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_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::{self, 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_semver::RustcVersion;
55 use rustc_session::Session;
56 use rustc_span::hygiene::{ExpnKind, MacroKind};
57 use rustc_span::source_map::original_sp;
59 use rustc_span::symbol::{kw, Symbol};
60 use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
61 use rustc_target::abi::Integer;
62 use rustc_trait_selection::traits::query::normalize::AtExt;
63 use smallvec::SmallVec;
65 use crate::consts::{constant, Constant};
67 pub fn parse_msrv(msrv: &str, sess: Option<&Session>, span: Option<Span>) -> Option<RustcVersion> {
68 if let Ok(version) = RustcVersion::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<&RustcVersion>, lint_msrv: &RustcVersion) -> bool {
79 msrv.map_or(true, |msrv| msrv.meets(*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 /// Convenience function to get the `DefId` of a trait by path.
373 /// It could be a trait or trait alias.
374 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
375 let res = match path_to_res(cx, path) {
381 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
382 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
387 /// Checks whether a type implements a trait.
388 /// See also `get_trait_def_id`.
389 pub fn implements_trait<'tcx>(
390 cx: &LateContext<'tcx>,
393 ty_params: &[GenericArg<'tcx>],
395 // Do not check on infer_types to avoid panic in evaluate_obligation.
396 if ty.has_infer_types() {
399 let ty = cx.tcx.erase_regions(ty);
400 if ty.has_escaping_bound_vars() {
403 let ty_params = cx.tcx.mk_substs(ty_params.iter());
404 cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
407 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
409 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
412 /// struct Point(isize, isize);
414 /// impl std::ops::Add for Point {
415 /// type Output = Self;
417 /// fn add(self, other: Self) -> Self {
422 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
423 // Get the implemented trait for the current function
424 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
426 if parent_impl != hir::CRATE_HIR_ID;
427 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
428 if let hir::ItemKind::Impl(impl_) = &item.kind;
429 then { return impl_.of_trait.as_ref(); }
434 /// Checks whether this type implements `Drop`.
435 pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
436 match ty.ty_adt_def() {
437 Some(def) => def.has_dtor(cx.tcx),
442 /// Returns the method names and argument list of nested method call expressions that make up
443 /// `expr`. method/span lists are sorted with the most recent call first.
444 pub fn method_calls<'tcx>(
445 expr: &'tcx Expr<'tcx>,
447 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
448 let mut method_names = Vec::with_capacity(max_depth);
449 let mut arg_lists = Vec::with_capacity(max_depth);
450 let mut spans = Vec::with_capacity(max_depth);
452 let mut current = expr;
453 for _ in 0..max_depth {
454 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
455 if args.iter().any(|e| e.span.from_expansion()) {
458 method_names.push(path.ident.name);
459 arg_lists.push(&**args);
467 (method_names, arg_lists, spans)
470 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
472 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
473 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
474 /// containing the `Expr`s for
475 /// `.bar()` and `.baz()`
476 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
477 let mut current = expr;
478 let mut matched = Vec::with_capacity(methods.len());
479 for method_name in methods.iter().rev() {
480 // method chains are stored last -> first
481 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
482 if path.ident.name.as_str() == *method_name {
483 if args.iter().any(|e| e.span.from_expansion()) {
486 matched.push(&**args); // build up `matched` backwards
487 current = &args[0] // go to parent expression
495 // Reverse `matched` so that it is in the same order as `methods`.
500 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
501 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
503 .entry_fn(LOCAL_CRATE)
504 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
507 /// Returns `true` if the expression is in the program's `#[panic_handler]`.
508 pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
509 let parent = cx.tcx.hir().get_parent_item(e.hir_id);
510 let def_id = cx.tcx.hir().local_def_id(parent).to_def_id();
511 Some(def_id) == cx.tcx.lang_items().panic_impl()
514 /// Gets the name of the item the expression is in, if available.
515 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
516 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
517 match cx.tcx.hir().find(parent_id) {
519 Node::Item(Item { ident, .. })
520 | Node::TraitItem(TraitItem { ident, .. })
521 | Node::ImplItem(ImplItem { ident, .. }),
522 ) => Some(ident.name),
527 /// Gets the name of a `Pat`, if any.
528 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
530 PatKind::Binding(.., ref spname, _) => Some(spname.name),
531 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
532 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
537 struct ContainsName {
542 impl<'tcx> Visitor<'tcx> for ContainsName {
543 type Map = Map<'tcx>;
545 fn visit_name(&mut self, _: Span, name: Symbol) {
546 if self.name == name {
550 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
551 NestedVisitorMap::None
555 /// Checks if an `Expr` contains a certain name.
556 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
557 let mut cn = ContainsName { name, result: false };
562 /// Returns `true` if `expr` contains a return expression
563 pub fn contains_return(expr: &hir::Expr<'_>) -> bool {
564 struct RetCallFinder {
568 impl<'tcx> hir::intravisit::Visitor<'tcx> for RetCallFinder {
569 type Map = Map<'tcx>;
571 fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) {
575 if let hir::ExprKind::Ret(..) = &expr.kind {
578 hir::intravisit::walk_expr(self, expr);
582 fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap<Self::Map> {
583 hir::intravisit::NestedVisitorMap::None
587 let mut visitor = RetCallFinder { found: false };
588 visitor.visit_expr(expr);
592 struct FindMacroCalls<'a, 'b> {
593 names: &'a [&'b str],
597 impl<'a, 'b, 'tcx> Visitor<'tcx> for FindMacroCalls<'a, 'b> {
598 type Map = Map<'tcx>;
600 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
601 if self.names.iter().any(|fun| is_expn_of(expr.span, fun).is_some()) {
602 self.result.push(expr.span);
604 // and check sub-expressions
605 intravisit::walk_expr(self, expr);
608 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
609 NestedVisitorMap::None
613 /// Finds calls of the specified macros in a function body.
614 pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
615 let mut fmc = FindMacroCalls {
619 fmc.visit_expr(&body.value);
623 /// Converts a span to a code snippet if available, otherwise use default.
625 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
626 /// to convert a given `Span` to a `str`.
630 /// snippet(cx, expr.span, "..")
632 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
633 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
636 /// Same as `snippet`, but it adapts the applicability level by following rules:
638 /// - Applicability level `Unspecified` will never be changed.
639 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
640 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
641 /// `HasPlaceholders`
642 pub fn snippet_with_applicability<'a, T: LintContext>(
646 applicability: &mut Applicability,
648 if *applicability != Applicability::Unspecified && span.from_expansion() {
649 *applicability = Applicability::MaybeIncorrect;
651 snippet_opt(cx, span).map_or_else(
653 if *applicability == Applicability::MachineApplicable {
654 *applicability = Applicability::HasPlaceholders;
656 Cow::Borrowed(default)
662 /// Same as `snippet`, but should only be used when it's clear that the input span is
663 /// not a macro argument.
664 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
665 snippet(cx, span.source_callsite(), default)
668 /// Converts a span to a code snippet. Returns `None` if not available.
669 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
670 cx.sess().source_map().span_to_snippet(span).ok()
673 /// Converts a span (from a block) to a code snippet if available, otherwise use default.
675 /// This trims the code of indentation, except for the first line. Use it for blocks or block-like
676 /// things which need to be printed as such.
678 /// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
679 /// resulting snippet of the given span.
684 /// snippet_block(cx, block.span, "..", None)
685 /// // where, `block` is the block of the if expr
689 /// // will return the snippet
696 /// snippet_block(cx, block.span, "..", Some(if_expr.span))
697 /// // where, `block` is the block of the if expr
701 /// // will return the snippet
704 /// } // aligned with `if`
706 /// Note that the first line of the snippet always has 0 indentation.
707 pub fn snippet_block<'a, T: LintContext>(
711 indent_relative_to: Option<Span>,
713 let snip = snippet(cx, span, default);
714 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
715 reindent_multiline(snip, true, indent)
718 /// Same as `snippet_block`, but adapts the applicability level by the rules of
719 /// `snippet_with_applicability`.
720 pub fn snippet_block_with_applicability<'a, T: LintContext>(
724 indent_relative_to: Option<Span>,
725 applicability: &mut Applicability,
727 let snip = snippet_with_applicability(cx, span, default, applicability);
728 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
729 reindent_multiline(snip, true, indent)
732 /// Returns a new Span that extends the original Span to the first non-whitespace char of the first
738 /// // will be converted to
742 pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
743 first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
746 fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
747 let line_span = line_span(cx, span);
748 snippet_opt(cx, line_span).and_then(|snip| {
749 snip.find(|c: char| !c.is_whitespace())
750 .map(|pos| line_span.lo() + BytePos::from_usize(pos))
754 /// Returns the indentation of the line of a span
758 /// // ^^ -- will return 0
760 /// // ^^ -- will return 4
762 pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
763 snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
766 /// Returns the positon just before rarrow
769 /// fn into(self) -> () {}
771 /// // in case of unformatted code
772 /// fn into2(self)-> () {}
774 /// fn into3(self) -> () {}
777 pub fn position_before_rarrow(s: &str) -> Option<usize> {
778 s.rfind("->").map(|rpos| {
780 let chars: Vec<char> = s.chars().collect();
782 if let Some(c) = chars.get(rpos - 1) {
783 if c.is_whitespace() {
794 /// Extends the span to the beginning of the spans line, incl. whitespaces.
799 /// // will be converted to
801 /// // ^^^^^^^^^^^^^^
803 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
804 let span = original_sp(span, DUMMY_SP);
805 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
806 let line_no = source_map_and_line.line;
807 let line_start = source_map_and_line.sf.lines[line_no];
808 Span::new(line_start, span.hi(), span.ctxt())
811 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
812 /// Also takes an `Option<String>` which can be put inside the braces.
813 pub fn expr_block<'a, T: LintContext>(
816 option: Option<String>,
818 indent_relative_to: Option<Span>,
820 let code = snippet_block(cx, expr.span, default, indent_relative_to);
821 let string = option.unwrap_or_default();
822 if expr.span.from_expansion() {
823 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
824 } else if let ExprKind::Block(_, _) = expr.kind {
825 Cow::Owned(format!("{}{}", code, string))
826 } else if string.is_empty() {
827 Cow::Owned(format!("{{ {} }}", code))
829 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
833 /// Reindent a multiline string with possibility of ignoring the first line.
834 #[allow(clippy::needless_pass_by_value)]
835 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
836 let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
837 let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
838 reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
841 fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
844 .skip(ignore_first as usize)
849 // ignore empty lines
850 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
855 let indent = indent.unwrap_or(0);
859 if (ignore_first && i == 0) || l.is_empty() {
861 } else if x > indent {
862 l.split_at(x - indent).1.to_owned()
864 " ".repeat(indent - x) + l
867 .collect::<Vec<String>>()
871 /// Gets the parent expression, if any –- this is useful to constrain a lint.
872 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
873 let map = &cx.tcx.hir();
874 let hir_id = e.hir_id;
875 let parent_id = map.get_parent_node(hir_id);
876 if hir_id == parent_id {
879 map.find(parent_id).and_then(|node| {
880 if let Node::Expr(parent) = node {
888 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
889 let map = &cx.tcx.hir();
890 let enclosing_node = map
891 .get_enclosing_scope(hir_id)
892 .and_then(|enclosing_id| map.find(enclosing_id));
893 enclosing_node.and_then(|node| match node {
894 Node::Block(block) => Some(block),
896 kind: ItemKind::Fn(_, _, eid),
899 | Node::ImplItem(&ImplItem {
900 kind: ImplItemKind::Fn(_, eid),
902 }) => match cx.tcx.hir().body(eid).value.kind {
903 ExprKind::Block(ref block, _) => Some(block),
910 /// Returns the base type for HIR references and pointers.
911 pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
913 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
918 /// Returns the base type for references and raw pointers, and count reference
920 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
921 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
923 ty::Ref(_, ty, _) => inner(ty, depth + 1),
930 /// Checks whether the given expression is a constant integer of the given value.
931 /// unlike `is_integer_literal`, this version does const folding
932 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
933 if is_integer_literal(e, value) {
936 let map = cx.tcx.hir();
937 let parent_item = map.get_parent_item(e.hir_id);
938 if let Some((Constant::Int(v), _)) = map
939 .maybe_body_owned_by(parent_item)
940 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
948 /// Checks whether the given expression is a constant literal of the given value.
949 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
950 // FIXME: use constant folding
951 if let ExprKind::Lit(ref spanned) = expr.kind {
952 if let LitKind::Int(v, _) = spanned.node {
959 /// Returns `true` if the given `Expr` has been coerced before.
961 /// Examples of coercions can be found in the Nomicon at
962 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
964 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
965 /// information on adjustments and coercions.
966 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
967 cx.typeck_results().adjustments().get(e.hir_id).is_some()
970 /// Returns the pre-expansion span if is this comes from an expansion of the
972 /// See also `is_direct_expn_of`.
974 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
976 if span.from_expansion() {
977 let data = span.ctxt().outer_expn_data();
978 let new_span = data.call_site;
980 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
981 if mac_name.as_str() == name {
982 return Some(new_span);
993 /// Returns the pre-expansion span if the span directly comes from an expansion
994 /// of the macro `name`.
995 /// The difference with `is_expn_of` is that in
999 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
1001 /// `is_direct_expn_of`.
1003 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
1004 if span.from_expansion() {
1005 let data = span.ctxt().outer_expn_data();
1006 let new_span = data.call_site;
1008 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
1009 if mac_name.as_str() == name {
1010 return Some(new_span);
1018 /// Convenience function to get the return type of a function.
1019 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
1020 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
1021 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
1022 cx.tcx.erase_late_bound_regions(ret_ty)
1025 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
1026 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
1027 ty.walk().any(|inner| match inner.unpack() {
1028 GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
1029 GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
1033 /// Returns `true` if the given type is an `unsafe` function.
1034 pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1036 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
1041 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1042 ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
1045 /// Checks if an expression is constructing a tuple-like enum variant or struct
1046 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1047 if let ExprKind::Call(ref fun, _) = expr.kind {
1048 if let ExprKind::Path(ref qp) = fun.kind {
1049 let res = cx.qpath_res(qp, fun.hir_id);
1051 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
1052 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
1060 /// Returns `true` if a pattern is refutable.
1061 // TODO: should be implemented using rustc/mir_build/thir machinery
1062 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
1063 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
1065 cx.qpath_res(qpath, id),
1066 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
1070 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
1071 i.any(|pat| is_refutable(cx, pat))
1075 PatKind::Wild => false,
1076 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
1077 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
1078 PatKind::Lit(..) | PatKind::Range(..) => true,
1079 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
1080 PatKind::Or(ref pats) => {
1081 // TODO: should be the honest check, that pats is exhaustive set
1082 are_refutable(cx, pats.iter().map(|pat| &**pat))
1084 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
1085 PatKind::Struct(ref qpath, ref fields, _) => {
1086 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
1088 PatKind::TupleStruct(ref qpath, ref pats, _) => {
1089 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
1091 PatKind::Slice(ref head, ref middle, ref tail) => {
1092 match &cx.typeck_results().node_type(pat.hir_id).kind() {
1094 // [..] is the only irrefutable slice pattern.
1095 !head.is_empty() || middle.is_none() || !tail.is_empty()
1097 ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
1107 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
1108 /// implementations have.
1109 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
1110 attrs.iter().any(|attr| attr.has_name(sym::automatically_derived))
1113 /// Remove blocks around an expression.
1115 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
1117 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
1118 while let ExprKind::Block(ref block, ..) = expr.kind {
1119 match (block.stmts.is_empty(), block.expr.as_ref()) {
1120 (true, Some(e)) => expr = e,
1127 pub fn is_self(slf: &Param<'_>) -> bool {
1128 if let PatKind::Binding(.., name, _) = slf.pat.kind {
1129 name.name == kw::SelfLower
1135 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1137 if let TyKind::Path(ref qp) = slf.kind;
1138 if let QPath::Resolved(None, ref path) = *qp;
1139 if let Res::SelfTy(..) = path.res;
1147 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1148 (0..decl.inputs.len()).map(move |i| &body.params[i])
1151 /// Checks if a given expression is a match expression expanded from the `?`
1152 /// operator or the `try` macro.
1153 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1154 fn is_ok(arm: &Arm<'_>) -> bool {
1156 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1157 if match_qpath(path, &paths::RESULT_OK[1..]);
1158 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1159 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.kind;
1160 if let Res::Local(lid) = path.res;
1169 fn is_err(arm: &Arm<'_>) -> bool {
1170 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1171 match_qpath(path, &paths::RESULT_ERR[1..])
1177 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1178 // desugared from a `?` operator
1179 if let MatchSource::TryDesugar = *source {
1185 if arms[0].guard.is_none();
1186 if arms[1].guard.is_none();
1187 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1188 (is_ok(&arms[1]) && is_err(&arms[0]));
1198 /// Returns `true` if the lint is allowed in the current context
1200 /// Useful for skipping long running code when it's unnecessary
1201 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1202 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1205 pub fn get_arg_name(pat: &Pat<'_>) -> Option<Symbol> {
1207 PatKind::Binding(.., ident, None) => Some(ident.name),
1208 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1213 pub fn int_bits(tcx: TyCtxt<'_>, ity: ty::IntTy) -> u64 {
1214 Integer::from_int_ty(&tcx, ity).size().bits()
1217 #[allow(clippy::cast_possible_wrap)]
1218 /// Turn a constant int byte representation into an i128
1219 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ty::IntTy) -> i128 {
1220 let amt = 128 - int_bits(tcx, ity);
1221 ((u as i128) << amt) >> amt
1224 #[allow(clippy::cast_sign_loss)]
1225 /// clip unused bytes
1226 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ty::IntTy) -> u128 {
1227 let amt = 128 - int_bits(tcx, ity);
1228 ((u as u128) << amt) >> amt
1231 /// clip unused bytes
1232 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ty::UintTy) -> u128 {
1233 let bits = Integer::from_uint_ty(&tcx, ity).size().bits();
1234 let amt = 128 - bits;
1238 /// Removes block comments from the given `Vec` of lines.
1243 /// without_block_comments(vec!["/*", "foo", "*/"]);
1246 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1247 /// // => vec!["bar"]
1249 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1250 let mut without = vec![];
1252 let mut nest_level = 0;
1255 if line.contains("/*") {
1258 } else if line.contains("*/") {
1263 if nest_level == 0 {
1271 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1272 let map = &tcx.hir();
1273 let mut prev_enclosing_node = None;
1274 let mut enclosing_node = node;
1275 while Some(enclosing_node) != prev_enclosing_node {
1276 if is_automatically_derived(map.attrs(enclosing_node)) {
1279 prev_enclosing_node = Some(enclosing_node);
1280 enclosing_node = map.get_parent_item(enclosing_node);
1285 /// Returns true if ty has `iter` or `iter_mut` methods
1286 pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1287 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1288 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1289 // so we can't use its `lookup_method` method.
1290 let into_iter_collections: [&[&str]; 13] = [
1297 &paths::LINKED_LIST,
1298 &paths::BINARY_HEAP,
1306 let ty_to_check = match probably_ref_ty.kind() {
1307 ty::Ref(_, ty_to_check, _) => ty_to_check,
1308 _ => probably_ref_ty,
1311 let def_id = match ty_to_check.kind() {
1312 ty::Array(..) => return Some("array"),
1313 ty::Slice(..) => return Some("slice"),
1314 ty::Adt(adt, _) => adt.did,
1318 for path in &into_iter_collections {
1319 if match_def_path(cx, def_id, path) {
1320 return Some(*path.last().unwrap());
1326 /// Matches a function call with the given path and returns the arguments.
1331 /// if let Some(args) = match_function_call(cx, cmp_max_call, &paths::CMP_MAX);
1333 pub fn match_function_call<'tcx>(
1334 cx: &LateContext<'tcx>,
1335 expr: &'tcx Expr<'_>,
1337 ) -> Option<&'tcx [Expr<'tcx>]> {
1339 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1340 if let ExprKind::Path(ref qpath) = fun.kind;
1341 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1342 if match_def_path(cx, fun_def_id, path);
1350 /// Checks if `Ty` is normalizable. This function is useful
1351 /// to avoid crashes on `layout_of`.
1352 pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
1353 cx.tcx.infer_ctxt().enter(|infcx| {
1354 let cause = rustc_middle::traits::ObligationCause::dummy();
1355 infcx.at(&cause, param_env).normalize(ty).is_ok()
1359 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1360 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1361 // accepts only that. We should probably move to Symbols in Clippy as well.
1362 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1363 cx.match_def_path(did, &syms)
1366 pub fn match_panic_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<&'tcx [Expr<'tcx>]> {
1367 match_function_call(cx, expr, &paths::BEGIN_PANIC)
1368 .or_else(|| match_function_call(cx, expr, &paths::BEGIN_PANIC_FMT))
1369 .or_else(|| match_function_call(cx, expr, &paths::PANIC_ANY))
1370 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC))
1371 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_FMT))
1372 .or_else(|| match_function_call(cx, expr, &paths::PANICKING_PANIC_STR))
1375 pub fn match_panic_def_id(cx: &LateContext<'_>, did: DefId) -> bool {
1376 match_def_path(cx, did, &paths::BEGIN_PANIC)
1377 || match_def_path(cx, did, &paths::BEGIN_PANIC_FMT)
1378 || match_def_path(cx, did, &paths::PANIC_ANY)
1379 || match_def_path(cx, did, &paths::PANICKING_PANIC)
1380 || match_def_path(cx, did, &paths::PANICKING_PANIC_FMT)
1381 || match_def_path(cx, did, &paths::PANICKING_PANIC_STR)
1384 /// Returns the list of condition expressions and the list of blocks in a
1385 /// sequence of `if/else`.
1386 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1387 /// `if a { c } else if b { d } else { e }`.
1388 pub fn if_sequence<'tcx>(
1389 mut expr: &'tcx Expr<'tcx>,
1390 ) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
1391 let mut conds = SmallVec::new();
1392 let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
1394 while let ExprKind::If(ref cond, ref then_expr, ref else_expr) = expr.kind {
1395 conds.push(&**cond);
1396 if let ExprKind::Block(ref block, _) = then_expr.kind {
1399 panic!("ExprKind::If node is not an ExprKind::Block");
1402 if let Some(ref else_expr) = *else_expr {
1409 // final `else {..}`
1410 if !blocks.is_empty() {
1411 if let ExprKind::Block(ref block, _) = expr.kind {
1412 blocks.push(&**block);
1419 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1420 let map = cx.tcx.hir();
1421 let parent_id = map.get_parent_node(expr.hir_id);
1422 let parent_node = map.get(parent_id);
1426 kind: ExprKind::If(_, _, _),
1432 // Finds the attribute with the given name, if any
1433 pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
1436 .find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
1439 // Finds the `#[must_use]` attribute, if any
1440 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1441 attr_by_name(attrs, "must_use")
1444 // Returns whether the type has #[must_use] attribute
1445 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1447 ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
1448 ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
1450 | ty::Array(ref ty, _)
1451 | ty::RawPtr(ty::TypeAndMut { ref ty, .. })
1452 | ty::Ref(_, ref ty, _) => {
1453 // for the Array case we don't need to care for the len == 0 case
1454 // because we don't want to lint functions returning empty arrays
1455 is_must_use_ty(cx, *ty)
1457 ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
1458 ty::Opaque(ref def_id, _) => {
1459 for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
1460 if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder() {
1461 if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
1468 ty::Dynamic(binder, _) => {
1469 for predicate in binder.iter() {
1470 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
1471 if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
1482 // check if expr is calling method or function with #[must_use] attribute
1483 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1484 let did = match expr.kind {
1485 ExprKind::Call(ref path, _) => if_chain! {
1486 if let ExprKind::Path(ref qpath) = path.kind;
1487 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1494 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1498 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1501 pub fn is_no_std_crate(krate: &Crate<'_>) -> bool {
1502 krate.item.attrs.iter().any(|attr| {
1503 if let ast::AttrKind::Normal(ref attr, _) = attr.kind {
1504 attr.path == sym::no_std
1511 /// Check if parent of a hir node is a trait implementation block.
1512 /// For example, `f` in
1514 /// impl Trait for S {
1518 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1519 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1520 matches!(item.kind, ItemKind::Impl(hir::Impl { of_trait: Some(_), .. }))
1526 /// Check if it's even possible to satisfy the `where` clause for the item.
1528 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1531 /// fn foo() where i32: Iterator {
1532 /// for _ in 2i32 {}
1535 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1536 use rustc_trait_selection::traits;
1542 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1543 traits::impossible_predicates(
1545 traits::elaborate_predicates(cx.tcx, predicates)
1546 .map(|o| o.predicate)
1547 .collect::<Vec<_>>(),
1551 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1552 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1554 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1557 kind: ExprKind::Path(qpath),
1561 ) => cx.typeck_results().qpath_res(qpath, expr.hir_id).opt_def_id(),
1566 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1567 lints.iter().any(|lint| {
1569 cx.tcx.lint_level_at_node(lint, id),
1570 (Level::Forbid | Level::Deny | Level::Warn, _)
1575 /// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
1576 /// number type, a str, or an array, slice, or tuple of those types).
1577 pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
1579 ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
1580 ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
1581 ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
1582 ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
1587 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1588 /// slice iff the given expression is a slice of primitives (as defined in the
1589 /// `is_recursively_primitive_type` function) and None otherwise.
1590 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1591 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1592 let expr_kind = expr_type.kind();
1593 let is_primitive = match expr_kind {
1594 ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1595 ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
1596 if let ty::Slice(element_type) = inner_ty.kind() {
1597 is_recursively_primitive_type(element_type)
1606 // if we have wrappers like Array, Slice or Tuple, print these
1607 // and get the type enclosed in the slice ref
1608 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1609 ty::Slice(..) => return Some("slice".into()),
1610 ty::Array(..) => return Some("array".into()),
1611 ty::Tuple(..) => return Some("tuple".into()),
1613 // is_recursively_primitive_type() should have taken care
1614 // of the rest and we can rely on the type that is found
1615 let refs_peeled = expr_type.peel_refs();
1616 return Some(refs_peeled.walk().last().unwrap().to_string());
1623 /// returns list of all pairs (a, b) from `exprs` such that `eq(a, b)`
1624 /// `hash` must be comformed with `eq`
1625 pub fn search_same<T, Hash, Eq>(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)>
1627 Hash: Fn(&T) -> u64,
1628 Eq: Fn(&T, &T) -> bool,
1630 if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) {
1631 return vec![(&exprs[0], &exprs[1])];
1634 let mut match_expr_list: Vec<(&T, &T)> = Vec::new();
1636 let mut map: FxHashMap<_, Vec<&_>> =
1637 FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default());
1640 match map.entry(hash(expr)) {
1641 Entry::Occupied(mut o) => {
1644 match_expr_list.push((o, expr));
1647 o.get_mut().push(expr);
1649 Entry::Vacant(v) => {
1650 v.insert(vec![expr]);
1659 macro_rules! unwrap_cargo_metadata {
1660 ($cx: ident, $lint: ident, $deps: expr) => {{
1661 let mut command = cargo_metadata::MetadataCommand::new();
1666 match command.exec() {
1667 Ok(metadata) => metadata,
1669 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1676 pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
1678 if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind;
1679 if let Res::Def(_, def_id) = path.res;
1681 cx.tcx.has_attr(def_id, sym::cfg) || cx.tcx.has_attr(def_id, sym::cfg_attr)
1690 use super::{reindent_multiline, without_block_comments};
1693 fn test_reindent_multiline_single_line() {
1694 assert_eq!("", reindent_multiline("".into(), false, None));
1695 assert_eq!("...", reindent_multiline("...".into(), false, None));
1696 assert_eq!("...", reindent_multiline(" ...".into(), false, None));
1697 assert_eq!("...", reindent_multiline("\t...".into(), false, None));
1698 assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
1703 fn test_reindent_multiline_block() {
1709 }", reindent_multiline(" if x {
1713 }".into(), false, None));
1719 }", reindent_multiline(" if x {
1723 }".into(), false, None));
1728 fn test_reindent_multiline_empty_line() {
1735 }", reindent_multiline(" if x {
1740 }".into(), false, None));
1745 fn test_reindent_multiline_lines_deeper() {
1751 }", reindent_multiline("\
1756 }".into(), true, Some(8)));
1760 fn test_without_block_comments_lines_without_block_comments() {
1761 let result = without_block_comments(vec!["/*", "", "*/"]);
1762 println!("result: {:?}", result);
1763 assert!(result.is_empty());
1765 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1766 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1768 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1769 assert!(result.is_empty());
1771 let result = without_block_comments(vec!["/* one-line comment */"]);
1772 assert!(result.is_empty());
1774 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1775 assert!(result.is_empty());
1777 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1778 assert!(result.is_empty());
1780 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1781 assert_eq!(result, vec!["foo", "bar", "baz"]);