Unrecognized option: 'write-mode'

[volzkzg]

I was trying to use write-mode configuration in my CI server.

cargo +nightly-2018-05-17 fmt -- --write-mode check

It turns out to be
Unrecognized option: 'write-mode'

I just installed a specific nightly version 2018-05-17 and install rustfmt by
rustup component add rustfmt-preview --toolchain nightly-2018-05-17

[nrc]

Use --check rather than --write-mode=check

[volzkzg]

@nrc Now it turns out to be
cargo manifest failed.

It works now, thanks!