AUR Build failure: error[E0658]: impl Trait in associated types is unstable

[recolic]

System info

ArchLinux rolling, built from AUR.

Build log

PC➜  ~ pikaur -S gtk-qq-git --noconfirm --overwrite '/*'
Reading repository package databases...
Reading local package database...
Resolving AUR dependencies...
looking for conflicting AUR packages...
Not showing diff for gtk-qq-git package (--noconfirm)
:: Skipping review of PKGBUILD for gtk-qq-git package (--noconfirm)

Reading local package database...
:: Installing repository dependencies for gtk-qq-git:
resolving dependencies...
looking for conflicting packages...

Packages (4) ninja-1.11.1-3  python-tqdm-4.65.0-3  meson-1.2.0-2  rustup-1.26.0-3

Total Installed Size:  21.05 MiB

:: Proceed with installation? [Y/n] 
(4/4) checking keys in keyring                                                                                     [####################################################################] 100%
(4/4) checking package integrity                                                                                   [####################################################################] 100%
(4/4) loading package files                                                                                        [####################################################################] 100%
(4/4) checking for file conflicts                                                                                  [####################################################################] 100%
(4/4) checking available disk space                                                                                [####################################################################] 100%
:: Processing package changes...
(1/4) installing rustup                                                                                            [####################################################################] 100%
You may need to run rustup update stable
and possibly also rustup self upgrade-data
Optional dependencies for rustup
    lldb: rust-lldb script
    gdb: rust-gdb script [installed]
(2/4) installing ninja                                                                                             [####################################################################] 100%
(3/4) installing python-tqdm                                                                                       [####################################################################] 100%
Optional dependencies for python-tqdm
    python-requests: telegram [installed]
(4/4) installing meson                                                                                             [####################################################################] 100%
:: Running post-transaction hooks...
(1/1) Arming ConditionNeedsUpdate...
Reading local package database...
:: Downloading the latest sources for a devel package gtk-qq-git...

:: Starting the build:
==> Making package: gtk-qq-git 0.2.0.r164.gac4ee76-1 (Fri 28 Jul 2023 08:37:49 PM PDT)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
  -> Updating gtk-qq git repo...
  -> Found gtk-qq.desktop
  -> Found gtk-qq.png
==> Validating source files with sha512sums...
    gtk-qq ... Skipped
    gtk-qq.desktop ... Passed
    gtk-qq.png ... Passed
==> Extracting sources...
  -> Creating working copy of gtk-qq git repo...
Reset branch 'makepkg'
==> Starting prepare()...
rustc 1.73.0-nightly (04abc370b 2023-07-28)
/home/recolic/.cache/pikaur/build/gtk-qq-git/PKGBUILD: line 32: [: ==: unary operator expected
Directory already configured.

Just run your build command (e.g. ninja) and Meson will regenerate as necessary.
If ninja fails, run "ninja reconfigure" or "meson setup --reconfigure"
to force Meson to regenerate.

If build failures persist, run "meson setup --wipe" to rebuild from scratch
using the same options as passed when configuring the build.
To change option values, run "meson configure" instead.
INFO: autodetecting backend as ninja
INFO: calculating backend command to run: /usr/bin/ninja -C /home/recolic/.cache/pikaur/build/gtk-qq-git/src/gtk-qq/builddir
ninja: Entering directory `/home/recolic/.cache/pikaur/build/gtk-qq-git/src/gtk-qq/builddir'
ninja: no work to do.
==> Starting pkgver()...
==> Removing existing $pkgdir/ directory...
==> Starting build()...
info: using existing install for 'nightly-x86_64-unknown-linux-gnu'
info: override toolchain for '/home/recolic/.cache/pikaur/build/gtk-qq-git/src/gtk-qq' set to 'nightly-x86_64-unknown-linux-gnu'

  nightly-x86_64-unknown-linux-gnu unchanged - rustc 1.73.0-nightly (04abc370b 2023-07-28)

   Compiling gdk-pixbuf v0.16.0 (https://github.com/gtk-rs/gtk-rs-core#41d93071)
   Compiling ricq-core v0.1.17 (https://github.com/lz1998/ricq.git?rev=56620d755f35f7b6ade52991be62360b3377547c#56620d75)
   Compiling gdk4 v0.5.0 (https://github.com/gtk-rs/gtk4-rs#d771fdc7)
error[E0658]: `impl Trait` in associated types is unstable
   --> /home/recolic/.cargo/git/checkouts/ricq-6bb4bd71a72b13ed/56620d7/ricq-core/src/msg/mod.rs:100:21
    |
100 |     type IntoIter = impl Iterator<Item = RQElem> + 'static;
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #63063 <https://github.com/rust-lang/rust/issues/63063> for more information
    = help: add `#![feature(impl_trait_in_assoc_type)]` to the crate attributes to enable

   Compiling gsk4 v0.5.0 (https://github.com/gtk-rs/gtk4-rs#d771fdc7)
   Compiling gtk4 v0.5.0 (https://github.com/gtk-rs/gtk4-rs#d771fdc7)
For more information about this error, try `rustc --explain E0658`.
error: could not compile `ricq-core` (lib) due to previous error
warning: build failed, waiting for other jobs to finish...
==> ERROR: A failure occurred in build().
    Aborting...

Command 'makepkg --force' failed to execute.
:: Removing already installed dependencies for gtk-qq-git:
checking dependencies...
:: kate optionally requires rust: Rust LSP support

Packages (4) meson-1.2.0-2  ninja-1.11.1-3  python-tqdm-4.65.0-3  rustup-1.26.0-3

Total Removed Size:  21.05 MiB

:: Do you want to remove these packages? [Y/n] 
:: Processing package changes...
(1/4) removing meson                                                                                               [####################################################################] 100%
(2/4) removing python-tqdm                                                                                         [####################################################################] 100%
(3/4) removing rustup                                                                                              [####################################################################] 100%
(4/4) removing ninja                                                                                               [####################################################################] 100%
:: Running post-transaction hooks...
(1/1) Arming ConditionNeedsUpdate...

Can't build 'gtk-qq-git'.

Failed to build following packages:
gtk-qq-git