Auto merge of #118879 - Nadrieril:lint-range-gap, r=estebank

Lint singleton gaps after exclusive ranges

In the discussion to stabilize exclusive range patterns (https://github.com/rust-lang/rust/issues/37854), it has often come up that they're likely to cause off-by-one mistakes. We already have the `overlapping_range_endpoints` lint, so I [proposed](https://github.com/rust-lang/rust/issues/37854#issuecomment-1845580712) a lint to catch the complementary mistake.

This PR adds a new `non_contiguous_range_endpoints` lint that catches likely off-by-one errors with exclusive range patterns. Here's the idea (see the test file for more examples):
```rust
match x {
    0..10 => ..., // WARN: this range doesn't match `10_u8` because `..` is an exclusive range
    11..20 => ..., // this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
    _ => ...,
}
// help: use an inclusive range instead: `0_u8..=10_u8`
```

More precisely: for any exclusive range `lo..hi`, if `hi+1` is matched by another range but `hi` isn't, we suggest writing an inclusive range `lo..=hi` instead. We also catch `lo..T::MAX`.

6 files changed, 350 insertions, 38 deletions

diff --git a/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.rs b/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.rs
index 0f5f49c4ca4..07156d9a08a 100644
--- a/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.rs
+++ b/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.rs
@@ -1,5 +1,6 @@
 #![feature(exclusive_range_pattern)]
 #![allow(overlapping_range_endpoints)]
+#![allow(non_contiguous_range_endpoints)]
 #![deny(unreachable_patterns)]
 
 macro_rules! m {
diff --git a/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.stderr b/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.stderr
index b585de20629..90d0fd7483a 100644
--- a/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.stderr
+++ b/tests/ui/pattern/usefulness/integer-ranges/exhaustiveness.stderr
@@ -1,5 +1,5 @@
 error[E0004]: non-exhaustive patterns: `u8::MAX` not covered
-  --> $DIR/exhaustiveness.rs:47:8
+  --> $DIR/exhaustiveness.rs:48:8
    |
 LL |     m!(0u8, 0..255);
    |        ^^^ pattern `u8::MAX` not covered
@@ -11,7 +11,7 @@ LL |         match $s { $($t)+ => {}, u8::MAX => todo!() }
    |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `u8::MAX` not covered
-  --> $DIR/exhaustiveness.rs:48:8
+  --> $DIR/exhaustiveness.rs:49:8
    |
 LL |     m!(0u8, 0..=254);
    |        ^^^ pattern `u8::MAX` not covered
@@ -23,7 +23,7 @@ LL |         match $s { $($t)+ => {}, u8::MAX => todo!() }
    |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_u8` not covered
-  --> $DIR/exhaustiveness.rs:49:8
+  --> $DIR/exhaustiveness.rs:50:8
    |
 LL |     m!(0u8, 1..=255);
    |        ^^^ pattern `0_u8` not covered
@@ -35,7 +35,7 @@ LL |         match $s { $($t)+ => {}, 0_u8 => todo!() }
    |                                +++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `42_u8` not covered
-  --> $DIR/exhaustiveness.rs:50:8
+  --> $DIR/exhaustiveness.rs:51:8
    |
 LL |     m!(0u8, 0..42 | 43..=255);
    |        ^^^ pattern `42_u8` not covered
@@ -47,7 +47,7 @@ LL |         match $s { $($t)+ => {}, 42_u8 => todo!() }
    |                                ++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MAX` not covered
-  --> $DIR/exhaustiveness.rs:51:8
+  --> $DIR/exhaustiveness.rs:52:8
    |
 LL |     m!(0i8, -128..127);
    |        ^^^ pattern `i8::MAX` not covered
@@ -59,7 +59,7 @@ LL |         match $s { $($t)+ => {}, i8::MAX => todo!() }
    |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MAX` not covered
-  --> $DIR/exhaustiveness.rs:52:8
+  --> $DIR/exhaustiveness.rs:53:8
    |
 LL |     m!(0i8, -128..=126);
    |        ^^^ pattern `i8::MAX` not covered
@@ -71,7 +71,7 @@ LL |         match $s { $($t)+ => {}, i8::MAX => todo!() }
    |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `i8::MIN` not covered
-  --> $DIR/exhaustiveness.rs:53:8
+  --> $DIR/exhaustiveness.rs:54:8
    |
 LL |     m!(0i8, -127..=127);
    |        ^^^ pattern `i8::MIN` not covered
@@ -83,7 +83,7 @@ LL |         match $s { $($t)+ => {}, i8::MIN => todo!() }
    |                                ++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_i8` not covered
-  --> $DIR/exhaustiveness.rs:54:11
+  --> $DIR/exhaustiveness.rs:55:11
    |
 LL |     match 0i8 {
    |           ^^^ pattern `0_i8` not covered
@@ -96,7 +96,7 @@ LL +         0_i8 => todo!()
    |
 
 error[E0004]: non-exhaustive patterns: `u128::MAX` not covered
-  --> $DIR/exhaustiveness.rs:59:8
+  --> $DIR/exhaustiveness.rs:60:8
    |
 LL |     m!(0u128, 0..=ALMOST_MAX);
    |        ^^^^^ pattern `u128::MAX` not covered
@@ -108,7 +108,7 @@ LL |         match $s { $($t)+ => {}, u128::MAX => todo!() }
    |                                ++++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `5_u128..=u128::MAX` not covered
-  --> $DIR/exhaustiveness.rs:60:8
+  --> $DIR/exhaustiveness.rs:61:8
    |
 LL |     m!(0u128, 0..=4);
    |        ^^^^^ pattern `5_u128..=u128::MAX` not covered
@@ -120,7 +120,7 @@ LL |         match $s { $($t)+ => {}, 5_u128..=u128::MAX => todo!() }
    |                                +++++++++++++++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `0_u128` not covered
-  --> $DIR/exhaustiveness.rs:61:8
+  --> $DIR/exhaustiveness.rs:62:8
    |
 LL |     m!(0u128, 1..=u128::MAX);
    |        ^^^^^ pattern `0_u128` not covered
@@ -132,7 +132,7 @@ LL |         match $s { $($t)+ => {}, 0_u128 => todo!() }
    |                                +++++++++++++++++++
 
 error[E0004]: non-exhaustive patterns: `(126_u8..=127_u8, false)` not covered
-  --> $DIR/exhaustiveness.rs:69:11
+  --> $DIR/exhaustiveness.rs:70:11
    |
 LL |     match (0u8, true) {
    |           ^^^^^^^^^^^ pattern `(126_u8..=127_u8, false)` not covered
diff --git a/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.rs b/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.rs
new file mode 100644
index 00000000000..78849d7e143
--- /dev/null
+++ b/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.rs
@@ -0,0 +1,117 @@
+#![feature(exclusive_range_pattern)]
+#![deny(non_contiguous_range_endpoints)]
+
+macro_rules! m {
+    ($s:expr, $t1:pat, $t2:pat) => {
+        match $s {
+            $t1 => {}
+            $t2 => {}
+            _ => {}
+        }
+    };
+}
+
+fn main() {
+    match 0u8 {
+        20..30 => {} //~ ERROR multiple ranges are one apart
+        31..=40 => {}
+        _ => {}
+    }
+    match 0u8 {
+        20..30 => {} //~ ERROR multiple ranges are one apart
+        31 => {}
+        _ => {}
+    }
+
+    m!(0u8, 20..30, 31..=40); //~ ERROR multiple ranges are one apart
+    m!(0u8, 31..=40, 20..30); //~ ERROR multiple ranges are one apart
+    m!(0u8, 20..30, 29..=40); //~ WARN multiple patterns overlap on their endpoints
+    m!(0u8, 20..30, 30..=40);
+    m!(0u8, 20..30, 31..=40); //~ ERROR multiple ranges are one apart
+    m!(0u8, 20..30, 32..=40);
+    m!(0u8, 20..30, 31..=32); //~ ERROR multiple ranges are one apart
+    // Don't lint two singletons.
+    m!(0u8, 30, 32);
+    // Don't lint on the equivalent inclusive range
+    m!(0u8, 20..=29, 31..=40);
+    // Don't lint if the lower one is a singleton.
+    m!(0u8, 30, 32..=40);
+
+    // Catch the `lo..MAX` case.
+    match 0u8 {
+        0..255 => {} //~ ERROR exclusive range missing `u8::MAX`
+        _ => {}
+    }
+    // Except for `usize`, since `0..=usize::MAX` isn't exhaustive either.
+    match 0usize {
+        0..usize::MAX => {}
+        _ => {}
+    }
+
+    // Don't lint if the gap is caught by another range.
+    match 0u8 {
+        0..10 => {}
+        11..20 => {}
+        10 => {}
+        _ => {}
+    }
+    match 0u8 {
+        0..10 => {}
+        11..20 => {}
+        5..15 => {}
+        _ => {}
+    }
+    match 0u8 {
+        0..255 => {}
+        255 => {}
+    }
+
+    // Test multiple at once
+    match 0u8 {
+        0..10 => {} //~ ERROR multiple ranges are one apart
+        11..20 => {}
+        11..30 => {}
+        _ => {}
+    }
+    match 0u8 {
+        0..10 => {}  //~ ERROR multiple ranges are one apart
+        11..20 => {} //~ ERROR multiple ranges are one apart
+        21..30 => {}
+        _ => {}
+    }
+    match 0u8 {
+        00..20 => {} //~ ERROR multiple ranges are one apart
+        10..20 => {} //~ ERROR multiple ranges are one apart
+        21..30 => {}
+        21..40 => {}
+        _ => {}
+    }
+
+    // Test nested
+    match (0u8, true) {
+        (0..10, true) => {} //~ ERROR multiple ranges are one apart
+        (11..20, true) => {}
+        _ => {}
+    }
+    match (true, 0u8) {
+        (true, 0..10) => {} //~ ERROR multiple ranges are one apart
+        (true, 11..20) => {}
+        _ => {}
+    }
+    // Asymmetry due to how exhaustiveness is computed.
+    match (0u8, true) {
+        (0..10, true) => {} //~ ERROR multiple ranges are one apart
+        (11..20, false) => {}
+        _ => {}
+    }
+    match (true, 0u8) {
+        (true, 0..10) => {}
+        (false, 11..20) => {}
+        _ => {}
+    }
+    match Some(0u8) {
+        Some(0..10) => {} //~ ERROR multiple ranges are one apart
+        Some(11..20) => {}
+        _ => {}
+    }
+}
diff --git a/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.stderr b/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.stderr
new file mode 100644
index 00000000000..e5c2d788ba4
--- /dev/null
+++ b/tests/ui/pattern/usefulness/integer-ranges/gap_between_ranges.stderr
@@ -0,0 +1,193 @@
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:16:9
+   |
+LL |         20..30 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `30_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `20_u8..=30_u8`
+LL |         31..=40 => {}
+   |         ------- this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+   |
+note: the lint level is defined here
+  --> $DIR/gap_between_ranges.rs:2:9
+   |
+LL | #![deny(non_contiguous_range_endpoints)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:21:9
+   |
+LL |         20..30 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `30_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `20_u8..=30_u8`
+LL |         31 => {}
+   |         -- this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:26:13
+   |
+LL |     m!(0u8, 20..30, 31..=40);
+   |             ^^^^^^  ------- this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+   |             |
+   |             this range doesn't match `30_u8` because `..` is an exclusive range
+   |             help: use an inclusive range instead: `20_u8..=30_u8`
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:27:22
+   |
+LL |     m!(0u8, 31..=40, 20..30);
+   |             -------  ^^^^^^
+   |             |        |
+   |             |        this range doesn't match `30_u8` because `..` is an exclusive range
+   |             |        help: use an inclusive range instead: `20_u8..=30_u8`
+   |             this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+
+warning: multiple patterns overlap on their endpoints
+  --> $DIR/gap_between_ranges.rs:28:21
+   |
+LL |     m!(0u8, 20..30, 29..=40);
+   |             ------  ^^^^^^^ ... with this range
+   |             |
+   |             this range overlaps on `29_u8`...
+   |
+   = note: you likely meant to write mutually exclusive ranges
+   = note: `#[warn(overlapping_range_endpoints)]` on by default
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:30:13
+   |
+LL |     m!(0u8, 20..30, 31..=40);
+   |             ^^^^^^  ------- this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+   |             |
+   |             this range doesn't match `30_u8` because `..` is an exclusive range
+   |             help: use an inclusive range instead: `20_u8..=30_u8`
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:32:13
+   |
+LL |     m!(0u8, 20..30, 31..=32);
+   |             ^^^^^^  ------- this could appear to continue range `20_u8..30_u8`, but `30_u8` isn't matched by either of them
+   |             |
+   |             this range doesn't match `30_u8` because `..` is an exclusive range
+   |             help: use an inclusive range instead: `20_u8..=30_u8`
+
+error: exclusive range missing `u8::MAX`
+  --> $DIR/gap_between_ranges.rs:42:9
+   |
+LL |         0..255 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `u8::MAX` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `0_u8..=u8::MAX`
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:71:9
+   |
+LL |         0..10 => {}
+   |         ^^^^^
+   |         |
+   |         this range doesn't match `10_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         11..20 => {}
+   |         ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+LL |         11..30 => {}
+   |         ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:77:9
+   |
+LL |         0..10 => {}
+   |         ^^^^^
+   |         |
+   |         this range doesn't match `10_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         11..20 => {}
+   |         ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:78:9
+   |
+LL |         11..20 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `20_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `11_u8..=20_u8`
+LL |         21..30 => {}
+   |         ------ this could appear to continue range `11_u8..20_u8`, but `20_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:83:9
+   |
+LL |         00..20 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `20_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `0_u8..=20_u8`
+LL |         10..20 => {}
+LL |         21..30 => {}
+   |         ------ this could appear to continue range `0_u8..20_u8`, but `20_u8` isn't matched by either of them
+LL |         21..40 => {}
+   |         ------ this could appear to continue range `0_u8..20_u8`, but `20_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:84:9
+   |
+LL |         10..20 => {}
+   |         ^^^^^^
+   |         |
+   |         this range doesn't match `20_u8` because `..` is an exclusive range
+   |         help: use an inclusive range instead: `10_u8..=20_u8`
+LL |         21..30 => {}
+   |         ------ this could appear to continue range `10_u8..20_u8`, but `20_u8` isn't matched by either of them
+LL |         21..40 => {}
+   |         ------ this could appear to continue range `10_u8..20_u8`, but `20_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:92:10
+   |
+LL |         (0..10, true) => {}
+   |          ^^^^^
+   |          |
+   |          this range doesn't match `10_u8` because `..` is an exclusive range
+   |          help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         (11..20, true) => {}
+   |          ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:97:16
+   |
+LL |         (true, 0..10) => {}
+   |                ^^^^^
+   |                |
+   |                this range doesn't match `10_u8` because `..` is an exclusive range
+   |                help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         (true, 11..20) => {}
+   |                ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:103:10
+   |
+LL |         (0..10, true) => {}
+   |          ^^^^^
+   |          |
+   |          this range doesn't match `10_u8` because `..` is an exclusive range
+   |          help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         (11..20, false) => {}
+   |          ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: multiple ranges are one apart
+  --> $DIR/gap_between_ranges.rs:113:14
+   |
+LL |         Some(0..10) => {}
+   |              ^^^^^
+   |              |
+   |              this range doesn't match `10_u8` because `..` is an exclusive range
+   |              help: use an inclusive range instead: `0_u8..=10_u8`
+LL |         Some(11..20) => {}
+   |              ------ this could appear to continue range `0_u8..10_u8`, but `10_u8` isn't matched by either of them
+
+error: aborting due to 16 previous errors; 1 warning emitted
+
diff --git a/tests/ui/pattern/usefulness/integer-ranges/reachability.rs b/tests/ui/pattern/usefulness/integer-ranges/reachability.rs
index 247fdd91572..13b84e2c44b 100644
--- a/tests/ui/pattern/usefulness/integer-ranges/reachability.rs
+++ b/tests/ui/pattern/usefulness/integer-ranges/reachability.rs
@@ -1,5 +1,6 @@
 #![feature(exclusive_range_pattern)]
 #![allow(overlapping_range_endpoints)]
+#![allow(non_contiguous_range_endpoints)]
 #![deny(unreachable_patterns)]
 
 macro_rules! m {
diff --git a/tests/ui/pattern/usefulness/integer-ranges/reachability.stderr b/tests/ui/pattern/usefulness/integer-ranges/reachability.stderr
index c5b028d2038..0f52dfd83b9 100644
--- a/tests/ui/pattern/usefulness/integer-ranges/reachability.stderr
+++ b/tests/ui/pattern/usefulness/integer-ranges/reachability.stderr
@@ -1,137 +1,137 @@
 error: unreachable pattern
-  --> $DIR/reachability.rs:18:17
+  --> $DIR/reachability.rs:19:17
    |
 LL |     m!(0u8, 42, 42);
    |                 ^^
    |
 note: the lint level is defined here
-  --> $DIR/reachability.rs:3:9
+  --> $DIR/reachability.rs:4:9
    |
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:22:22
+  --> $DIR/reachability.rs:23:22
    |
 LL |     m!(0u8, 20..=30, 20);
    |                      ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:23:22
+  --> $DIR/reachability.rs:24:22
    |
 LL |     m!(0u8, 20..=30, 21);
    |                      ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:24:22
+  --> $DIR/reachability.rs:25:22
    |
 LL |     m!(0u8, 20..=30, 25);
    |                      ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:25:22
+  --> $DIR/reachability.rs:26:22
    |
 LL |     m!(0u8, 20..=30, 29);
    |                      ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:26:22
+  --> $DIR/reachability.rs:27:22
    |
 LL |     m!(0u8, 20..=30, 30);
    |                      ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:29:21
+  --> $DIR/reachability.rs:30:21
    |
 LL |     m!(0u8, 20..30, 20);
    |                     ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:30:21
+  --> $DIR/reachability.rs:31:21
    |
 LL |     m!(0u8, 20..30, 21);
    |                     ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:31:21
+  --> $DIR/reachability.rs:32:21
    |
 LL |     m!(0u8, 20..30, 25);
    |                     ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:32:21
+  --> $DIR/reachability.rs:33:21
    |
 LL |     m!(0u8, 20..30, 29);
    |                     ^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:36:22
+  --> $DIR/reachability.rs:37:22
    |
 LL |     m!(0u8, 20..=30, 20..=30);
    |                      ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:37:22
+  --> $DIR/reachability.rs:38:22
    |
 LL |     m!(0u8, 20.. 30, 20.. 30);
    |                      ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:38:22
+  --> $DIR/reachability.rs:39:22
    |
 LL |     m!(0u8, 20..=30, 20.. 30);
    |                      ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:40:22
+  --> $DIR/reachability.rs:41:22
    |
 LL |     m!(0u8, 20..=30, 21..=30);
    |                      ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:41:22
+  --> $DIR/reachability.rs:42:22
    |
 LL |     m!(0u8, 20..=30, 20..=29);
    |                      ^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:43:24
+  --> $DIR/reachability.rs:44:24
    |
 LL |     m!('a', 'A'..='z', 'a'..='z');
    |                        ^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:50:9
+  --> $DIR/reachability.rs:51:9
    |
 LL |         5..=8 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:56:9
+  --> $DIR/reachability.rs:57:9
    |
 LL |         5..15 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:63:9
+  --> $DIR/reachability.rs:64:9
    |
 LL |         5..25 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:71:9
+  --> $DIR/reachability.rs:72:9
    |
 LL |         5..25 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:77:9
+  --> $DIR/reachability.rs:78:9
    |
 LL |         5..15 => {},
    |         ^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:84:9
+  --> $DIR/reachability.rs:85:9
    |
 LL |         _ => {},
    |         - matches any value
@@ -139,19 +139,19 @@ LL |         '\u{D7FF}'..='\u{E000}' => {},
    |         ^^^^^^^^^^^^^^^^^^^^^^^ unreachable pattern
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:89:9
+  --> $DIR/reachability.rs:90:9
    |
 LL |         '\u{D7FF}'..='\u{E000}' => {},
    |         ^^^^^^^^^^^^^^^^^^^^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:105:9
+  --> $DIR/reachability.rs:106:9
    |
 LL |         &FOO => {}
    |         ^^^^
 
 error: unreachable pattern
-  --> $DIR/reachability.rs:106:9
+  --> $DIR/reachability.rs:107:9
    |
 LL |         BAR => {}
    |         ^^^