diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 22be4b61c..05ef4426e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,6 +47,9 @@ jobs:
         run: npm install --ci
         working-directory: benchmarks
 
+      - name: Error on warning
+        run: echo "RUSTFLAGS=-D warnings" >> $GITHUB_ENV
+
       - name: Cache
         uses: actions/cache@v2
         with:
diff --git a/src/lib.rs b/src/lib.rs
index 5a20b4f3f..c02f1bc0f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,7 +1,5 @@
 // Copyright 2020-2021 the Deno authors. All rights reserved. MIT license.
 
-#![deny(warnings)]
-
 #[macro_use]
 extern crate log;