on infer_types to avoid panic in evaluate_obligation.
409 if ty.has_infer_types() {
412 let ty = cx.tcx.erase_regions(ty);
413 if ty.has_escaping_bound_vars() {
416 let ty_params = cx.tcx.mk_substs(ty_params.iter());
417 cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
420 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
422 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
425 /// struct Point(isize, isize);
427 /// impl std::ops::Add for Point {
428 /// type Output = Self;
430 /// fn add(self, other: Self) -> Self {
435 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
436 // Get the implemented trait for the current function
437 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
439 if parent_impl != hir::CRATE_HIR_ID;
440 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
441 if let hir::ItemKind::Impl{ of_trait: trait_ref, .. } = &item.kind;
442 then { return trait_ref.as_ref(); }
447 /// Checks whether this type implements `Drop`.
448 pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
449 match ty.ty_adt_def() {
450 Some(def) => def.has_dtor(cx.tcx),
455 /// Returns the method names and argument list of nested method call expressions that make up
456 /// `expr`. method/span lists are sorted with the most recent call first.
457 pub fn method_calls<'tcx>(
458 expr: &'tcx Expr<'tcx>,
460 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
461 let mut method_names = Vec::with_capacity(max_depth);
462 let mut arg_lists = Vec::with_capacity(max_depth);
463 let mut spans = Vec::with_capacity(max_depth);
465 let mut current = expr;
466 for _ in 0..max_depth {
467 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
468 if args.iter().any(|e| e.span.from_expansion()) {
471 method_names.push(path.ident.name);
472 arg_lists.push(&**args);
480 (method_names, arg_lists, spans)
483 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
485 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
486 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
487 /// containing the `Expr`s for
488 /// `.bar()` and `.baz()`
489 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
490 let mut current = expr;
491 let mut matched = Vec::with_capacity(methods.len());
492 for method_name in methods.iter().rev() {
493 // method chains are stored last -> first
494 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
495 if path.ident.name.as_str() == *method_name {
496 if args.iter().any(|e| e.span.from_expansion()) {
499 matched.push(&**args); // build up `matched` backwards
500 current = &args[0] // go to parent expression
508 // Reverse `matched` so that it is in the same order as `methods`.
513 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
514 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
516 .entry_fn(LOCAL_CRATE)
517 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
520 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
521 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
522 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
523 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
524 Some(def_id) == cx.tcx.lang_items().panic_impl()
527 /// Gets the name of the item the expression is in, if available.
528 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
529 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
530 match cx.tcx.hir().find(parent_id) {
532 Node::Item(Item { ident, .. })
533 | Node::TraitItem(TraitItem { ident, .. })
534 | Node::ImplItem(ImplItem { ident, .. }),
535 ) => Some(ident.name),
540 /// Gets the name of a `Pat`, if any.
541 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
543 PatKind::Binding(.., ref spname, _) => Some(spname.name),
544 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
545 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
550 struct ContainsName {
555 impl<'tcx> Visitor<'tcx> for ContainsName {
556 type Map = Map<'tcx>;
558 fn visit_name(&mut self, _: Span, name: Symbol) {
559 if self.name == name {
563 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
564 NestedVisitorMap::None
568 /// Checks if an `Expr` contains a certain name.
569 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
570 let mut cn = ContainsName { name, result: false };
575 /// Returns `true` if `expr` contains a return expression
576 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
577 struct RetCallFinder {
581 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
582 type Map = Map<'tcx>;
584 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
588 if let hir::ExprKind::Ret(..) = &expr.kind {
591 hir::intravisit::walk_expr(self, expr);
595 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
596 hir::intravisit::NestedVisitorMap::None
600 let mut visitor = RetCallFinder { found: false };
601 visitor.visit_expr(expr);
605 /// Converts a span to a code snippet if available, otherwise use default.
607 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
608 /// to convert a given `Span` to a `str`.
612 /// snippet(cx, expr.span, "..")
614 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
615 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
618 /// Same as `snippet`, but it adapts the applicability level by following rules:
620 /// - Applicability level `Unspecified` will never be changed.
621 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
622 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
623 /// `HasPlaceholders`
624 pub fn snippet_with_applicability<'a, T: LintContext>(
628 applicability: &mut Applicability,
630 if *applicability != Applicability::Unspecified && span.from_expansion() {
631 *applicability = Applicability::MaybeIncorrect;
633 snippet_opt(cx, span).map_or_else(
635 if *applicability == Applicability::MachineApplicable {
636 *applicability = Applicability::HasPlaceholders;
638 Cow::Borrowed(default)
644 /// Same as `snippet`, but should only be used when it's clear that the input span is
645 /// not a macro argument.
646 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
647 snippet(cx, span.source_callsite(), default)
650 /// Converts a span to a code snippet. Returns `None` if not available.
651 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
652 cx.sess().source_map().span_to_snippet(span).ok()
655 /// Converts a span (from a block) to a code snippet if available, otherwise use default.
657 /// This trims the code of indentation, except for the first line. Use it for blocks or block-like
658 /// things which need to be printed as such.
660 /// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
661 /// resulting snippet of the given span.
666 /// snippet_block(cx, block.span, "..", None)
667 /// // where, `block` is the block of the if expr
671 /// // will return the snippet
678 /// snippet_block(cx, block.span, "..", Some(if_expr.span))
679 /// // where, `block` is the block of the if expr
683 /// // will return the snippet
686 /// } // aligned with `if`
688 /// Note that the first line of the snippet always has 0 indentation.
689 pub fn snippet_block<'a, T: LintContext>(
693 indent_relative_to: Option<Span>,
695 let snip = snippet(cx, span, default);
696 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
697 reindent_multiline(snip, true, indent)
700 /// Same as `snippet_block`, but adapts the applicability level by the rules of
701 /// `snippet_with_applicability`.
702 pub fn snippet_block_with_applicability<'a, T: LintContext>(
706 indent_relative_to: Option<Span>,
707 applicability: &mut Applicability,
709 let snip = snippet_with_applicability(cx, span, default, applicability);
710 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
711 reindent_multiline(snip, true, indent)
714 /// Returns a new Span that extends the original Span to the first non-whitespace char of the first
720 /// // will be converted to
724 pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
725 first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
728 fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
729 let line_span = line_span(cx, span);
730 snippet_opt(cx, line_span).and_then(|snip| {
731 snip.find(|c: char| !c.is_whitespace())
732 .map(|pos| line_span.lo() + BytePos::from_usize(pos))
736 /// Returns the indentation of the line of a span
740 /// // ^^ -- will return 0
742 /// // ^^ -- will return 4
744 pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
745 snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
748 /// Returns the positon just before rarrow
751 /// fn into(self) -> () {}
753 /// // in case of unformatted code
754 /// fn into2(self)-> () {}
756 /// fn into3(self) -> () {}
759 #[allow(clippy::needless_pass_by_value)]
760 pub fn position_before_rarrow(s: String) -> Option<usize> {
761 s.rfind("->").map(|rpos| {
763 let chars: Vec<char> = s.chars().collect();
765 if let Some(c) = chars.get(rpos - 1) {
766 if c.is_whitespace() {
777 /// Extends the span to the beginning of the spans line, incl. whitespaces.
782 /// // will be converted to
784 /// // ^^^^^^^^^^^^^^
786 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
787 let span = original_sp(span, DUMMY_SP);
788 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
789 let line_no = source_map_and_line.line;
790 let line_start = source_map_and_line.sf.lines[line_no];
791 Span::new(line_start, span.hi(), span.ctxt())
794 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
795 /// Also takes an `Option<String>` which can be put inside the braces.
796 pub fn expr_block<'a, T: LintContext>(
799 option: Option<String>,
801 indent_relative_to: Option<Span>,
803 let code = snippet_block(cx, expr.span, default, indent_relative_to);
804 let string = option.unwrap_or_default();
805 if expr.span.from_expansion() {
806 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
807 } else if let ExprKind::Block(_, _) = expr.kind {
808 Cow::Owned(format!("{}{}", code, string))
809 } else if string.is_empty() {
810 Cow::Owned(format!("{{ {} }}", code))
812 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
816 /// Reindent a multiline string with possibility of ignoring the first line.
817 #[allow(clippy::needless_pass_by_value)]
818 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
819 let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
820 let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
821 reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
824 fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
827 .skip(ignore_first as usize)
832 // ignore empty lines
833 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
838 let indent = indent.unwrap_or(0);
842 if (ignore_first && i == 0) || l.is_empty() {
844 } else if x > indent {
845 l.split_at(x - indent).1.to_owned()
847 " ".repeat(indent - x) + l
850 .collect::<Vec<String>>()
854 /// Gets the parent expression, if any –- this is useful to constrain a lint.
855 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
856 let map = &cx.tcx.hir();
857 let hir_id = e.hir_id;
858 let parent_id = map.get_parent_node(hir_id);
859 if hir_id == parent_id {
862 map.find(parent_id).and_then(|node| {
863 if let Node::Expr(parent) = node {
871 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
872 let map = &cx.tcx.hir();
873 let enclosing_node = map
874 .get_enclosing_scope(hir_id)
875 .and_then(|enclosing_id| map.find(enclosing_id));
876 enclosing_node.and_then(|node| match node {
877 Node::Block(block) => Some(block),
879 kind: ItemKind::Fn(_, _, eid),
882 | Node::ImplItem(&ImplItem {
883 kind: ImplItemKind::Fn(_, eid),
885 }) => match cx.tcx.hir().body(eid).value.kind {
886 ExprKind::Block(ref block, _) => Some(block),
893 /// Returns the base type for HIR references and pointers.
894 pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
896 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
901 /// Returns the base type for references and raw pointers, and count reference
903 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
904 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
906 ty::Ref(_, ty, _) => inner(ty, depth + 1),
913 /// Checks whether the given expression is a constant integer of the given value.
914 /// unlike `is_integer_literal`, this version does const folding
915 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
916 if is_integer_literal(e, value) {
919 let map = cx.tcx.hir();
920 let parent_item = map.get_parent_item(e.hir_id);
921 if let Some((Constant::Int(v), _)) = map
922 .maybe_body_owned_by(parent_item)
923 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
931 /// Checks whether the given expression is a constant literal of the given value.
932 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
933 // FIXME: use constant folding
934 if let ExprKind::Lit(ref spanned) = expr.kind {
935 if let LitKind::Int(v, _) = spanned.node {
942 /// Returns `true` if the given `Expr` has been coerced before.
944 /// Examples of coercions can be found in the Nomicon at
945 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
947 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
948 /// information on adjustments and coercions.
949 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
950 cx.typeck_results().adjustments().get(e.hir_id).is_some()
953 /// Returns the pre-expansion span if is this comes from an expansion of the
955 /// See also `is_direct_expn_of`.
957 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
959 if span.from_expansion() {
960 let data = span.ctxt().outer_expn_data();
961 let new_span = data.call_site;
963 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
964 if mac_name.as_str() == name {
965 return Some(new_span);
976 /// Returns the pre-expansion span if the span directly comes from an expansion
977 /// of the macro `name`.
978 /// The difference with `is_expn_of` is that in
982 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
984 /// `is_direct_expn_of`.
986 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
987 if span.from_expansion() {
988 let data = span.ctxt().outer_expn_data();
989 let new_span = data.call_site;
991 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
992 if mac_name.as_str() == name {
993 return Some(new_span);
1001 /// Convenience function to get the return type of a function.
1002 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1003 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1004 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1005 cx.tcx.erase_late_bound_regions(ret_ty)
1008 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
1009 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
1010 ty.walk().any(|inner| match inner.unpack() {
1011 GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
1012 GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
1016 /// Returns `true` if the given type is an `unsafe` function.
1017 pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1019 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
1024 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1025 ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
1028 /// Checks if an expression is constructing a tuple-like enum variant or struct
1029 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1030 if let ExprKind::Call(ref fun, _) = expr.kind {
1031 if let ExprKind::Path(ref qp) = fun.kind {
1032 let res = cx.qpath_res(qp, fun.hir_id);
1034 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1035 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1043 /// Returns `true` if a pattern is refutable.
1044 // TODO: should be implemented using rustc/mir_build/thir machinery
1045 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1046 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1048 cx.qpath_res(qpath, id),
1049 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1053 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1054 i.any(|pat| is_refutable(cx, pat))
1058 PatKind::Wild => false,
1059 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1060 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1061 PatKind::Lit(..) | PatKind::Range(..) => true,
1062 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1063 PatKind::Or(ref pats) => {
1064 // TODO: should be the honest check, that pats is exhaustive set
1065 are_refutable(cx, pats.iter().map(|pat| &**pat))
1067 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1068 PatKind::Struct(ref qpath, ref fields, _) => {
1069 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1071 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1072 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1074 PatKind::Slice(ref head, ref middle, ref tail) => {
1075 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1077 // [..] is the only irrefutable slice pattern.
1078 !head.is_empty() || middle.is_none() || !tail.is_empty()
1080 ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
1090 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1091 /// implementations have.
1092 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1093 attrs.iter().any(|attr| attr.has_name(rustc_sym::automatically_derived))
1096 /// Remove blocks around an expression.
1098 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1100 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1101 while let ExprKind::Block(ref block, ..) = expr.kind {
1102 match (block.stmts.is_empty(), block.expr.as_ref()) {
1103 (true, Some(e)) => expr = e,
1110 pub fn is_self(slf: &Param<'_>) -> bool {
1111 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1112 name.name == kw::SelfLower
1118 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1120 if let TyKind::Path(ref qp) = slf.kind;
1121 if let QPath::Resolved(None, ref path) = *qp;
1122 if let Res::SelfTy(..) = path.res;
1130 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1131 (0..decl.inputs.len()).map(move |i| &body.params[i])
1134 /// Checks if a given expression is a match expression expanded from the `?`
1135 /// operator or the `try` macro.
1136 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1137 fn is_ok(arm: &Arm<'_>) -> bool {
1139 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1140 if match_qpath(path, &paths::RESULT_OK[1..]);
1141 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1142 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.kind;
1143 if let Res::Local(lid) = path.res;
1152 fn is_err(arm: &Arm<'_>) -> bool {
1153 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1154 match_qpath(path, &paths::RESULT_ERR[1..])
1160 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1161 // desugared from a `?` operator
1162 if let MatchSource::TryDesugar = *source {
1168 if arms[0].guard.is_none();
1169 if arms[1].guard.is_none();
1170 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1171 (is_ok(&arms[1]) && is_err(&arms[0]));
1181 /// Returns `true` if the lint is allowed in the current context
1183 /// Useful for skipping long running code when it's unnecessary
1184 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1185 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1188 pub fn get_arg_name(pat: &Pat<'_>) -> Option<Symbol> {
1190 PatKind::Binding(.., ident, None) => Some(ident.name),
1191 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1196 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
1197 Integer::from_attr(&tcx, attr::IntType::SignedInt(ity)).size().bits()
1200 #[allow(clippy::cast_possible_wrap)]
1201 /// Turn a constant int byte representation into an i128
1202 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
1203 let amt = 128 - int_bits(tcx, ity);
1204 ((u as i128) << amt) >> amt
1207 #[allow(clippy::cast_sign_loss)]
1208 /// clip unused bytes
1209 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
1210 let amt = 128 - int_bits(tcx, ity);
1211 ((u as u128) << amt) >> amt
1214 /// clip unused bytes
1215 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
1216 let bits = Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity)).size().bits();
1217 let amt = 128 - bits;
1221 /// Removes block comments from the given `Vec` of lines.
1226 /// without_block_comments(vec!["/*", "foo", "*/"]);
1229 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1230 /// // => vec!["bar"]
1232 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1233 let mut without = vec![];
1235 let mut nest_level = 0;
1238 if line.contains("/*") {
1241 } else if line.contains("*/") {
1246 if nest_level == 0 {
1254 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1255 let map = &tcx.hir();
1256 let mut prev_enclosing_node = None;
1257 let mut enclosing_node = node;
1258 while Some(enclosing_node) != prev_enclosing_node {
1259 if is_automatically_derived(map.attrs(enclosing_node)) {
1262 prev_enclosing_node = Some(enclosing_node);
1263 enclosing_node = map.get_parent_item(enclosing_node);
1268 /// Returns true if ty has `iter` or `iter_mut` methods
1269 pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1270 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1271 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1272 // so we can't use its `lookup_method` method.
1273 let into_iter_collections: [&[&str]; 13] = [
1280 &paths::LINKED_LIST,
1281 &paths::BINARY_HEAP,
1289 let ty_to_check = match probably_ref_ty.kind() {
1290 ty::Ref(_, ty_to_check, _) => ty_to_check,
1291 _ => probably_ref_ty,
1294 let def_id = match ty_to_check.kind() {
1295 ty::Array(..) => return Some("array"),
1296 ty::Slice(..) => return Some("slice"),
1297 ty::Adt(adt, _) => adt.did,
1301 for path in &into_iter_collections {
1302 if match_def_path(cx, def_id, path) {
1303 return Some(*path.last().unwrap());
1309 /// Matches a function call with the given path and returns the arguments.
1314 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1316 pub fn match_function_call<'tcx>(
1317 cx: &LateContext<'tcx>,
1318 expr: &'tcx Expr<'_>,
1320 ) -> Option<&'tcx [Expr<'tcx>]> {
1322 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1323 if let ExprKind::Path(ref qpath) = fun.kind;
1324 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1325 if match_def_path(cx, fun_def_id, path);
1333 /// Checks if `Ty` is normalizable. This function is useful
1334 /// to avoid crashes on `layout_of`.
1335 pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
1336 cx.tcx.infer_ctxt().enter(|infcx| {
1337 let cause = rustc_middle::traits::ObligationCause::dummy();
1338 infcx.at(&cause, param_env).normalize(ty).is_ok()
1342 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1343 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1344 // accepts only that. We should probably move to Symbols in Clippy as well.
1345 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1346 cx.match_def_path(did, &syms)
1349 pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
1350 match_function_call(cx, expr, &paths::BEGIN_PANIC)
1351 .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
1352 .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
1353 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
1354 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
1355 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
1358 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1359 match_def_path(cx, did, &paths::BEGIN_PANIC)
1360 || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
1361 || match_def_path(cx, did, &paths::PANIC_ANY)
1362 || match_def_path(cx, did, &paths::PANICKING_PANIC)
1363 || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
1364 || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
1367 /// Returns the list of condition expressions and the list of blocks in a
1368 /// sequence of `if/else`.
1369 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1370 /// `if a { c } else if b { d } else { e }`.
1371 pub fn if_sequence<'tcx>(
1372 mut expr: &'tcx Expr<'tcx>,
1373 ) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
1374 let mut conds = SmallVec::new();
1375 let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
1377 while let Some((ref cond, ref then_expr, ref else_expr)) = higher::if_block(&expr) {
1378 conds.push(&**cond);
1379 if let ExprKind::Block(ref block, _) = then_expr.kind {
1382 panic!("ExprKind::If node is not an ExprKind::Block");
1385 if let Some(ref else_expr) = *else_expr {
1392 // final `else {..}`
1393 if !blocks.is_empty() {
1394 if let ExprKind::Block(ref block, _) = expr.kind {
1395 blocks.push(&**block);
1402 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1403 let map = cx.tcx.hir();
1404 let parent_id = map.get_parent_node(expr.hir_id);
1405 let parent_node = map.get(parent_id);
1408 Node::Expr(e) => higher::if_block(&e).is_some(),
1409 Node::Arm(e) => higher::if_block(&e.body).is_some(),
1414 // Finds the attribute with the given name, if any
1415 pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
1418 .find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
1421 // Finds the `#[must_use]` attribute, if any
1422 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1423 attr_by_name(attrs, "must_use")
1426 // Returns whether the type has #[must_use] attribute
1427 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1429 ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
1430 ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
1432 | ty::Array(ref ty, _)
1433 | ty::RawPtr(ty::TypeAndMut { ref ty, .. })
1434 | ty::Ref(_, ref ty, _) => {
1435 // for the Array case we don't need to care for the len == 0 case
1436 // because we don't want to lint functions returning empty arrays
1437 is_must_use_ty(cx, *ty)
1439 ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
1440 ty::Opaque(ref def_id, _) => {
1441 for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
1442 if let ty::PredicateAtom::Trait(trait_predicate, _) = predicate.skip_binders() {
1443 if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
1450 ty::Dynamic(binder, _) => {
1451 for predicate in binder.skip_binder().iter() {
1452 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate {
1453 if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
1464 // check if expr is calling method or function with #[must_use] attribute
1465 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1466 let did = match expr.kind {
1467 ExprKind::Call(ref path, _) => if_chain! {
1468 if let ExprKind::Path(ref qpath) = path.kind;
1469 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1476 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1480 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1483 pub fn is_no_std_crate(krate: &Crate<'_>) -> bool {
1484 krate.item.attrs.iter().any(|attr| {
1485 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1486 attr.path == symbol::sym::no_std
1493 /// Check if parent of a hir node is a trait implementation block.
1494 /// For example, `f` in
1496 /// impl Trait for S {
1500 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1501 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1502 matches!(item.kind, ItemKind::Impl{ of_trait: Some(_), .. })
1508 /// Check if it's even possible to satisfy the `where` clause for the item.
1510 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1513 /// fn foo() where i32: Iterator {
1514 /// for _ in 2i32 {}
1517 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1518 use rustc_trait_selection::traits;
1524 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1525 traits::impossible_predicates(
1527 traits::elaborate_predicates(cx.tcx, predicates)
1528 .map(|o| o.predicate)
1529 .collect::<Vec<_>>(),
1533 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1534 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1536 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1539 kind: ExprKind::Path(qpath),
1543 ) => cx.typeck_results().qpath_res(qpath, expr.hir_id).opt_def_id(),
1548 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1549 lints.iter().any(|lint| {
1551 cx.tcx.lint_level_at_node(lint, id),
1552 (Level::Forbid | Level::Deny | Level::Warn, _)
1557 /// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
1558 /// number type, a str, or an array, slice, or tuple of those types).
1559 pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
1561 ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
1562 ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
1563 ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
1564 ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
1569 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1570 /// slice iff the given expression is a slice of primitives (as defined in the
1571 /// `is_recursively_primitive_type` function) and None otherwise.
1572 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1573 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1574 let expr_kind = expr_type.kind();
1575 let is_primitive = match expr_kind {
1576 ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1577 ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
1578 if let ty::Slice(element_type) = inner_ty.kind() {
1579 is_recursively_primitive_type(element_type)
1588 // if we have wrappers like Array, Slice or Tuple, print these
1589 // and get the type enclosed in the slice ref
1590 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1591 ty::Slice(..) => return Some("slice".into()),
1592 ty::Array(..) => return Some("array".into()),
1593 ty::Tuple(..) => return Some("tuple".into()),
1595 // is_recursively_primitive_type() should have taken care
1596 // of the rest and we can rely on the type that is found
1597 let refs_peeled = expr_type.peel_refs();
1598 return Some(refs_peeled.walk().last().unwrap().to_string());
1605 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1606 /// `hash` must be comformed with `eq`
1607 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1609 Hash: Fn(&T) -> u64,
1610 Eq: Fn(&T, &T) -> bool,
1612 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1613 return vec![(&exprs[0], &exprs[1])];
1616 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1618 let mut map: FxHashMap<_, Vec<&_>> =
1619 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1622 match map.entry(hash(expr)) {
1623 Entry::Occupied(mut o) => {
1626 match_expr_list.push((o, expr));
1629 o.get_mut().push(expr);
1631 Entry::Vacant(v) => {
1632 v.insert(vec![expr]);
1641 macro_rules! unwrap_cargo_metadata {
1642 ($cx: ident, $lint: ident, $deps: expr) => {{
1643 let mut command = cargo_metadata::MetadataCommand::new();
1648 match command.exec() {
1649 Ok(metadata) => metadata,
1651 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1660 use super::{reindent_multiline, without_block_comments};
1663 fn test_reindent_multiline_single_line() {
1664 assert_eq!("", reindent_multiline("".into(), false, None));
1665 assert_eq!("...", reindent_multiline("...".into(), false, None));
1666 assert_eq!("...", reindent_multiline(" ...".into(), false, None));
1667 assert_eq!("...", reindent_multiline("\t...".into(), false, None));
1668 assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
1673 fn test_reindent_multiline_block() {
1679 }", reindent_multiline(" if x {
1683 }".into(), false, None));
1689 }", reindent_multiline(" if x {
1693 }".into(), false, None));
1698 fn test_reindent_multiline_empty_line() {
1705 }", reindent_multiline(" if x {
1710 }".into(), false, None));
1715 fn test_reindent_multiline_lines_deeper() {
1721 }", reindent_multiline("\
1726 }".into(), true, Some(8)));
1730 fn test_without_block_comments_lines_without_block_comments() {
1731 let result = without_block_comments(vec!["/*", "", "*/"]);
1732 println!("result: {:?}", result);
1733 assert!(result.is_empty());
1735 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1736 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1738 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1739 assert!(result.is_empty());
1741 let result = without_block_comments(vec!["/* one-line comment */"]);
1742 assert!(result.is_empty());
1744 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1745 assert!(result.is_empty());
1747 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1748 assert!(result.is_empty());
1750 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1751 assert_eq!(result, vec!["foo", "bar", "baz"]);