Use 2018 edition for rustfmt

[zrzka]

Not sure about adding cargo fmt -- --check to .travis.yml (see #264), keeping it out for now.

Fixes #264

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[ordian]

@zrzka we already have

parity-common/.travis.yml

Line 12 in 53678a1

- cargo fmt -- --check

it doesn't seem to be enforced, let's fix that

[zrzka]

@ordian missed it, thanks. Travis CI:

The exit code of after_success, after_failure, after_script, after_deploy and subsequent stages do not affect the build result. However, if one of these stages times out, the build is marked as failed.

I think it should be enough to change after_script to script.

[ordian]

Please fix the formatting https://travis-ci.org/paritytech/parity-common/jobs/614448593#L217
Also, are you sure that the script section in stable doesn't override the global script section? We want to run both on stable.

[zrzka]

Also, are you sure that the script section in stable doesn't override the global script section? We want to run both on stable.

It does. I moved it to the global script section:

script:
   - if [ "$TRAVIS_RUST_VERSION" == "stable" ] && [ "$TRAVIS_OS_NAME" == "linux" ]; then
     cargo fmt -- --check;
     fi