clippy 0.0.54

A bunch of helpful lints to avoid common pitfalls in Rust
language: rust
rust: nightly
sudo: false

script:
 - python util/update_lints.py -c
 - cargo build --features debugging
 - rm -rf target/ Cargo.lock
 - cargo test --features debugging

 # only test regex_macros if it compiles
 - if [[ "$(cargo build --features 'debugging test-regex_macros')" = 101 ]]; then cargo test --features 'debugging test-regex_macros'; fi