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<_> =