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;
25 pub use self::attrs::*;
26 pub use self::diagnostics::*;
27 pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash};
32 use if_chain::if_chain;
33 use rustc_ast::ast::{self, Attribute, LitKind};
34 use rustc_attr as attr;
35 use rustc_errors::Applicability;
37 use rustc_hir::def::{DefKind, Res};
38 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
39 use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
42 def, Arm, Block, Body, Constness, Crate, Expr, ExprKind, FnDecl, HirId, ImplItem, ImplItemKind, Item, ItemKind,
43 MatchSource, Param, Pat, PatKind, Path, PathSegment, QPath, TraitItem, TraitItemKind, TraitRef, TyKind, Unsafety,
45 use rustc_infer::infer::TyCtxtInferExt;
46 use rustc_lint::{LateContext, Level, Lint, LintContext};
47 use rustc_middle::hir::map::Map;
48 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
49 use rustc_middle::ty::{self, layout::IntegerExt, Ty, TyCtxt, TypeFoldable};
50 use rustc_span::hygiene::{ExpnKind, MacroKind};
51 use rustc_span::source_map::original_sp;
52 use rustc_span::symbol::{self, kw, Symbol};
53 use rustc_span::{BytePos, Pos, Span, DUMMY_SP};
54 use rustc_target::abi::Integer;
55 use rustc_trait_selection::traits::query::normalize::AtExt;
56 use smallvec::SmallVec;
58 use crate::consts::{constant, Constant};
60 /// Returns `true` if the two spans come from differing expansions (i.e., one is
61 /// from a macro and one isn't).
63 pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
64 rhs.ctxt() != lhs.ctxt()
67 /// Returns `true` if the given `NodeId` is inside a constant context
72 /// if in_constant(cx, expr.hir_id) {
76 pub fn in_constant(cx: &LateContext<'_>, id: HirId) -> bool {
77 let parent_id = cx.tcx.hir().get_parent_item(id);
78 match cx.tcx.hir().get(parent_id) {
80 kind: ItemKind::Const(..) | ItemKind::Static(..),
83 | Node::TraitItem(&TraitItem {
84 kind: TraitItemKind::Const(..),
87 | Node::ImplItem(&ImplItem {
88 kind: ImplItemKind::Const(..),
91 | Node::AnonConst(_) => true,
93 kind: ItemKind::Fn(ref sig, ..),
96 | Node::ImplItem(&ImplItem {
97 kind: ImplItemKind::Fn(ref sig, _),
99 }) => sig.header.constness == Constness::Const,
104 /// Returns `true` if this `span` was expanded by any macro.
106 pub fn in_macro(span: Span) -> bool {
107 if span.from_expansion() {
108 !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
114 // If the snippet is empty, it's an attribute that was inserted during macro
115 // expansion and we want to ignore those, because they could come from external
116 // sources that the user has no control over.
117 // For some reason these attributes don't have any expansion info on them, so
118 // we have to check it this way until there is a better way.
119 pub fn is_present_in_source<T: LintContext>(cx: &T, span: Span) -> bool {
120 if let Some(snippet) = snippet_opt(cx, span) {
121 if snippet.is_empty() {
128 /// Checks if given pattern is a wildcard (`_`)
129 pub fn is_wild<'tcx>(pat: &impl std::ops::Deref<Target = Pat<'tcx>>) -> bool {
130 matches!(pat.kind, PatKind::Wild)
133 /// Checks if type is struct, enum or union type with the given def path.
135 /// If the type is a diagnostic item, use `is_type_diagnostic_item` instead.
136 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
137 pub fn match_type(cx: &LateContext<'_>, ty: Ty<'_>, path: &[&str]) -> bool {
139 ty::Adt(adt, _) => match_def_path(cx, adt.did, path),
144 /// Checks if the type is equal to a diagnostic item
146 /// If you change the signature, remember to update the internal lint `MatchTypeOnDiagItem`
147 pub fn is_type_diagnostic_item(cx: &LateContext<'_>, ty: Ty<'_>, diag_item: Symbol) -> bool {
149 ty::Adt(adt, _) => cx.tcx.is_diagnostic_item(diag_item, adt.did),
154 /// Checks if the type is equal to a lang item
155 pub fn is_type_lang_item(cx: &LateContext<'_>, ty: Ty<'_>, lang_item: hir::LangItem) -> bool {
157 ty::Adt(adt, _) => cx.tcx.lang_items().require(lang_item).unwrap() == adt.did,
162 /// Checks if the method call given in `expr` belongs to the given trait.
163 pub fn match_trait_method(cx: &LateContext<'_>, expr: &Expr<'_>, path: &[&str]) -> bool {
164 let def_id = cx.typeck_results().type_dependent_def_id(expr.hir_id).unwrap();
165 let trt_id = cx.tcx.trait_of_item(def_id);
166 trt_id.map_or(false, |trt_id| match_def_path(cx, trt_id, path))
169 /// Checks if an expression references a variable of the given name.
170 pub fn match_var(expr: &Expr<'_>, var: Symbol) -> bool {
171 if let ExprKind::Path(QPath::Resolved(None, ref path)) = expr.kind {
172 if let [p] = path.segments {
173 return p.ident.name == var;
179 pub fn last_path_segment<'tcx>(path: &QPath<'tcx>) -> &'tcx PathSegment<'tcx> {
181 QPath::Resolved(_, ref path) => path.segments.last().expect("A path must have at least one segment"),
182 QPath::TypeRelative(_, ref seg) => seg,
183 QPath::LangItem(..) => panic!("last_path_segment: lang item has no path segments"),
187 pub fn single_segment_path<'tcx>(path: &QPath<'tcx>) -> Option<&'tcx PathSegment<'tcx>> {
189 QPath::Resolved(_, ref path) => path.segments.get(0),
190 QPath::TypeRelative(_, ref seg) => Some(seg),
191 QPath::LangItem(..) => None,
195 /// Matches a `QPath` against a slice of segment string literals.
197 /// There is also `match_path` if you are dealing with a `rustc_hir::Path` instead of a
198 /// `rustc_hir::QPath`.
202 /// match_qpath(path, &["std", "rt", "begin_unwind"])
204 pub fn match_qpath(path: &QPath<'_>, segments: &[&str]) -> bool {
206 QPath::Resolved(_, ref path) => match_path(path, segments),
207 QPath::TypeRelative(ref ty, ref segment) => match ty.kind {
208 TyKind::Path(ref inner_path) => {
209 if let [prefix @ .., end] = segments {
210 if match_qpath(inner_path, prefix) {
211 return segment.ident.name.as_str() == *end;
218 QPath::LangItem(..) => false,
222 /// Matches a `Path` against a slice of segment string literals.
224 /// There is also `match_qpath` if you are dealing with a `rustc_hir::QPath` instead of a
225 /// `rustc_hir::Path`.
230 /// if match_path(&trait_ref.path, &paths::HASH) {
231 /// // This is the `std::hash::Hash` trait.
234 /// if match_path(ty_path, &["rustc", "lint", "Lint"]) {
235 /// // This is a `rustc_middle::lint::Lint`.
238 pub fn match_path(path: &Path<'_>, segments: &[&str]) -> bool {
242 .zip(segments.iter().rev())
243 .all(|(a, b)| a.ident.name.as_str() == *b)
246 /// Matches a `Path` against a slice of segment string literals, e.g.
250 /// match_path_ast(path, &["std", "rt", "begin_unwind"])
252 pub fn match_path_ast(path: &ast::Path, segments: &[&str]) -> bool {
256 .zip(segments.iter().rev())
257 .all(|(a, b)| a.ident.name.as_str() == *b)
260 /// Gets the definition associated to a path.
261 pub fn path_to_res(cx: &LateContext<'_>, path: &[&str]) -> Option<def::Res> {
262 let crates = cx.tcx.crates();
265 .find(|&&krate| cx.tcx.crate_name(krate).as_str() == path[0]);
266 if let Some(krate) = krate {
269 index: CRATE_DEF_INDEX,
271 let mut current_item = None;
272 let mut items = cx.tcx.item_children(krate);
273 let mut path_it = path.iter().skip(1).peekable();
276 let segment = match path_it.next() {
277 Some(segment) => segment,
281 // `get_def_path` seems to generate these empty segments for extern blocks.
282 // We can just ignore them.
283 if segment.is_empty() {
287 let result = SmallVec::<[_; 8]>::new();
288 for item in mem::replace(&mut items, cx.tcx.arena.alloc_slice(&result)).iter() {
289 if item.ident.name.as_str() == *segment {
290 if path_it.peek().is_none() {
291 return Some(item.res);
294 current_item = Some(item);
295 items = cx.tcx.item_children(item.res.def_id());
300 // The segment isn't a child_item.
301 // Try to find it under an inherent impl.
303 if path_it.peek().is_none();
304 if let Some(current_item) = current_item;
305 let item_def_id = current_item.res.def_id();
306 if cx.tcx.def_kind(item_def_id) == DefKind::Struct;
308 // Bad `find_map` suggestion. See #4193.
309 #[allow(clippy::find_map)]
310 return cx.tcx.inherent_impls(item_def_id).iter()
311 .flat_map(|&impl_def_id| cx.tcx.item_children(impl_def_id))
312 .find(|item| item.ident.name.as_str() == *segment)
313 .map(|item| item.res);
322 pub fn qpath_res(cx: &LateContext<'_>, qpath: &hir::QPath<'_>, id: hir::HirId) -> Res {
324 hir::QPath::Resolved(_, path) => path.res,
325 hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => {
326 if cx.tcx.has_typeck_results(id.owner.to_def_id()) {
327 cx.tcx.typeck(id.owner).qpath_res(qpath, id)
335 /// Convenience function to get the `DefId` of a trait by path.
336 /// It could be a trait or trait alias.
337 pub fn get_trait_def_id(cx: &LateContext<'_>, path: &[&str]) -> Option<DefId> {
338 let res = match path_to_res(cx, path) {
344 Res::Def(DefKind::Trait | DefKind::TraitAlias, trait_id) => Some(trait_id),
345 Res::Err => unreachable!("this trait resolution is impossible: {:?}", &path),
350 /// Checks whether a type implements a trait.
351 /// See also `get_trait_def_id`.
352 pub fn implements_trait<'tcx>(
353 cx: &LateContext<'tcx>,
356 ty_params: &[GenericArg<'tcx>],
358 // Do not check on infer_types to avoid panic in evaluate_obligation.
359 if ty.has_infer_types() {
362 let ty = cx.tcx.erase_regions(&ty);
363 let ty_params = cx.tcx.mk_substs(ty_params.iter());
364 cx.tcx.type_implements_trait((trait_id, ty, ty_params, cx.param_env))
367 /// Gets the `hir::TraitRef` of the trait the given method is implemented for.
369 /// Use this if you want to find the `TraitRef` of the `Add` trait in this example:
372 /// struct Point(isize, isize);
374 /// impl std::ops::Add for Point {
375 /// type Output = Self;
377 /// fn add(self, other: Self) -> Self {
382 pub fn trait_ref_of_method<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx TraitRef<'tcx>> {
383 // Get the implemented trait for the current function
384 let parent_impl = cx.tcx.hir().get_parent_item(hir_id);
386 if parent_impl != hir::CRATE_HIR_ID;
387 if let hir::Node::Item(item) = cx.tcx.hir().get(parent_impl);
388 if let hir::ItemKind::Impl{ of_trait: trait_ref, .. } = &item.kind;
389 then { return trait_ref.as_ref(); }
394 /// Checks whether this type implements `Drop`.
395 pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
396 match ty.ty_adt_def() {
397 Some(def) => def.has_dtor(cx.tcx),
402 /// Returns the method names and argument list of nested method call expressions that make up
403 /// `expr`. method/span lists are sorted with the most recent call first.
404 pub fn method_calls<'tcx>(
405 expr: &'tcx Expr<'tcx>,
407 ) -> (Vec<Symbol>, Vec<&'tcx [Expr<'tcx>]>, Vec<Span>) {
408 let mut method_names = Vec::with_capacity(max_depth);
409 let mut arg_lists = Vec::with_capacity(max_depth);
410 let mut spans = Vec::with_capacity(max_depth);
412 let mut current = expr;
413 for _ in 0..max_depth {
414 if let ExprKind::MethodCall(path, span, args, _) = ¤t.kind {
415 if args.iter().any(|e| e.span.from_expansion()) {
418 method_names.push(path.ident.name);
419 arg_lists.push(&**args);
427 (method_names, arg_lists, spans)
430 /// Matches an `Expr` against a chain of methods, and return the matched `Expr`s.
432 /// For example, if `expr` represents the `.baz()` in `foo.bar().baz()`,
433 /// `method_chain_args(expr, &["bar", "baz"])` will return a `Vec`
434 /// containing the `Expr`s for
435 /// `.bar()` and `.baz()`
436 pub fn method_chain_args<'a>(expr: &'a Expr<'_>, methods: &[&str]) -> Option<Vec<&'a [Expr<'a>]>> {
437 let mut current = expr;
438 let mut matched = Vec::with_capacity(methods.len());
439 for method_name in methods.iter().rev() {
440 // method chains are stored last -> first
441 if let ExprKind::MethodCall(ref path, _, ref args, _) = current.kind {
442 if path.ident.name.as_str() == *method_name {
443 if args.iter().any(|e| e.span.from_expansion()) {
446 matched.push(&**args); // build up `matched` backwards
447 current = &args[0] // go to parent expression
455 // Reverse `matched` so that it is in the same order as `methods`.
460 /// Returns `true` if the provided `def_id` is an entrypoint to a program.
461 pub fn is_entrypoint_fn(cx: &LateContext<'_>, def_id: DefId) -> bool {
463 .entry_fn(LOCAL_CRATE)
464 .map_or(false, |(entry_fn_def_id, _)| def_id == entry_fn_def_id.to_def_id())
467 /// Gets the name of the item the expression is in, if available.
468 pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
469 let parent_id = cx.tcx.hir().get_parent_item(expr.hir_id);
470 match cx.tcx.hir().find(parent_id) {
472 Node::Item(Item { ident, .. })
473 | Node::TraitItem(TraitItem { ident, .. })
474 | Node::ImplItem(ImplItem { ident, .. }),
475 ) => Some(ident.name),
480 /// Gets the name of a `Pat`, if any.
481 pub fn get_pat_name(pat: &Pat<'_>) -> Option<Symbol> {
483 PatKind::Binding(.., ref spname, _) => Some(spname.name),
484 PatKind::Path(ref qpath) => single_segment_path(qpath).map(|ps| ps.ident.name),
485 PatKind::Box(ref p) | PatKind::Ref(ref p, _) => get_pat_name(&*p),
490 struct ContainsName {
495 impl<'tcx> Visitor<'tcx> for ContainsName {
496 type Map = Map<'tcx>;
498 fn visit_name(&mut self, _: Span, name: Symbol) {
499 if self.name == name {
503 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
504 NestedVisitorMap::None
508 /// Checks if an `Expr` contains a certain name.
509 pub fn contains_name(name: Symbol, expr: &Expr<'_>) -> bool {
510 let mut cn = ContainsName { name, result: false };
515 /// Converts a span to a code snippet if available, otherwise use default.
517 /// This is useful if you want to provide suggestions for your lint or more generally, if you want
518 /// to convert a given `Span` to a `str`.
522 /// snippet(cx, expr.span, "..")
524 pub fn snippet<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
525 snippet_opt(cx, span).map_or_else(|| Cow::Borrowed(default), From::from)
528 /// Same as `snippet`, but it adapts the applicability level by following rules:
530 /// - Applicability level `Unspecified` will never be changed.
531 /// - If the span is inside a macro, change the applicability level to `MaybeIncorrect`.
532 /// - If the default value is used and the applicability level is `MachineApplicable`, change it to
533 /// `HasPlaceholders`
534 pub fn snippet_with_applicability<'a, T: LintContext>(
538 applicability: &mut Applicability,
540 if *applicability != Applicability::Unspecified && span.from_expansion() {
541 *applicability = Applicability::MaybeIncorrect;
543 snippet_opt(cx, span).map_or_else(
545 if *applicability == Applicability::MachineApplicable {
546 *applicability = Applicability::HasPlaceholders;
548 Cow::Borrowed(default)
554 /// Same as `snippet`, but should only be used when it's clear that the input span is
555 /// not a macro argument.
556 pub fn snippet_with_macro_callsite<'a, T: LintContext>(cx: &T, span: Span, default: &'a str) -> Cow<'a, str> {
557 snippet(cx, span.source_callsite(), default)
560 /// Converts a span to a code snippet. Returns `None` if not available.
561 pub fn snippet_opt<T: LintContext>(cx: &T, span: Span) -> Option<String> {
562 cx.sess().source_map().span_to_snippet(span).ok()
565 /// Converts a span (from a block) to a code snippet if available, otherwise use default.
567 /// This trims the code of indentation, except for the first line. Use it for blocks or block-like
568 /// things which need to be printed as such.
570 /// The `indent_relative_to` arg can be used, to provide a span, where the indentation of the
571 /// resulting snippet of the given span.
576 /// snippet_block(cx, block.span, "..", None)
577 /// // where, `block` is the block of the if expr
581 /// // will return the snippet
588 /// snippet_block(cx, block.span, "..", Some(if_expr.span))
589 /// // where, `block` is the block of the if expr
593 /// // will return the snippet
596 /// } // aligned with `if`
598 /// Note that the first line of the snippet always has 0 indentation.
599 pub fn snippet_block<'a, T: LintContext>(
603 indent_relative_to: Option<Span>,
605 let snip = snippet(cx, span, default);
606 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
607 reindent_multiline(snip, true, indent)
610 /// Same as `snippet_block`, but adapts the applicability level by the rules of
611 /// `snippet_with_applicability`.
612 pub fn snippet_block_with_applicability<'a, T: LintContext>(
616 indent_relative_to: Option<Span>,
617 applicability: &mut Applicability,
619 let snip = snippet_with_applicability(cx, span, default, applicability);
620 let indent = indent_relative_to.and_then(|s| indent_of(cx, s));
621 reindent_multiline(snip, true, indent)
624 /// Returns a new Span that extends the original Span to the first non-whitespace char of the first
630 /// // will be converted to
634 pub fn first_line_of_span<T: LintContext>(cx: &T, span: Span) -> Span {
635 first_char_in_first_line(cx, span).map_or(span, |first_char_pos| span.with_lo(first_char_pos))
638 fn first_char_in_first_line<T: LintContext>(cx: &T, span: Span) -> Option<BytePos> {
639 let line_span = line_span(cx, span);
640 snippet_opt(cx, line_span).and_then(|snip| {
641 snip.find(|c: char| !c.is_whitespace())
642 .map(|pos| line_span.lo() + BytePos::from_usize(pos))
646 /// Returns the indentation of the line of a span
650 /// // ^^ -- will return 0
652 /// // ^^ -- will return 4
654 pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
655 snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
658 /// Extends the span to the beginning of the spans line, incl. whitespaces.
663 /// // will be converted to
665 /// // ^^^^^^^^^^^^^^
667 fn line_span<T: LintContext>(cx: &T, span: Span) -> Span {
668 let span = original_sp(span, DUMMY_SP);
669 let source_map_and_line = cx.sess().source_map().lookup_line(span.lo()).unwrap();
670 let line_no = source_map_and_line.line;
671 let line_start = source_map_and_line.sf.lines[line_no];
672 Span::new(line_start, span.hi(), span.ctxt())
675 /// Like `snippet_block`, but add braces if the expr is not an `ExprKind::Block`.
676 /// Also takes an `Option<String>` which can be put inside the braces.
677 pub fn expr_block<'a, T: LintContext>(
680 option: Option<String>,
682 indent_relative_to: Option<Span>,
684 let code = snippet_block(cx, expr.span, default, indent_relative_to);
685 let string = option.unwrap_or_default();
686 if expr.span.from_expansion() {
687 Cow::Owned(format!("{{ {} }}", snippet_with_macro_callsite(cx, expr.span, default)))
688 } else if let ExprKind::Block(_, _) = expr.kind {
689 Cow::Owned(format!("{}{}", code, string))
690 } else if string.is_empty() {
691 Cow::Owned(format!("{{ {} }}", code))
693 Cow::Owned(format!("{{\n{};\n{}\n}}", code, string))
697 /// Reindent a multiline string with possibility of ignoring the first line.
698 #[allow(clippy::needless_pass_by_value)]
699 pub fn reindent_multiline(s: Cow<'_, str>, ignore_first: bool, indent: Option<usize>) -> Cow<'_, str> {
700 let s_space = reindent_multiline_inner(&s, ignore_first, indent, ' ');
701 let s_tab = reindent_multiline_inner(&s_space, ignore_first, indent, '\t');
702 reindent_multiline_inner(&s_tab, ignore_first, indent, ' ').into()
705 fn reindent_multiline_inner(s: &str, ignore_first: bool, indent: Option<usize>, ch: char) -> String {
708 .skip(ignore_first as usize)
713 // ignore empty lines
714 Some(l.char_indices().find(|&(_, x)| x != ch).unwrap_or((l.len(), ch)).0)
719 let indent = indent.unwrap_or(0);
723 if (ignore_first && i == 0) || l.is_empty() {
725 } else if x > indent {
726 l.split_at(x - indent).1.to_owned()
728 " ".repeat(indent - x) + l
731 .collect::<Vec<String>>()
735 /// Gets the parent expression, if any –- this is useful to constrain a lint.
736 pub fn get_parent_expr<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
737 let map = &cx.tcx.hir();
738 let hir_id = e.hir_id;
739 let parent_id = map.get_parent_node(hir_id);
740 if hir_id == parent_id {
743 map.find(parent_id).and_then(|node| {
744 if let Node::Expr(parent) = node {
752 pub fn get_enclosing_block<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Block<'tcx>> {
753 let map = &cx.tcx.hir();
754 let enclosing_node = map
755 .get_enclosing_scope(hir_id)
756 .and_then(|enclosing_id| map.find(enclosing_id));
757 enclosing_node.and_then(|node| match node {
758 Node::Block(block) => Some(block),
760 kind: ItemKind::Fn(_, _, eid),
763 | Node::ImplItem(&ImplItem {
764 kind: ImplItemKind::Fn(_, eid),
766 }) => match cx.tcx.hir().body(eid).value.kind {
767 ExprKind::Block(ref block, _) => Some(block),
774 /// Returns the base type for HIR references and pointers.
775 pub fn walk_ptrs_hir_ty<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
777 TyKind::Ptr(ref mut_ty) | TyKind::Rptr(_, ref mut_ty) => walk_ptrs_hir_ty(&mut_ty.ty),
782 /// Returns the base type for references and raw pointers, and count reference
784 pub fn walk_ptrs_ty_depth(ty: Ty<'_>) -> (Ty<'_>, usize) {
785 fn inner(ty: Ty<'_>, depth: usize) -> (Ty<'_>, usize) {
787 ty::Ref(_, ty, _) => inner(ty, depth + 1),
794 /// Checks whether the given expression is a constant integer of the given value.
795 /// unlike `is_integer_literal`, this version does const folding
796 pub fn is_integer_const(cx: &LateContext<'_>, e: &Expr<'_>, value: u128) -> bool {
797 if is_integer_literal(e, value) {
800 let map = cx.tcx.hir();
801 let parent_item = map.get_parent_item(e.hir_id);
802 if let Some((Constant::Int(v), _)) = map
803 .maybe_body_owned_by(parent_item)
804 .and_then(|body_id| constant(cx, cx.tcx.typeck_body(body_id), e))
812 /// Checks whether the given expression is a constant literal of the given value.
813 pub fn is_integer_literal(expr: &Expr<'_>, value: u128) -> bool {
814 // FIXME: use constant folding
815 if let ExprKind::Lit(ref spanned) = expr.kind {
816 if let LitKind::Int(v, _) = spanned.node {
823 /// Returns `true` if the given `Expr` has been coerced before.
825 /// Examples of coercions can be found in the Nomicon at
826 /// <https://doc.rust-lang.org/nomicon/coercions.html>.
828 /// See `rustc_middle::ty::adjustment::Adjustment` and `rustc_typeck::check::coercion` for more
829 /// information on adjustments and coercions.
830 pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
831 cx.typeck_results().adjustments().get(e.hir_id).is_some()
834 /// Returns the pre-expansion span if is this comes from an expansion of the
836 /// See also `is_direct_expn_of`.
838 pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
840 if span.from_expansion() {
841 let data = span.ctxt().outer_expn_data();
842 let new_span = data.call_site;
844 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
845 if mac_name.as_str() == name {
846 return Some(new_span);
857 /// Returns the pre-expansion span if the span directly comes from an expansion
858 /// of the macro `name`.
859 /// The difference with `is_expn_of` is that in
863 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
865 /// `is_direct_expn_of`.
867 pub fn is_direct_expn_of(span: Span, name: &str) -> Option<Span> {
868 if span.from_expansion() {
869 let data = span.ctxt().outer_expn_data();
870 let new_span = data.call_site;
872 if let ExpnKind::Macro(MacroKind::Bang, mac_name) = data.kind {
873 if mac_name.as_str() == name {
874 return Some(new_span);
882 /// Convenience function to get the return type of a function.
883 pub fn return_ty<'tcx>(cx: &LateContext<'tcx>, fn_item: hir::HirId) -> Ty<'tcx> {
884 let fn_def_id = cx.tcx.hir().local_def_id(fn_item);
885 let ret_ty = cx.tcx.fn_sig(fn_def_id).output();
886 cx.tcx.erase_late_bound_regions(&ret_ty)
889 /// Walks into `ty` and returns `true` if any inner type is the same as `other_ty`
890 pub fn contains_ty(ty: Ty<'_>, other_ty: Ty<'_>) -> bool {
891 ty.walk().any(|inner| match inner.unpack() {
892 GenericArgKind::Type(inner_ty) => ty::TyS::same_type(other_ty, inner_ty),
893 GenericArgKind::Lifetime(_) | GenericArgKind::Const(_) => false,
897 /// Returns `true` if the given type is an `unsafe` function.
898 pub fn type_is_unsafe_function<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
900 ty::FnDef(..) | ty::FnPtr(_) => ty.fn_sig(cx.tcx).unsafety() == Unsafety::Unsafe,
905 pub fn is_copy<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
906 ty.is_copy_modulo_regions(cx.tcx.at(DUMMY_SP), cx.param_env)
909 /// Checks if an expression is constructing a tuple-like enum variant or struct
910 pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
911 if let ExprKind::Call(ref fun, _) = expr.kind {
912 if let ExprKind::Path(ref qp) = fun.kind {
913 let res = cx.qpath_res(qp, fun.hir_id);
915 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
916 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),
924 /// Returns `true` if a pattern is refutable.
925 // TODO: should be implemented using rustc/mir_build/thir machinery
926 pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
927 fn is_enum_variant(cx: &LateContext<'_>, qpath: &QPath<'_>, id: HirId) -> bool {
929 cx.qpath_res(qpath, id),
930 def::Res::Def(DefKind::Variant, ..) | Res::Def(DefKind::Ctor(def::CtorOf::Variant, _), _)
934 fn are_refutable<'a, I: Iterator<Item = &'a Pat<'a>>>(cx: &LateContext<'_>, mut i: I) -> bool {
935 i.any(|pat| is_refutable(cx, pat))
939 PatKind::Wild => false,
940 PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
941 PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => is_refutable(cx, pat),
942 PatKind::Lit(..) | PatKind::Range(..) => true,
943 PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
944 PatKind::Or(ref pats) => {
945 // TODO: should be the honest check, that pats is exhaustive set
946 are_refutable(cx, pats.iter().map(|pat| &**pat))
948 PatKind::Tuple(ref pats, _) => are_refutable(cx, pats.iter().map(|pat| &**pat)),
949 PatKind::Struct(ref qpath, ref fields, _) => {
950 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, fields.iter().map(|field| &*field.pat))
952 PatKind::TupleStruct(ref qpath, ref pats, _) => {
953 is_enum_variant(cx, qpath, pat.hir_id) || are_refutable(cx, pats.iter().map(|pat| &**pat))
955 PatKind::Slice(ref head, ref middle, ref tail) => {
956 match &cx.typeck_results().node_type(pat.hir_id).kind() {
958 // [..] is the only irrefutable slice pattern.
959 !head.is_empty() || middle.is_none() || !tail.is_empty()
961 ty::Array(..) => are_refutable(cx, head.iter().chain(middle).chain(tail.iter()).map(|pat| &**pat)),
971 /// Checks for the `#[automatically_derived]` attribute all `#[derive]`d
972 /// implementations have.
973 pub fn is_automatically_derived(attrs: &[ast::Attribute]) -> bool {
974 attrs.iter().any(|attr| attr.has_name(sym!(automatically_derived)))
977 /// Remove blocks around an expression.
979 /// Ie. `x`, `{ x }` and `{{{{ x }}}}` all give `x`. `{ x; y }` and `{}` return
981 pub fn remove_blocks<'tcx>(mut expr: &'tcx Expr<'tcx>) -> &'tcx Expr<'tcx> {
982 while let ExprKind::Block(ref block, ..) = expr.kind {
983 match (block.stmts.is_empty(), block.expr.as_ref()) {
984 (true, Some(e)) => expr = e,
991 pub fn is_self(slf: &Param<'_>) -> bool {
992 if let PatKind::Binding(.., name, _) = slf.pat.kind {
993 name.name == kw::SelfLower
999 pub fn is_self_ty(slf: &hir::Ty<'_>) -> bool {
1001 if let TyKind::Path(ref qp) = slf.kind;
1002 if let QPath::Resolved(None, ref path) = *qp;
1003 if let Res::SelfTy(..) = path.res;
1011 pub fn iter_input_pats<'tcx>(decl: &FnDecl<'_>, body: &'tcx Body<'_>) -> impl Iterator<Item = &'tcx Param<'tcx>> {
1012 (0..decl.inputs.len()).map(move |i| &body.params[i])
1015 /// Checks if a given expression is a match expression expanded from the `?`
1016 /// operator or the `try` macro.
1017 pub fn is_try<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
1018 fn is_ok(arm: &Arm<'_>) -> bool {
1020 if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pat.kind;
1021 if match_qpath(path, &paths::RESULT_OK[1..]);
1022 if let PatKind::Binding(_, hir_id, _, None) = pat[0].kind;
1023 if let ExprKind::Path(QPath::Resolved(None, ref path)) = arm.body.kind;
1024 if let Res::Local(lid) = path.res;
1033 fn is_err(arm: &Arm<'_>) -> bool {
1034 if let PatKind::TupleStruct(ref path, _, _) = arm.pat.kind {
1035 match_qpath(path, &paths::RESULT_ERR[1..])
1041 if let ExprKind::Match(_, ref arms, ref source) = expr.kind {
1042 // desugared from a `?` operator
1043 if let MatchSource::TryDesugar = *source {
1049 if arms[0].guard.is_none();
1050 if arms[1].guard.is_none();
1051 if (is_ok(&arms[0]) && is_err(&arms[1])) ||
1052 (is_ok(&arms[1]) && is_err(&arms[0]));
1062 /// Returns `true` if the lint is allowed in the current context
1064 /// Useful for skipping long running code when it's unnecessary
1065 pub fn is_allowed(cx: &LateContext<'_>, lint: &'static Lint, id: HirId) -> bool {
1066 cx.tcx.lint_level_at_node(lint, id).0 == Level::Allow
1069 pub fn get_arg_name(pat: &Pat<'_>) -> Option<Symbol> {
1071 PatKind::Binding(.., ident, None) => Some(ident.name),
1072 PatKind::Ref(ref subpat, _) => get_arg_name(subpat),
1077 pub fn int_bits(tcx: TyCtxt<'_>, ity: ast::IntTy) -> u64 {
1078 Integer::from_attr(&tcx, attr::IntType::SignedInt(ity)).size().bits()
1081 #[allow(clippy::cast_possible_wrap)]
1082 /// Turn a constant int byte representation into an i128
1083 pub fn sext(tcx: TyCtxt<'_>, u: u128, ity: ast::IntTy) -> i128 {
1084 let amt = 128 - int_bits(tcx, ity);
1085 ((u as i128) << amt) >> amt
1088 #[allow(clippy::cast_sign_loss)]
1089 /// clip unused bytes
1090 pub fn unsext(tcx: TyCtxt<'_>, u: i128, ity: ast::IntTy) -> u128 {
1091 let amt = 128 - int_bits(tcx, ity);
1092 ((u as u128) << amt) >> amt
1095 /// clip unused bytes
1096 pub fn clip(tcx: TyCtxt<'_>, u: u128, ity: ast::UintTy) -> u128 {
1097 let bits = Integer::from_attr(&tcx, attr::IntType::UnsignedInt(ity)).size().bits();
1098 let amt = 128 - bits;
1102 /// Removes block comments from the given `Vec` of lines.
1107 /// without_block_comments(vec!["/*", "foo", "*/"]);
1110 /// without_block_comments(vec!["bar", "/*", "foo", "*/"]);
1111 /// // => vec!["bar"]
1113 pub fn without_block_comments(lines: Vec<&str>) -> Vec<&str> {
1114 let mut without = vec![];
1116 let mut nest_level = 0;
1119 if line.contains("/*") {
1122 } else if line.contains("*/") {
1127 if nest_level == 0 {
1135 pub fn any_parent_is_automatically_derived(tcx: TyCtxt<'_>, node: HirId) -> bool {
1136 let map = &tcx.hir();
1137 let mut prev_enclosing_node = None;
1138 let mut enclosing_node = node;
1139 while Some(enclosing_node) != prev_enclosing_node {
1140 if is_automatically_derived(map.attrs(enclosing_node)) {
1143 prev_enclosing_node = Some(enclosing_node);
1144 enclosing_node = map.get_parent_item(enclosing_node);
1149 /// Returns true if ty has `iter` or `iter_mut` methods
1150 pub fn has_iter_method(cx: &LateContext<'_>, probably_ref_ty: Ty<'_>) -> Option<&'static str> {
1151 // FIXME: instead of this hard-coded list, we should check if `<adt>::iter`
1152 // exists and has the desired signature. Unfortunately FnCtxt is not exported
1153 // so we can't use its `lookup_method` method.
1154 let into_iter_collections: [&[&str]; 13] = [
1161 &paths::LINKED_LIST,
1162 &paths::BINARY_HEAP,
1170 let ty_to_check = match probably_ref_ty.kind() {
1171 ty::Ref(_, ty_to_check, _) => ty_to_check,
1172 _ => probably_ref_ty,
1175 let def_id = match ty_to_check.kind() {
1176 ty::Array(..) => return Some("array"),
1177 ty::Slice(..) => return Some("slice"),
1178 ty::Adt(adt, _) => adt.did,
1182 for path in &into_iter_collections {
1183 if match_def_path(cx, def_id, path) {
1184 return Some(*path.last().unwrap());
1190 /// Matches a function call with the given path and returns the arguments.
1195 /// if let Some(args) = match_function_call(cx, begin_panic_call, &paths::BEGIN_PANIC);
1197 pub fn match_function_call<'tcx>(
1198 cx: &LateContext<'tcx>,
1199 expr: &'tcx Expr<'_>,
1201 ) -> Option<&'tcx [Expr<'tcx>]> {
1203 if let ExprKind::Call(ref fun, ref args) = expr.kind;
1204 if let ExprKind::Path(ref qpath) = fun.kind;
1205 if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
1206 if match_def_path(cx, fun_def_id, path);
1214 /// Checks if `Ty` is normalizable. This function is useful
1215 /// to avoid crashes on `layout_of`.
1216 pub fn is_normalizable<'tcx>(cx: &LateContext<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> bool {
1217 cx.tcx.infer_ctxt().enter(|infcx| {
1218 let cause = rustc_middle::traits::ObligationCause::dummy();
1219 infcx.at(&cause, param_env).normalize(&ty).is_ok()
1223 pub fn match_def_path<'tcx>(cx: &LateContext<'tcx>, did: DefId, syms: &[&str]) -> bool {
1224 // We have to convert `syms` to `&[Symbol]` here because rustc's `match_def_path`
1225 // accepts only that. We should probably move to Symbols in Clippy as well.
1226 let syms = syms.iter().map(|p| Symbol::intern(p)).collect::<Vec<Symbol>>();
1227 cx.match_def_path(did, &syms)
1230 /// Returns the list of condition expressions and the list of blocks in a
1231 /// sequence of `if/else`.
1232 /// E.g., this returns `([a, b], [c, d, e])` for the expression
1233 /// `if a { c } else if b { d } else { e }`.
1234 pub fn if_sequence<'tcx>(
1235 mut expr: &'tcx Expr<'tcx>,
1236 ) -> (SmallVec<[&'tcx Expr<'tcx>; 1]>, SmallVec<[&'tcx Block<'tcx>; 1]>) {
1237 let mut conds = SmallVec::new();
1238 let mut blocks: SmallVec<[&Block<'_>; 1]> = SmallVec::new();
1240 while let Some((ref cond, ref then_expr, ref else_expr)) = higher::if_block(&expr) {
1241 conds.push(&**cond);
1242 if let ExprKind::Block(ref block, _) = then_expr.kind {
1245 panic!("ExprKind::If node is not an ExprKind::Block");
1248 if let Some(ref else_expr) = *else_expr {
1255 // final `else {..}`
1256 if !blocks.is_empty() {
1257 if let ExprKind::Block(ref block, _) = expr.kind {
1258 blocks.push(&**block);
1265 pub fn parent_node_is_if_expr(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool {
1266 let map = cx.tcx.hir();
1267 let parent_id = map.get_parent_node(expr.hir_id);
1268 let parent_node = map.get(parent_id);
1271 Node::Expr(e) => higher::if_block(&e).is_some(),
1272 Node::Arm(e) => higher::if_block(&e.body).is_some(),
1277 // Finds the attribute with the given name, if any
1278 pub fn attr_by_name<'a>(attrs: &'a [Attribute], name: &'_ str) -> Option<&'a Attribute> {
1281 .find(|attr| attr.ident().map_or(false, |ident| ident.as_str() == name))
1284 // Finds the `#[must_use]` attribute, if any
1285 pub fn must_use_attr(attrs: &[Attribute]) -> Option<&Attribute> {
1286 attr_by_name(attrs, "must_use")
1289 // Returns whether the type has #[must_use] attribute
1290 pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
1292 ty::Adt(ref adt, _) => must_use_attr(&cx.tcx.get_attrs(adt.did)).is_some(),
1293 ty::Foreign(ref did) => must_use_attr(&cx.tcx.get_attrs(*did)).is_some(),
1295 | ty::Array(ref ty, _)
1296 | ty::RawPtr(ty::TypeAndMut { ref ty, .. })
1297 | ty::Ref(_, ref ty, _) => {
1298 // for the Array case we don't need to care for the len == 0 case
1299 // because we don't want to lint functions returning empty arrays
1300 is_must_use_ty(cx, *ty)
1302 ty::Tuple(ref substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
1303 ty::Opaque(ref def_id, _) => {
1304 for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
1305 if let ty::PredicateAtom::Trait(trait_predicate, _) = predicate.skip_binders() {
1306 if must_use_attr(&cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
1313 ty::Dynamic(binder, _) => {
1314 for predicate in binder.skip_binder().iter() {
1315 if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate {
1316 if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
1327 // check if expr is calling method or function with #[must_use] attribute
1328 pub fn is_must_use_func_call(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
1329 let did = match expr.kind {
1330 ExprKind::Call(ref path, _) => if_chain! {
1331 if let ExprKind::Path(ref qpath) = path.kind;
1332 if let def::Res::Def(_, did) = cx.qpath_res(qpath, path.hir_id);
1339 ExprKind::MethodCall(_, _, _, _) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1343 did.map_or(false, |did| must_use_attr(&cx.tcx.get_attrs(did)).is_some())
1346 pub fn is_no_std_crate(krate: &Crate<'_>) -> bool {
1347 krate.item.attrs.iter().any(|attr| {
1348 if let ast::AttrKind::Normal(ref attr) = attr.kind {
1349 attr.path == symbol::sym::no_std
1356 /// Check if parent of a hir node is a trait implementation block.
1357 /// For example, `f` in
1359 /// impl Trait for S {
1363 pub fn is_trait_impl_item(cx: &LateContext<'_>, hir_id: HirId) -> bool {
1364 if let Some(Node::Item(item)) = cx.tcx.hir().find(cx.tcx.hir().get_parent_node(hir_id)) {
1365 matches!(item.kind, ItemKind::Impl{ of_trait: Some(_), .. })
1371 /// Check if it's even possible to satisfy the `where` clause for the item.
1373 /// `trivial_bounds` feature allows functions with unsatisfiable bounds, for example:
1376 /// fn foo() where i32: Iterator {
1377 /// for _ in 2i32 {}
1380 pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
1381 use rustc_trait_selection::traits;
1387 .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
1388 traits::impossible_predicates(
1390 traits::elaborate_predicates(cx.tcx, predicates)
1391 .map(|o| o.predicate)
1392 .collect::<Vec<_>>(),
1396 /// Returns the `DefId` of the callee if the given expression is a function or method call.
1397 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
1399 ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
1402 kind: ExprKind::Path(qpath),
1406 ) => cx.typeck_results().qpath_res(qpath, expr.hir_id).opt_def_id(),
1411 pub fn run_lints(cx: &LateContext<'_>, lints: &[&'static Lint], id: HirId) -> bool {
1412 lints.iter().any(|lint| {
1414 cx.tcx.lint_level_at_node(lint, id),
1415 (Level::Forbid | Level::Deny | Level::Warn, _)
1420 /// Returns true iff the given type is a primitive (a bool or char, any integer or floating-point
1421 /// number type, a str, or an array, slice, or tuple of those types).
1422 pub fn is_recursively_primitive_type(ty: Ty<'_>) -> bool {
1424 ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Str => true,
1425 ty::Ref(_, inner, _) if *inner.kind() == ty::Str => true,
1426 ty::Array(inner_type, _) | ty::Slice(inner_type) => is_recursively_primitive_type(inner_type),
1427 ty::Tuple(inner_types) => inner_types.types().all(is_recursively_primitive_type),
1432 /// Returns Option<String> where String is a textual representation of the type encapsulated in the
1433 /// slice iff the given expression is a slice of primitives (as defined in the
1434 /// `is_recursively_primitive_type` function) and None otherwise.
1435 pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
1436 let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
1437 let expr_kind = expr_type.kind();
1438 let is_primitive = match expr_kind {
1439 ty::Slice(element_type) => is_recursively_primitive_type(element_type),
1440 ty::Ref(_, inner_ty, _) if matches!(inner_ty.kind(), &ty::Slice(_)) => {
1441 if let ty::Slice(element_type) = inner_ty.kind() {
1442 is_recursively_primitive_type(element_type)
1451 // if we have wrappers like Array, Slice or Tuple, print these
1452 // and get the type enclosed in the slice ref
1453 match expr_type.peel_refs().walk().nth(1).unwrap().expect_ty().kind() {
1454 ty::Slice(..) => return Some("slice".into()),
1455 ty::Array(..) => return Some("array".into()),
1456 ty::Tuple(..) => return Some("tuple".into()),
1458 // is_recursively_primitive_type() should have taken care
1459 // of the rest and we can rely on the type that is found
1460 let refs_peeled = expr_type.peel_refs();
1461 return Some(refs_peeled.walk().last().unwrap().to_string());
1469 macro_rules! unwrap_cargo_metadata {
1470 ($cx: ident, $lint: ident, $deps: expr) => {{
1471 let mut command = cargo_metadata::MetadataCommand::new();
1476 match command.exec() {
1477 Ok(metadata) => metadata,
1479 span_lint($cx, $lint, DUMMY_SP, &format!("could not read cargo metadata: {}", err));
1488 use super::{reindent_multiline, without_block_comments};
1491 fn test_reindent_multiline_single_line() {
1492 assert_eq!("", reindent_multiline("".into(), false, None));
1493 assert_eq!("...", reindent_multiline("...".into(), false, None));
1494 assert_eq!("...", reindent_multiline(" ...".into(), false, None));
1495 assert_eq!("...", reindent_multiline("\t...".into(), false, None));
1496 assert_eq!("...", reindent_multiline("\t\t...".into(), false, None));
1501 fn test_reindent_multiline_block() {
1507 }", reindent_multiline(" if x {
1511 }".into(), false, None));
1517 }", reindent_multiline(" if x {
1521 }".into(), false, None));
1526 fn test_reindent_multiline_empty_line() {
1533 }", reindent_multiline(" if x {
1538 }".into(), false, None));
1543 fn test_reindent_multiline_lines_deeper() {
1549 }", reindent_multiline("\
1554 }".into(), true, Some(8)));
1558 fn test_without_block_comments_lines_without_block_comments() {
1559 let result = without_block_comments(vec!["/*", "", "*/"]);
1560 println!("result: {:?}", result);
1561 assert!(result.is_empty());
1563 let result = without_block_comments(vec!["", "/*", "", "*/", "#[crate_type = \"lib\"]", "/*", "", "*/", ""]);
1564 assert_eq!(result, vec!["", "#[crate_type = \"lib\"]", ""]);
1566 let result = without_block_comments(vec!["/* rust", "", "*/"]);
1567 assert!(result.is_empty());
1569 let result = without_block_comments(vec!["/* one-line comment */"]);
1570 assert!(result.is_empty());
1572 let result = without_block_comments(vec!["/* nested", "/* multi-line", "comment", "*/", "test", "*/"]);
1573 assert!(result.is_empty());
1575 let result = without_block_comments(vec!["/* nested /* inline /* comment */ test */ */"]);
1576 assert!(result.is_empty());
1578 let result = without_block_comments(vec!["foo", "bar", "baz"]);
1579 assert_eq!(result, vec!["foo", "bar", "baz"]);