Fixed the idiom version.

Author: mdashti

.circleci/config.yml

@@ -65,7 +65,7 @@ jobs:
           command: "cargo fmt --check"
       - run:
           name: "Clippy"
-          command: "cargo clippy --all --all-targets -- -Dwarnings"
+          command: "cargo clippy --all --all-targets -- -Dwarnings -Drust-2018-idioms"
       - run:
           name: "Tests"
           command: "cargo clean && cargo build && cargo test && bash .circleci/run_tests.sh && .circleci/generate_coverage.sh"