On Fri, May 29, 2020 at 03:17:51PM +0200, Marius Bakke wrote:
> On the 'staging' branch, "librsvg-next" (a dependency of GNOME) fails to
> compile the 'xml-rs' Rust crate:
> 
> --8<---------------cut here---------------start------------->8---
>    Compiling xml-rs v0.8.1
> error[E0658]: `cfg(doctest)` is experimental and subject to change
>  --> /tmp/guix-build-librsvg-2.46.4.drv-0/librsvg-2.46.4/vendor/rust-xml-rs-0.8.1.tar.gz/src/lib.rs:9:7
>   |
> 9 | #[cfg(doctest)]
>   |       ^^^^^^^
>   |
>   = note: for more information, see https://github.com/rust-lang/rust/issues/62210

That's a feature that was stabilized in Rust 1.40. I have a WIP patch
that updates Rust upto 1.43.1, but it's blocked on a LLVM 9 patch backport I
haven't had time to prepare yet. I won't have the time to look into it
properly right now, but here are the relevant links:

https://github.com/rust-lang/llvm-project/commit/7d5e7c023053660ffe494d72ce471e48ecc7f49b
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=959877
https://github.com/rust-lang/llvm-project/pull/43

Regards,
Jakub Kądziołka