Review

compiler/rustc_middle/src/thir.rs

@@ -979,6 +979,9 @@ impl<'tcx> PatRangeBoundary<'tcx> {
     ) -> Option<Ordering> {
         use PatRangeBoundary::*;
         match (self, other) {
+            // When comparing with infinities, we must remember that `0u8..` and `0u8..=255`
+            // describe the same range. These two shortcuts are ok, but for the rest we must check
+            // bit values.
             (PosInfinity, PosInfinity) => return Some(Ordering::Equal),
             (NegInfinity, NegInfinity) => return Some(Ordering::Equal),
 

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

@@ -1192,17 +1192,25 @@ impl ConstructorSet {
                 }
             }
             ConstructorSet::Bool => {
-                let mut seen_bools = [false, false];
+                let mut seen_false = false;
+                let mut seen_true = false;
                 for b in seen.map(|ctor| ctor.as_bool().unwrap()) {
-                    seen_bools[b as usize] = true;
-                }
-                for b in [true, false] {
-                    if seen_bools[b as usize] {
-                        present.push(Bool(b));
+                    if b {
+                        seen_true = true;
                     } else {
-                        missing.push(Bool(b));
+                        seen_false = true;
                     }
                 }
+                if seen_false {
+                    present.push(Bool(false));
+                } else {
+                    missing.push(Bool(false));
+                }
+                if seen_true {
+                    present.push(Bool(true));
+                } else {
+                    missing.push(Bool(true));
+                }
             }
             ConstructorSet::Integers { range_1, range_2 } => {
                 let seen_ranges: Vec<_> =