diff -r 59ad165f6cdb -r f44a7d8660ea tests/test-check-rust-format.t
--- a/tests/test-check-rust-format.t	Thu Apr 16 22:30:11 2020 +0900
+++ b/tests/test-check-rust-format.t	Fri Apr 17 19:35:18 2020 +0900
@@ -5,5 +5,5 @@
   $ cd "$TESTDIR"/..
   $ RUSTFMT=$(rustup which --toolchain nightly rustfmt)
   $ for f in `testrepohg files 'glob:**/*.rs'` ; do
-  >   $RUSTFMT --check --unstable-features --color=never $f
+  >   $RUSTFMT --check --edition=2018 --unstable-features --color=never $f
   > done