1 use crate::consts::{constant, miri_to_const, Constant};
2 use crate::utils::paths;
3 use crate::utils::sugg::Sugg;
4 use crate::utils::usage::is_unused;
6 expr_block, is_allowed, is_expn_of, is_wild, match_qpath, match_type, multispan_sugg, remove_blocks, snippet,
7 snippet_with_applicability, span_lint_and_help, span_lint_and_sugg, span_lint_and_then, span_note_and_lint,
10 use if_chain::if_chain;
11 use rustc::lint::in_external_macro;
12 use rustc::ty::{self, Ty};
13 use rustc_errors::Applicability;
14 use rustc_hir::def::CtorKind;
16 use rustc_lint::{LateContext, LateLintPass, LintContext};
17 use rustc_session::{declare_lint_pass, declare_tool_lint};
18 use rustc_span::source_map::Span;
19 use std::cmp::Ordering;
20 use std::collections::Bound;
21 use syntax::ast::LitKind;
23 declare_clippy_lint! {
24 /// **What it does:** Checks for matches with a single arm where an `if let`
25 /// will usually suffice.
27 /// **Why is this bad?** Just readability – `if let` nests less than a `match`.
29 /// **Known problems:** None.
33 /// # fn bar(stool: &str) {}
34 /// # let x = Some("abc");
36 /// Some(ref foo) => bar(foo),
42 "a `match` statement with a single nontrivial arm (i.e., where the other arm is `_ => {}`) instead of `if let`"
45 declare_clippy_lint! {
46 /// **What it does:** Checks for matches with two arms where an `if let else` will
49 /// **Why is this bad?** Just readability – `if let` nests less than a `match`.
51 /// **Known problems:** Personal style preferences may differ.
58 /// # fn bar(foo: &usize) {}
59 /// # let other_ref: usize = 1;
60 /// # let x: Option<&usize> = Some(&1);
62 /// Some(ref foo) => bar(foo),
63 /// _ => bar(&other_ref),
67 /// Using `if let` with `else`:
70 /// # fn bar(foo: &usize) {}
71 /// # let other_ref: usize = 1;
72 /// # let x: Option<&usize> = Some(&1);
73 /// if let Some(ref foo) = x {
79 pub SINGLE_MATCH_ELSE,
81 "a `match` statement with two arms where the second arm's pattern is a placeholder instead of a specific match pattern"
84 declare_clippy_lint! {
85 /// **What it does:** Checks for matches where all arms match a reference,
86 /// suggesting to remove the reference and deref the matched expression
87 /// instead. It also checks for `if let &foo = bar` blocks.
89 /// **Why is this bad?** It just makes the code less readable. That reference
90 /// destructuring adds nothing to the code.
92 /// **Known problems:** None.
97 /// &A(ref y) => foo(y),
104 "a `match` or `if let` with all arms prefixed with `&` instead of deref-ing the match expression"
107 declare_clippy_lint! {
108 /// **What it does:** Checks for matches where match expression is a `bool`. It
109 /// suggests to replace the expression with an `if...else` block.
111 /// **Why is this bad?** It makes the code less readable.
113 /// **Known problems:** None.
119 /// let condition: bool = true;
120 /// match condition {
125 /// Use if/else instead:
129 /// let condition: bool = true;
138 "a `match` on a boolean expression instead of an `if..else` block"
141 declare_clippy_lint! {
142 /// **What it does:** Checks for overlapping match arms.
144 /// **Why is this bad?** It is likely to be an error and if not, makes the code
147 /// **Known problems:** None.
153 /// 1...10 => println!("1 ... 10"),
154 /// 5...15 => println!("5 ... 15"),
158 pub MATCH_OVERLAPPING_ARM,
160 "a `match` with overlapping arms"
163 declare_clippy_lint! {
164 /// **What it does:** Checks for arm which matches all errors with `Err(_)`
165 /// and take drastic actions like `panic!`.
167 /// **Why is this bad?** It is generally a bad practice, just like
168 /// catching all exceptions in java with `catch(Exception)`
170 /// **Known problems:** None.
174 /// let x: Result<i32, &str> = Ok(3);
176 /// Ok(_) => println!("ok"),
177 /// Err(_) => panic!("err"),
180 pub MATCH_WILD_ERR_ARM,
182 "a `match` with `Err(_)` arm and take drastic actions"
185 declare_clippy_lint! {
186 /// **What it does:** Checks for match which is used to add a reference to an
189 /// **Why is this bad?** Using `as_ref()` or `as_mut()` instead is shorter.
191 /// **Known problems:** None.
195 /// let x: Option<()> = None;
196 /// let r: Option<&()> = match x {
198 /// Some(ref v) => Some(v),
203 "a `match` on an Option value instead of using `as_ref()` or `as_mut`"
206 declare_clippy_lint! {
207 /// **What it does:** Checks for wildcard enum matches using `_`.
209 /// **Why is this bad?** New enum variants added by library updates can be missed.
211 /// **Known problems:** Suggested replacements may be incorrect if guards exhaustively cover some
212 /// variants, and also may not use correct path to enum if it's not present in the current scope.
216 /// # enum Foo { A(usize), B(usize) }
217 /// # let x = Foo::B(1);
223 pub WILDCARD_ENUM_MATCH_ARM,
225 "a wildcard enum match arm using `_`"
228 declare_clippy_lint! {
229 /// **What it does:** Checks for wildcard pattern used with others patterns in same match arm.
231 /// **Why is this bad?** Wildcard pattern already covers any other pattern as it will match anyway.
232 /// It makes the code less readable, especially to spot wildcard pattern use in match arm.
234 /// **Known problems:** None.
243 pub WILDCARD_IN_OR_PATTERNS,
245 "a wildcard pattern used with others patterns in same match arm"
248 declare_lint_pass!(Matches => [
253 MATCH_OVERLAPPING_ARM,
256 WILDCARD_ENUM_MATCH_ARM,
257 WILDCARD_IN_OR_PATTERNS
260 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Matches {
261 fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
262 if in_external_macro(cx.sess(), expr.span) {
265 if let ExprKind::Match(ref ex, ref arms, MatchSource::Normal) = expr.kind {
266 check_single_match(cx, ex, arms, expr);
267 check_match_bool(cx, ex, arms, expr);
268 check_overlapping_arms(cx, ex, arms);
269 check_wild_err_arm(cx, ex, arms);
270 check_wild_enum_match(cx, ex, arms);
271 check_match_as_ref(cx, ex, arms, expr);
272 check_wild_in_or_pats(cx, arms);
274 if let ExprKind::Match(ref ex, ref arms, _) = expr.kind {
275 check_match_ref_pats(cx, ex, arms, expr);
281 fn check_single_match(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
282 if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
283 if let PatKind::Or(..) = arms[0].pat.kind {
284 // don't lint for or patterns for now, this makes
285 // the lint noisy in unnecessary situations
288 let els = remove_blocks(&arms[1].body);
289 let els = if is_unit_expr(els) {
291 } else if let ExprKind::Block(_, _) = els.kind {
292 // matches with blocks that contain statements are prettier as `if let + else`
295 // allow match arms with just expressions
298 let ty = cx.tables.expr_ty(ex);
299 if ty.kind != ty::Bool || is_allowed(cx, MATCH_BOOL, ex.hir_id) {
300 check_single_match_single_pattern(cx, ex, arms, expr, els);
301 check_single_match_opt_like(cx, ex, arms, expr, ty, els);
306 fn check_single_match_single_pattern(
307 cx: &LateContext<'_, '_>,
311 els: Option<&Expr<'_>>,
313 if is_wild(&arms[1].pat) {
314 report_single_match_single_pattern(cx, ex, arms, expr, els);
318 fn report_single_match_single_pattern(
319 cx: &LateContext<'_, '_>,
323 els: Option<&Expr<'_>>,
325 let lint = if els.is_some() { SINGLE_MATCH_ELSE } else { SINGLE_MATCH };
326 let els_str = els.map_or(String::new(), |els| {
327 format!(" else {}", expr_block(cx, els, None, ".."))
333 "you seem to be trying to use match for destructuring a single pattern. Consider using `if \
337 "if let {} = {} {}{}",
338 snippet(cx, arms[0].pat.span, ".."),
339 snippet(cx, ex.span, ".."),
340 expr_block(cx, &arms[0].body, None, ".."),
343 Applicability::HasPlaceholders,
347 fn check_single_match_opt_like(
348 cx: &LateContext<'_, '_>,
353 els: Option<&Expr<'_>>,
355 // list of candidate `Enum`s we know will never get any more members
357 (&paths::COW, "Borrowed"),
358 (&paths::COW, "Cow::Borrowed"),
359 (&paths::COW, "Cow::Owned"),
360 (&paths::COW, "Owned"),
361 (&paths::OPTION, "None"),
362 (&paths::RESULT, "Err"),
363 (&paths::RESULT, "Ok"),
366 let path = match arms[1].pat.kind {
367 PatKind::TupleStruct(ref path, ref inner, _) => {
368 // Contains any non wildcard patterns (e.g., `Err(err)`)?
369 if !inner.iter().all(is_wild) {
372 print::to_string(print::NO_ANN, |s| s.print_qpath(path, false))
374 PatKind::Binding(BindingAnnotation::Unannotated, .., ident, None) => ident.to_string(),
375 PatKind::Path(ref path) => print::to_string(print::NO_ANN, |s| s.print_qpath(path, false)),
379 for &(ty_path, pat_path) in candidates {
380 if path == *pat_path && match_type(cx, ty, ty_path) {
381 report_single_match_single_pattern(cx, ex, arms, expr, els);
386 fn check_match_bool(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
387 // Type of expression is `bool`.
388 if cx.tables.expr_ty(ex).kind == ty::Bool {
393 "you seem to be trying to match on a boolean expression",
397 let exprs = if let PatKind::Lit(ref arm_bool) = arms[0].pat.kind {
398 if let ExprKind::Lit(ref lit) = arm_bool.kind {
400 LitKind::Bool(true) => Some((&*arms[0].body, &*arms[1].body)),
401 LitKind::Bool(false) => Some((&*arms[1].body, &*arms[0].body)),
411 if let Some((true_expr, false_expr)) = exprs {
412 let sugg = match (is_unit_expr(true_expr), is_unit_expr(false_expr)) {
413 (false, false) => Some(format!(
415 snippet(cx, ex.span, "b"),
416 expr_block(cx, true_expr, None, ".."),
417 expr_block(cx, false_expr, None, "..")
419 (false, true) => Some(format!(
421 snippet(cx, ex.span, "b"),
422 expr_block(cx, true_expr, None, "..")
425 let test = Sugg::hir(cx, ex, "..");
426 Some(format!("if {} {}", !test, expr_block(cx, false_expr, None, "..")))
428 (true, true) => None,
431 if let Some(sugg) = sugg {
434 "consider using an `if`/`else` expression",
436 Applicability::HasPlaceholders,
446 fn check_overlapping_arms<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ex: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) {
447 if arms.len() >= 2 && cx.tables.expr_ty(ex).is_integral() {
448 let ranges = all_ranges(cx, arms, cx.tables.expr_ty(ex));
449 let type_ranges = type_ranges(&ranges);
450 if !type_ranges.is_empty() {
451 if let Some((start, end)) = overlapping(&type_ranges) {
454 MATCH_OVERLAPPING_ARM,
456 "some ranges overlap",
458 "overlaps with this",
465 fn check_wild_err_arm(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
466 let ex_ty = walk_ptrs_ty(cx.tables.expr_ty(ex));
467 if match_type(cx, ex_ty, &paths::RESULT) {
469 if let PatKind::TupleStruct(ref path, ref inner, _) = arm.pat.kind {
470 let path_str = print::to_string(print::NO_ANN, |s| s.print_qpath(path, false));
471 if path_str == "Err" {
472 let mut matching_wild = inner.iter().any(is_wild);
473 let mut ident_bind_name = String::from("_");
475 // Looking for unused bindings (i.e.: `_e`)
476 inner.iter().for_each(|pat| {
477 if let PatKind::Binding(.., ident, None) = &pat.kind {
478 if ident.as_str().starts_with('_') && is_unused(ident, arm.body) {
479 ident_bind_name = (&ident.name.as_str()).to_string();
480 matching_wild = true;
487 if let ExprKind::Block(ref block, _) = arm.body.kind;
488 if is_panic_block(block);
490 // `Err(_)` or `Err(_e)` arm with `panic!` found
491 span_note_and_lint(cx,
494 &format!("`Err({})` matches all errors", &ident_bind_name),
496 "match each error separately or use the error output",
506 fn check_wild_enum_match(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
507 let ty = cx.tables.expr_ty(ex);
509 // If there isn't a nice closed set of possible values that can be conveniently enumerated,
510 // don't complain about not enumerating the mall.
514 // First pass - check for violation, but don't do much book-keeping because this is hopefully
515 // the uncommon case, and the book-keeping is slightly expensive.
516 let mut wildcard_span = None;
517 let mut wildcard_ident = None;
519 if let PatKind::Wild = arm.pat.kind {
520 wildcard_span = Some(arm.pat.span);
521 } else if let PatKind::Binding(_, _, ident, None) = arm.pat.kind {
522 wildcard_span = Some(arm.pat.span);
523 wildcard_ident = Some(ident);
527 if let Some(wildcard_span) = wildcard_span {
528 // Accumulate the variants which should be put in place of the wildcard because they're not
531 let mut missing_variants = vec![];
532 if let ty::Adt(def, _) = ty.kind {
533 for variant in &def.variants {
534 missing_variants.push(variant);
539 if arm.guard.is_some() {
540 // Guards mean that this case probably isn't exhaustively covered. Technically
541 // this is incorrect, as we should really check whether each variant is exhaustively
542 // covered by the set of guards that cover it, but that's really hard to do.
545 if let PatKind::Path(ref path) = arm.pat.kind {
546 if let QPath::Resolved(_, p) = path {
547 missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
549 } else if let PatKind::TupleStruct(ref path, ..) = arm.pat.kind {
550 if let QPath::Resolved(_, p) = path {
551 missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
556 let mut suggestion: Vec<String> = missing_variants
559 let suffix = match v.ctor_kind {
560 CtorKind::Fn => "(..)",
561 CtorKind::Const | CtorKind::Fictive => "",
563 let ident_str = if let Some(ident) = wildcard_ident {
564 format!("{} @ ", ident.name)
568 // This path assumes that the enum type is imported into scope.
569 format!("{}{}{}", ident_str, cx.tcx.def_path_str(v.def_id), suffix)
573 if suggestion.is_empty() {
577 let mut message = "wildcard match will miss any future added variants";
579 if let ty::Adt(def, _) = ty.kind {
580 if def.is_variant_list_non_exhaustive() {
581 message = "match on non-exhaustive enum doesn't explicitly match all known variants";
582 suggestion.push(String::from("_"));
588 WILDCARD_ENUM_MATCH_ARM,
592 suggestion.join(" | "),
593 Applicability::MachineApplicable,
598 // If the block contains only a `panic!` macro (as expression or statement)
599 fn is_panic_block(block: &Block<'_>) -> bool {
600 match (&block.expr, block.stmts.len(), block.stmts.first()) {
601 (&Some(ref exp), 0, _) => {
602 is_expn_of(exp.span, "panic").is_some() && is_expn_of(exp.span, "unreachable").is_none()
604 (&None, 1, Some(stmt)) => {
605 is_expn_of(stmt.span, "panic").is_some() && is_expn_of(stmt.span, "unreachable").is_none()
611 fn check_match_ref_pats(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
612 if has_only_ref_pats(arms) {
613 let mut suggs = Vec::new();
614 let (title, msg) = if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = ex.kind {
615 let span = ex.span.source_callsite();
616 suggs.push((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
618 "you don't need to add `&` to both the expression and the patterns",
622 let span = ex.span.source_callsite();
623 suggs.push((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
625 "you don't need to add `&` to all patterns",
626 "instead of prefixing all patterns with `&`, you can dereference the expression",
630 suggs.extend(arms.iter().filter_map(|a| {
631 if let PatKind::Ref(ref refp, _) = a.pat.kind {
632 Some((a.pat.span, snippet(cx, refp.span, "..").to_string()))
638 span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |db| {
639 if !expr.span.from_expansion() {
640 multispan_sugg(db, msg.to_owned(), suggs);
646 fn check_match_as_ref(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
647 if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
648 let arm_ref: Option<BindingAnnotation> = if is_none_arm(&arms[0]) {
649 is_ref_some_arm(&arms[1])
650 } else if is_none_arm(&arms[1]) {
651 is_ref_some_arm(&arms[0])
655 if let Some(rb) = arm_ref {
656 let suggestion = if rb == BindingAnnotation::Ref {
662 let output_ty = cx.tables.expr_ty(expr);
663 let input_ty = cx.tables.expr_ty(ex);
665 let cast = if_chain! {
666 if let ty::Adt(_, substs) = input_ty.kind;
667 let input_ty = substs.type_at(0);
668 if let ty::Adt(_, substs) = output_ty.kind;
669 let output_ty = substs.type_at(0);
670 if let ty::Ref(_, output_ty, _) = output_ty.kind;
671 if input_ty != output_ty;
679 let mut applicability = Applicability::MachineApplicable;
684 &format!("use `{}()` instead", suggestion),
688 snippet_with_applicability(cx, ex.span, "_", &mut applicability),
698 fn check_wild_in_or_pats(cx: &LateContext<'_, '_>, arms: &[Arm<'_>]) {
700 if let PatKind::Or(ref fields) = arm.pat.kind {
701 // look for multiple fields in this arm that contains at least one Wild pattern
702 if fields.len() > 1 && fields.iter().any(is_wild) {
705 WILDCARD_IN_OR_PATTERNS,
707 "wildcard pattern covers any other pattern as it will match anyway.",
708 "Consider handling `_` separately.",
715 /// Gets all arms that are unbounded `PatRange`s.
716 fn all_ranges<'a, 'tcx>(
717 cx: &LateContext<'a, 'tcx>,
718 arms: &'tcx [Arm<'_>],
720 ) -> Vec<SpannedRange<Constant>> {
724 ref pat, guard: None, ..
727 if let PatKind::Range(ref lhs, ref rhs, range_end) = pat.kind {
728 let lhs = match lhs {
729 Some(lhs) => constant(cx, cx.tables, lhs)?.0,
730 None => miri_to_const(ty.numeric_min_val(cx.tcx)?)?,
732 let rhs = match rhs {
733 Some(rhs) => constant(cx, cx.tables, rhs)?.0,
734 None => miri_to_const(ty.numeric_max_val(cx.tcx)?)?,
736 let rhs = match range_end {
737 RangeEnd::Included => Bound::Included(rhs),
738 RangeEnd::Excluded => Bound::Excluded(rhs),
740 return Some(SpannedRange {
746 if let PatKind::Lit(ref value) = pat.kind {
747 let value = constant(cx, cx.tables, value)?.0;
748 return Some(SpannedRange {
750 node: (value.clone(), Bound::Included(value)),
759 #[derive(Debug, Eq, PartialEq)]
760 pub struct SpannedRange<T> {
762 pub node: (T, Bound<T>),
765 type TypedRanges = Vec<SpannedRange<u128>>;
767 /// Gets all `Int` ranges or all `Uint` ranges. Mixed types are an error anyway
768 /// and other types than
769 /// `Uint` and `Int` probably don't make sense.
770 fn type_ranges(ranges: &[SpannedRange<Constant>]) -> TypedRanges {
773 .filter_map(|range| match range.node {
774 (Constant::Int(start), Bound::Included(Constant::Int(end))) => Some(SpannedRange {
776 node: (start, Bound::Included(end)),
778 (Constant::Int(start), Bound::Excluded(Constant::Int(end))) => Some(SpannedRange {
780 node: (start, Bound::Excluded(end)),
782 (Constant::Int(start), Bound::Unbounded) => Some(SpannedRange {
784 node: (start, Bound::Unbounded),
791 fn is_unit_expr(expr: &Expr<'_>) -> bool {
793 ExprKind::Tup(ref v) if v.is_empty() => true,
794 ExprKind::Block(ref b, _) if b.stmts.is_empty() && b.expr.is_none() => true,
799 // Checks if arm has the form `None => None`
800 fn is_none_arm(arm: &Arm<'_>) -> bool {
802 PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => true,
807 // Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
808 fn is_ref_some_arm(arm: &Arm<'_>) -> Option<BindingAnnotation> {
810 if let PatKind::TupleStruct(ref path, ref pats, _) = arm.pat.kind;
811 if pats.len() == 1 && match_qpath(path, &paths::OPTION_SOME);
812 if let PatKind::Binding(rb, .., ident, _) = pats[0].kind;
813 if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
814 if let ExprKind::Call(ref e, ref args) = remove_blocks(&arm.body).kind;
815 if let ExprKind::Path(ref some_path) = e.kind;
816 if match_qpath(some_path, &paths::OPTION_SOME) && args.len() == 1;
817 if let ExprKind::Path(ref qpath) = args[0].kind;
818 if let &QPath::Resolved(_, ref path2) = qpath;
819 if path2.segments.len() == 1 && ident.name == path2.segments[0].ident.name;
827 fn has_only_ref_pats(arms: &[Arm<'_>]) -> bool {
832 PatKind::Ref(..) => Some(true), // &-patterns
833 PatKind::Wild => Some(false), // an "anything" wildcard is also fine
834 _ => None, // any other pattern is not fine
837 .collect::<Option<Vec<bool>>>();
838 // look for Some(v) where there's at least one true element
839 mapped.map_or(false, |v| v.iter().any(|el| *el))
842 pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
846 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
848 Start(T, &'a SpannedRange<T>),
849 End(Bound<T>, &'a SpannedRange<T>),
852 impl<'a, T: Copy> Kind<'a, T> {
853 fn range(&self) -> &'a SpannedRange<T> {
855 Kind::Start(_, r) | Kind::End(_, r) => r,
859 fn value(self) -> Bound<T> {
861 Kind::Start(t, _) => Bound::Included(t),
862 Kind::End(t, _) => t,
867 impl<'a, T: Copy + Ord> PartialOrd for Kind<'a, T> {
868 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
869 Some(self.cmp(other))
873 impl<'a, T: Copy + Ord> Ord for Kind<'a, T> {
874 fn cmp(&self, other: &Self) -> Ordering {
875 match (self.value(), other.value()) {
876 (Bound::Included(a), Bound::Included(b)) | (Bound::Excluded(a), Bound::Excluded(b)) => a.cmp(&b),
877 // Range patterns cannot be unbounded (yet)
878 (Bound::Unbounded, _) | (_, Bound::Unbounded) => unimplemented!(),
879 (Bound::Included(a), Bound::Excluded(b)) => match a.cmp(&b) {
880 Ordering::Equal => Ordering::Greater,
883 (Bound::Excluded(a), Bound::Included(b)) => match a.cmp(&b) {
884 Ordering::Equal => Ordering::Less,
891 let mut values = Vec::with_capacity(2 * ranges.len());
894 values.push(Kind::Start(r.node.0, r));
895 values.push(Kind::End(r.node.1, r));
900 for (a, b) in values.iter().zip(values.iter().skip(1)) {
902 (&Kind::Start(_, ra), &Kind::End(_, rb)) => {
903 if ra.node != rb.node {
904 return Some((ra, rb));
907 (&Kind::End(a, _), &Kind::Start(b, _)) if a != Bound::Included(b) => (),
908 _ => return Some((a.range(), b.range())),