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Merge CollapsibleMatch into Matches lint pass

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This commit is contained in:
Jason Newcomb 2022-06-03 12:14:24 -04:00
parent 7c0d649db2
commit 81e44502ac
9 changed files with 139 additions and 113 deletions
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2
clippy_lints/src/lib.register_all.rs
View File

@ -38,7 +38,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
LintId::of(casts::UNNECESSARY_CAST),
LintId::of(collapsible_if::COLLAPSIBLE_ELSE_IF),
LintId::of(collapsible_if::COLLAPSIBLE_IF),
LintId::of(collapsible_match::COLLAPSIBLE_MATCH),
LintId::of(comparison_chain::COMPARISON_CHAIN),
LintId::of(copies::IFS_SAME_COND),
LintId::of(copies::IF_SAME_THEN_ELSE),
@ -143,6 +142,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN),
LintId::of(match_result_ok::MATCH_RESULT_OK),
LintId::of(match_str_case_mismatch::MATCH_STR_CASE_MISMATCH),
LintId::of(matches::COLLAPSIBLE_MATCH),
LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
LintId::of(matches::MATCH_AS_REF),
LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),

2
clippy_lints/src/lib.register_lints.rs
View File

@ -93,7 +93,6 @@ store.register_lints(&[
cognitive_complexity::COGNITIVE_COMPLEXITY,
collapsible_if::COLLAPSIBLE_ELSE_IF,
collapsible_if::COLLAPSIBLE_IF,
collapsible_match::COLLAPSIBLE_MATCH,
comparison_chain::COMPARISON_CHAIN,
copies::BRANCHES_SHARING_CODE,
copies::IFS_SAME_COND,
@ -263,6 +262,7 @@ store.register_lints(&[
match_on_vec_items::MATCH_ON_VEC_ITEMS,
match_result_ok::MATCH_RESULT_OK,
match_str_case_mismatch::MATCH_STR_CASE_MISMATCH,
matches::COLLAPSIBLE_MATCH,
matches::INFALLIBLE_DESTRUCTURING_MATCH,
matches::MATCH_AS_REF,
matches::MATCH_BOOL,

2
clippy_lints/src/lib.register_style.rs
View File

@ -12,7 +12,6 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
LintId::of(casts::FN_TO_NUMERIC_CAST_WITH_TRUNCATION),
LintId::of(collapsible_if::COLLAPSIBLE_ELSE_IF),
LintId::of(collapsible_if::COLLAPSIBLE_IF),
LintId::of(collapsible_match::COLLAPSIBLE_MATCH),
LintId::of(comparison_chain::COMPARISON_CHAIN),
LintId::of(default::FIELD_REASSIGN_WITH_DEFAULT),
LintId::of(dereference::NEEDLESS_BORROW),
@ -50,6 +49,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
LintId::of(manual_non_exhaustive::MANUAL_NON_EXHAUSTIVE),
LintId::of(map_clone::MAP_CLONE),
LintId::of(match_result_ok::MATCH_RESULT_OK),
LintId::of(matches::COLLAPSIBLE_MATCH),
LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH),
LintId::of(matches::MATCH_LIKE_MATCHES_MACRO),
LintId::of(matches::MATCH_OVERLAPPING_ARM),

2
clippy_lints/src/lib.rs
View File

@ -192,7 +192,6 @@ mod casts;
mod checked_conversions;
mod cognitive_complexity;
mod collapsible_if;
mod collapsible_match;
mod comparison_chain;
mod copies;
mod copy_iterator;
@ -568,7 +567,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|| Box::new(len_zero::LenZero));
store.register_late_pass(|| Box::new(attrs::Attributes));
store.register_late_pass(|| Box::new(blocks_in_if_conditions::BlocksInIfConditions));
store.register_late_pass(|| Box::new(collapsible_match::CollapsibleMatch));
store.register_late_pass(|| Box::new(unicode::Unicode));
store.register_late_pass(|| Box::new(uninit_vec::UninitVec));
store.register_late_pass(|| Box::new(unit_hash::UnitHash));

70
clippy_lints/src/collapsible_match.rs → clippy_lints/src/matches/collapsible_match.rs
View File

@ -6,68 +6,28 @@ use if_chain::if_chain;
use rustc_errors::MultiSpan;
use rustc_hir::LangItem::OptionNone;
use rustc_hir::{Arm, Expr, Guard, HirId, Let, Pat, PatKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_lint::LateContext;
use rustc_span::Span;
declare_clippy_lint! {
/// ### What it does
/// Finds nested `match` or `if let` expressions where the patterns may be "collapsed" together
/// without adding any branches.
///
/// Note that this lint is not intended to find _all_ cases where nested match patterns can be merged, but only
/// cases where merging would most likely make the code more readable.
///
/// ### Why is this bad?
/// It is unnecessarily verbose and complex.
///
/// ### Example
/// ```rust
/// fn func(opt: Option<Result<u64, String>>) {
/// let n = match opt {
/// Some(n) => match n {
/// Ok(n) => n,
/// _ => return,
/// }
/// None => return,
/// };
/// }
/// ```
/// Use instead:
/// ```rust
/// fn func(opt: Option<Result<u64, String>>) {
/// let n = match opt {
/// Some(Ok(n)) => n,
/// _ => return,
/// };
/// }
/// ```
#[clippy::version = "1.50.0"]
pub COLLAPSIBLE_MATCH,
style,
"Nested `match` or `if let` expressions where the patterns may be \"collapsed\" together."
}
use super::COLLAPSIBLE_MATCH;
declare_lint_pass!(CollapsibleMatch => [COLLAPSIBLE_MATCH]);
impl<'tcx> LateLintPass<'tcx> for CollapsibleMatch {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
match IfLetOrMatch::parse(cx, expr) {
Some(IfLetOrMatch::Match(_, arms, _)) => {
if let Some(els_arm) = arms.iter().rfind(|arm| arm_is_wild_like(cx, arm)) {
for arm in arms {
check_arm(cx, true, arm.pat, arm.body, arm.guard.as_ref(), Some(els_arm.body));
}
}
},
Some(IfLetOrMatch::IfLet(_, pat, body, els)) => {
check_arm(cx, false, pat, body, None, els);
},
None => {},
pub(super) fn check_match<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
if let Some(els_arm) = arms.iter().rfind(|arm| arm_is_wild_like(cx, arm)) {
for arm in arms {
check_arm(cx, true, arm.pat, arm.body, arm.guard.as_ref(), Some(els_arm.body));
}
}
}
pub(super) fn check_if_let<'tcx>(
cx: &LateContext<'tcx>,
pat: &'tcx Pat<'_>,
body: &'tcx Expr<'_>,
else_expr: Option<&'tcx Expr<'_>>,
) {
check_arm(cx, false, pat, body, None, else_expr);
}
fn check_arm<'tcx>(
cx: &LateContext<'tcx>,
outer_is_match: bool,

34
clippy_lints/src/matches/match_like_matches.rs
View File

@ -1,6 +1,6 @@
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::is_wild;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::{higher, is_wild};
use rustc_ast::{Attribute, LitKind};
use rustc_errors::Applicability;
use rustc_hir::{Arm, BorrowKind, Expr, ExprKind, Guard, Pat};
@ -11,22 +11,24 @@ use rustc_span::source_map::Spanned;
use super::MATCH_LIKE_MATCHES_MACRO;
/// Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!`
pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let Some(higher::IfLet {
let_pat,
pub(crate) fn check_if_let<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
let_pat: &'tcx Pat<'_>,
let_expr: &'tcx Expr<'_>,
then_expr: &'tcx Expr<'_>,
else_expr: &'tcx Expr<'_>,
) {
find_matches_sugg(
cx,
let_expr,
if_then,
if_else: Some(if_else),
}) = higher::IfLet::hir(cx, expr)
{
find_matches_sugg(
cx,
let_expr,
IntoIterator::into_iter([(&[][..], Some(let_pat), if_then, None), (&[][..], None, if_else, None)]),
expr,
true,
);
}
IntoIterator::into_iter([
(&[][..], Some(let_pat), then_expr, None),
(&[][..], None, else_expr, None),
]),
expr,
true,
);
}
pub(super) fn check_match<'tcx>(

90
clippy_lints/src/matches/mod.rs
View File

@ -1,12 +1,14 @@
use clippy_utils::source::{snippet_opt, span_starts_with, walk_span_to_context};
use clippy_utils::{meets_msrv, msrvs};
use clippy_utils::{higher, meets_msrv, msrvs};
use rustc_hir::{Arm, Expr, ExprKind, Local, MatchSource, Pat};
use rustc_lexer::{tokenize, TokenKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{Span, SpanData, SyntaxContext};
mod collapsible_match;
mod infallible_destructuring_match;
mod match_as_ref;
mod match_bool;
@ -610,6 +612,44 @@ declare_clippy_lint! {
"`match` or match-like `if let` that are unnecessary"
}
declare_clippy_lint! {
/// ### What it does
/// Finds nested `match` or `if let` expressions where the patterns may be "collapsed" together
/// without adding any branches.
///
/// Note that this lint is not intended to find _all_ cases where nested match patterns can be merged, but only
/// cases where merging would most likely make the code more readable.
///
/// ### Why is this bad?
/// It is unnecessarily verbose and complex.
///
/// ### Example
/// ```rust
/// fn func(opt: Option<Result<u64, String>>) {
/// let n = match opt {
/// Some(n) => match n {
/// Ok(n) => n,
/// _ => return,
/// }
/// None => return,
/// };
/// }
/// ```
/// Use instead:
/// ```rust
/// fn func(opt: Option<Result<u64, String>>) {
/// let n = match opt {
/// Some(Ok(n)) => n,
/// _ => return,
/// };
/// }
/// ```
#[clippy::version = "1.50.0"]
pub COLLAPSIBLE_MATCH,
style,
"Nested `match` or `if let` expressions where the patterns may be \"collapsed\" together."
}
#[derive(Default)]
pub struct Matches {
msrv: Option<RustcVersion>,
@ -644,19 +684,29 @@ impl_lint_pass!(Matches => [
MATCH_LIKE_MATCHES_MACRO,
MATCH_SAME_ARMS,
NEEDLESS_MATCH,
COLLAPSIBLE_MATCH,
]);
impl<'tcx> LateLintPass<'tcx> for Matches {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if expr.span.from_expansion() {
if in_external_macro(cx.sess(), expr.span) {
return;
}
let from_expansion = expr.span.from_expansion();
if let ExprKind::Match(ex, arms, source) = expr.kind {
if !span_starts_with(cx, expr.span, "match") {
return;
}
if !contains_cfg_arm(cx, expr, ex, arms) {
collapsible_match::check_match(cx, arms);
if !from_expansion {
// These don't depend on a relationship between multiple arms
match_wild_err_arm::check(cx, ex, arms);
wild_in_or_pats::check(cx, arms);
}
if !from_expansion && !contains_cfg_arm(cx, expr, ex, arms) {
if source == MatchSource::Normal {
if !(meets_msrv(self.msrv, msrvs::MATCHES_MACRO)
&& match_like_matches::check_match(cx, expr, ex, arms))
@ -680,16 +730,32 @@ impl<'tcx> LateLintPass<'tcx> for Matches {
}
match_ref_pats::check(cx, ex, arms.iter().map(|el| el.pat), expr);
}
// These don't depend on a relationship between multiple arms
match_wild_err_arm::check(cx, ex, arms);
wild_in_or_pats::check(cx, arms);
} else {
if meets_msrv(self.msrv, msrvs::MATCHES_MACRO) {
match_like_matches::check(cx, expr);
} else if let Some(if_let) = higher::IfLet::hir(cx, expr) {
collapsible_match::check_if_let(cx, if_let.let_pat, if_let.if_then, if_let.if_else);
if !from_expansion {
if let Some(else_expr) = if_let.if_else {
if meets_msrv(self.msrv, msrvs::MATCHES_MACRO) {
match_like_matches::check_if_let(
cx,
expr,
if_let.let_pat,
if_let.let_expr,
if_let.if_then,
else_expr,
);
}
}
redundant_pattern_match::check_if_let(
cx,
expr,
if_let.let_pat,
if_let.let_expr,
if_let.if_else.is_some(),
);
needless_match::check_if_let(cx, expr, &if_let);
}
} else if !from_expansion {
redundant_pattern_match::check(cx, expr);
needless_match::check(cx, expr);
}
}

30
clippy_lints/src/matches/needless_match.rs
View File

@ -47,20 +47,18 @@ pub(crate) fn check_match(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>],
/// some_enum
/// }
/// ```
pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>) {
if let Some(ref if_let) = higher::IfLet::hir(cx, ex) {
if !is_else_clause(cx.tcx, ex) && expr_ty_matches_p_ty(cx, if_let.let_expr, ex) && check_if_let(cx, if_let) {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
NEEDLESS_MATCH,
ex.span,
"this if-let expression is unnecessary",
"replace it with",
snippet_with_applicability(cx, if_let.let_expr.span, "..", &mut applicability).to_string(),
applicability,
);
}
pub(crate) fn check_if_let<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'_>, if_let: &higher::IfLet<'tcx>) {
if !is_else_clause(cx.tcx, ex) && expr_ty_matches_p_ty(cx, if_let.let_expr, ex) && check_if_let_inner(cx, if_let) {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
NEEDLESS_MATCH,
ex.span,
"this if-let expression is unnecessary",
"replace it with",
snippet_with_applicability(cx, if_let.let_expr.span, "..", &mut applicability).to_string(),
applicability,
);
}
}
@ -77,7 +75,7 @@ fn check_all_arms(cx: &LateContext<'_>, match_expr: &Expr<'_>, arms: &[Arm<'_>])
true
}
fn check_if_let(cx: &LateContext<'_>, if_let: &higher::IfLet<'_>) -> bool {
fn check_if_let_inner(cx: &LateContext<'_>, if_let: &higher::IfLet<'_>) -> bool {
if let Some(if_else) = if_let.if_else {
if !pat_same_as_expr(if_let.let_pat, peel_blocks_with_stmt(if_let.if_then)) {
return false;
@ -85,7 +83,7 @@ fn check_if_let(cx: &LateContext<'_>, if_let: &higher::IfLet<'_>) -> bool {
// Recursively check for each `else if let` phrase,
if let Some(ref nested_if_let) = higher::IfLet::hir(cx, if_else) {
return check_if_let(cx, nested_if_let);
return check_if_let_inner(cx, nested_if_let);
}
if matches!(if_else.kind, ExprKind::Block(..)) {

20
clippy_lints/src/matches/redundant_pattern_match.rs
View File

@ -18,19 +18,21 @@ use rustc_middle::ty::{self, subst::GenericArgKind, DefIdTree, Ty};
use rustc_span::sym;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if let Some(higher::IfLet {
if_else,
let_pat,
let_expr,
..
}) = higher::IfLet::hir(cx, expr)
{
find_sugg_for_if_let(cx, expr, let_pat, let_expr, "if", if_else.is_some());
} else if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
find_sugg_for_if_let(cx, expr, let_pat, let_expr, "while", false);
}
}
pub(super) fn check_if_let<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
pat: &'tcx Pat<'_>,
scrutinee: &'tcx Expr<'_>,
has_else: bool,
) {
find_sugg_for_if_let(cx, expr, pat, scrutinee, "if", has_else);
}
// Extract the generic arguments out of a type
fn try_get_generic_ty(ty: Ty<'_>, index: usize) -> Option<Ty<'_>> {
if_chain! {