The problem is caused by the special path, it’s a valid path in Linux.
I encountered the problem by chance and wasted sometime on it, so share it.
$ mkdir '\\'
$ cd '\\'
$ git clone https://aur.archlinux.org/vscodium-bin.git
Cloning into 'vscodium-bin'...
done.
$ cd vscodium-bin/
$ makepkg
==> Making package: vscodium-bin 1.51.1-1 (Sun 15 Nov 2020 01:10:39 PM CST)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
-> Found vscodium-bin.desktop
-> Downloading VSCodium-linux-x64-1.51.1.tar.gz...
** Resuming transfer from byte position 1110016
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 89.9M 100 89.9M 0 0 256M 0 --:--:-- --:--:-- --:--:-- 252M
==> Validating source files with sha256sums...
vscodium-bin.desktop ... FAILED
==> ERROR: One or more files did not pass the validity check!