Auto merge of #12448 - WeiTheShinobi:fix_single_match, r=dswij

[`single_match`]: Fix duplicate diagnostics

Relates to #12379

edit two test file
`tests/ui/single_match_else.rs`
`tests/ui/single_match.rs`

those two test file point to the same lint

---

changelog: [`single_match`] Fix duplicate diagnostics

Author: bors

clippy_lints/src/matches/single_match.rs

@@ -55,23 +55,15 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr:
         };
 
         let ty = cx.typeck_results().expr_ty(ex);
-        if *ty.kind() != ty::Bool || is_lint_allowed(cx, MATCH_BOOL, ex.hir_id) {
-            check_single_pattern(cx, ex, arms, expr, els);
-            check_opt_like(cx, ex, arms, expr, ty, els);
+        if (*ty.kind() != ty::Bool || is_lint_allowed(cx, MATCH_BOOL, ex.hir_id)) &&
+            (check_single_pattern(arms) || check_opt_like(cx, arms, ty)) {
+            report_single_pattern(cx, ex, arms, expr, els);
         }
     }
 }
 
-fn check_single_pattern(
-    cx: &LateContext<'_>,
-    ex: &Expr<'_>,
-    arms: &[Arm<'_>],
-    expr: &Expr<'_>,
-    els: Option<&Expr<'_>>,
-) {
-    if is_wild(arms[1].pat) {
-        report_single_pattern(cx, ex, arms, expr, els);
-    }
+fn check_single_pattern(arms: &[Arm<'_>]) -> bool {
+    is_wild(arms[1].pat)
 }
 
 fn report_single_pattern(
@@ -140,19 +132,10 @@ fn report_single_pattern(
     span_lint_and_sugg(cx, lint, expr.span, msg, "try", sugg, app);
 }
 
-fn check_opt_like<'a>(
-    cx: &LateContext<'a>,
-    ex: &Expr<'_>,
-    arms: &[Arm<'_>],
-    expr: &Expr<'_>,
-    ty: Ty<'a>,
-    els: Option<&Expr<'_>>,
-) {
+fn check_opt_like<'a>(cx: &LateContext<'a>, arms: &[Arm<'_>], ty: Ty<'a>) -> bool {
     // We don't want to lint if the second arm contains an enum which could
     // have more variants in the future.
-    if form_exhaustive_matches(cx, ty, arms[0].pat, arms[1].pat) {
-        report_single_pattern(cx, ex, arms, expr, els);
-    }
+    form_exhaustive_matches(cx, ty, arms[0].pat, arms[1].pat)
 }
 
 /// Returns `true` if all of the types in the pattern are enums which we know

tests/ui/single_match.fixed

@@ -1,5 +1,3 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::single_match)]
 #![allow(
     unused,

tests/ui/single_match.rs

@@ -1,5 +1,3 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::single_match)]
 #![allow(
     unused,

tests/ui/single_match.stderr

@@ -1,5 +1,5 @@
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:17:5
+  --> tests/ui/single_match.rs:15:5
    |
 LL | /     match x {
 LL | |         Some(y) => {
@@ -19,7 +19,7 @@ LL ~     };
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:25:5
+  --> tests/ui/single_match.rs:23:5
    |
 LL | /     match x {
 LL | |         // Note the missing block braces.
@@ -31,7 +31,7 @@ LL | |     }
    | |_____^ help: try: `if let Some(y) = x { println!("{:?}", y) }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:34:5
+  --> tests/ui/single_match.rs:32:5
    |
 LL | /     match z {
 LL | |         (2..=3, 7..=9) => dummy(),
@@ -40,7 +40,7 @@ LL | |     };
    | |_____^ help: try: `if let (2..=3, 7..=9) = z { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:63:5
+  --> tests/ui/single_match.rs:61:5
    |
 LL | /     match x {
 LL | |         Some(y) => dummy(),
@@ -49,7 +49,7 @@ LL | |     };
    | |_____^ help: try: `if let Some(y) = x { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:68:5
+  --> tests/ui/single_match.rs:66:5
    |
 LL | /     match y {
 LL | |         Ok(y) => dummy(),
@@ -58,7 +58,7 @@ LL | |     };
    | |_____^ help: try: `if let Ok(y) = y { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:75:5
+  --> tests/ui/single_match.rs:73:5
    |
 LL | /     match c {
 LL | |         Cow::Borrowed(..) => dummy(),
@@ -67,7 +67,7 @@ LL | |     };
    | |_____^ help: try: `if let Cow::Borrowed(..) = c { dummy() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:96:5
+  --> tests/ui/single_match.rs:94:5
    |
 LL | /     match x {
 LL | |         "test" => println!(),
@@ -76,7 +76,7 @@ LL | |     }
    | |_____^ help: try: `if x == "test" { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:109:5
+  --> tests/ui/single_match.rs:107:5
    |
 LL | /     match x {
 LL | |         Foo::A => println!(),
@@ -85,7 +85,7 @@ LL | |     }
    | |_____^ help: try: `if x == Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:115:5
+  --> tests/ui/single_match.rs:113:5
    |
 LL | /     match x {
 LL | |         FOO_C => println!(),
@@ -94,7 +94,7 @@ LL | |     }
    | |_____^ help: try: `if x == FOO_C { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:120:5
+  --> tests/ui/single_match.rs:118:5
    |
 LL | /     match &&x {
 LL | |         Foo::A => println!(),
@@ -103,7 +103,7 @@ LL | |     }
    | |_____^ help: try: `if x == Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:126:5
+  --> tests/ui/single_match.rs:124:5
    |
 LL | /     match &x {
 LL | |         Foo::A => println!(),
@@ -112,7 +112,7 @@ LL | |     }
    | |_____^ help: try: `if x == &Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:143:5
+  --> tests/ui/single_match.rs:141:5
    |
 LL | /     match x {
 LL | |         Bar::A => println!(),
@@ -121,7 +121,7 @@ LL | |     }
    | |_____^ help: try: `if let Bar::A = x { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:151:5
+  --> tests/ui/single_match.rs:149:5
    |
 LL | /     match x {
 LL | |         None => println!(),
@@ -130,7 +130,7 @@ LL | |     };
    | |_____^ help: try: `if let None = x { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:173:5
+  --> tests/ui/single_match.rs:171:5
    |
 LL | /     match x {
 LL | |         (Some(_), _) => {},
@@ -139,7 +139,7 @@ LL | |     }
    | |_____^ help: try: `if let (Some(_), _) = x {}`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:179:5
+  --> tests/ui/single_match.rs:177:5
    |
 LL | /     match x {
 LL | |         (Some(E::V), _) => todo!(),
@@ -148,7 +148,7 @@ LL | |     }
    | |_____^ help: try: `if let (Some(E::V), _) = x { todo!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:185:5
+  --> tests/ui/single_match.rs:183:5
    |
 LL | /     match (Some(42), Some(E::V), Some(42)) {
 LL | |         (.., Some(E::V), _) => {},
@@ -157,7 +157,7 @@ LL | |     }
    | |_____^ help: try: `if let (.., Some(E::V), _) = (Some(42), Some(E::V), Some(42)) {}`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:257:5
+  --> tests/ui/single_match.rs:255:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -177,7 +177,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:265:5
+  --> tests/ui/single_match.rs:263:5
    |
 LL | /     match bar {
 LL | |         #[rustfmt::skip]

tests/ui/single_match_else.fixed

@@ -1,5 +1,4 @@
 //@aux-build: proc_macros.rs
-//@compile-flags: -Zdeduplicate-diagnostics=yes
 
 #![warn(clippy::single_match_else)]
 #![allow(unused, clippy::needless_return, clippy::no_effect, clippy::uninlined_format_args)]

tests/ui/single_match_else.rs

@@ -1,5 +1,4 @@
 //@aux-build: proc_macros.rs
-//@compile-flags: -Zdeduplicate-diagnostics=yes
 
 #![warn(clippy::single_match_else)]
 #![allow(unused, clippy::needless_return, clippy::no_effect, clippy::uninlined_format_args)]

tests/ui/single_match_else.stderr

@@ -1,5 +1,5 @@
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:18:13
+  --> tests/ui/single_match_else.rs:17:13
    |
 LL |       let _ = match ExprNode::Butterflies {
    |  _____________^
@@ -22,7 +22,7 @@ LL ~     };
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:83:5
+  --> tests/ui/single_match_else.rs:82:5
    |
 LL | /     match Some(1) {
 LL | |         Some(a) => println!("${:?}", a),
@@ -42,7 +42,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:92:5
+  --> tests/ui/single_match_else.rs:91:5
    |
 LL | /     match Some(1) {
 LL | |         Some(a) => println!("${:?}", a),
@@ -62,7 +62,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:102:5
+  --> tests/ui/single_match_else.rs:101:5
    |
 LL | /     match Result::<i32, Infallible>::Ok(1) {
 LL | |         Ok(a) => println!("${:?}", a),
@@ -82,7 +82,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:111:5
+  --> tests/ui/single_match_else.rs:110:5
    |
 LL | /     match Cow::from("moo") {
 LL | |         Cow::Owned(a) => println!("${:?}", a),
@@ -102,7 +102,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:121:5
+  --> tests/ui/single_match_else.rs:120:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -125,7 +125,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:132:5
+  --> tests/ui/single_match_else.rs:131:5
    |
 LL | /     match bar {
 LL | |         Some(v) => {
@@ -149,7 +149,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:144:5
+  --> tests/ui/single_match_else.rs:143:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -173,7 +173,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:156:5
+  --> tests/ui/single_match_else.rs:155:5
    |
 LL | /     match bar {
 LL | |         #[rustfmt::skip]