Add a machine-applicable suggestion to "unreachable pattern"

compiler/rustc_mir_build/messages.ftl

@@ -338,6 +338,7 @@ mir_build_unreachable_pattern = unreachable pattern
     .unreachable_covered_by_catchall = matches any value
     .unreachable_covered_by_one = matches all the relevant values
     .unreachable_covered_by_many = multiple earlier patterns match some of the same values
+    .suggestion = remove the match arm
 
 mir_build_unsafe_fn_safe_body = an unsafe function restricts its caller, but its body is safe by default
 mir_build_unsafe_not_inherited = items do not inherit unsafety from separate enclosing items

compiler/rustc_mir_build/src/errors.rs

@@ -598,6 +598,8 @@ pub(crate) struct UnreachablePattern<'tcx> {
     #[note(mir_build_unreachable_covered_by_many)]
     pub(crate) covered_by_many: Option<MultiSpan>,
     pub(crate) covered_by_many_n_more_count: usize,
+    #[suggestion(code = "", applicability = "machine-applicable")]
+    pub(crate) suggest_remove: Option<Span>,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_mir_build/src/thir/pattern/check_match.rs

@@ -413,7 +413,7 @@ impl<'p, 'tcx> MatchVisitor<'p, 'tcx> {
                 // Emit lints in the order in which they occur in the file.
                 redundant_subpats.sort_unstable_by_key(|(pat, _)| pat.data().span);
                 for (pat, explanation) in redundant_subpats {
-                    report_unreachable_pattern(cx, arm.arm_data, pat, &explanation)
+                    report_unreachable_pattern(cx, arm.arm_data, pat, &explanation, None)
                 }
             }
         }
@@ -474,7 +474,11 @@ impl<'p, 'tcx> MatchVisitor<'p, 'tcx> {
             hir::MatchSource::ForLoopDesugar
             | hir::MatchSource::Postfix
             | hir::MatchSource::Normal
-            | hir::MatchSource::FormatArgs => report_arm_reachability(&cx, &report),
+            | hir::MatchSource::FormatArgs => {
+                let is_match_arm =
+                    matches!(source, hir::MatchSource::Postfix | hir::MatchSource::Normal);
+                report_arm_reachability(&cx, &report, is_match_arm);
+            }
             // Unreachable patterns in try and await expressions occur when one of
             // the arms are an uninhabited type. Which is OK.
             hir::MatchSource::AwaitDesugar | hir::MatchSource::TryDesugar(_) => {}
@@ -626,7 +630,7 @@ impl<'p, 'tcx> MatchVisitor<'p, 'tcx> {
     ) -> Result<RefutableFlag, ErrorGuaranteed> {
         let (cx, report) = self.analyze_binding(pat, Refutable, scrut)?;
         // Report if the pattern is unreachable, which can only occur when the type is uninhabited.
-        report_arm_reachability(&cx, &report);
+        report_arm_reachability(&cx, &report, false);
         // If the list of witnesses is empty, the match is exhaustive, i.e. the `if let` pattern is
         // irrefutable.
         Ok(if report.non_exhaustiveness_witnesses.is_empty() { Irrefutable } else { Refutable })
@@ -916,6 +920,7 @@ fn report_unreachable_pattern<'p, 'tcx>(
     hir_id: HirId,
     pat: &DeconstructedPat<'p, 'tcx>,
     explanation: &RedundancyExplanation<'p, 'tcx>,
+    whole_arm_span: Option<Span>,
 ) {
     static CAP_COVERED_BY_MANY: usize = 4;
     let pat_span = pat.data().span;
@@ -928,6 +933,7 @@ fn report_unreachable_pattern<'p, 'tcx>(
         covered_by_one: None,
         covered_by_many: None,
         covered_by_many_n_more_count: 0,
+        suggest_remove: None,
     };
     match explanation.covered_by.as_slice() {
         [] => {
@@ -935,6 +941,7 @@ fn report_unreachable_pattern<'p, 'tcx>(
             lint.span = None; // Don't label the pattern itself
             lint.uninhabited_note = Some(()); // Give a link about empty types
             lint.matches_no_values = Some(pat_span);
+            lint.suggest_remove = whole_arm_span; // Suggest to remove the match arm
             pat.walk(&mut |subpat| {
                 let ty = **subpat.ty();
                 if cx.is_uninhabited(ty) {
@@ -982,10 +989,28 @@ fn report_unreachable_pattern<'p, 'tcx>(
 }
 
 /// Report unreachable arms, if any.
-fn report_arm_reachability<'p, 'tcx>(cx: &PatCtxt<'p, 'tcx>, report: &UsefulnessReport<'p, 'tcx>) {
+fn report_arm_reachability<'p, 'tcx>(
+    cx: &PatCtxt<'p, 'tcx>,
+    report: &UsefulnessReport<'p, 'tcx>,
+    is_match_arm: bool,
+) {
+    let sm = cx.tcx.sess.source_map();
     for (arm, is_useful) in report.arm_usefulness.iter() {
         if let Usefulness::Redundant(explanation) = is_useful {
-            report_unreachable_pattern(cx, arm.arm_data, arm.pat, explanation)
+            let hir_id = arm.arm_data;
+            let arm_span = cx.tcx.hir().span(hir_id);
+            let whole_arm_span = if is_match_arm {
+                // If the arm is followed by a comma, extend the span to include it.
+                let with_whitespace = sm.span_extend_while_whitespace(arm_span);
+                if let Some(comma) = sm.span_look_ahead(with_whitespace, ",", Some(1)) {
+                    Some(arm_span.to(comma))
+                } else {
+                    Some(arm_span)
+                }
+            } else {
+                None
+            };
+            report_unreachable_pattern(cx, hir_id, arm.pat, explanation, whole_arm_span)
         }
     }
 }

tests/ui/pattern/usefulness/empty-match-check-notes.exhaustive_patterns.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:17:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `EmptyEnum` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `EmptyEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:22:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `EmptyEnum` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `EmptyEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -23,7 +29,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:31:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `EmptyForeignEnum` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `EmptyForeignEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -31,7 +40,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:36:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `EmptyForeignEnum` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `EmptyForeignEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/empty-match-check-notes.normal.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:17:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `EmptyEnum` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `EmptyEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:22:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `EmptyEnum` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `EmptyEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -23,7 +29,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:31:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `EmptyForeignEnum` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `EmptyForeignEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -31,7 +40,10 @@ error: unreachable pattern
   --> $DIR/empty-match-check-notes.rs:36:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `EmptyForeignEnum` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `EmptyForeignEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/empty-types.exhaustive_patterns.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:49:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:52:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -38,7 +44,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:70:9
    |
 LL |         (_, _) => {}
-   |         ^^^^^^ matches no values because `(u32, !)` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `(u32, !)` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -46,7 +55,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:76:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `(!, !)` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `(!, !)` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -54,7 +66,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:79:9
    |
 LL |         (_, _) => {}
-   |         ^^^^^^ matches no values because `(!, !)` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `(!, !)` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -62,7 +77,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:83:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -89,7 +107,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:94:9
    |
 LL |         Err(_) => {}
-   |         ^^^^^^ matches no values because `!` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -97,7 +118,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:99:9
    |
 LL |         Err(_) => {}
-   |         ^^^^^^ matches no values because `!` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -137,7 +161,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:112:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `Result<!, !>` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -145,7 +172,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:115:9
    |
 LL |         Ok(_) => {}
-   |         ^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -153,7 +183,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:118:9
    |
 LL |         Ok(_) => {}
-   |         ^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -161,7 +194,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:119:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `Result<!, !>` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -169,7 +205,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:122:9
    |
 LL |         Ok(_) => {}
-   |         ^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -177,7 +216,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:123:9
    |
 LL |         Err(_) => {}
-   |         ^^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -185,7 +227,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:132:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -193,7 +238,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:135:13
    |
 LL |             _ if false => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^---------------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -201,7 +249,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:143:13
    |
 LL |             Some(_) => {}
-   |             ^^^^^^^ matches no values because `Void` is uninhabited
+   |             ^^^^^^^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -217,7 +268,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:199:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -225,7 +279,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:204:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -233,7 +290,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:209:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -241,7 +301,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:214:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -249,7 +312,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:220:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -257,7 +323,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:281:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -265,7 +334,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:284:9
    |
 LL |         (_, _) => {}
-   |         ^^^^^^ matches no values because `(!, !)` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `(!, !)` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -273,7 +345,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:287:9
    |
 LL |         Ok(_) => {}
-   |         ^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -281,7 +356,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:288:9
    |
 LL |         Err(_) => {}
-   |         ^^^^^^ matches no values because `Result<!, !>` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `Result<!, !>` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -344,7 +422,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:368:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `[!; 3]` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `[!; 3]` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -352,7 +433,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:371:9
    |
 LL |         [_, _, _] => {}
-   |         ^^^^^^^^^ matches no values because `[!; 3]` is uninhabited
+   |         ^^^^^^^^^------
+   |         |
+   |         matches no values because `[!; 3]` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -360,7 +444,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:374:9
    |
 LL |         [_, ..] => {}
-   |         ^^^^^^^ matches no values because `[!; 3]` is uninhabited
+   |         ^^^^^^^------
+   |         |
+   |         matches no values because `[!; 3]` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -404,7 +491,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:416:9
    |
 LL |         Some(_) => {}
-   |         ^^^^^^^ matches no values because `!` is uninhabited
+   |         ^^^^^^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -412,7 +502,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:421:9
    |
 LL |         Some(_a) => {}
-   |         ^^^^^^^^ matches no values because `!` is uninhabited
+   |         ^^^^^^^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -438,7 +531,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:603:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -446,7 +542,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:606:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -454,7 +553,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:609:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -462,7 +564,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:612:9
    |
 LL |         _x if false => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/empty-types.never_pats.stderr

@@ -11,7 +11,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:49:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -24,7 +27,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:52:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -47,7 +53,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:83:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -120,7 +129,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:132:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -128,7 +140,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:135:13
    |
 LL |             _ if false => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^---------------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -155,7 +170,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:199:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -163,7 +181,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:204:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -171,7 +192,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:209:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -179,7 +203,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:214:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -187,7 +214,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:220:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -195,7 +225,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:281:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -476,7 +509,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:603:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -484,7 +520,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:606:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -492,7 +531,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:609:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -500,7 +542,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:612:9
    |
 LL |         _x if false => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/empty-types.normal.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:49:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:52:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -38,7 +44,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:83:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -111,7 +120,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:132:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -119,7 +131,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:135:13
    |
 LL |             _ if false => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^---------------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -146,7 +161,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:199:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -154,7 +172,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:204:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -162,7 +183,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:209:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -170,7 +194,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:214:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -178,7 +205,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:220:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `!` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `!` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -186,7 +216,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:281:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -467,7 +500,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:603:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -475,7 +511,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:606:9
    |
 LL |         _x => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -483,7 +522,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:609:9
    |
 LL |         _ if false => {}
-   |         ^ matches no values because `!` is uninhabited
+   |         ^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -491,7 +533,10 @@ error: unreachable pattern
   --> $DIR/empty-types.rs:612:9
    |
 LL |         _x if false => {}
-   |         ^^ matches no values because `!` is uninhabited
+   |         ^^---------------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/explain-unreachable-pats.stderr

@@ -59,7 +59,10 @@ error: unreachable pattern
   --> $DIR/explain-unreachable-pats.rs:52:9
    |
 LL |         Err(_) => {}
-   |         ^^^^^^ matches no values because `!` is uninhabited
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `!` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -67,7 +70,10 @@ error: unreachable pattern
   --> $DIR/explain-unreachable-pats.rs:66:9
    |
 LL |         (Err(_), Err(_)) => {}
-   |         ^^^^^^^^^^^^^^^^ matches no values because `Void2` is uninhabited
+   |         ^^^^^^^^^^^^^^^^------
+   |         |
+   |         matches no values because `Void2` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -75,7 +81,10 @@ error: unreachable pattern
   --> $DIR/explain-unreachable-pats.rs:73:9
    |
 LL |         (Err(_), Err(_)) => {}
-   |         ^^^^^^^^^^^^^^^^ matches no values because `Void1` is uninhabited
+   |         ^^^^^^^^^^^^^^^^------
+   |         |
+   |         matches no values because `Void1` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/impl-trait.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:17:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:31:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -23,7 +29,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:45:13
    |
 LL |             Some(_) => {}
-   |             ^^^^^^^ matches no values because `Void` is uninhabited
+   |             ^^^^^^^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -39,7 +48,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:59:13
    |
 LL |             Some(_) => {}
-   |             ^^^^^^^ matches no values because `Void` is uninhabited
+   |             ^^^^^^^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -55,7 +67,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:76:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `Void` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -71,7 +86,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:94:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `Void` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `Void` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -95,7 +113,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:138:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `SecretelyVoid` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `SecretelyVoid` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 
@@ -103,7 +124,10 @@ error: unreachable pattern
   --> $DIR/impl-trait.rs:151:13
    |
 LL |             _ => {}
-   |             ^ matches no values because `SecretelyDoubleVoid` is uninhabited
+   |             ^------
+   |             |
+   |             matches no values because `SecretelyDoubleVoid` is uninhabited
+   |             help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/pattern/usefulness/rustfix-unreachable-pattern.fixed

@@ -0,0 +1,23 @@
+//@ run-rustfix
+#![feature(never_patterns)]
+#![feature(exhaustive_patterns)]
+#![allow(incomplete_features)]
+#![deny(unreachable_patterns)]
+
+enum Void {}
+
+#[rustfmt::skip]
+fn main() {
+    let res: Result<(), Void> = Ok(());
+    match res {
+        Ok(_) => {}
+         //~ ERROR unreachable
+         //~ ERROR unreachable
+    }
+
+    match res {
+        Ok(_x) => {}
+         //~ ERROR unreachable
+         //~ ERROR unreachable
+    }
+}

tests/ui/pattern/usefulness/rustfix-unreachable-pattern.rs

@@ -0,0 +1,23 @@
+//@ run-rustfix
+#![feature(never_patterns)]
+#![feature(exhaustive_patterns)]
+#![allow(incomplete_features)]
+#![deny(unreachable_patterns)]
+
+enum Void {}
+
+#[rustfmt::skip]
+fn main() {
+    let res: Result<(), Void> = Ok(());
+    match res {
+        Ok(_) => {}
+        Err(_) => {} //~ ERROR unreachable
+        Err(_) => {}, //~ ERROR unreachable
+    }
+
+    match res {
+        Ok(_x) => {}
+        Err(!), //~ ERROR unreachable
+        Err(!) //~ ERROR unreachable
+    }
+}

tests/ui/pattern/usefulness/rustfix-unreachable-pattern.stderr

@@ -0,0 +1,51 @@
+error: unreachable pattern
+  --> $DIR/rustfix-unreachable-pattern.rs:14:9
+   |
+LL |         Err(_) => {}
+   |         ^^^^^^------
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
+   |
+   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
+note: the lint level is defined here
+  --> $DIR/rustfix-unreachable-pattern.rs:5:9
+   |
+LL | #![deny(unreachable_patterns)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: unreachable pattern
+  --> $DIR/rustfix-unreachable-pattern.rs:15:9
+   |
+LL |         Err(_) => {},
+   |         ^^^^^^-------
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
+   |
+   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
+
+error: unreachable pattern
+  --> $DIR/rustfix-unreachable-pattern.rs:20:9
+   |
+LL |         Err(!),
+   |         ^^^^^^-
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
+   |
+   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
+
+error: unreachable pattern
+  --> $DIR/rustfix-unreachable-pattern.rs:21:9
+   |
+LL |         Err(!)
+   |         ^^^^^^
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
+   |
+   = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
+
+error: aborting due to 4 previous errors
+

tests/ui/reachable/unreachable-try-pattern.stderr

@@ -17,7 +17,10 @@ warning: unreachable pattern
   --> $DIR/unreachable-try-pattern.rs:19:24
    |
 LL |     let y = (match x { Ok(n) => Ok(n as u32), Err(e) => Err(e) })?;
-   |                        ^^^^^ matches no values because `!` is uninhabited
+   |                        ^^^^^-----------------
+   |                        |
+   |                        matches no values because `!` is uninhabited
+   |                        help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -30,7 +33,10 @@ warning: unreachable pattern
   --> $DIR/unreachable-try-pattern.rs:30:40
    |
 LL |     let y = (match x { Ok(n) => Ok(n), Err(e) => Err(e) })?;
-   |                                        ^^^^^^ matches no values because `Void` is uninhabited
+   |                                        ^^^^^^----------
+   |                                        |
+   |                                        matches no values because `Void` is uninhabited
+   |                                        help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/rfcs/rfc-0000-never_patterns/unreachable.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/unreachable.rs:15:9
    |
 LL |         Err(!),
-   |         ^^^^^^ matches no values because `Void` is uninhabited
+   |         ^^^^^^-
+   |         |
+   |         matches no values because `Void` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here

tests/ui/rfcs/rfc-2008-non-exhaustive/enum_same_crate_empty_match.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/enum_same_crate_empty_match.rs:28:9
    |
 LL |         _ => {}
-   |         ^ matches no values because `EmptyNonExhaustiveEnum` is uninhabited
+   |         ^------
+   |         |
+   |         matches no values because `EmptyNonExhaustiveEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here

tests/ui/rfcs/rfc-2008-non-exhaustive/uninhabited/patterns.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/patterns.rs:42:9
    |
 LL |         Some(_x) => (),
-   |         ^^^^^^^^ matches no values because `UninhabitedVariants` is uninhabited
+   |         ^^^^^^^^-------
+   |         |
+   |         matches no values because `UninhabitedVariants` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here

tests/ui/rfcs/rfc-2008-non-exhaustive/uninhabited/patterns_same_crate.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/patterns_same_crate.rs:53:9
    |
 LL |         Some(_x) => (),
-   |         ^^^^^^^^ matches no values because `UninhabitedEnum` is uninhabited
+   |         ^^^^^^^^-------
+   |         |
+   |         matches no values because `UninhabitedEnum` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/patterns_same_crate.rs:58:9
    |
 LL |         Some(_x) => (),
-   |         ^^^^^^^^ matches no values because `UninhabitedVariants` is uninhabited
+   |         ^^^^^^^^-------
+   |         |
+   |         matches no values because `UninhabitedVariants` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 

tests/ui/uninhabited/uninhabited-patterns.stderr

@@ -2,7 +2,10 @@ error: unreachable pattern
   --> $DIR/uninhabited-patterns.rs:30:9
    |
 LL |         Ok(box _) => (),
-   |         ^^^^^^^^^ matches no values because `NotSoSecretlyEmpty` is uninhabited
+   |         ^^^^^^^^^-------
+   |         |
+   |         matches no values because `NotSoSecretlyEmpty` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
 note: the lint level is defined here
@@ -15,7 +18,10 @@ error: unreachable pattern
   --> $DIR/uninhabited-patterns.rs:39:9
    |
 LL |         Err(Ok(_y)) => (),
-   |         ^^^^^^^^^^^ matches no values because `NotSoSecretlyEmpty` is uninhabited
+   |         ^^^^^^^^^^^-------
+   |         |
+   |         matches no values because `NotSoSecretlyEmpty` is uninhabited
+   |         help: remove the match arm
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types