diff --git a/polkadot/.gitlab-ci.yml b/polkadot/.gitlab-ci.yml
index c1f760130be88d538cc04a6ea8170a2cfa12c665..55689a4215c5a224ffc147557067216bc3fda39c 100644
--- a/polkadot/.gitlab-ci.yml
+++ b/polkadot/.gitlab-ci.yml
@@ -132,7 +132,7 @@ test-linux-stable:                 &test
     RUST_TOOLCHAIN: stable
     # Enable debug assertions since we are running optimized builds for testing
     # but still want to have debug assertions.
-    RUSTFLAGS: -Cdebug-assertions=y
+    RUSTFLAGS: "-Cdebug-assertions=y -Dwarnings"
     TARGET: native
   script:
     - time cargo test --all --release --verbose --locked --features runtime-benchmarks