travis: cargo fmt now wants --check

diff --git a/.travis.yml b/.travis.yml
index e23b82ee2e1863c740c96e84cac9e933d9f5766f..e12f11185e5c3460e0a277ecaebad14d5c2343c1 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,7 +10,7 @@ matrix:
       install:
         - rustup component add rustfmt-preview
       script:
-        - cargo fmt -- --write-mode=diff
+        - cargo fmt -- --check
   allow_failures:
     - rust: nightly
 script: cargo test --release --verbose --all