add unnested_or_patterns lint

CHANGELOG.md

@@ -1683,6 +1683,7 @@ Released 2018-09-13
 [`unnecessary_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
 [`unneeded_field_pattern`]: https://rust-lang.github.io/rust-clippy/master/index.html#unneeded_field_pattern
 [`unneeded_wildcard_pattern`]: https://rust-lang.github.io/rust-clippy/master/index.html#unneeded_wildcard_pattern
+[`unnested_or_patterns`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnested_or_patterns
 [`unreachable`]: https://rust-lang.github.io/rust-clippy/master/index.html#unreachable
 [`unreadable_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#unreadable_literal
 [`unsafe_derive_deserialize`]: https://rust-lang.github.io/rust-clippy/master/index.html#unsafe_derive_deserialize

clippy_lints/src/lib.rs

@@ -1,5 +1,6 @@
 // error-pattern:cargo-clippy
 
+#![feature(bindings_after_at)]
 #![feature(box_syntax)]
 #![feature(box_patterns)]
 #![feature(or_patterns)]
@@ -12,6 +13,7 @@
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 #![feature(crate_visibility_modifier)]
 #![feature(concat_idents)]
+#![feature(drain_filter)]
 
 // FIXME: switch to something more ergonomic here, once available.
 // (Currently there is no way to opt into sysroot crates without `extern crate`.)
@@ -319,6 +321,7 @@ mod types;
 mod unicode;
 mod unnamed_address;
 mod unnecessary_sort_by;
+mod unnested_or_patterns;
 mod unsafe_removed_from_name;
 mod unused_io_amount;
 mod unused_self;
@@ -836,6 +839,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &unnamed_address::FN_ADDRESS_COMPARISONS,
         &unnamed_address::VTABLE_ADDRESS_COMPARISONS,
         &unnecessary_sort_by::UNNECESSARY_SORT_BY,
+        &unnested_or_patterns::UNNESTED_OR_PATTERNS,
         &unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME,
         &unused_io_amount::UNUSED_IO_AMOUNT,
         &unused_self::UNUSED_SELF,
@@ -1073,6 +1077,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(move || box non_expressive_names::NonExpressiveNames {
         single_char_binding_names_threshold,
     });
+    store.register_early_pass(|| box unnested_or_patterns::UnnestedOrPatterns);
 
     store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
@@ -1433,6 +1438,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&unnamed_address::FN_ADDRESS_COMPARISONS),
         LintId::of(&unnamed_address::VTABLE_ADDRESS_COMPARISONS),
         LintId::of(&unnecessary_sort_by::UNNECESSARY_SORT_BY),
+        LintId::of(&unnested_or_patterns::UNNESTED_OR_PATTERNS),
         LintId::of(&unsafe_removed_from_name::UNSAFE_REMOVED_FROM_NAME),
         LintId::of(&unused_io_amount::UNUSED_IO_AMOUNT),
         LintId::of(&unwrap::PANICKING_UNWRAP),
@@ -1616,6 +1622,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&types::UNNECESSARY_CAST),
         LintId::of(&types::VEC_BOX),
         LintId::of(&unnecessary_sort_by::UNNECESSARY_SORT_BY),
+        LintId::of(&unnested_or_patterns::UNNESTED_OR_PATTERNS),
         LintId::of(&unwrap::UNNECESSARY_UNWRAP),
         LintId::of(&useless_conversion::USELESS_CONVERSION),
         LintId::of(&zero_div_zero::ZERO_DIVIDED_BY_ZERO),

clippy_lints/src/unnested_or_patterns.rs

@@ -0,0 +1,407 @@
+#![allow(clippy::wildcard_imports, clippy::enum_glob_use)]
+
+use crate::utils::ast_utils::{eq_field_pat, eq_id, eq_pat, eq_path};
+use crate::utils::{over, span_lint_and_then};
+use rustc_ast::ast::{self, Pat, PatKind, PatKind::*, DUMMY_NODE_ID};
+use rustc_ast::mut_visit::*;
+use rustc_ast::ptr::P;
+use rustc_ast_pretty::pprust;
+use rustc_errors::Applicability;
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::DUMMY_SP;
+
+use std::cell::Cell;
+use std::mem;
+
+declare_clippy_lint! {
+    /// **What it does:**
+    ///
+    /// Checks for unnested or-patterns, e.g., `Some(0) | Some(2)` and
+    /// suggests replacing the pattern with a nested one, `Some(0 | 2)`.
+    ///
+    /// Another way to think of this is that it rewrites patterns in
+    /// *disjunctive normal form (DNF)* into *conjunctive normal form (CNF)*.
+    ///
+    /// **Why is this bad?**
+    ///
+    /// In the example above, `Some` is repeated, which unncessarily complicates the pattern.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// fn main() {
+    ///     if let Some(0) | Some(2) = Some(0) {}
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// #![feature(or_patterns)]
+    ///
+    /// fn main() {
+    ///     if let Some(0 | 2) = Some(0) {}
+    /// }
+    /// ```
+    pub UNNESTED_OR_PATTERNS,
+    complexity,
+    "unnested or-patterns, e.g., `Foo(Bar) | Foo(Baz) instead of `Foo(Bar | Baz)`"
+}
+
+declare_lint_pass!(UnnestedOrPatterns => [UNNESTED_OR_PATTERNS]);
+
+impl EarlyLintPass for UnnestedOrPatterns {
+    fn check_arm(&mut self, cx: &EarlyContext<'_>, a: &ast::Arm) {
+        lint_unnested_or_patterns(cx, &a.pat);
+    }
+
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
+        if let ast::ExprKind::Let(pat, _) = &e.kind {
+            lint_unnested_or_patterns(cx, pat);
+        }
+    }
+
+    fn check_param(&mut self, cx: &EarlyContext<'_>, p: &ast::Param) {
+        lint_unnested_or_patterns(cx, &p.pat);
+    }
+
+    fn check_local(&mut self, cx: &EarlyContext<'_>, l: &ast::Local) {
+        lint_unnested_or_patterns(cx, &l.pat);
+    }
+}
+
+fn lint_unnested_or_patterns(cx: &EarlyContext<'_>, pat: &Pat) {
+    if !cx.sess.opts.unstable_features.is_nightly_build() {
+        // User cannot do `#![feature(or_patterns)]`, so bail.
+        return;
+    }
+
+    if let Ident(.., None) | Lit(_) | Wild | Path(..) | Range(..) | Rest | MacCall(_) = pat.kind {
+        // This is a leaf pattern, so cloning is unprofitable.
+        return;
+    }
+
+    let mut pat = P(pat.clone());
+
+    // Nix all the paren patterns everywhere so that they aren't in our way.
+    remove_all_parens(&mut pat);
+
+    // Transform all unnested or-patterns into nested ones, and if there were none, quit.
+    if !unnest_or_patterns(&mut pat) {
+        return;
+    }
+
+    span_lint_and_then(cx, UNNESTED_OR_PATTERNS, pat.span, "unnested or-patterns", |db| {
+        insert_necessary_parens(&mut pat);
+        db.span_suggestion_verbose(
+            pat.span,
+            "nest the patterns",
+            pprust::pat_to_string(&pat),
+            Applicability::MachineApplicable,
+        );
+    });
+}
+
+/// Remove all `(p)` patterns in `pat`.
+fn remove_all_parens(pat: &mut P<Pat>) {
+    struct Visitor;
+    impl MutVisitor for Visitor {
+        fn visit_pat(&mut self, pat: &mut P<Pat>) {
+            noop_visit_pat(pat, self);
+            let inner = match &mut pat.kind {
+                Paren(i) => mem::replace(&mut i.kind, Wild),
+                _ => return,
+            };
+            pat.kind = inner;
+        }
+    }
+    Visitor.visit_pat(pat);
+}
+
+/// Insert parens where necessary according to Rust's precedence rules for patterns.
+fn insert_necessary_parens(pat: &mut P<Pat>) {
+    struct Visitor;
+    impl MutVisitor for Visitor {
+        fn visit_pat(&mut self, pat: &mut P<Pat>) {
+            use ast::{BindingMode::*, Mutability::*};
+            noop_visit_pat(pat, self);
+            let target = match &mut pat.kind {
+                // `i @ a | b`, `box a | b`, and `& mut? a | b`.
+                Ident(.., Some(p)) | Box(p) | Ref(p, _) if matches!(&p.kind, Or(ps) if ps.len() > 1) => p,
+                Ref(p, Not) if matches!(p.kind, Ident(ByValue(Mut), ..)) => p, // `&(mut x)`
+                _ => return,
+            };
+            target.kind = Paren(P(take_pat(target)));
+        }
+    }
+    Visitor.visit_pat(pat);
+}
+
+/// Unnest or-patterns `p0 | ... | p1` in the pattern `pat`.
+/// For example, this would transform `Some(0) | FOO | Some(2)` into `Some(0 | 2) | FOO`.
+fn unnest_or_patterns(pat: &mut P<Pat>) -> bool {
+    struct Visitor {
+        changed: bool,
+    }
+    impl MutVisitor for Visitor {
+        fn visit_pat(&mut self, p: &mut P<Pat>) {
+            // This is a bottom up transformation, so recurse first.
+            noop_visit_pat(p, self);
+
+            // Don't have an or-pattern? Just quit early on.
+            let alternatives = match &mut p.kind {
+                Or(ps) => ps,
+                _ => return,
+            };
+
+            // Collapse or-patterns directly nested in or-patterns.
+            let mut idx = 0;
+            let mut this_level_changed = false;
+            while idx < alternatives.len() {
+                let inner = if let Or(ps) = &mut alternatives[idx].kind {
+                    mem::take(ps)
+                } else {
+                    idx += 1;
+                    continue;
+                };
+                this_level_changed = true;
+                alternatives.splice(idx..=idx, inner);
+            }
+
+            // Focus on `p_n` and then try to transform all `p_i` where `i > n`.
+            let mut focus_idx = 0;
+            while focus_idx < alternatives.len() {
+                this_level_changed |= transform_with_focus_on_idx(alternatives, focus_idx);
+                focus_idx += 1;
+            }
+            self.changed |= this_level_changed;
+
+            // Deal with `Some(Some(0)) | Some(Some(1))`.
+            if this_level_changed {
+                noop_visit_pat(p, self);
+            }
+        }
+    }
+
+    let mut visitor = Visitor { changed: false };
+    visitor.visit_pat(pat);
+    visitor.changed
+}
+
+/// Match `$scrutinee` against `$pat` and extract `$then` from it.
+/// Panics if there is no match.
+macro_rules! always_pat {
+    ($scrutinee:expr, $pat:pat => $then:expr) => {
+        match $scrutinee {
+            $pat => $then,
+            _ => unreachable!(),
+        }
+    };
+}
+
+/// Focus on `focus_idx` in `alternatives`,
+/// attempting to extend it with elements of the same constructor `C`
+/// in `alternatives[focus_idx + 1..]`.
+fn transform_with_focus_on_idx(alternatives: &mut Vec<P<Pat>>, focus_idx: usize) -> bool {
+    // Extract the kind; we'll need to make some changes in it.
+    let mut focus_kind = mem::replace(&mut alternatives[focus_idx].kind, PatKind::Wild);
+    // We'll focus on `alternatives[focus_idx]`,
+    // so we're draining from `alternatives[focus_idx + 1..]`.
+    let start = focus_idx + 1;
+
+    // We're trying to find whatever kind (~"constructor") we found in `alternatives[start..]`.
+    let changed = match &mut focus_kind {
+        // These pattern forms are "leafs" and do not have sub-patterns.
+        // Therefore they are not some form of constructor `C`,
+        // with which a pattern `C(P0)` may be formed,
+        // which we would want to join with other `C(Pj)`s.
+        Ident(.., None) | Lit(_) | Wild | Path(..) | Range(..) | Rest | MacCall(_)
+        // Dealt with elsewhere.
+        | Or(_) | Paren(_) => false,
+        // Transform `box x | ... | box y` into `box (x | y)`.
+        //
+        // The cases below until `Slice(...)` deal *singleton* products.
+        // These patterns have the shape `C(p)`, and not e.g., `C(p0, ..., pn)`.
+        Box(target) => extend_with_matching(
+            target, start, alternatives,
+            |k| matches!(k, Box(_)),
+            |k| always_pat!(k, Box(p) => p),
+        ),
+        // Transform `&m x | ... | &m y` into `&m (x, y)`.
+        Ref(target, m1) => extend_with_matching(
+            target, start, alternatives,
+            |k| matches!(k, Ref(_, m2) if m1 == m2), // Mutabilities must match.
+            |k| always_pat!(k, Ref(p, _) => p),
+        ),
+        // Transform `b @ p0 | ... b @ p1` into `b @ (p0 | p1)`.
+        Ident(b1, i1, Some(target)) => extend_with_matching(
+            target, start, alternatives,
+            // Binding names must match.
+            |k| matches!(k, Ident(b2, i2, Some(_)) if b1 == b2 && eq_id(*i1, *i2)),
+            |k| always_pat!(k, Ident(_, _, Some(p)) => p),
+        ),
+        // Transform `[pre, x, post] | ... | [pre, y, post]` into `[pre, x | y, post]`.
+        Slice(ps1) => extend_with_matching_product(
+            ps1, start, alternatives,
+            |k, ps1, idx| matches!(k, Slice(ps2) if eq_pre_post(ps1, ps2, idx)),
+            |k| always_pat!(k, Slice(ps) => ps),
+        ),
+        // Transform `(pre, x, post) | ... | (pre, y, post)` into `(pre, x | y, post]`.
+        Tuple(ps1) => extend_with_matching_product(
+            ps1, start, alternatives,
+            |k, ps1, idx| matches!(k, Tuple(ps2) if eq_pre_post(ps1, ps2, idx)),
+            |k| always_pat!(k, Tuple(ps) => ps),
+        ),
+        // Transform `S(pre, x, post) | ... | S(pre, y, post)` into `S(pre, x | y, post]`.
+        TupleStruct(path1, ps1) => extend_with_matching_product(
+            ps1, start, alternatives,
+            |k, ps1, idx| matches!(
+                k,
+                TupleStruct(path2, ps2) if eq_path(path1, path2) && eq_pre_post(ps1, ps2, idx)
+            ),
+            |k| always_pat!(k, TupleStruct(_, ps) => ps),
+        ),
+        // Transform a record pattern `S { fp_0, ..., fp_n }`.
+        Struct(path1, fps1, rest1) => extend_with_struct_pat(path1, fps1, *rest1, start, alternatives),
+    };
+
+    alternatives[focus_idx].kind = focus_kind;
+    changed
+}
+
+/// Here we focusing on a record pattern `S { fp_0, ..., fp_n }`.
+/// In particular, for a record pattern, the order in which the field patterns is irrelevant.
+/// So when we fixate on some `ident_k: pat_k`, we try to find `ident_k` in the other pattern
+/// and check that all `fp_i` where `i ∈ ((0...n) \ k)` between two patterns are equal.
+fn extend_with_struct_pat(
+    path1: &ast::Path,
+    fps1: &mut Vec<ast::FieldPat>,
+    rest1: bool,
+    start: usize,
+    alternatives: &mut Vec<P<Pat>>,
+) -> bool {
+    (0..fps1.len()).any(|idx| {
+        let pos_in_2 = Cell::new(None); // The element `k`.
+        let tail_or = drain_matching(
+            start,
+            alternatives,
+            |k| {
+                matches!(k, Struct(path2, fps2, rest2)
+                if rest1 == *rest2 // If one struct pattern has `..` so must the other.
+                && eq_path(path1, path2)
+                && fps1.len() == fps2.len()
+                && fps1.iter().enumerate().all(|(idx_1, fp1)| {
+                    if idx_1 == idx {
+                        // In the case of `k`, we merely require identical field names
+                        // so that we will transform into `ident_k: p1_k | p2_k`.
+                        let pos = fps2.iter().position(|fp2| eq_id(fp1.ident, fp2.ident));
+                        pos_in_2.set(pos);
+                        pos.is_some()
+                    } else {
+                        fps2.iter().any(|fp2| eq_field_pat(fp1, fp2))
+                    }
+                }))
+            },
+            // Extract `p2_k`.
+            |k| always_pat!(k, Struct(_, mut fps, _) => fps.swap_remove(pos_in_2.take().unwrap()).pat),
+        );
+        extend_with_tail_or(&mut fps1[idx].pat, tail_or)
+    })
+}
+
+/// Like `extend_with_matching` but for products with > 1 factor, e.g., `C(p_0, ..., p_n)`.
+/// Here, the idea is that we fixate on some `p_k` in `C`,
+/// allowing it to vary between two `targets` and `ps2` (returned by `extract`),
+/// while also requiring `ps1[..n] ~ ps2[..n]` (pre) and `ps1[n + 1..] ~ ps2[n + 1..]` (post),
+/// where `~` denotes semantic equality.
+fn extend_with_matching_product(
+    targets: &mut Vec<P<Pat>>,
+    start: usize,
+    alternatives: &mut Vec<P<Pat>>,
+    predicate: impl Fn(&PatKind, &[P<Pat>], usize) -> bool,
+    extract: impl Fn(PatKind) -> Vec<P<Pat>>,
+) -> bool {
+    (0..targets.len()).any(|idx| {
+        let tail_or = drain_matching(
+            start,
+            alternatives,
+            |k| predicate(k, targets, idx),
+            |k| extract(k).swap_remove(idx),
+        );
+        extend_with_tail_or(&mut targets[idx], tail_or)
+    })
+}
+
+/// Extract the pattern from the given one and replace it with `Wild`.
+/// This is meant for temporarily swapping out the pattern for manipulation.
+fn take_pat(from: &mut Pat) -> Pat {
+    let dummy = Pat {
+        id: DUMMY_NODE_ID,
+        kind: Wild,
+        span: DUMMY_SP,
+    };
+    mem::replace(from, dummy)
+}
+
+/// Extend `target` as an or-pattern with the alternatives
+/// in `tail_or` if there are any and return if there were.
+fn extend_with_tail_or(target: &mut Pat, tail_or: Vec<P<Pat>>) -> bool {
+    fn extend(target: &mut Pat, mut tail_or: Vec<P<Pat>>) {
+        match target {
+            // On an existing or-pattern in the target, append to it.
+            Pat { kind: Or(ps), .. } => ps.append(&mut tail_or),
+            // Otherwise convert the target to an or-pattern.
+            target => {
+                let mut init_or = vec![P(take_pat(target))];
+                init_or.append(&mut tail_or);
+                target.kind = Or(init_or);
+            },
+        }
+    }
+
+    let changed = !tail_or.is_empty();
+    if changed {
+        // Extend the target.
+        extend(target, tail_or);
+    }
+    changed
+}
+
+// Extract all inner patterns in `alternatives` matching our `predicate`.
+// Only elements beginning with `start` are considered for extraction.
+fn drain_matching(
+    start: usize,
+    alternatives: &mut Vec<P<Pat>>,
+    predicate: impl Fn(&PatKind) -> bool,
+    extract: impl Fn(PatKind) -> P<Pat>,
+) -> Vec<P<Pat>> {
+    let mut tail_or = vec![];
+    let mut idx = 0;
+    for pat in alternatives.drain_filter(|p| {
+        // Check if we should extract, but only if `idx >= start`.
+        idx += 1;
+        idx > start && predicate(&p.kind)
+    }) {
+        tail_or.push(extract(pat.into_inner().kind));
+    }
+    tail_or
+}
+
+fn extend_with_matching(
+    target: &mut Pat,
+    start: usize,
+    alternatives: &mut Vec<P<Pat>>,
+    predicate: impl Fn(&PatKind) -> bool,
+    extract: impl Fn(PatKind) -> P<Pat>,
+) -> bool {
+    extend_with_tail_or(target, drain_matching(start, alternatives, predicate, extract))
+}
+
+/// Are the patterns in `ps1` and `ps2` equal save for `ps1[idx]` compared to `ps2[idx]`?
+fn eq_pre_post(ps1: &[P<Pat>], ps2: &[P<Pat>], idx: usize) -> bool {
+    ps1[idx].is_rest() == ps2[idx].is_rest() // Avoid `[x, ..] | [x, 0]` => `[x, .. | 0]`.
+        && ps1.len() == ps2.len()
+        && over(&ps1[..idx], &ps2[..idx], |l, r| eq_pat(l, r))
+        && over(&ps1[idx + 1..], &ps2[idx + 1..], |l, r| eq_pat(l, r))
+}

clippy_lints/src/utils/ast_utils.rs

@@ -0,0 +1,525 @@
+//! Utilities for manipulating and extracting information from `rustc_ast::ast`.
+//!
+//! - The `eq_foobar` functions test for semantic equality but ignores `NodeId`s and `Span`s.
+
+#![allow(clippy::similar_names, clippy::wildcard_imports, clippy::enum_glob_use)]
+
+use crate::utils::{both, over};
+use rustc_ast::ast::{self, *};
+use rustc_ast::ptr::P;
+use std::mem;
+
+/// Checks if each element in the first slice is contained within the latter as per `eq_fn`.
+pub fn unordered_over<X>(left: &[X], right: &[X], mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
+    left.len() == right.len() && left.iter().all(|l| right.iter().any(|r| eq_fn(l, r)))
+}
+
+pub fn eq_id(l: Ident, r: Ident) -> bool {
+    l.name == r.name
+}
+
+pub fn eq_pat(l: &Pat, r: &Pat) -> bool {
+    use PatKind::*;
+    match (&l.kind, &r.kind) {
+        (Paren(l), _) => eq_pat(l, r),
+        (_, Paren(r)) => eq_pat(l, r),
+        (Wild, Wild) | (Rest, Rest) => true,
+        (Lit(l), Lit(r)) => eq_expr(l, r),
+        (Ident(b1, i1, s1), Ident(b2, i2, s2)) => b1 == b2 && eq_id(*i1, *i2) && both(s1, s2, |l, r| eq_pat(l, r)),
+        (Range(lf, lt, le), Range(rf, rt, re)) => {
+            eq_expr_opt(lf, rf) && eq_expr_opt(lt, rt) && eq_range_end(&le.node, &re.node)
+        },
+        (Box(l), Box(r))
+        | (Ref(l, Mutability::Not), Ref(r, Mutability::Not))
+        | (Ref(l, Mutability::Mut), Ref(r, Mutability::Mut)) => eq_pat(l, r),
+        (Tuple(l), Tuple(r)) | (Slice(l), Slice(r)) => over(l, r, |l, r| eq_pat(l, r)),
+        (Path(lq, lp), Path(rq, rp)) => both(lq, rq, |l, r| eq_qself(l, r)) && eq_path(lp, rp),
+        (TupleStruct(lp, lfs), TupleStruct(rp, rfs)) => eq_path(lp, rp) && over(lfs, rfs, |l, r| eq_pat(l, r)),
+        (Struct(lp, lfs, lr), Struct(rp, rfs, rr)) => {
+            lr == rr && eq_path(lp, rp) && unordered_over(lfs, rfs, |lf, rf| eq_field_pat(lf, rf))
+        },
+        (Or(ls), Or(rs)) => unordered_over(ls, rs, |l, r| eq_pat(l, r)),
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_range_end(l: &RangeEnd, r: &RangeEnd) -> bool {
+    match (l, r) {
+        (RangeEnd::Excluded, RangeEnd::Excluded) => true,
+        (RangeEnd::Included(l), RangeEnd::Included(r)) => {
+            matches!(l, RangeSyntax::DotDotEq) == matches!(r, RangeSyntax::DotDotEq)
+        },
+        _ => false,
+    }
+}
+
+pub fn eq_field_pat(l: &FieldPat, r: &FieldPat) -> bool {
+    l.is_placeholder == r.is_placeholder
+        && eq_id(l.ident, r.ident)
+        && eq_pat(&l.pat, &r.pat)
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+}
+
+pub fn eq_qself(l: &QSelf, r: &QSelf) -> bool {
+    l.position == r.position && eq_ty(&l.ty, &r.ty)
+}
+
+pub fn eq_path(l: &Path, r: &Path) -> bool {
+    over(&l.segments, &r.segments, |l, r| eq_path_seg(l, r))
+}
+
+pub fn eq_path_seg(l: &PathSegment, r: &PathSegment) -> bool {
+    eq_id(l.ident, r.ident) && both(&l.args, &r.args, |l, r| eq_generic_args(l, r))
+}
+
+pub fn eq_generic_args(l: &GenericArgs, r: &GenericArgs) -> bool {
+    match (l, r) {
+        (GenericArgs::AngleBracketed(l), GenericArgs::AngleBracketed(r)) => {
+            over(&l.args, &r.args, |l, r| eq_angle_arg(l, r))
+        },
+        (GenericArgs::Parenthesized(l), GenericArgs::Parenthesized(r)) => {
+            over(&l.inputs, &r.inputs, |l, r| eq_ty(l, r)) && eq_fn_ret_ty(&l.output, &r.output)
+        },
+        _ => false,
+    }
+}
+
+pub fn eq_angle_arg(l: &AngleBracketedArg, r: &AngleBracketedArg) -> bool {
+    match (l, r) {
+        (AngleBracketedArg::Arg(l), AngleBracketedArg::Arg(r)) => eq_generic_arg(l, r),
+        (AngleBracketedArg::Constraint(l), AngleBracketedArg::Constraint(r)) => eq_assoc_constraint(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_generic_arg(l: &GenericArg, r: &GenericArg) -> bool {
+    match (l, r) {
+        (GenericArg::Lifetime(l), GenericArg::Lifetime(r)) => eq_id(l.ident, r.ident),
+        (GenericArg::Type(l), GenericArg::Type(r)) => eq_ty(l, r),
+        (GenericArg::Const(l), GenericArg::Const(r)) => eq_expr(&l.value, &r.value),
+        _ => false,
+    }
+}
+
+pub fn eq_expr_opt(l: &Option<P<Expr>>, r: &Option<P<Expr>>) -> bool {
+    both(l, r, |l, r| eq_expr(l, r))
+}
+
+pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
+    use ExprKind::*;
+    if !over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r)) {
+        return false;
+    }
+    match (&l.kind, &r.kind) {
+        (Paren(l), _) => eq_expr(l, r),
+        (_, Paren(r)) => eq_expr(l, r),
+        (Err, Err) => true,
+        (Box(l), Box(r)) | (Try(l), Try(r)) | (Await(l), Await(r)) => eq_expr(l, r),
+        (Array(l), Array(r)) | (Tup(l), Tup(r)) => over(l, r, |l, r| eq_expr(l, r)),
+        (Repeat(le, ls), Repeat(re, rs)) => eq_expr(le, re) && eq_expr(&ls.value, &rs.value),
+        (Call(lc, la), Call(rc, ra)) => eq_expr(lc, rc) && over(la, ra, |l, r| eq_expr(l, r)),
+        (MethodCall(lc, la), MethodCall(rc, ra)) => eq_path_seg(lc, rc) && over(la, ra, |l, r| eq_expr(l, r)),
+        (Binary(lo, ll, lr), Binary(ro, rl, rr)) => lo.node == ro.node && eq_expr(ll, rl) && eq_expr(lr, rr),
+        (Unary(lo, l), Unary(ro, r)) => mem::discriminant(lo) == mem::discriminant(ro) && eq_expr(l, r),
+        (Lit(l), Lit(r)) => l.kind == r.kind,
+        (Cast(l, lt), Cast(r, rt)) | (Type(l, lt), Type(r, rt)) => eq_expr(l, r) && eq_ty(lt, rt),
+        (Let(lp, le), Let(rp, re)) => eq_pat(lp, rp) && eq_expr(le, re),
+        (If(lc, lt, le), If(rc, rt, re)) => eq_expr(lc, rc) && eq_block(lt, rt) && eq_expr_opt(le, re),
+        (While(lc, lt, ll), While(rc, rt, rl)) => eq_label(ll, rl) && eq_expr(lc, rc) && eq_block(lt, rt),
+        (ForLoop(lp, li, lt, ll), ForLoop(rp, ri, rt, rl)) => {
+            eq_label(ll, rl) && eq_pat(lp, rp) && eq_expr(li, ri) && eq_block(lt, rt)
+        },
+        (Loop(lt, ll), Loop(rt, rl)) => eq_label(ll, rl) && eq_block(lt, rt),
+        (Block(lb, ll), Block(rb, rl)) => eq_label(ll, rl) && eq_block(lb, rb),
+        (TryBlock(l), TryBlock(r)) => eq_block(l, r),
+        (Yield(l), Yield(r)) | (Ret(l), Ret(r)) => eq_expr_opt(l, r),
+        (Break(ll, le), Break(rl, re)) => eq_label(ll, rl) && eq_expr_opt(le, re),
+        (Continue(ll), Continue(rl)) => eq_label(ll, rl),
+        (Assign(l1, l2, _), Assign(r1, r2, _)) | (Index(l1, l2), Index(r1, r2)) => eq_expr(l1, r1) && eq_expr(l2, r2),
+        (AssignOp(lo, lp, lv), AssignOp(ro, rp, rv)) => lo.node == ro.node && eq_expr(lp, rp) && eq_expr(lv, rv),
+        (Field(lp, lf), Field(rp, rf)) => eq_id(*lf, *rf) && eq_expr(lp, rp),
+        (Match(ls, la), Match(rs, ra)) => eq_expr(ls, rs) && over(la, ra, |l, r| eq_arm(l, r)),
+        (Closure(lc, la, lm, lf, lb, _), Closure(rc, ra, rm, rf, rb, _)) => {
+            lc == rc && la.is_async() == ra.is_async() && lm == rm && eq_fn_decl(lf, rf) && eq_expr(lb, rb)
+        },
+        (Async(lc, _, lb), Async(rc, _, rb)) => lc == rc && eq_block(lb, rb),
+        (Range(lf, lt, ll), Range(rf, rt, rl)) => ll == rl && eq_expr_opt(lf, rf) && eq_expr_opt(lt, rt),
+        (AddrOf(lbk, lm, le), AddrOf(rbk, rm, re)) => lbk == rbk && lm == rm && eq_expr(le, re),
+        (Path(lq, lp), Path(rq, rp)) => both(lq, rq, |l, r| eq_qself(l, r)) && eq_path(lp, rp),
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        (Struct(lp, lfs, lb), Struct(rp, rfs, rb)) => {
+            eq_path(lp, rp) && eq_expr_opt(lb, rb) && unordered_over(lfs, rfs, |l, r| eq_field(l, r))
+        },
+        _ => false,
+    }
+}
+
+pub fn eq_field(l: &Field, r: &Field) -> bool {
+    l.is_placeholder == r.is_placeholder
+        && eq_id(l.ident, r.ident)
+        && eq_expr(&l.expr, &r.expr)
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+}
+
+pub fn eq_arm(l: &Arm, r: &Arm) -> bool {
+    l.is_placeholder == r.is_placeholder
+        && eq_pat(&l.pat, &r.pat)
+        && eq_expr(&l.body, &r.body)
+        && eq_expr_opt(&l.guard, &r.guard)
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+}
+
+pub fn eq_label(l: &Option<Label>, r: &Option<Label>) -> bool {
+    both(l, r, |l, r| eq_id(l.ident, r.ident))
+}
+
+pub fn eq_block(l: &Block, r: &Block) -> bool {
+    l.rules == r.rules && over(&l.stmts, &r.stmts, |l, r| eq_stmt(l, r))
+}
+
+pub fn eq_stmt(l: &Stmt, r: &Stmt) -> bool {
+    use StmtKind::*;
+    match (&l.kind, &r.kind) {
+        (Local(l), Local(r)) => {
+            eq_pat(&l.pat, &r.pat)
+                && both(&l.ty, &r.ty, |l, r| eq_ty(l, r))
+                && eq_expr_opt(&l.init, &r.init)
+                && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+        },
+        (Item(l), Item(r)) => eq_item(l, r, eq_item_kind),
+        (Expr(l), Expr(r)) | (Semi(l), Semi(r)) => eq_expr(l, r),
+        (Empty, Empty) => true,
+        (MacCall(l), MacCall(r)) => l.1 == r.1 && eq_mac_call(&l.0, &r.0) && over(&l.2, &r.2, |l, r| eq_attr(l, r)),
+        _ => false,
+    }
+}
+
+pub fn eq_item<K>(l: &Item<K>, r: &Item<K>, mut eq_kind: impl FnMut(&K, &K) -> bool) -> bool {
+    eq_id(l.ident, r.ident)
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+        && eq_vis(&l.vis, &r.vis)
+        && eq_kind(&l.kind, &r.kind)
+}
+
+pub fn eq_item_kind(l: &ItemKind, r: &ItemKind) -> bool {
+    use ItemKind::*;
+    match (l, r) {
+        (ExternCrate(l), ExternCrate(r)) => l == r,
+        (Use(l), Use(r)) => eq_use_tree(l, r),
+        (Static(lt, lm, le), Static(rt, rm, re)) => lm == rm && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        (Const(ld, lt, le), Const(rd, rt, re)) => eq_defaultness(*ld, *rd) && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        (Fn(ld, lf, lg, lb), Fn(rd, rf, rg, rb)) => {
+            eq_defaultness(*ld, *rd) && eq_fn_sig(lf, rf) && eq_generics(lg, rg) && both(lb, rb, |l, r| eq_block(l, r))
+        },
+        (Mod(l), Mod(r)) => l.inline == r.inline && over(&l.items, &r.items, |l, r| eq_item(l, r, eq_item_kind)),
+        (ForeignMod(l), ForeignMod(r)) => {
+            both(&l.abi, &r.abi, |l, r| eq_str_lit(l, r))
+                && over(&l.items, &r.items, |l, r| eq_item(l, r, eq_foreign_item_kind))
+        },
+        (TyAlias(ld, lg, lb, lt), TyAlias(rd, rg, rb, rt)) => {
+            eq_defaultness(*ld, *rd)
+                && eq_generics(lg, rg)
+                && over(lb, rb, |l, r| eq_generic_bound(l, r))
+                && both(lt, rt, |l, r| eq_ty(l, r))
+        },
+        (Enum(le, lg), Enum(re, rg)) => {
+            over(&le.variants, &re.variants, |l, r| eq_variant(l, r)) && eq_generics(lg, rg)
+        },
+        (Struct(lv, lg), Struct(rv, rg)) | (Union(lv, lg), Union(rv, rg)) => {
+            eq_variant_data(lv, rv) && eq_generics(lg, rg)
+        },
+        (Trait(la, lu, lg, lb, li), Trait(ra, ru, rg, rb, ri)) => {
+            la == ra
+                && matches!(lu, Unsafe::No) == matches!(ru, Unsafe::No)
+                && eq_generics(lg, rg)
+                && over(lb, rb, |l, r| eq_generic_bound(l, r))
+                && over(li, ri, |l, r| eq_item(l, r, eq_assoc_item_kind))
+        },
+        (TraitAlias(lg, lb), TraitAlias(rg, rb)) => eq_generics(lg, rg) && over(lb, rb, |l, r| eq_generic_bound(l, r)),
+        (
+            Impl {
+                unsafety: lu,
+                polarity: lp,
+                defaultness: ld,
+                constness: lc,
+                generics: lg,
+                of_trait: lot,
+                self_ty: lst,
+                items: li,
+            },
+            Impl {
+                unsafety: ru,
+                polarity: rp,
+                defaultness: rd,
+                constness: rc,
+                generics: rg,
+                of_trait: rot,
+                self_ty: rst,
+                items: ri,
+            },
+        ) => {
+            matches!(lu, Unsafe::No) == matches!(ru, Unsafe::No)
+                && matches!(lp, ImplPolarity::Positive) == matches!(rp, ImplPolarity::Positive)
+                && eq_defaultness(*ld, *rd)
+                && matches!(lc, ast::Const::No) == matches!(rc, ast::Const::No)
+                && eq_generics(lg, rg)
+                && both(lot, rot, |l, r| eq_path(&l.path, &r.path))
+                && eq_ty(lst, rst)
+                && over(li, ri, |l, r| eq_item(l, r, eq_assoc_item_kind))
+        },
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        (MacroDef(l), MacroDef(r)) => l.macro_rules == r.macro_rules && eq_mac_args(&l.body, &r.body),
+        _ => false,
+    }
+}
+
+pub fn eq_foreign_item_kind(l: &ForeignItemKind, r: &ForeignItemKind) -> bool {
+    use ForeignItemKind::*;
+    match (l, r) {
+        (Static(lt, lm, le), Static(rt, rm, re)) => lm == rm && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        (Fn(ld, lf, lg, lb), Fn(rd, rf, rg, rb)) => {
+            eq_defaultness(*ld, *rd) && eq_fn_sig(lf, rf) && eq_generics(lg, rg) && both(lb, rb, |l, r| eq_block(l, r))
+        },
+        (TyAlias(ld, lg, lb, lt), TyAlias(rd, rg, rb, rt)) => {
+            eq_defaultness(*ld, *rd)
+                && eq_generics(lg, rg)
+                && over(lb, rb, |l, r| eq_generic_bound(l, r))
+                && both(lt, rt, |l, r| eq_ty(l, r))
+        },
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_assoc_item_kind(l: &AssocItemKind, r: &AssocItemKind) -> bool {
+    use AssocItemKind::*;
+    match (l, r) {
+        (Const(ld, lt, le), Const(rd, rt, re)) => eq_defaultness(*ld, *rd) && eq_ty(lt, rt) && eq_expr_opt(le, re),
+        (Fn(ld, lf, lg, lb), Fn(rd, rf, rg, rb)) => {
+            eq_defaultness(*ld, *rd) && eq_fn_sig(lf, rf) && eq_generics(lg, rg) && both(lb, rb, |l, r| eq_block(l, r))
+        },
+        (TyAlias(ld, lg, lb, lt), TyAlias(rd, rg, rb, rt)) => {
+            eq_defaultness(*ld, *rd)
+                && eq_generics(lg, rg)
+                && over(lb, rb, |l, r| eq_generic_bound(l, r))
+                && both(lt, rt, |l, r| eq_ty(l, r))
+        },
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_variant(l: &Variant, r: &Variant) -> bool {
+    l.is_placeholder == r.is_placeholder
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+        && eq_vis(&l.vis, &r.vis)
+        && eq_id(l.ident, r.ident)
+        && eq_variant_data(&l.data, &r.data)
+        && both(&l.disr_expr, &r.disr_expr, |l, r| eq_expr(&l.value, &r.value))
+}
+
+pub fn eq_variant_data(l: &VariantData, r: &VariantData) -> bool {
+    use VariantData::*;
+    match (l, r) {
+        (Unit(_), Unit(_)) => true,
+        (Struct(l, _), Struct(r, _)) | (Tuple(l, _), Tuple(r, _)) => over(l, r, |l, r| eq_struct_field(l, r)),
+        _ => false,
+    }
+}
+
+pub fn eq_struct_field(l: &StructField, r: &StructField) -> bool {
+    l.is_placeholder == r.is_placeholder
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+        && eq_vis(&l.vis, &r.vis)
+        && both(&l.ident, &r.ident, |l, r| eq_id(*l, *r))
+        && eq_ty(&l.ty, &r.ty)
+}
+
+pub fn eq_fn_sig(l: &FnSig, r: &FnSig) -> bool {
+    eq_fn_decl(&l.decl, &r.decl) && eq_fn_header(&l.header, &r.header)
+}
+
+pub fn eq_fn_header(l: &FnHeader, r: &FnHeader) -> bool {
+    matches!(l.unsafety, Unsafe::No) == matches!(r.unsafety, Unsafe::No)
+        && l.asyncness.is_async() == r.asyncness.is_async()
+        && matches!(l.constness, Const::No) == matches!(r.constness, Const::No)
+        && eq_ext(&l.ext, &r.ext)
+}
+
+pub fn eq_generics(l: &Generics, r: &Generics) -> bool {
+    over(&l.params, &r.params, |l, r| eq_generic_param(l, r))
+        && over(&l.where_clause.predicates, &r.where_clause.predicates, |l, r| {
+            eq_where_predicate(l, r)
+        })
+}
+
+pub fn eq_where_predicate(l: &WherePredicate, r: &WherePredicate) -> bool {
+    use WherePredicate::*;
+    match (l, r) {
+        (BoundPredicate(l), BoundPredicate(r)) => {
+            over(&l.bound_generic_params, &r.bound_generic_params, |l, r| {
+                eq_generic_param(l, r)
+            }) && eq_ty(&l.bounded_ty, &r.bounded_ty)
+                && over(&l.bounds, &r.bounds, |l, r| eq_generic_bound(l, r))
+        },
+        (RegionPredicate(l), RegionPredicate(r)) => {
+            eq_id(l.lifetime.ident, r.lifetime.ident) && over(&l.bounds, &r.bounds, |l, r| eq_generic_bound(l, r))
+        },
+        (EqPredicate(l), EqPredicate(r)) => eq_ty(&l.lhs_ty, &r.lhs_ty) && eq_ty(&l.rhs_ty, &r.rhs_ty),
+        _ => false,
+    }
+}
+
+pub fn eq_use_tree(l: &UseTree, r: &UseTree) -> bool {
+    eq_path(&l.prefix, &r.prefix) && eq_use_tree_kind(&l.kind, &r.kind)
+}
+
+pub fn eq_use_tree_kind(l: &UseTreeKind, r: &UseTreeKind) -> bool {
+    use UseTreeKind::*;
+    match (l, r) {
+        (Glob, Glob) => true,
+        (Simple(l, _, _), Simple(r, _, _)) => both(l, r, |l, r| eq_id(*l, *r)),
+        (Nested(l), Nested(r)) => over(l, r, |(l, _), (r, _)| eq_use_tree(l, r)),
+        _ => false,
+    }
+}
+
+pub fn eq_defaultness(l: Defaultness, r: Defaultness) -> bool {
+    match (l, r) {
+        (Defaultness::Final, Defaultness::Final) | (Defaultness::Default(_), Defaultness::Default(_)) => true,
+        _ => false,
+    }
+}
+
+pub fn eq_vis(l: &Visibility, r: &Visibility) -> bool {
+    use VisibilityKind::*;
+    match (&l.node, &r.node) {
+        (Public, Public) | (Inherited, Inherited) | (Crate(_), Crate(_)) => true,
+        (Restricted { path: l, .. }, Restricted { path: r, .. }) => eq_path(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_fn_decl(l: &FnDecl, r: &FnDecl) -> bool {
+    eq_fn_ret_ty(&l.output, &r.output)
+        && over(&l.inputs, &r.inputs, |l, r| {
+            l.is_placeholder == r.is_placeholder
+                && eq_pat(&l.pat, &r.pat)
+                && eq_ty(&l.ty, &r.ty)
+                && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+        })
+}
+
+pub fn eq_fn_ret_ty(l: &FnRetTy, r: &FnRetTy) -> bool {
+    match (l, r) {
+        (FnRetTy::Default(_), FnRetTy::Default(_)) => true,
+        (FnRetTy::Ty(l), FnRetTy::Ty(r)) => eq_ty(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_ty(l: &Ty, r: &Ty) -> bool {
+    use TyKind::*;
+    match (&l.kind, &r.kind) {
+        (Paren(l), _) => eq_ty(l, r),
+        (_, Paren(r)) => eq_ty(l, r),
+        (Never, Never) | (Infer, Infer) | (ImplicitSelf, ImplicitSelf) | (Err, Err) | (CVarArgs, CVarArgs) => true,
+        (Slice(l), Slice(r)) => eq_ty(l, r),
+        (Array(le, ls), Array(re, rs)) => eq_ty(le, re) && eq_expr(&ls.value, &rs.value),
+        (Ptr(l), Ptr(r)) => l.mutbl == r.mutbl && eq_ty(&l.ty, &r.ty),
+        (Rptr(ll, l), Rptr(rl, r)) => {
+            both(ll, rl, |l, r| eq_id(l.ident, r.ident)) && l.mutbl == r.mutbl && eq_ty(&l.ty, &r.ty)
+        },
+        (BareFn(l), BareFn(r)) => {
+            l.unsafety == r.unsafety
+                && eq_ext(&l.ext, &r.ext)
+                && over(&l.generic_params, &r.generic_params, |l, r| eq_generic_param(l, r))
+                && eq_fn_decl(&l.decl, &r.decl)
+        },
+        (Tup(l), Tup(r)) => over(l, r, |l, r| eq_ty(l, r)),
+        (Path(lq, lp), Path(rq, rp)) => both(lq, rq, |l, r| eq_qself(l, r)) && eq_path(lp, rp),
+        (TraitObject(lg, ls), TraitObject(rg, rs)) => ls == rs && over(lg, rg, |l, r| eq_generic_bound(l, r)),
+        (ImplTrait(_, lg), ImplTrait(_, rg)) => over(lg, rg, |l, r| eq_generic_bound(l, r)),
+        (Typeof(l), Typeof(r)) => eq_expr(&l.value, &r.value),
+        (MacCall(l), MacCall(r)) => eq_mac_call(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_ext(l: &Extern, r: &Extern) -> bool {
+    use Extern::*;
+    match (l, r) {
+        (None, None) | (Implicit, Implicit) => true,
+        (Explicit(l), Explicit(r)) => eq_str_lit(l, r),
+        _ => false,
+    }
+}
+
+pub fn eq_str_lit(l: &StrLit, r: &StrLit) -> bool {
+    l.style == r.style && l.symbol == r.symbol && l.suffix == r.suffix
+}
+
+pub fn eq_poly_ref_trait(l: &PolyTraitRef, r: &PolyTraitRef) -> bool {
+    eq_path(&l.trait_ref.path, &r.trait_ref.path)
+        && over(&l.bound_generic_params, &r.bound_generic_params, |l, r| {
+            eq_generic_param(l, r)
+        })
+}
+
+pub fn eq_generic_param(l: &GenericParam, r: &GenericParam) -> bool {
+    use GenericParamKind::*;
+    l.is_placeholder == r.is_placeholder
+        && eq_id(l.ident, r.ident)
+        && over(&l.bounds, &r.bounds, |l, r| eq_generic_bound(l, r))
+        && match (&l.kind, &r.kind) {
+            (Lifetime, Lifetime) => true,
+            (Type { default: l }, Type { default: r }) => both(l, r, |l, r| eq_ty(l, r)),
+            (Const { ty: l }, Const { ty: r }) => eq_ty(l, r),
+            _ => false,
+        }
+        && over(&l.attrs, &r.attrs, |l, r| eq_attr(l, r))
+}
+
+pub fn eq_generic_bound(l: &GenericBound, r: &GenericBound) -> bool {
+    use GenericBound::*;
+    match (l, r) {
+        (Trait(ptr1, tbm1), Trait(ptr2, tbm2)) => tbm1 == tbm2 && eq_poly_ref_trait(ptr1, ptr2),
+        (Outlives(l), Outlives(r)) => eq_id(l.ident, r.ident),
+        _ => false,
+    }
+}
+
+pub fn eq_assoc_constraint(l: &AssocTyConstraint, r: &AssocTyConstraint) -> bool {
+    use AssocTyConstraintKind::*;
+    eq_id(l.ident, r.ident)
+        && match (&l.kind, &r.kind) {
+            (Equality { ty: l }, Equality { ty: r }) => eq_ty(l, r),
+            (Bound { bounds: l }, Bound { bounds: r }) => over(l, r, |l, r| eq_generic_bound(l, r)),
+            _ => false,
+        }
+}
+
+pub fn eq_mac_call(l: &MacCall, r: &MacCall) -> bool {
+    eq_path(&l.path, &r.path) && eq_mac_args(&l.args, &r.args)
+}
+
+pub fn eq_attr(l: &Attribute, r: &Attribute) -> bool {
+    use AttrKind::*;
+    l.style == r.style
+        && match (&l.kind, &r.kind) {
+            (DocComment(l), DocComment(r)) => l == r,
+            (Normal(l), Normal(r)) => eq_path(&l.path, &r.path) && eq_mac_args(&l.args, &r.args),
+            _ => false,
+        }
+}
+
+pub fn eq_mac_args(l: &MacArgs, r: &MacArgs) -> bool {
+    use MacArgs::*;
+    match (l, r) {
+        (Empty, Empty) => true,
+        (Delimited(_, ld, lts), Delimited(_, rd, rts)) => ld == rd && lts.eq_unspanned(rts),
+        (Eq(_, lts), Eq(_, rts)) => lts.eq_unspanned(rts),
+        _ => false,
+    }
+}

clippy_lints/src/utils/hir_utils.rs

@@ -332,19 +332,13 @@ fn swap_binop<'a>(
 
 /// Checks if the two `Option`s are both `None` or some equal values as per
 /// `eq_fn`.
-fn both<X, F>(l: &Option<X>, r: &Option<X>, mut eq_fn: F) -> bool
-where
-    F: FnMut(&X, &X) -> bool,
-{
+pub fn both<X>(l: &Option<X>, r: &Option<X>, mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
     l.as_ref()
         .map_or_else(|| r.is_none(), |x| r.as_ref().map_or(false, |y| eq_fn(x, y)))
 }
 
 /// Checks if two slices are equal as per `eq_fn`.
-fn over<X, F>(left: &[X], right: &[X], mut eq_fn: F) -> bool
-where
-    F: FnMut(&X, &X) -> bool,
-{
+pub fn over<X>(left: &[X], right: &[X], mut eq_fn: impl FnMut(&X, &X) -> bool) -> bool {
     left.len() == right.len() && left.iter().zip(right).all(|(x, y)| eq_fn(x, y))
 }
 

clippy_lints/src/utils/mod.rs

@@ -1,6 +1,7 @@
 #[macro_use]
 pub mod sym;
 
+pub mod ast_utils;
 pub mod attrs;
 pub mod author;
 pub mod camel_case;
@@ -19,7 +20,7 @@ pub mod sugg;
 pub mod usage;
 pub use self::attrs::*;
 pub use self::diagnostics::*;
-pub use self::hir_utils::{SpanlessEq, SpanlessHash};
+pub use self::hir_utils::{both, over, SpanlessEq, SpanlessHash};
 
 use std::borrow::Cow;
 use std::mem;

src/lintlist/mod.rs

@@ -2327,6 +2327,13 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
         deprecation: None,
         module: "misc_early",
     },
+    Lint {
+        name: "unnested_or_patterns",
+        group: "complexity",
+        desc: "unnested or-patterns, e.g., `Foo(Bar) | Foo(Baz) instead of `Foo(Bar | Baz)`",
+        deprecation: None,
+        module: "unnested_or_patterns",
+    },
     Lint {
         name: "unreachable",
         group: "restriction",

tests/ui/neg_cmp_op_on_partial_ord.rs

@@ -4,6 +4,7 @@
 
 use std::cmp::Ordering;
 
+#[allow(clippy::unnested_or_patterns)]
 #[warn(clippy::neg_cmp_op_on_partial_ord)]
 fn main() {
     let a_value = 1.0;

tests/ui/neg_cmp_op_on_partial_ord.stderr

@@ -1,5 +1,5 @@
 error: The use of negated comparison operators on partially ordered types produces code that is hard to read and refactor. Please consider using the `partial_cmp` method instead, to make it clear that the two values could be incomparable.
-  --> $DIR/neg_cmp_op_on_partial_ord.rs:15:21
+  --> $DIR/neg_cmp_op_on_partial_ord.rs:16:21
    |
 LL |     let _not_less = !(a_value < another_value);
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,19 +7,19 @@ LL |     let _not_less = !(a_value < another_value);
    = note: `-D clippy::neg-cmp-op-on-partial-ord` implied by `-D warnings`
 
 error: The use of negated comparison operators on partially ordered types produces code that is hard to read and refactor. Please consider using the `partial_cmp` method instead, to make it clear that the two values could be incomparable.
-  --> $DIR/neg_cmp_op_on_partial_ord.rs:18:30
+  --> $DIR/neg_cmp_op_on_partial_ord.rs:19:30
    |
 LL |     let _not_less_or_equal = !(a_value <= another_value);
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: The use of negated comparison operators on partially ordered types produces code that is hard to read and refactor. Please consider using the `partial_cmp` method instead, to make it clear that the two values could be incomparable.
-  --> $DIR/neg_cmp_op_on_partial_ord.rs:21:24
+  --> $DIR/neg_cmp_op_on_partial_ord.rs:22:24
    |
 LL |     let _not_greater = !(a_value > another_value);
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: The use of negated comparison operators on partially ordered types produces code that is hard to read and refactor. Please consider using the `partial_cmp` method instead, to make it clear that the two values could be incomparable.
-  --> $DIR/neg_cmp_op_on_partial_ord.rs:24:33
+  --> $DIR/neg_cmp_op_on_partial_ord.rs:25:33
    |
 LL |     let _not_greater_or_equal = !(a_value >= another_value);
    |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/unnested_or_patterns.fixed

@@ -0,0 +1,41 @@
+// run-rustfix
+
+#![feature(or_patterns)]
+#![feature(box_patterns)]
+#![warn(clippy::unnested_or_patterns)]
+#![allow(clippy::cognitive_complexity, clippy::match_ref_pats)]
+#![allow(unreachable_patterns, irrefutable_let_patterns, unused_variables)]
+
+fn main() {
+    if let box (0 | 2) = Box::new(0) {}
+    if let box (0 | 1 | 2 | 3 | 4) = Box::new(0) {}
+    const C0: &u8 = &1;
+    if let &(0 | 2) | C0 = &0 {}
+    if let &mut (0 | 2) = &mut 0 {}
+    if let x @ (0 | 2) = 0 {}
+    if let (0, 1 | 2 | 3) = (0, 0) {}
+    if let (1 | 2 | 3, 0) = (0, 0) {}
+    if let (x, ..) | (x, 1 | 2) = (0, 1) {}
+    if let [0 | 1] = [0] {}
+    if let [x, 0 | 1] = [0, 1] {}
+    if let [x, 0 | 1 | 2] = [0, 1] {}
+    if let [x, ..] | [x, 1 | 2] = [0, 1] {}
+    struct TS(u8, u8);
+    if let TS(0 | 1, x) = TS(0, 0) {}
+    if let TS(1 | 2 | 3, 0) = TS(0, 0) {}
+    if let TS(x, ..) | TS(x, 1 | 2) = TS(0, 0) {}
+    struct S {
+        x: u8,
+        y: u8,
+    }
+    if let S { x: 0 | 1, y } = (S { x: 0, y: 1 }) {}
+    if let S { x: 0, y, .. } | S { y, x: 1 } = (S { x: 0, y: 1 }) {}
+    if let Some(Some(0 | 1)) = None {}
+    if let Some(Some(0 | 1 | 2)) = None {}
+    if let Some(Some(0 | 1 | 2 | 3 | 4)) = None {}
+    if let Some(Some(0 | 1 | 2)) = None {}
+    if let ((0 | 1 | 2,),) = ((0,),) {}
+    if let 0 | 1 | 2 = 0 {}
+    if let box (0 | 1 | 2 | 3 | 4) = Box::new(0) {}
+    if let box box (0 | 2 | 4) = Box::new(Box::new(0)) {}
+}

tests/ui/unnested_or_patterns.rs

@@ -0,0 +1,41 @@
+// run-rustfix
+
+#![feature(or_patterns)]
+#![feature(box_patterns)]
+#![warn(clippy::unnested_or_patterns)]
+#![allow(clippy::cognitive_complexity, clippy::match_ref_pats)]
+#![allow(unreachable_patterns, irrefutable_let_patterns, unused_variables)]
+
+fn main() {
+    if let box 0 | box 2 = Box::new(0) {}
+    if let box ((0 | 1)) | box (2 | 3) | box 4 = Box::new(0) {}
+    const C0: &u8 = &1;
+    if let &0 | C0 | &2 = &0 {}
+    if let &mut 0 | &mut 2 = &mut 0 {}
+    if let x @ 0 | x @ 2 = 0 {}
+    if let (0, 1) | (0, 2) | (0, 3) = (0, 0) {}
+    if let (1, 0) | (2, 0) | (3, 0) = (0, 0) {}
+    if let (x, ..) | (x, 1) | (x, 2) = (0, 1) {}
+    if let [0] | [1] = [0] {}
+    if let [x, 0] | [x, 1] = [0, 1] {}
+    if let [x, 0] | [x, 1] | [x, 2] = [0, 1] {}
+    if let [x, ..] | [x, 1] | [x, 2] = [0, 1] {}
+    struct TS(u8, u8);
+    if let TS(0, x) | TS(1, x) = TS(0, 0) {}
+    if let TS(1, 0) | TS(2, 0) | TS(3, 0) = TS(0, 0) {}
+    if let TS(x, ..) | TS(x, 1) | TS(x, 2) = TS(0, 0) {}
+    struct S {
+        x: u8,
+        y: u8,
+    }
+    if let S { x: 0, y } | S { y, x: 1 } = (S { x: 0, y: 1 }) {}
+    if let S { x: 0, y, .. } | S { y, x: 1 } = (S { x: 0, y: 1 }) {}
+    if let Some(Some(0)) | Some(Some(1)) = None {}
+    if let Some(Some(0)) | Some(Some(1) | Some(2)) = None {}
+    if let Some(Some(0 | 1) | Some(2)) | Some(Some(3) | Some(4)) = None {}
+    if let Some(Some(0) | Some(1 | 2)) = None {}
+    if let ((0,),) | ((1,) | (2,),) = ((0,),) {}
+    if let 0 | (1 | 2) = 0 {}
+    if let box (0 | 1) | (box 2 | box (3 | 4)) = Box::new(0) {}
+    if let box box 0 | box (box 2 | box 4) = Box::new(Box::new(0)) {}
+}

tests/ui/unnested_or_patterns.stderr

@@ -0,0 +1,267 @@
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:10:12
+   |
+LL |     if let box 0 | box 2 = Box::new(0) {}
+   |            ^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::unnested-or-patterns` implied by `-D warnings`
+help: nest the patterns
+   |
+LL |     if let box (0 | 2) = Box::new(0) {}
+   |            ^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:11:12
+   |
+LL |     if let box ((0 | 1)) | box (2 | 3) | box 4 = Box::new(0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let box (0 | 1 | 2 | 3 | 4) = Box::new(0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:13:12
+   |
+LL |     if let &0 | C0 | &2 = &0 {}
+   |            ^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let &(0 | 2) | C0 = &0 {}
+   |            ^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:14:12
+   |
+LL |     if let &mut 0 | &mut 2 = &mut 0 {}
+   |            ^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let &mut (0 | 2) = &mut 0 {}
+   |            ^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:15:12
+   |
+LL |     if let x @ 0 | x @ 2 = 0 {}
+   |            ^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let x @ (0 | 2) = 0 {}
+   |            ^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:16:12
+   |
+LL |     if let (0, 1) | (0, 2) | (0, 3) = (0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let (0, 1 | 2 | 3) = (0, 0) {}
+   |            ^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:17:12
+   |
+LL |     if let (1, 0) | (2, 0) | (3, 0) = (0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let (1 | 2 | 3, 0) = (0, 0) {}
+   |            ^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:18:12
+   |
+LL |     if let (x, ..) | (x, 1) | (x, 2) = (0, 1) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let (x, ..) | (x, 1 | 2) = (0, 1) {}
+   |            ^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:19:12
+   |
+LL |     if let [0] | [1] = [0] {}
+   |            ^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let [0 | 1] = [0] {}
+   |            ^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:20:12
+   |
+LL |     if let [x, 0] | [x, 1] = [0, 1] {}
+   |            ^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let [x, 0 | 1] = [0, 1] {}
+   |            ^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:21:12
+   |
+LL |     if let [x, 0] | [x, 1] | [x, 2] = [0, 1] {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let [x, 0 | 1 | 2] = [0, 1] {}
+   |            ^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:22:12
+   |
+LL |     if let [x, ..] | [x, 1] | [x, 2] = [0, 1] {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let [x, ..] | [x, 1 | 2] = [0, 1] {}
+   |            ^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:24:12
+   |
+LL |     if let TS(0, x) | TS(1, x) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let TS(0 | 1, x) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:25:12
+   |
+LL |     if let TS(1, 0) | TS(2, 0) | TS(3, 0) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let TS(1 | 2 | 3, 0) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:26:12
+   |
+LL |     if let TS(x, ..) | TS(x, 1) | TS(x, 2) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let TS(x, ..) | TS(x, 1 | 2) = TS(0, 0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:31:12
+   |
+LL |     if let S { x: 0, y } | S { y, x: 1 } = (S { x: 0, y: 1 }) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let S { x: 0 | 1, y } = (S { x: 0, y: 1 }) {}
+   |            ^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:33:12
+   |
+LL |     if let Some(Some(0)) | Some(Some(1)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let Some(Some(0 | 1)) = None {}
+   |            ^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:34:12
+   |
+LL |     if let Some(Some(0)) | Some(Some(1) | Some(2)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let Some(Some(0 | 1 | 2)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:35:12
+   |
+LL |     if let Some(Some(0 | 1) | Some(2)) | Some(Some(3) | Some(4)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let Some(Some(0 | 1 | 2 | 3 | 4)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:36:12
+   |
+LL |     if let Some(Some(0) | Some(1 | 2)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let Some(Some(0 | 1 | 2)) = None {}
+   |            ^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:37:12
+   |
+LL |     if let ((0,),) | ((1,) | (2,),) = ((0,),) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let ((0 | 1 | 2,),) = ((0,),) {}
+   |            ^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:38:12
+   |
+LL |     if let 0 | (1 | 2) = 0 {}
+   |            ^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let 0 | 1 | 2 = 0 {}
+   |            ^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:39:12
+   |
+LL |     if let box (0 | 1) | (box 2 | box (3 | 4)) = Box::new(0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let box (0 | 1 | 2 | 3 | 4) = Box::new(0) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: unnested or-patterns
+  --> $DIR/unnested_or_patterns.rs:40:12
+   |
+LL |     if let box box 0 | box (box 2 | box 4) = Box::new(Box::new(0)) {}
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: nest the patterns
+   |
+LL |     if let box box (0 | 2 | 4) = Box::new(Box::new(0)) {}
+   |            ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 24 previous errors
+

tests/ui/wildcard_enum_match_arm.fixed

@@ -6,7 +6,8 @@
     unused_variables,
     dead_code,
     clippy::single_match,
-    clippy::wildcard_in_or_patterns
+    clippy::wildcard_in_or_patterns,
+    clippy::unnested_or_patterns
 )]
 
 use std::io::ErrorKind;

tests/ui/wildcard_enum_match_arm.rs

@@ -6,7 +6,8 @@
     unused_variables,
     dead_code,
     clippy::single_match,
-    clippy::wildcard_in_or_patterns
+    clippy::wildcard_in_or_patterns,
+    clippy::unnested_or_patterns
 )]
 
 use std::io::ErrorKind;

tests/ui/wildcard_enum_match_arm.stderr

@@ -1,5 +1,5 @@
 error: wildcard match will miss any future added variants
-  --> $DIR/wildcard_enum_match_arm.rs:37:9
+  --> $DIR/wildcard_enum_match_arm.rs:38:9
    |
 LL |         _ => eprintln!("Not red"),
    |         ^ help: try this: `Color::Green | Color::Blue | Color::Rgb(..) | Color::Cyan`
@@ -11,25 +11,25 @@ LL | #![deny(clippy::wildcard_enum_match_arm)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: wildcard match will miss any future added variants
-  --> $DIR/wildcard_enum_match_arm.rs:41:9
+  --> $DIR/wildcard_enum_match_arm.rs:42:9
    |
 LL |         _not_red => eprintln!("Not red"),
    |         ^^^^^^^^ help: try this: `_not_red @ Color::Green | _not_red @ Color::Blue | _not_red @ Color::Rgb(..) | _not_red @ Color::Cyan`
 
 error: wildcard match will miss any future added variants
-  --> $DIR/wildcard_enum_match_arm.rs:45:9
+  --> $DIR/wildcard_enum_match_arm.rs:46:9
    |
 LL |         not_red => format!("{:?}", not_red),
    |         ^^^^^^^ help: try this: `not_red @ Color::Green | not_red @ Color::Blue | not_red @ Color::Rgb(..) | not_red @ Color::Cyan`
 
 error: wildcard match will miss any future added variants
-  --> $DIR/wildcard_enum_match_arm.rs:61:9
+  --> $DIR/wildcard_enum_match_arm.rs:62:9
    |
 LL |         _ => "No red",
    |         ^ help: try this: `Color::Red | Color::Green | Color::Blue | Color::Rgb(..) | Color::Cyan`
 
 error: match on non-exhaustive enum doesn't explicitly match all known variants
-  --> $DIR/wildcard_enum_match_arm.rs:78:9
+  --> $DIR/wildcard_enum_match_arm.rs:79:9
    |
 LL |         _ => {},
    |         ^ help: try this: `std::io::ErrorKind::PermissionDenied | std::io::ErrorKind::ConnectionRefused | std::io::ErrorKind::ConnectionReset | std::io::ErrorKind::ConnectionAborted | std::io::ErrorKind::NotConnected | std::io::ErrorKind::AddrInUse | std::io::ErrorKind::AddrNotAvailable | std::io::ErrorKind::BrokenPipe | std::io::ErrorKind::AlreadyExists | std::io::ErrorKind::WouldBlock | std::io::ErrorKind::InvalidInput | std::io::ErrorKind::InvalidData | std::io::ErrorKind::TimedOut | std::io::ErrorKind::WriteZero | std::io::ErrorKind::Interrupted | std::io::ErrorKind::Other | std::io::ErrorKind::UnexpectedEof | _`