Fix unreachable patterns

[notgull]

No description provided.

[jayvdb]

To add a bit more detail, on beta 1.82 & nightly

> cargo +beta build
   Compiling crossbeam-utils v0.8.20
   Compiling pin-project-lite v0.2.14
   Compiling parking v2.2.1
   Compiling concurrent-queue v2.5.0
   Compiling event-listener v5.3.1
   Compiling event-listener-strategy v0.5.2
   Compiling async-lock v3.4.0 (/home/jayvdb/rust/async-lock)
warning: unreachable pattern
   --> src/once_cell.rs:487:13
    |
487 |             Err(infallible) => match infallible {},
    |             ^^^^^^^^^^^^^^^ matches no values because `Infallible` is uninhabited
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types
    = note: `#[warn(unreachable_patterns)]` on by default

warning: unreachable pattern
   --> src/once_cell.rs:522:13
    |
522 |             Err(infallible) => match infallible {},
    |             ^^^^^^^^^^^^^^^ matches no values because `Infallible` is uninhabited
    |
    = note: to learn more about uninhabited types, see https://doc.rust-lang.org/nomicon/exotic-sizes.html#empty-types

warning: `async-lock` (lib) generated 2 warnings
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.67s

[taiki-e]

I think it's a compiler bug: rust-lang/rust#129352

[jayvdb]

Ok, also raised "upstream" at matklad/once_cell#261