Aster is a crate developed by @erickt which provides tools for building ASTs (similar to, but better than,
libsyntax/ext/build.rs). It is used by serde, and thus by Servo among others. It requires to be kept in sync with libsyntax.
There is a PR to add this as an unstable library to the Rust distro. The motivation is to keep it in sync with libsyntax. Given that this is a fairly large (8 kloc) chunk of code and we have tried to reduce the number of libs in the main Rust repo, it would be nice if we could find a better solution. If there is some way for crates like Aster to keep ahead of libsyntax breakage I believe other crates and tools would benefit (Rustfmt certainly would).
So, ideas? Opinions on landing 28006?