use of unstable library feature 'bool_to_option'

[tu-maurice]

Hello, I'm trying to build shakmaty version 0.18.0, but I'm running into the following build error. Maybe you could give me a hint what I am doing wrong. I'm using rustc version 1.49. Is version 1.50 required by any chance?

error[E0658]: use of unstable library feature 'bool_to_option'
   --> /build/fishnet-2.2.6-vendor.tar.gz/shakmaty/src/fen.rs:454:110
    |
454 |         } else if let Some(split_point) = board_part.iter().enumerate().filter_map(|(idx, ch)| (*ch == b'/').then(|| idx)).nth(7) {
    |                                                                                                              ^^^^
    |
    = note: see issue #64260 <https://github.com/rust-lang/rust/issues/64260> for more information

error: aborting due to previous error

For more information about this error, try `rustc --explain E0658`.
error: could not compile `shakmaty`

[niklasf]

Yep, exactly. It became stable in Rust 1.50.

[tu-maurice]

Alright. Thanks.