diff options
| -rw-r--r-- | compiler/rustc_mir_build/messages.ftl | 2 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/errors.rs | 1 | ||||
| -rw-r--r-- | compiler/rustc_mir_build/src/thir/pattern/check_match.rs | 20 | ||||
| -rw-r--r-- | tests/ui/pattern/usefulness/explain-unreachable-pats.rs | 19 | ||||
| -rw-r--r-- | tests/ui/pattern/usefulness/explain-unreachable-pats.stderr | 42 |
5 files changed, 72 insertions, 12 deletions
diff --git a/compiler/rustc_mir_build/messages.ftl b/compiler/rustc_mir_build/messages.ftl index b6258045566..15da430759b 100644 --- a/compiler/rustc_mir_build/messages.ftl +++ b/compiler/rustc_mir_build/messages.ftl @@ -327,6 +327,8 @@ mir_build_union_pattern = cannot use unions in constant patterns mir_build_unreachable_making_this_unreachable = collectively making this unreachable +mir_build_unreachable_making_this_unreachable_n_more = ...and {$covered_by_many_n_more_count} other patterns collectively make this unreachable + mir_build_unreachable_matches_same_values = matches some of the same values mir_build_unreachable_pattern = unreachable pattern diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs index a45a0311e32..76b765ad4cd 100644 --- a/compiler/rustc_mir_build/src/errors.rs +++ b/compiler/rustc_mir_build/src/errors.rs @@ -596,6 +596,7 @@ pub(crate) struct UnreachablePattern<'tcx> { pub(crate) covered_by_one: Option<Span>, #[note(mir_build_unreachable_covered_by_many)] pub(crate) covered_by_many: Option<MultiSpan>, + pub(crate) covered_by_many_n_more_count: usize, } #[derive(Subdiagnostic)] diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs index a948e5d0c21..ca563e01569 100644 --- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs +++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs @@ -917,6 +917,7 @@ fn report_unreachable_pattern<'p, 'tcx>( pat: &DeconstructedPat<'p, 'tcx>, explanation: &RedundancyExplanation<'p, 'tcx>, ) { + static CAP_COVERED_BY_MANY: usize = 4; let pat_span = pat.data().span; let mut lint = UnreachablePattern { span: Some(pat_span), @@ -925,6 +926,7 @@ fn report_unreachable_pattern<'p, 'tcx>( covered_by_catchall: None, covered_by_one: None, covered_by_many: None, + covered_by_many_n_more_count: 0, }; match explanation.covered_by.as_slice() { [] => { @@ -950,15 +952,27 @@ fn report_unreachable_pattern<'p, 'tcx>( lint.covered_by_one = Some(covering_pat.data().span); } covering_pats => { + let mut iter = covering_pats.iter(); let mut multispan = MultiSpan::from_span(pat_span); - for p in covering_pats { + for p in iter.by_ref().take(CAP_COVERED_BY_MANY) { multispan.push_span_label( p.data().span, fluent::mir_build_unreachable_matches_same_values, ); } - multispan - .push_span_label(pat_span, fluent::mir_build_unreachable_making_this_unreachable); + let remain = iter.count(); + if remain == 0 { + multispan.push_span_label( + pat_span, + fluent::mir_build_unreachable_making_this_unreachable, + ); + } else { + lint.covered_by_many_n_more_count = remain; + multispan.push_span_label( + pat_span, + fluent::mir_build_unreachable_making_this_unreachable_n_more, + ); + } lint.covered_by_many = Some(multispan); } } diff --git a/tests/ui/pattern/usefulness/explain-unreachable-pats.rs b/tests/ui/pattern/usefulness/explain-unreachable-pats.rs index 746343246c6..1cfa5212414 100644 --- a/tests/ui/pattern/usefulness/explain-unreachable-pats.rs +++ b/tests/ui/pattern/usefulness/explain-unreachable-pats.rs @@ -26,6 +26,25 @@ fn main() { _ => {} } + match 0u8 { + 1 => {} + //~^ NOTE matches some of the same values + 2 => {} + //~^ NOTE matches some of the same values + 3 => {} + //~^ NOTE matches some of the same values + 4 => {} + //~^ NOTE matches some of the same values + 5 => {} + 6 => {} + 1 ..= 6 => {} + //~^ ERROR unreachable pattern + //~| NOTE no value can reach this + //~| NOTE multiple earlier patterns match some of the same values + //~| NOTE ...and 2 other patterns + _ => {} + } + let res: Result<(),!> = Ok(()); match res { Ok(_) => {} diff --git a/tests/ui/pattern/usefulness/explain-unreachable-pats.stderr b/tests/ui/pattern/usefulness/explain-unreachable-pats.stderr index 0dfd0980050..1378dce6063 100644 --- a/tests/ui/pattern/usefulness/explain-unreachable-pats.stderr +++ b/tests/ui/pattern/usefulness/explain-unreachable-pats.stderr @@ -32,7 +32,31 @@ LL | (1 | 2,) => {} | ^^^^^^^^ collectively making this unreachable error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:32:9 + --> $DIR/explain-unreachable-pats.rs:40:9 + | +LL | 1 ..= 6 => {} + | ^^^^^^^ no value can reach this + | +note: multiple earlier patterns match some of the same values + --> $DIR/explain-unreachable-pats.rs:40:9 + | +LL | 1 => {} + | - matches some of the same values +LL | +LL | 2 => {} + | - matches some of the same values +LL | +LL | 3 => {} + | - matches some of the same values +LL | +LL | 4 => {} + | - matches some of the same values +... +LL | 1 ..= 6 => {} + | ^^^^^^^ ...and 2 other patterns collectively make this unreachable + +error: unreachable pattern + --> $DIR/explain-unreachable-pats.rs:51:9 | LL | Err(_) => {} | ^^^^^^ @@ -41,7 +65,7 @@ LL | Err(_) => {} = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:46:9 + --> $DIR/explain-unreachable-pats.rs:65:9 | LL | (Err(_), Err(_)) => {} | ^^^^^^^^^^^^^^^^ @@ -50,7 +74,7 @@ LL | (Err(_), Err(_)) => {} = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:53:9 + --> $DIR/explain-unreachable-pats.rs:72:9 | LL | (Err(_), Err(_)) => {} | ^^^^^^^^^^^^^^^^ @@ -59,7 +83,7 @@ LL | (Err(_), Err(_)) => {} = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:63:11 + --> $DIR/explain-unreachable-pats.rs:82:11 | LL | if let (0 | - matches all the relevant values @@ -68,13 +92,13 @@ LL | | 0, _) = (0, 0) {} | ^ no value can reach this error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:73:9 + --> $DIR/explain-unreachable-pats.rs:92:9 | LL | (_, true) => {} | ^^^^^^^^^ no value can reach this | note: multiple earlier patterns match some of the same values - --> $DIR/explain-unreachable-pats.rs:73:9 + --> $DIR/explain-unreachable-pats.rs:92:9 | LL | (true, _) => {} | --------- matches some of the same values @@ -86,7 +110,7 @@ LL | (_, true) => {} | ^^^^^^^^^ collectively making this unreachable error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:86:9 + --> $DIR/explain-unreachable-pats.rs:105:9 | LL | (true, _) => {} | --------- matches all the relevant values @@ -95,7 +119,7 @@ LL | (true, true) => {} | ^^^^^^^^^^^^ no value can reach this error: unreachable pattern - --> $DIR/explain-unreachable-pats.rs:98:9 + --> $DIR/explain-unreachable-pats.rs:117:9 | LL | (_, true, 0..10) => {} | ---------------- matches all the relevant values @@ -103,5 +127,5 @@ LL | (_, true, 0..10) => {} LL | (_, true, 3) => {} | ^^^^^^^^^^^^ no value can reach this -error: aborting due to 9 previous errors +error: aborting due to 10 previous errors |