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 span_lint_and_help, span_lint_and_note,
7 expr_block, in_macro, is_allowed, is_expn_of, is_wild, match_qpath, match_type, multispan_sugg, remove_blocks,
8 snippet, snippet_with_applicability, span_lint_and_sugg, span_lint_and_then,
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_clippy_lint! {
249 /// **What it does:** Checks for useless match that binds to only one value.
251 /// **Why is this bad?** Readability and needless complexity.
253 /// **Known problems:** This situation frequently happen in macros, so can't lint there.
268 /// let (c, d) = (a, b);
270 pub MATCH_SINGLE_BINDING,
272 "a match with a single binding instead of using `let` statement"
275 declare_lint_pass!(Matches => [
280 MATCH_OVERLAPPING_ARM,
283 WILDCARD_ENUM_MATCH_ARM,
284 WILDCARD_IN_OR_PATTERNS,
285 MATCH_SINGLE_BINDING,
288 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Matches {
289 fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
290 if in_external_macro(cx.sess(), expr.span) {
293 if let ExprKind::Match(ref ex, ref arms, MatchSource::Normal) = expr.kind {
294 check_single_match(cx, ex, arms, expr);
295 check_match_bool(cx, ex, arms, expr);
296 check_overlapping_arms(cx, ex, arms);
297 check_wild_err_arm(cx, ex, arms);
298 check_wild_enum_match(cx, ex, arms);
299 check_match_as_ref(cx, ex, arms, expr);
300 check_wild_in_or_pats(cx, arms);
301 check_match_single_binding(cx, ex, arms, expr);
303 if let ExprKind::Match(ref ex, ref arms, _) = expr.kind {
304 check_match_ref_pats(cx, ex, arms, expr);
310 fn check_single_match(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
311 if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
312 if let PatKind::Or(..) = arms[0].pat.kind {
313 // don't lint for or patterns for now, this makes
314 // the lint noisy in unnecessary situations
317 let els = remove_blocks(&arms[1].body);
318 let els = if is_unit_expr(els) {
320 } else if let ExprKind::Block(_, _) = els.kind {
321 // matches with blocks that contain statements are prettier as `if let + else`
324 // allow match arms with just expressions
327 let ty = cx.tables.expr_ty(ex);
328 if ty.kind != ty::Bool || is_allowed(cx, MATCH_BOOL, ex.hir_id) {
329 check_single_match_single_pattern(cx, ex, arms, expr, els);
330 check_single_match_opt_like(cx, ex, arms, expr, ty, els);
335 fn check_single_match_single_pattern(
336 cx: &LateContext<'_, '_>,
340 els: Option<&Expr<'_>>,
342 if is_wild(&arms[1].pat) {
343 report_single_match_single_pattern(cx, ex, arms, expr, els);
347 fn report_single_match_single_pattern(
348 cx: &LateContext<'_, '_>,
352 els: Option<&Expr<'_>>,
354 let lint = if els.is_some() { SINGLE_MATCH_ELSE } else { SINGLE_MATCH };
355 let els_str = els.map_or(String::new(), |els| {
356 format!(" else {}", expr_block(cx, els, None, ".."))
362 "you seem to be trying to use match for destructuring a single pattern. Consider using `if \
366 "if let {} = {} {}{}",
367 snippet(cx, arms[0].pat.span, ".."),
368 snippet(cx, ex.span, ".."),
369 expr_block(cx, &arms[0].body, None, ".."),
372 Applicability::HasPlaceholders,
376 fn check_single_match_opt_like(
377 cx: &LateContext<'_, '_>,
382 els: Option<&Expr<'_>>,
384 // list of candidate `Enum`s we know will never get any more members
386 (&paths::COW, "Borrowed"),
387 (&paths::COW, "Cow::Borrowed"),
388 (&paths::COW, "Cow::Owned"),
389 (&paths::COW, "Owned"),
390 (&paths::OPTION, "None"),
391 (&paths::RESULT, "Err"),
392 (&paths::RESULT, "Ok"),
395 let path = match arms[1].pat.kind {
396 PatKind::TupleStruct(ref path, ref inner, _) => {
397 // Contains any non wildcard patterns (e.g., `Err(err)`)?
398 if !inner.iter().all(is_wild) {
401 print::to_string(print::NO_ANN, |s| s.print_qpath(path, false))
403 PatKind::Binding(BindingAnnotation::Unannotated, .., ident, None) => ident.to_string(),
404 PatKind::Path(ref path) => print::to_string(print::NO_ANN, |s| s.print_qpath(path, false)),
408 for &(ty_path, pat_path) in candidates {
409 if path == *pat_path && match_type(cx, ty, ty_path) {
410 report_single_match_single_pattern(cx, ex, arms, expr, els);
415 fn check_match_bool(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
416 // Type of expression is `bool`.
417 if cx.tables.expr_ty(ex).kind == ty::Bool {
422 "you seem to be trying to match on a boolean expression",
426 let exprs = if let PatKind::Lit(ref arm_bool) = arms[0].pat.kind {
427 if let ExprKind::Lit(ref lit) = arm_bool.kind {
429 LitKind::Bool(true) => Some((&*arms[0].body, &*arms[1].body)),
430 LitKind::Bool(false) => Some((&*arms[1].body, &*arms[0].body)),
440 if let Some((true_expr, false_expr)) = exprs {
441 let sugg = match (is_unit_expr(true_expr), is_unit_expr(false_expr)) {
442 (false, false) => Some(format!(
444 snippet(cx, ex.span, "b"),
445 expr_block(cx, true_expr, None, ".."),
446 expr_block(cx, false_expr, None, "..")
448 (false, true) => Some(format!(
450 snippet(cx, ex.span, "b"),
451 expr_block(cx, true_expr, None, "..")
454 let test = Sugg::hir(cx, ex, "..");
455 Some(format!("if {} {}", !test, expr_block(cx, false_expr, None, "..")))
457 (true, true) => None,
460 if let Some(sugg) = sugg {
463 "consider using an `if`/`else` expression",
465 Applicability::HasPlaceholders,
475 fn check_overlapping_arms<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ex: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) {
476 if arms.len() >= 2 && cx.tables.expr_ty(ex).is_integral() {
477 let ranges = all_ranges(cx, arms, cx.tables.expr_ty(ex));
478 let type_ranges = type_ranges(&ranges);
479 if !type_ranges.is_empty() {
480 if let Some((start, end)) = overlapping(&type_ranges) {
483 MATCH_OVERLAPPING_ARM,
485 "some ranges overlap",
487 "overlaps with this",
494 fn check_wild_err_arm(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
495 let ex_ty = walk_ptrs_ty(cx.tables.expr_ty(ex));
496 if match_type(cx, ex_ty, &paths::RESULT) {
498 if let PatKind::TupleStruct(ref path, ref inner, _) = arm.pat.kind {
499 let path_str = print::to_string(print::NO_ANN, |s| s.print_qpath(path, false));
500 if path_str == "Err" {
501 let mut matching_wild = inner.iter().any(is_wild);
502 let mut ident_bind_name = String::from("_");
504 // Looking for unused bindings (i.e.: `_e`)
505 inner.iter().for_each(|pat| {
506 if let PatKind::Binding(.., ident, None) = &pat.kind {
507 if ident.as_str().starts_with('_') && is_unused(ident, arm.body) {
508 ident_bind_name = (&ident.name.as_str()).to_string();
509 matching_wild = true;
516 if let ExprKind::Block(ref block, _) = arm.body.kind;
517 if is_panic_block(block);
519 // `Err(_)` or `Err(_e)` arm with `panic!` found
520 span_lint_and_note(cx,
523 &format!("`Err({})` matches all errors", &ident_bind_name),
525 "match each error separately or use the error output",
535 fn check_wild_enum_match(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
536 let ty = cx.tables.expr_ty(ex);
538 // If there isn't a nice closed set of possible values that can be conveniently enumerated,
539 // don't complain about not enumerating the mall.
543 // First pass - check for violation, but don't do much book-keeping because this is hopefully
544 // the uncommon case, and the book-keeping is slightly expensive.
545 let mut wildcard_span = None;
546 let mut wildcard_ident = None;
548 if let PatKind::Wild = arm.pat.kind {
549 wildcard_span = Some(arm.pat.span);
550 } else if let PatKind::Binding(_, _, ident, None) = arm.pat.kind {
551 wildcard_span = Some(arm.pat.span);
552 wildcard_ident = Some(ident);
556 if let Some(wildcard_span) = wildcard_span {
557 // Accumulate the variants which should be put in place of the wildcard because they're not
560 let mut missing_variants = vec![];
561 if let ty::Adt(def, _) = ty.kind {
562 for variant in &def.variants {
563 missing_variants.push(variant);
568 if arm.guard.is_some() {
569 // Guards mean that this case probably isn't exhaustively covered. Technically
570 // this is incorrect, as we should really check whether each variant is exhaustively
571 // covered by the set of guards that cover it, but that's really hard to do.
574 if let PatKind::Path(ref path) = arm.pat.kind {
575 if let QPath::Resolved(_, p) = path {
576 missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
578 } else if let PatKind::TupleStruct(ref path, ..) = arm.pat.kind {
579 if let QPath::Resolved(_, p) = path {
580 missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
585 let mut suggestion: Vec<String> = missing_variants
588 let suffix = match v.ctor_kind {
589 CtorKind::Fn => "(..)",
590 CtorKind::Const | CtorKind::Fictive => "",
592 let ident_str = if let Some(ident) = wildcard_ident {
593 format!("{} @ ", ident.name)
597 // This path assumes that the enum type is imported into scope.
598 format!("{}{}{}", ident_str, cx.tcx.def_path_str(v.def_id), suffix)
602 if suggestion.is_empty() {
606 let mut message = "wildcard match will miss any future added variants";
608 if let ty::Adt(def, _) = ty.kind {
609 if def.is_variant_list_non_exhaustive() {
610 message = "match on non-exhaustive enum doesn't explicitly match all known variants";
611 suggestion.push(String::from("_"));
617 WILDCARD_ENUM_MATCH_ARM,
621 suggestion.join(" | "),
622 Applicability::MachineApplicable,
627 // If the block contains only a `panic!` macro (as expression or statement)
628 fn is_panic_block(block: &Block<'_>) -> bool {
629 match (&block.expr, block.stmts.len(), block.stmts.first()) {
630 (&Some(ref exp), 0, _) => {
631 is_expn_of(exp.span, "panic").is_some() && is_expn_of(exp.span, "unreachable").is_none()
633 (&None, 1, Some(stmt)) => {
634 is_expn_of(stmt.span, "panic").is_some() && is_expn_of(stmt.span, "unreachable").is_none()
640 fn check_match_ref_pats(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
641 if has_only_ref_pats(arms) {
642 let mut suggs = Vec::new();
643 let (title, msg) = if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = ex.kind {
644 let span = ex.span.source_callsite();
645 suggs.push((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
647 "you don't need to add `&` to both the expression and the patterns",
651 let span = ex.span.source_callsite();
652 suggs.push((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
654 "you don't need to add `&` to all patterns",
655 "instead of prefixing all patterns with `&`, you can dereference the expression",
659 suggs.extend(arms.iter().filter_map(|a| {
660 if let PatKind::Ref(ref refp, _) = a.pat.kind {
661 Some((a.pat.span, snippet(cx, refp.span, "..").to_string()))
667 span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |db| {
668 if !expr.span.from_expansion() {
669 multispan_sugg(db, msg.to_owned(), suggs);
675 fn check_match_as_ref(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
676 if arms.len() == 2 && arms[0].guard.is_none() && arms[1].guard.is_none() {
677 let arm_ref: Option<BindingAnnotation> = if is_none_arm(&arms[0]) {
678 is_ref_some_arm(&arms[1])
679 } else if is_none_arm(&arms[1]) {
680 is_ref_some_arm(&arms[0])
684 if let Some(rb) = arm_ref {
685 let suggestion = if rb == BindingAnnotation::Ref {
691 let output_ty = cx.tables.expr_ty(expr);
692 let input_ty = cx.tables.expr_ty(ex);
694 let cast = if_chain! {
695 if let ty::Adt(_, substs) = input_ty.kind;
696 let input_ty = substs.type_at(0);
697 if let ty::Adt(_, substs) = output_ty.kind;
698 let output_ty = substs.type_at(0);
699 if let ty::Ref(_, output_ty, _) = output_ty.kind;
700 if input_ty != output_ty;
708 let mut applicability = Applicability::MachineApplicable;
713 &format!("use `{}()` instead", suggestion),
717 snippet_with_applicability(cx, ex.span, "_", &mut applicability),
727 fn check_wild_in_or_pats(cx: &LateContext<'_, '_>, arms: &[Arm<'_>]) {
729 if let PatKind::Or(ref fields) = arm.pat.kind {
730 // look for multiple fields in this arm that contains at least one Wild pattern
731 if fields.len() > 1 && fields.iter().any(is_wild) {
734 WILDCARD_IN_OR_PATTERNS,
736 "wildcard pattern covers any other pattern as it will match anyway.",
737 "Consider handling `_` separately.",
744 fn check_match_single_binding(cx: &LateContext<'_, '_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
745 if in_macro(expr.span) {
749 let bind_names = arms[0].pat.span;
750 let matched_vars = ex.span;
753 MATCH_SINGLE_BINDING,
755 "this match could be written as a `let` statement",
759 snippet(cx, bind_names, ".."),
760 snippet(cx, matched_vars, "..")
762 Applicability::HasPlaceholders,
767 /// Gets all arms that are unbounded `PatRange`s.
768 fn all_ranges<'a, 'tcx>(
769 cx: &LateContext<'a, 'tcx>,
770 arms: &'tcx [Arm<'_>],
772 ) -> Vec<SpannedRange<Constant>> {
776 ref pat, guard: None, ..
779 if let PatKind::Range(ref lhs, ref rhs, range_end) = pat.kind {
780 let lhs = match lhs {
781 Some(lhs) => constant(cx, cx.tables, lhs)?.0,
782 None => miri_to_const(ty.numeric_min_val(cx.tcx)?)?,
784 let rhs = match rhs {
785 Some(rhs) => constant(cx, cx.tables, rhs)?.0,
786 None => miri_to_const(ty.numeric_max_val(cx.tcx)?)?,
788 let rhs = match range_end {
789 RangeEnd::Included => Bound::Included(rhs),
790 RangeEnd::Excluded => Bound::Excluded(rhs),
792 return Some(SpannedRange {
798 if let PatKind::Lit(ref value) = pat.kind {
799 let value = constant(cx, cx.tables, value)?.0;
800 return Some(SpannedRange {
802 node: (value.clone(), Bound::Included(value)),
811 #[derive(Debug, Eq, PartialEq)]
812 pub struct SpannedRange<T> {
814 pub node: (T, Bound<T>),
817 type TypedRanges = Vec<SpannedRange<u128>>;
819 /// Gets all `Int` ranges or all `Uint` ranges. Mixed types are an error anyway
820 /// and other types than
821 /// `Uint` and `Int` probably don't make sense.
822 fn type_ranges(ranges: &[SpannedRange<Constant>]) -> TypedRanges {
825 .filter_map(|range| match range.node {
826 (Constant::Int(start), Bound::Included(Constant::Int(end))) => Some(SpannedRange {
828 node: (start, Bound::Included(end)),
830 (Constant::Int(start), Bound::Excluded(Constant::Int(end))) => Some(SpannedRange {
832 node: (start, Bound::Excluded(end)),
834 (Constant::Int(start), Bound::Unbounded) => Some(SpannedRange {
836 node: (start, Bound::Unbounded),
843 fn is_unit_expr(expr: &Expr<'_>) -> bool {
845 ExprKind::Tup(ref v) if v.is_empty() => true,
846 ExprKind::Block(ref b, _) if b.stmts.is_empty() && b.expr.is_none() => true,
851 // Checks if arm has the form `None => None`
852 fn is_none_arm(arm: &Arm<'_>) -> bool {
854 PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => true,
859 // Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
860 fn is_ref_some_arm(arm: &Arm<'_>) -> Option<BindingAnnotation> {
862 if let PatKind::TupleStruct(ref path, ref pats, _) = arm.pat.kind;
863 if pats.len() == 1 && match_qpath(path, &paths::OPTION_SOME);
864 if let PatKind::Binding(rb, .., ident, _) = pats[0].kind;
865 if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
866 if let ExprKind::Call(ref e, ref args) = remove_blocks(&arm.body).kind;
867 if let ExprKind::Path(ref some_path) = e.kind;
868 if match_qpath(some_path, &paths::OPTION_SOME) && args.len() == 1;
869 if let ExprKind::Path(ref qpath) = args[0].kind;
870 if let &QPath::Resolved(_, ref path2) = qpath;
871 if path2.segments.len() == 1 && ident.name == path2.segments[0].ident.name;
879 fn has_only_ref_pats(arms: &[Arm<'_>]) -> bool {
884 PatKind::Ref(..) => Some(true), // &-patterns
885 PatKind::Wild => Some(false), // an "anything" wildcard is also fine
886 _ => None, // any other pattern is not fine
889 .collect::<Option<Vec<bool>>>();
890 // look for Some(v) where there's at least one true element
891 mapped.map_or(false, |v| v.iter().any(|el| *el))
894 pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
898 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
900 Start(T, &'a SpannedRange<T>),
901 End(Bound<T>, &'a SpannedRange<T>),
904 impl<'a, T: Copy> Kind<'a, T> {
905 fn range(&self) -> &'a SpannedRange<T> {
907 Kind::Start(_, r) | Kind::End(_, r) => r,
911 fn value(self) -> Bound<T> {
913 Kind::Start(t, _) => Bound::Included(t),
914 Kind::End(t, _) => t,
919 impl<'a, T: Copy + Ord> PartialOrd for Kind<'a, T> {
920 fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
921 Some(self.cmp(other))
925 impl<'a, T: Copy + Ord> Ord for Kind<'a, T> {
926 fn cmp(&self, other: &Self) -> Ordering {
927 match (self.value(), other.value()) {
928 (Bound::Included(a), Bound::Included(b)) | (Bound::Excluded(a), Bound::Excluded(b)) => a.cmp(&b),
929 // Range patterns cannot be unbounded (yet)
930 (Bound::Unbounded, _) | (_, Bound::Unbounded) => unimplemented!(),
931 (Bound::Included(a), Bound::Excluded(b)) => match a.cmp(&b) {
932 Ordering::Equal => Ordering::Greater,
935 (Bound::Excluded(a), Bound::Included(b)) => match a.cmp(&b) {
936 Ordering::Equal => Ordering::Less,
943 let mut values = Vec::with_capacity(2 * ranges.len());
946 values.push(Kind::Start(r.node.0, r));
947 values.push(Kind::End(r.node.1, r));
952 for (a, b) in values.iter().zip(values.iter().skip(1)) {
954 (&Kind::Start(_, ra), &Kind::End(_, rb)) => {
955 if ra.node != rb.node {
956 return Some((ra, rb));
959 (&Kind::End(a, _), &Kind::Start(b, _)) if a != Bound::Included(b) => (),
960 _ => return Some((a.range(), b.range())),