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improve [match_same_arms] messages, enable rustfix test #12794

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Merged
merged 1 commit into from
May 14, 2024
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improve [match_same_arms] messages, enable rustfix test #12794

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37 changes: 26 additions & 11 deletions clippy_lints/src/matches/match_same_arms.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
use clippy_utils::diagnostics::span_lint_hir_and_then;
use clippy_utils::source::snippet;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::{is_lint_allowed, path_to_local, search_same, SpanlessEq, SpanlessHash};
use core::cmp::Ordering;
use core::{iter, slice};
Expand All @@ -9,9 +9,9 @@ use rustc_errors::Applicability;
use rustc_hir::def_id::DefId;
use rustc_hir::{Arm, Expr, ExprKind, HirId, HirIdMap, HirIdMapEntry, HirIdSet, Pat, PatKind, RangeEnd};
use rustc_lint::builtin::NON_EXHAUSTIVE_OMITTED_PATTERNS;
use rustc_lint::LateContext;
use rustc_lint::{LateContext, LintContext};
use rustc_middle::ty;
use rustc_span::{ErrorGuaranteed, Symbol};
use rustc_span::{ErrorGuaranteed, Span, Symbol};

use super::MATCH_SAME_ARMS;

Expand Down Expand Up @@ -110,20 +110,22 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
&& check_same_body()
};

let mut appl = Applicability::MaybeIncorrect;
let indexed_arms: Vec<(usize, &Arm<'_>)> = arms.iter().enumerate().collect();
for (&(i, arm1), &(j, arm2)) in search_same(&indexed_arms, hash, eq) {
if matches!(arm2.pat.kind, PatKind::Wild) {
if !cx.tcx.features().non_exhaustive_omitted_patterns_lint
|| is_lint_allowed(cx, NON_EXHAUSTIVE_OMITTED_PATTERNS, arm2.hir_id)
{
let arm_span = adjusted_arm_span(cx, arm1.span);
span_lint_hir_and_then(
cx,
MATCH_SAME_ARMS,
arm1.hir_id,
arm1.span,
arm_span,
"this match arm has an identical body to the `_` wildcard arm",
|diag| {
diag.span_suggestion(arm1.span, "try removing the arm", "", Applicability::MaybeIncorrect)
diag.span_suggestion(arm_span, "try removing the arm", "", appl)
.help("or try changing either arm body")
.span_note(arm2.span, "`_` wildcard arm here");
},
Expand All @@ -144,23 +146,36 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'_>]) {
keep_arm.span,
"this match arm has an identical body to another arm",
|diag| {
let move_pat_snip = snippet(cx, move_arm.pat.span, "<pat2>");
let keep_pat_snip = snippet(cx, keep_arm.pat.span, "<pat1>");
let move_pat_snip = snippet_with_applicability(cx, move_arm.pat.span, "<pat2>", &mut appl);
let keep_pat_snip = snippet_with_applicability(cx, keep_arm.pat.span, "<pat1>", &mut appl);

diag.span_suggestion(
keep_arm.pat.span,
"try merging the arm patterns",
"or try merging the arm patterns",
format!("{keep_pat_snip} | {move_pat_snip}"),
Applicability::MaybeIncorrect,
appl,
)
.help("or try changing either arm body")
.span_note(move_arm.span, "other arm here");
.span_suggestion(
adjusted_arm_span(cx, move_arm.span),
"and remove this obsolete arm",
"",
appl,
)
.help("try changing either arm body");
},
);
}
}
}

/// Extend arm's span to include the comma and whitespaces after it.
fn adjusted_arm_span(cx: &LateContext<'_>, span: Span) -> Span {
let source_map = cx.sess().source_map();
source_map
.span_extend_while(span, |c| c == ',' || c.is_ascii_whitespace())
.unwrap_or(span)
}

#[derive(Clone, Copy)]
enum NormalizedPat<'a> {
Wild,
Expand Down
122 changes: 65 additions & 57 deletions tests/ui/match_same_arms.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ error: this match arm has an identical body to the `_` wildcard arm
--> tests/ui/match_same_arms.rs:12:9
|
LL | Abc::A => 0,
| ^^^^^^^^^^^ help: try removing the arm
| ^^^^^^^^^^^^^ help: try removing the arm
|
= help: or try changing either arm body
note: `_` wildcard arm here
Expand All @@ -17,106 +17,114 @@ error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:18:9
|
LL | (1, .., 3) => 42,
| ----------^^^^^^
| |
| help: try merging the arm patterns: `(1, .., 3) | (.., 3)`
| ^^^^^^^^^^^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:19:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | (1, .., 3) | (.., 3) => 42,
| ~~~~~~~~~~~~~~~~~~~~
help: and remove this obsolete arm
|
LL - (.., 3) => 42,
|
LL | (.., 3) => 42,
| ^^^^^^^^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:25:9
|
LL | 51 => 1,
| --^^^^^
| |
| help: try merging the arm patterns: `51 | 42`
| ^^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:24:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | 51 | 42 => 1,
| ~~~~~~~
help: and remove this obsolete arm
|
LL - 42 => 1,
|
LL | 42 => 1,
| ^^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:26:9
|
LL | 41 => 2,
| --^^^^^
| |
| help: try merging the arm patterns: `41 | 52`
| ^^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:27:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | 41 | 52 => 2,
| ~~~~~~~
help: and remove this obsolete arm
|
LL - 52 => 2,
|
LL | 52 => 2,
| ^^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:33:9
|
LL | 2 => 2,
| -^^^^^
| |
| help: try merging the arm patterns: `2 | 1`
| ^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:32:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | 2 | 1 => 2,
| ~~~~~
help: and remove this obsolete arm
|
LL - 1 => 2,
|
LL | 1 => 2,
| ^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:35:9
|
LL | 3 => 2,
| -^^^^^
| |
| help: try merging the arm patterns: `3 | 1`
| ^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:32:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | 3 | 1 => 2,
| ~~~~~
help: and remove this obsolete arm
|
LL - 1 => 2,
|
LL | 1 => 2,
| ^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:33:9
|
LL | 2 => 2,
| -^^^^^
| |
| help: try merging the arm patterns: `2 | 3`
| ^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:35:9
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | 2 | 3 => 2,
| ~~~~~
help: and remove this obsolete arm
|
LL - 3 => 2,
LL +
|
LL | 3 => 2,
| ^^^^^^

error: this match arm has an identical body to another arm
--> tests/ui/match_same_arms.rs:52:17
|
LL | CommandInfo::External { name, .. } => name.to_string(),
| ----------------------------------^^^^^^^^^^^^^^^^^^^^
| |
| help: try merging the arm patterns: `CommandInfo::External { name, .. } | CommandInfo::BuiltIn { name, .. }`
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: or try changing either arm body
note: other arm here
--> tests/ui/match_same_arms.rs:51:17
= help: try changing either arm body
help: or try merging the arm patterns
|
LL | CommandInfo::External { name, .. } | CommandInfo::BuiltIn { name, .. } => name.to_string(),
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
help: and remove this obsolete arm
|
LL - CommandInfo::BuiltIn { name, .. } => name.to_string(),
|
LL | CommandInfo::BuiltIn { name, .. } => name.to_string(),
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to 8 previous errors

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