Published the new 0.2.0 version of the rustc-tools crate. This tool aims to make rustc internals accessible (as much as possible).
Want to write a few lints for your project without adding them to clippy? Take a look at the example: https://github.com/GuillaumeGomez/rustc-tools/blob/master/examples/lint.rs
Just want a Rust parser? You can too: https://github.com/GuillaumeGomez/rustc-tools/blob/master/examples/ast.rs
Enjoy!