Changes needed for rust 2024 edition

[A6GibKm]

These were tested with https://gitlab.gnome.org/World/Rust/libadwaita-rs/-/merge_requests/94 and it solves the remaining issues. There are more changes that are likely needed. This would benefit from gtk-rs/gtk-rs-core#1663.

[sdroege]

Does this continue to compile without warnings (and clippy lints) with 1.80?

[A6GibKm]

Libadwaita-rs: Yes, gtk4-rs: Not even close.

[sdroege]

Then we can't really merge this until we update our MSRV to 1.85

[sdroege]

Then we can't really merge this until we update our MSRV to 1.85

That happened (1.86)

[A6GibKm]

I tested the current state against gtk4-rs and gtk-rs-core. They pass

cargo clippy --features=v4_20

cargo clippy --features=v2_84

respectively, when edition = 2021.

There was a warning:

error[E0308]: mismatched types
   --> glib/src/gstring.rs:154:37
    |
154 |                 end_ptr.offset_from(ptr as *const u8) as usize + 1,
    |                         ----------- ^^^^^^^^^^^^^^^^ expected `*const i8`, found `*const u8`
    |                         |
    |                         arguments to this method are incorrect
    |
    = note: expected raw pointer `*const i8`
               found raw pointer `*const u8`
note: method defined here
   --> /rustc/e4662966273ed58b51f9ff8d682accc202aa1210/library/core/src/ptr/const_ptr.rs:664:25

on manual code though.

When using edition 2024, gtk4-rs builds with warnings and gtk-rs-core throws enough warnings to fill the terminal and I cannot say whether they are all restricted to manual code.

When it comes to libadwaita-rs

cargo clippy --features=v1_8

passes with both editions with unrelated warnings.

[sdroege]

In any case, I think we want to avoid requiring applications to use edition 2024. At least 2021 should also work for applications, ideally also 2018 still.

[A6GibKm]

Applications can choose whichever edition they want. I have all my apps using 2024 atm. This just allows the bindings themselves to use this edition.