--check does not obey the newlines settings in rustfmt.toml #3849
Description
If you have a file with CRLF newlines and newline_style = "Unix" in rustfmt.toml or vice versa, then cargo fmt -- --check does not output any diff or exit with an error code.
Running cargo fmt itself updates the line endings as desired. --check seems to obey other settings in rustfmt.toml.
Occurs on both rustfmt 1.4.8-nightly (2019-10-04) and rustfmt 1.4.4-stable.