Warning: using procedural-masquerade crate

[mozfreddyb]

I get the following warning when compiling Firefox:

 3:27.18 warning: using `procedural-masquerade` crate
 3:27.18   --> toolkit/components/cascade_bloom_filter/src/lib.rs:24:1
 3:27.18    |
 3:27.18 24 | / rental! {
 3:27.18 25 | |     mod rentals {
 3:27.18 26 | |         use super::Cascade;
 3:27.18 27 | |
 3:27.18 ...  |
 3:27.18 33 | |     }
 3:27.18 34 | | }
 3:27.18    | |_^
 3:27.18    |
 3:27.18    = note: `#[warn(proc_macro_back_compat)]` on by default
 3:27.18    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
 3:27.18    = note: for more information, see issue #83125 <https://github.com/rust-lang/rust/issues/83125>
 3:27.18    = note: The `procedural-masquerade` crate has been unnecessary since Rust 1.30.0. Versions of this crate below 0.1.7 will eventually stop compiling.
 3:27.19    = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 3:27.19 warning: 1 warning emitted

[rmartinho]

As long as we're using rental 0.5.6 this should go away with future rust updates, see rust-lang/rust#84428.

However, since rental is now unmaintained we should probably replace it with some other crate. There's self_cell and ouroboros and maybe others, but I haven't really looked into them closely.

[rmartinho]

Actually, rust_cascade does not depend on rental, this error actually comes from cascade_bloom_filter.