message: build-on-stable etc
diff: language: rust
  rust:
  + - nightly
  - beta
  + - stable
  +matrix:
  + allow_failures:
  + - rust: nightly
  script:
  - RUST_BACKTRACE=1 CARGO_INCREMENTAL=0 cargo test --all
  - RUST_BACKTRACE=1 CARGO_INCREMENTAL=0 cargo test --tests --all
  