From 09e70536075fd92506ef985c5e662e1b2be3dd3d Mon Sep 17 00:00:00 2001 From: Aleksei Latyshev Date: Sat, 24 Oct 2020 18:05:02 +0300 Subject: [PATCH 1/2] simplify SpanlessEq::eq_path_segment --- clippy_lints/src/utils/hir_utils.rs | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/clippy_lints/src/utils/hir_utils.rs b/clippy_lints/src/utils/hir_utils.rs index c9e639e8728..e4ad105c351 100644 --- a/clippy_lints/src/utils/hir_utils.rs +++ b/clippy_lints/src/utils/hir_utils.rs @@ -261,14 +261,8 @@ pub fn eq_path_segments(&mut self, left: &[PathSegment<'_>], right: &[PathSegmen pub fn eq_path_segment(&mut self, left: &PathSegment<'_>, right: &PathSegment<'_>) -> bool { // The == of idents doesn't work with different contexts, // we have to be explicit about hygiene - if left.ident.as_str() != right.ident.as_str() { - return false; - } - match (&left.args, &right.args) { - (&None, &None) => true, - (&Some(ref l), &Some(ref r)) => self.eq_path_parameters(l, r), - _ => false, - } + left.ident.as_str() == right.ident.as_str() + && both(&left.args, &right.args, |l, r| self.eq_path_parameters(l, r)) } pub fn eq_ty(&mut self, left: &Ty<'_>, right: &Ty<'_>) -> bool { From 2b7dd313685279fce06f86bd739d798792135331 Mon Sep 17 00:00:00 2001 From: Aleksei Latyshev Date: Sat, 24 Oct 2020 18:06:07 +0300 Subject: [PATCH 2/2] improve MATCH_LIKE_MATCHES_MACRO lint - add tests - refactor match_same_arms lint - prioritize match_expr_like_matches_macro over match_same_arms --- clippy_lints/src/copies.rs | 215 +---------------- clippy_lints/src/lib.rs | 4 +- clippy_lints/src/matches.rs | 217 ++++++++++++++++-- clippy_lints/src/utils/mod.rs | 38 +++ src/lintlist/mod.rs | 2 +- tests/ui/match_expr_like_matches_macro.fixed | 68 +++++- tests/ui/match_expr_like_matches_macro.rs | 76 +++++- tests/ui/match_expr_like_matches_macro.stderr | 24 +- tests/ui/match_same_arms2.rs | 16 ++ tests/ui/match_same_arms2.stderr | 15 +- 10 files changed, 439 insertions(+), 236 deletions(-) diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs index 6c969c3ead0..46ce92ea6d7 100644 --- a/clippy_lints/src/copies.rs +++ b/clippy_lints/src/copies.rs @@ -1,13 +1,8 @@ -use crate::utils::{eq_expr_value, in_macro, SpanlessEq, SpanlessHash}; -use crate::utils::{get_parent_expr, higher, if_sequence, snippet, span_lint_and_note, span_lint_and_then}; -use rustc_data_structures::fx::FxHashMap; -use rustc_hir::{Arm, Block, Expr, ExprKind, MatchSource, Pat, PatKind}; +use crate::utils::{eq_expr_value, in_macro, search_same, SpanlessEq, SpanlessHash}; +use crate::utils::{get_parent_expr, higher, if_sequence, span_lint_and_note}; +use rustc_hir::{Block, Expr}; use rustc_lint::{LateContext, LateLintPass}; -use rustc_middle::ty::{Ty, TyS}; use rustc_session::{declare_lint_pass, declare_tool_lint}; -use rustc_span::symbol::Symbol; -use std::collections::hash_map::Entry; -use std::hash::BuildHasherDefault; declare_clippy_lint! { /// **What it does:** Checks for consecutive `if`s with the same condition. @@ -108,48 +103,7 @@ "`if` with the same `then` and `else` blocks" } -declare_clippy_lint! { - /// **What it does:** Checks for `match` with identical arm bodies. - /// - /// **Why is this bad?** This is probably a copy & paste error. If arm bodies - /// are the same on purpose, you can factor them - /// [using `|`](https://doc.rust-lang.org/book/patterns.html#multiple-patterns). - /// - /// **Known problems:** False positive possible with order dependent `match` - /// (see issue - /// [#860](https://github.com/rust-lang/rust-clippy/issues/860)). - /// - /// **Example:** - /// ```rust,ignore - /// match foo { - /// Bar => bar(), - /// Quz => quz(), - /// Baz => bar(), // <= oops - /// } - /// ``` - /// - /// This should probably be - /// ```rust,ignore - /// match foo { - /// Bar => bar(), - /// Quz => quz(), - /// Baz => baz(), // <= fixed - /// } - /// ``` - /// - /// or if the original code was not a typo: - /// ```rust,ignore - /// match foo { - /// Bar | Baz => bar(), // <= shows the intent better - /// Quz => quz(), - /// } - /// ``` - pub MATCH_SAME_ARMS, - pedantic, - "`match` with identical arm bodies" -} - -declare_lint_pass!(CopyAndPaste => [IFS_SAME_COND, SAME_FUNCTIONS_IN_IF_CONDITION, IF_SAME_THEN_ELSE, MATCH_SAME_ARMS]); +declare_lint_pass!(CopyAndPaste => [IFS_SAME_COND, SAME_FUNCTIONS_IN_IF_CONDITION, IF_SAME_THEN_ELSE]); impl<'tcx> LateLintPass<'tcx> for CopyAndPaste { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { @@ -167,7 +121,6 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { lint_same_then_else(cx, &blocks); lint_same_cond(cx, &conds); lint_same_fns_in_if_cond(cx, &conds); - lint_match_arms(cx, expr); } } } @@ -243,122 +196,6 @@ fn lint_same_fns_in_if_cond(cx: &LateContext<'_>, conds: &[&Expr<'_>]) { } } -/// Implementation of `MATCH_SAME_ARMS`. -fn lint_match_arms<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) { - fn same_bindings<'tcx>(lhs: &FxHashMap>, rhs: &FxHashMap>) -> bool { - lhs.len() == rhs.len() - && lhs - .iter() - .all(|(name, l_ty)| rhs.get(name).map_or(false, |r_ty| TyS::same_type(l_ty, r_ty))) - } - - if let ExprKind::Match(_, ref arms, MatchSource::Normal) = expr.kind { - let hash = |&(_, arm): &(usize, &Arm<'_>)| -> u64 { - let mut h = SpanlessHash::new(cx); - h.hash_expr(&arm.body); - h.finish() - }; - - let eq = |&(lindex, lhs): &(usize, &Arm<'_>), &(rindex, rhs): &(usize, &Arm<'_>)| -> bool { - let min_index = usize::min(lindex, rindex); - let max_index = usize::max(lindex, rindex); - - // Arms with a guard are ignored, those can’t always be merged together - // This is also the case for arms in-between each there is an arm with a guard - (min_index..=max_index).all(|index| arms[index].guard.is_none()) && - SpanlessEq::new(cx).eq_expr(&lhs.body, &rhs.body) && - // all patterns should have the same bindings - same_bindings(&bindings(cx, &lhs.pat), &bindings(cx, &rhs.pat)) - }; - - let indexed_arms: Vec<(usize, &Arm<'_>)> = arms.iter().enumerate().collect(); - for (&(_, i), &(_, j)) in search_same(&indexed_arms, hash, eq) { - span_lint_and_then( - cx, - MATCH_SAME_ARMS, - j.body.span, - "this `match` has identical arm bodies", - |diag| { - diag.span_note(i.body.span, "same as this"); - - // Note: this does not use `span_suggestion` on purpose: - // there is no clean way - // to remove the other arm. Building a span and suggest to replace it to "" - // makes an even more confusing error message. Also in order not to make up a - // span for the whole pattern, the suggestion is only shown when there is only - // one pattern. The user should know about `|` if they are already using it… - - let lhs = snippet(cx, i.pat.span, ""); - let rhs = snippet(cx, j.pat.span, ""); - - if let PatKind::Wild = j.pat.kind { - // if the last arm is _, then i could be integrated into _ - // note that i.pat cannot be _, because that would mean that we're - // hiding all the subsequent arms, and rust won't compile - diag.span_note( - i.body.span, - &format!( - "`{}` has the same arm body as the `_` wildcard, consider removing it", - lhs - ), - ); - } else { - diag.span_help(i.pat.span, &format!("consider refactoring into `{} | {}`", lhs, rhs)); - } - }, - ); - } - } -} - -/// Returns the list of bindings in a pattern. -fn bindings<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>) -> FxHashMap> { - fn bindings_impl<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>, map: &mut FxHashMap>) { - match pat.kind { - PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => bindings_impl(cx, pat, map), - PatKind::TupleStruct(_, pats, _) => { - for pat in pats { - bindings_impl(cx, pat, map); - } - }, - PatKind::Binding(.., ident, ref as_pat) => { - if let Entry::Vacant(v) = map.entry(ident.name) { - v.insert(cx.typeck_results().pat_ty(pat)); - } - if let Some(ref as_pat) = *as_pat { - bindings_impl(cx, as_pat, map); - } - }, - PatKind::Or(fields) | PatKind::Tuple(fields, _) => { - for pat in fields { - bindings_impl(cx, pat, map); - } - }, - PatKind::Struct(_, fields, _) => { - for pat in fields { - bindings_impl(cx, &pat.pat, map); - } - }, - PatKind::Slice(lhs, ref mid, rhs) => { - for pat in lhs { - bindings_impl(cx, pat, map); - } - if let Some(ref mid) = *mid { - bindings_impl(cx, mid, map); - } - for pat in rhs { - bindings_impl(cx, pat, map); - } - }, - PatKind::Lit(..) | PatKind::Range(..) | PatKind::Wild | PatKind::Path(..) => (), - } - } - - let mut result = FxHashMap::default(); - bindings_impl(cx, pat, &mut result); - result -} - fn search_same_sequenced(exprs: &[T], eq: Eq) -> Option<(&T, &T)> where Eq: Fn(&T, &T) -> bool, @@ -370,47 +207,3 @@ fn search_same_sequenced(exprs: &[T], eq: Eq) -> Option<(&T, &T)> } None } - -fn search_common_cases<'a, T, Eq>(exprs: &'a [T], eq: &Eq) -> Option<(&'a T, &'a T)> -where - Eq: Fn(&T, &T) -> bool, -{ - if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) { - Some((&exprs[0], &exprs[1])) - } else { - None - } -} - -fn search_same(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)> -where - Hash: Fn(&T) -> u64, - Eq: Fn(&T, &T) -> bool, -{ - if let Some(expr) = search_common_cases(&exprs, &eq) { - return vec![expr]; - } - - let mut match_expr_list: Vec<(&T, &T)> = Vec::new(); - - let mut map: FxHashMap<_, Vec<&_>> = - FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default()); - - for expr in exprs { - match map.entry(hash(expr)) { - Entry::Occupied(mut o) => { - for o in o.get() { - if eq(o, expr) { - match_expr_list.push((o, expr)); - } - } - o.get_mut().push(expr); - }, - Entry::Vacant(v) => { - v.insert(vec![expr]); - }, - } - } - - match_expr_list -} diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 7c8cb90fe1c..459fdd70443 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -528,7 +528,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &comparison_chain::COMPARISON_CHAIN, &copies::IFS_SAME_COND, &copies::IF_SAME_THEN_ELSE, - &copies::MATCH_SAME_ARMS, &copies::SAME_FUNCTIONS_IN_IF_CONDITION, ©_iterator::COPY_ITERATOR, &create_dir::CREATE_DIR, @@ -659,6 +658,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &matches::MATCH_LIKE_MATCHES_MACRO, &matches::MATCH_OVERLAPPING_ARM, &matches::MATCH_REF_PATS, + &matches::MATCH_SAME_ARMS, &matches::MATCH_SINGLE_BINDING, &matches::MATCH_WILDCARD_FOR_SINGLE_VARIANTS, &matches::MATCH_WILD_ERR_ARM, @@ -1204,7 +1204,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&attrs::INLINE_ALWAYS), LintId::of(&bit_mask::VERBOSE_BIT_MASK), LintId::of(&checked_conversions::CHECKED_CONVERSIONS), - LintId::of(&copies::MATCH_SAME_ARMS), LintId::of(&copies::SAME_FUNCTIONS_IN_IF_CONDITION), LintId::of(©_iterator::COPY_ITERATOR), LintId::of(&default_trait_access::DEFAULT_TRAIT_ACCESS), @@ -1234,6 +1233,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&map_err_ignore::MAP_ERR_IGNORE), LintId::of(&match_on_vec_items::MATCH_ON_VEC_ITEMS), LintId::of(&matches::MATCH_BOOL), + LintId::of(&matches::MATCH_SAME_ARMS), LintId::of(&matches::MATCH_WILDCARD_FOR_SINGLE_VARIANTS), LintId::of(&matches::MATCH_WILD_ERR_ARM), LintId::of(&matches::SINGLE_MATCH_ELSE), diff --git a/clippy_lints/src/matches.rs b/clippy_lints/src/matches.rs index d93433c607f..4bdfca1a292 100644 --- a/clippy_lints/src/matches.rs +++ b/clippy_lints/src/matches.rs @@ -1,5 +1,4 @@ use crate::consts::{constant, miri_to_const, Constant}; -use crate::utils::paths; use crate::utils::sugg::Sugg; use crate::utils::usage::is_unused; use crate::utils::{ @@ -8,8 +7,10 @@ snippet_block, snippet_with_applicability, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then, }; +use crate::utils::{paths, search_same, SpanlessEq, SpanlessHash}; use if_chain::if_chain; use rustc_ast::ast::LitKind; +use rustc_data_structures::fx::FxHashMap; use rustc_errors::Applicability; use rustc_hir::def::CtorKind; use rustc_hir::{ @@ -18,10 +19,12 @@ }; use rustc_lint::{LateContext, LateLintPass, LintContext}; use rustc_middle::lint::in_external_macro; -use rustc_middle::ty::{self, Ty}; +use rustc_middle::ty::{self, Ty, TyS}; use rustc_session::{declare_tool_lint, impl_lint_pass}; use rustc_span::source_map::{Span, Spanned}; +use rustc_span::Symbol; use std::cmp::Ordering; +use std::collections::hash_map::Entry; use std::collections::Bound; declare_clippy_lint! { @@ -475,6 +478,47 @@ "a match that could be written with the matches! macro" } +declare_clippy_lint! { + /// **What it does:** Checks for `match` with identical arm bodies. + /// + /// **Why is this bad?** This is probably a copy & paste error. If arm bodies + /// are the same on purpose, you can factor them + /// [using `|`](https://doc.rust-lang.org/book/patterns.html#multiple-patterns). + /// + /// **Known problems:** False positive possible with order dependent `match` + /// (see issue + /// [#860](https://github.com/rust-lang/rust-clippy/issues/860)). + /// + /// **Example:** + /// ```rust,ignore + /// match foo { + /// Bar => bar(), + /// Quz => quz(), + /// Baz => bar(), // <= oops + /// } + /// ``` + /// + /// This should probably be + /// ```rust,ignore + /// match foo { + /// Bar => bar(), + /// Quz => quz(), + /// Baz => baz(), // <= fixed + /// } + /// ``` + /// + /// or if the original code was not a typo: + /// ```rust,ignore + /// match foo { + /// Bar | Baz => bar(), // <= shows the intent better + /// Quz => quz(), + /// } + /// ``` + pub MATCH_SAME_ARMS, + pedantic, + "`match` with identical arm bodies" +} + #[derive(Default)] pub struct Matches { infallible_destructuring_match_linted: bool, @@ -495,7 +539,8 @@ pub struct Matches { INFALLIBLE_DESTRUCTURING_MATCH, REST_PAT_IN_FULLY_BOUND_STRUCTS, REDUNDANT_PATTERN_MATCHING, - MATCH_LIKE_MATCHES_MACRO + MATCH_LIKE_MATCHES_MACRO, + MATCH_SAME_ARMS, ]); impl<'tcx> LateLintPass<'tcx> for Matches { @@ -505,7 +550,9 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { } redundant_pattern_match::check(cx, expr); - check_match_like_matches(cx, expr); + if !check_match_like_matches(cx, expr) { + lint_match_arms(cx, expr); + } if let ExprKind::Match(ref ex, ref arms, MatchSource::Normal) = expr.kind { check_single_match(cx, ex, arms, expr); @@ -1063,32 +1110,47 @@ fn check_wild_in_or_pats(cx: &LateContext<'_>, arms: &[Arm<'_>]) { } /// Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!` -fn check_match_like_matches<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { +fn check_match_like_matches<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool { if let ExprKind::Match(ex, arms, ref match_source) = &expr.kind { match match_source { MatchSource::Normal => find_matches_sugg(cx, ex, arms, expr, false), MatchSource::IfLetDesugar { .. } => find_matches_sugg(cx, ex, arms, expr, true), - _ => return, + _ => false, } + } else { + false } } /// Lint a `match` or desugared `if let` for replacement by `matches!` -fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>, desugared: bool) { +fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>, desugared: bool) -> bool { if_chain! { - if arms.len() == 2; + if arms.len() >= 2; if cx.typeck_results().expr_ty(expr).is_bool(); - if is_wild(&arms[1].pat); - if let Some(first) = find_bool_lit(&arms[0].body.kind, desugared); - if let Some(second) = find_bool_lit(&arms[1].body.kind, desugared); - if first != second; + if let Some((b1_arm, b0_arms)) = arms.split_last(); + if let Some(b0) = find_bool_lit(&b0_arms[0].body.kind, desugared); + if let Some(b1) = find_bool_lit(&b1_arm.body.kind, desugared); + if is_wild(&b1_arm.pat); + if b0 != b1; + let if_guard = &b0_arms[0].guard; + if if_guard.is_none() || b0_arms.len() == 1; + if b0_arms[1..].iter() + .all(|arm| { + find_bool_lit(&arm.body.kind, desugared).map_or(false, |b| b == b0) && + arm.guard.is_none() + }); then { let mut applicability = Applicability::MachineApplicable; - - let pat_and_guard = if let Some(Guard::If(g)) = arms[0].guard { - format!("{} if {}", snippet_with_applicability(cx, arms[0].pat.span, "..", &mut applicability), snippet_with_applicability(cx, g.span, "..", &mut applicability)) + let pat = { + use itertools::Itertools as _; + b0_arms.iter() + .map(|arm| snippet_with_applicability(cx, arm.pat.span, "..", &mut applicability)) + .join(" | ") + }; + let pat_and_guard = if let Some(Guard::If(g)) = if_guard { + format!("{} if {}", pat, snippet_with_applicability(cx, g.span, "..", &mut applicability)) } else { - format!("{}", snippet_with_applicability(cx, arms[0].pat.span, "..", &mut applicability)) + pat }; span_lint_and_sugg( cx, @@ -1098,12 +1160,15 @@ fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr "try this", format!( "{}matches!({}, {})", - if first { "" } else { "!" }, + if b0 { "" } else { "!" }, snippet_with_applicability(cx, ex.span, "..", &mut applicability), pat_and_guard, ), applicability, - ) + ); + true + } else { + false } } } @@ -1657,3 +1722,119 @@ fn test_overlapping() { ],) ); } + +/// Implementation of `MATCH_SAME_ARMS`. +fn lint_match_arms<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>) { + fn same_bindings<'tcx>(lhs: &FxHashMap>, rhs: &FxHashMap>) -> bool { + lhs.len() == rhs.len() + && lhs + .iter() + .all(|(name, l_ty)| rhs.get(name).map_or(false, |r_ty| TyS::same_type(l_ty, r_ty))) + } + + if let ExprKind::Match(_, ref arms, MatchSource::Normal) = expr.kind { + let hash = |&(_, arm): &(usize, &Arm<'_>)| -> u64 { + let mut h = SpanlessHash::new(cx); + h.hash_expr(&arm.body); + h.finish() + }; + + let eq = |&(lindex, lhs): &(usize, &Arm<'_>), &(rindex, rhs): &(usize, &Arm<'_>)| -> bool { + let min_index = usize::min(lindex, rindex); + let max_index = usize::max(lindex, rindex); + + // Arms with a guard are ignored, those can’t always be merged together + // This is also the case for arms in-between each there is an arm with a guard + (min_index..=max_index).all(|index| arms[index].guard.is_none()) && + SpanlessEq::new(cx).eq_expr(&lhs.body, &rhs.body) && + // all patterns should have the same bindings + same_bindings(&bindings(cx, &lhs.pat), &bindings(cx, &rhs.pat)) + }; + + let indexed_arms: Vec<(usize, &Arm<'_>)> = arms.iter().enumerate().collect(); + for (&(_, i), &(_, j)) in search_same(&indexed_arms, hash, eq) { + span_lint_and_then( + cx, + MATCH_SAME_ARMS, + j.body.span, + "this `match` has identical arm bodies", + |diag| { + diag.span_note(i.body.span, "same as this"); + + // Note: this does not use `span_suggestion` on purpose: + // there is no clean way + // to remove the other arm. Building a span and suggest to replace it to "" + // makes an even more confusing error message. Also in order not to make up a + // span for the whole pattern, the suggestion is only shown when there is only + // one pattern. The user should know about `|` if they are already using it… + + let lhs = snippet(cx, i.pat.span, ""); + let rhs = snippet(cx, j.pat.span, ""); + + if let PatKind::Wild = j.pat.kind { + // if the last arm is _, then i could be integrated into _ + // note that i.pat cannot be _, because that would mean that we're + // hiding all the subsequent arms, and rust won't compile + diag.span_note( + i.body.span, + &format!( + "`{}` has the same arm body as the `_` wildcard, consider removing it", + lhs + ), + ); + } else { + diag.span_help(i.pat.span, &format!("consider refactoring into `{} | {}`", lhs, rhs)); + } + }, + ); + } + } +} + +/// Returns the list of bindings in a pattern. +fn bindings<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>) -> FxHashMap> { + fn bindings_impl<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'_>, map: &mut FxHashMap>) { + match pat.kind { + PatKind::Box(ref pat) | PatKind::Ref(ref pat, _) => bindings_impl(cx, pat, map), + PatKind::TupleStruct(_, pats, _) => { + for pat in pats { + bindings_impl(cx, pat, map); + } + }, + PatKind::Binding(.., ident, ref as_pat) => { + if let Entry::Vacant(v) = map.entry(ident.name) { + v.insert(cx.typeck_results().pat_ty(pat)); + } + if let Some(ref as_pat) = *as_pat { + bindings_impl(cx, as_pat, map); + } + }, + PatKind::Or(fields) | PatKind::Tuple(fields, _) => { + for pat in fields { + bindings_impl(cx, pat, map); + } + }, + PatKind::Struct(_, fields, _) => { + for pat in fields { + bindings_impl(cx, &pat.pat, map); + } + }, + PatKind::Slice(lhs, ref mid, rhs) => { + for pat in lhs { + bindings_impl(cx, pat, map); + } + if let Some(ref mid) = *mid { + bindings_impl(cx, mid, map); + } + for pat in rhs { + bindings_impl(cx, pat, map); + } + }, + PatKind::Lit(..) | PatKind::Range(..) | PatKind::Wild | PatKind::Path(..) => (), + } + } + + let mut result = FxHashMap::default(); + bindings_impl(cx, pat, &mut result); + result +} diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs index a1ecca0961a..0a8a4a5f9ae 100644 --- a/clippy_lints/src/utils/mod.rs +++ b/clippy_lints/src/utils/mod.rs @@ -27,11 +27,14 @@ pub use self::hir_utils::{both, eq_expr_value, over, SpanlessEq, SpanlessHash}; use std::borrow::Cow; +use std::collections::hash_map::Entry; +use std::hash::BuildHasherDefault; use std::mem; use if_chain::if_chain; use rustc_ast::ast::{self, Attribute, LitKind}; use rustc_attr as attr; +use rustc_data_structures::fx::FxHashMap; use rustc_errors::Applicability; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; @@ -1465,6 +1468,41 @@ pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option(exprs: &[T], hash: Hash, eq: Eq) -> Vec<(&T, &T)> +where + Hash: Fn(&T) -> u64, + Eq: Fn(&T, &T) -> bool, +{ + if exprs.len() == 2 && eq(&exprs[0], &exprs[1]) { + return vec![(&exprs[0], &exprs[1])]; + } + + let mut match_expr_list: Vec<(&T, &T)> = Vec::new(); + + let mut map: FxHashMap<_, Vec<&_>> = + FxHashMap::with_capacity_and_hasher(exprs.len(), BuildHasherDefault::default()); + + for expr in exprs { + match map.entry(hash(expr)) { + Entry::Occupied(mut o) => { + for o in o.get() { + if eq(o, expr) { + match_expr_list.push((o, expr)); + } + } + o.get_mut().push(expr); + }, + Entry::Vacant(v) => { + v.insert(vec![expr]); + }, + } + } + + match_expr_list +} + #[macro_export] macro_rules! unwrap_cargo_metadata { ($cx: ident, $lint: ident, $deps: expr) => {{ diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 6272ce45efb..aba436e5c02 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -1304,7 +1304,7 @@ group: "pedantic", desc: "`match` with identical arm bodies", deprecation: None, - module: "copies", + module: "matches", }, Lint { name: "match_single_binding", diff --git a/tests/ui/match_expr_like_matches_macro.fixed b/tests/ui/match_expr_like_matches_macro.fixed index f3e19092480..7f4ebf56673 100644 --- a/tests/ui/match_expr_like_matches_macro.fixed +++ b/tests/ui/match_expr_like_matches_macro.fixed @@ -1,7 +1,7 @@ // run-rustfix #![warn(clippy::match_like_matches_macro)] -#![allow(unreachable_patterns)] +#![allow(unreachable_patterns, dead_code)] fn main() { let x = Some(5); @@ -33,4 +33,70 @@ fn main() { _ => true, None => false, }; + + enum E { + A(u32), + B(i32), + C, + D, + }; + let x = E::A(2); + { + // lint + let _ans = matches!(x, E::A(_) | E::B(_)); + } + { + // lint + let _ans = !matches!(x, E::B(_) | E::C); + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(_) => false, + E::C => true, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => true, + E::B(_) => false, + E::C => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(a) if a < 10 => false, + E::B(a) if a < 10 => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(a) if a < 10 => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(a) => a == 10, + E::B(_) => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(_) => true, + _ => false, + }; + } } diff --git a/tests/ui/match_expr_like_matches_macro.rs b/tests/ui/match_expr_like_matches_macro.rs index fbae7c18b92..aee56dd4a5e 100644 --- a/tests/ui/match_expr_like_matches_macro.rs +++ b/tests/ui/match_expr_like_matches_macro.rs @@ -1,7 +1,7 @@ // run-rustfix #![warn(clippy::match_like_matches_macro)] -#![allow(unreachable_patterns)] +#![allow(unreachable_patterns, dead_code)] fn main() { let x = Some(5); @@ -45,4 +45,78 @@ fn main() { _ => true, None => false, }; + + enum E { + A(u32), + B(i32), + C, + D, + }; + let x = E::A(2); + { + // lint + let _ans = match x { + E::A(_) => true, + E::B(_) => true, + _ => false, + }; + } + { + // lint + let _ans = match x { + E::B(_) => false, + E::C => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(_) => false, + E::C => true, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => true, + E::B(_) => false, + E::C => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(a) if a < 10 => false, + E::B(a) if a < 10 => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(a) if a < 10 => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(a) => a == 10, + E::B(_) => false, + _ => true, + }; + } + { + // no lint + let _ans = match x { + E::A(_) => false, + E::B(_) => true, + _ => false, + }; + } } diff --git a/tests/ui/match_expr_like_matches_macro.stderr b/tests/ui/match_expr_like_matches_macro.stderr index 4668f8565a6..c52e41c7889 100644 --- a/tests/ui/match_expr_like_matches_macro.stderr +++ b/tests/ui/match_expr_like_matches_macro.stderr @@ -48,5 +48,27 @@ error: if let .. else expression looks like `matches!` macro LL | let _zzz = if let Some(5) = x { true } else { false }; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `matches!(x, Some(5))` -error: aborting due to 5 previous errors +error: match expression looks like `matches!` macro + --> $DIR/match_expr_like_matches_macro.rs:58:20 + | +LL | let _ans = match x { + | ____________________^ +LL | | E::A(_) => true, +LL | | E::B(_) => true, +LL | | _ => false, +LL | | }; + | |_________^ help: try this: `matches!(x, E::A(_) | E::B(_))` + +error: match expression looks like `matches!` macro + --> $DIR/match_expr_like_matches_macro.rs:66:20 + | +LL | let _ans = match x { + | ____________________^ +LL | | E::B(_) => false, +LL | | E::C => false, +LL | | _ => true, +LL | | }; + | |_________^ help: try this: `!matches!(x, E::B(_) | E::C)` + +error: aborting due to 7 previous errors diff --git a/tests/ui/match_same_arms2.rs b/tests/ui/match_same_arms2.rs index e1401d2796a..06d91497242 100644 --- a/tests/ui/match_same_arms2.rs +++ b/tests/ui/match_same_arms2.rs @@ -119,6 +119,22 @@ fn match_same_arms() { unreachable!(); }, } + + match_expr_like_matches_macro_priority(); +} + +fn match_expr_like_matches_macro_priority() { + enum E { + A, + B, + C, + } + let x = E::A; + let _ans = match x { + E::A => false, + E::B => false, + _ => true, + }; } fn main() {} diff --git a/tests/ui/match_same_arms2.stderr b/tests/ui/match_same_arms2.stderr index 26c65f32ad7..fccaf805616 100644 --- a/tests/ui/match_same_arms2.stderr +++ b/tests/ui/match_same_arms2.stderr @@ -141,5 +141,18 @@ LL | Ok(3) => println!("ok"), | ^^^^^ = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) -error: aborting due to 7 previous errors +error: match expression looks like `matches!` macro + --> $DIR/match_same_arms2.rs:133:16 + | +LL | let _ans = match x { + | ________________^ +LL | | E::A => false, +LL | | E::B => false, +LL | | _ => true, +LL | | }; + | |_____^ help: try this: `!matches!(x, E::A | E::B)` + | + = note: `-D clippy::match-like-matches-macro` implied by `-D warnings` + +error: aborting due to 8 previous errors