Fail dependant checks on cargo check warnings (#13922)

* Fail dependant checks on cargo check warnings

* Adjust feature flags for check-dependent-polkadot

substrate/scripts/ci/gitlab/pipeline/build.yml

@@ -12,6 +12,8 @@
   extends:
     - .docker-env
     - .test-refs-no-trigger-prs-only
+  variables:
+    RUSTFLAGS: "-D warnings"
   script:
     - git clone
       --depth=1
@@ -35,6 +37,10 @@ check-dependent-polkadot:
     COMPANION_OVERRIDES: |
       substrate: polkadot-v*
       polkadot: release-v*
+    # enable the same feature flags as polkadot's test-linux-stable
+    COMPANION_CHECK_COMMAND: >
+      cargo check --all-targets --workspace
+      --features=runtime-benchmarks,runtime-metrics,try-runtime
   rules:
     - if: $CI_COMMIT_REF_NAME =~ /^[0-9]+$/ #PRs