proc-macro2 0.2.3

A stable implementation of the upcoming new `proc_macro` API. Comes with an option, off by default, to also reimplement itself in terms of the upstream unstable API.
Documentation
language: rust
sudo: false

matrix:
  include:
    - rust: 1.15.0
    - rust: stable
    - rust: beta
    - rust: nightly
      before_script:
        - pip install 'travis-cargo<0.2' --user && export PATH=$HOME/.local/bin:$PATH
      script:
        - cargo test
        - cargo build --features nightly
        - cargo build --no-default-features
        - RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo test
        - RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build --features nightly
        - RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo doc --no-deps
      after_success:
        - travis-cargo --only nightly doc-upload

script:
  - cargo test
  - RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo test
env:
  global:
    - TRAVIS_CARGO_NIGHTLY_FEATURE=""
    - secure: "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"

notifications:
  email:
    on_success: never