Missed Optimization when Matching on Complete Unicode Character Ranges with an Unreachable Arm

Hello, I've noticed a bug with rustc:

#[inline(never)]
pub fn with_unreachable(c: char) -> bool {
    match c {
        ('\0'..='\u{d7ff}') => true,
        ('\u{e000}'..='\u{10ffff}') => true,
        _ => false
    }
}

#[inline(never)]
pub fn without_unreachable(c: char) -> bool {
    match c {
        ('\0'..='\u{d7ff}') => true,
        ('\u{e000}'..='\u{10ffff}') => true,
    }
}

which outputs:

example::with_unreachable::hd01eb55f04576fdc:
  cmp edi, 55296
  setb cl
  add edi, -57344
  cmp edi, 1056768
  setb al
  or al, cl
  ret

example::without_unreachable::h31c5b4f665ccfd93:
  mov al, 1
  ret

Gives a compiler warning telling us that _ => false is unreachable, but it seems that the optimiser isn't privy to this? We'd expect without_unreachable and with_unreachable to give the same assembly output.

Meta

The above is built with rustc 1.77.0 and flags -C debuginfo=1 --emit asm -Cllvm-args=--x86-asm-syntax=intel --crate-type rlib --color=always --edition 2021 -C opt-level=3

A link to the godbolt snippet: https://godbolt.org/z/hf7jje83W

Start by reproducing the two functions with the listed rustc 1.77.0 flags and compare their emitted assembly, using the linked Godbolt snippet as a reference. Trace the compiler optimization path responsible for matching complete Unicode ranges, then add or update a regression test showing that the unreachable-arm version produces the same optimized result as the version without that arm.