diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 438bedf4f7..d7c595e7e5 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -27,6 +27,9 @@ jobs:
           override: true
           components: rustfmt
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
+
       - name: cargo fmt --check
         uses: actions-rs/cargo@v1
         with:
@@ -78,6 +81,9 @@ jobs:
           target: ${{ matrix.target }}
           override: true
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
+
       - name: cargo check
         uses: actions-rs/cargo@v1
         with:
@@ -196,6 +202,8 @@ jobs:
           sudo apt update
           sudo apt install -y qemu-system-arm
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
 
       - name: Run-pass tests
         run:
@@ -244,6 +252,9 @@ jobs:
           target: ${{ matrix.target }}
           override: true
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
+
       - name: cargo check
         uses: actions-rs/cargo@v1
         with:
@@ -294,6 +305,9 @@ jobs:
           target: ${{ matrix.target }}
           override: true
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
+
       - name: cargo check
         uses: actions-rs/cargo@v1
         with:
@@ -403,6 +417,9 @@ jobs:
       - name: Remove cargo-config
         run: rm -f .cargo/config
 
+      - name: Fail on warnings
+        run: sed -i 's,//deny_warnings_placeholder_for_ci,#![deny(warnings)],' src/lib.rs macros/src/lib.rs
+
       - name: Build docs
         run: cargo doc
 
diff --git a/macros/src/lib.rs b/macros/src/lib.rs
index 02d472d180..adcd731680 100644
--- a/macros/src/lib.rs
+++ b/macros/src/lib.rs
@@ -1,9 +1,8 @@
-// #![deny(warnings)]
-
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/rtic-rs/cortex-m-rtic/master/book/en/src/RTIC.svg",
     html_favicon_url = "https://raw.githubusercontent.com/rtic-rs/cortex-m-rtic/master/book/en/src/RTIC.svg"
 )]
+//deny_warnings_placeholder_for_ci
 
 extern crate proc_macro;
 
diff --git a/src/lib.rs b/src/lib.rs
index 71cc86b2c9..5fe35a95e2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -32,12 +32,12 @@
 #![deny(missing_docs)]
 #![deny(rust_2018_compatibility)]
 #![deny(rust_2018_idioms)]
-#![deny(warnings)]
 #![no_std]
 #![doc(
     html_logo_url = "https://raw.githubusercontent.com/rtic-rs/cortex-m-rtic/master/book/en/src/RTIC.svg",
     html_favicon_url = "https://raw.githubusercontent.com/rtic-rs/cortex-m-rtic/master/book/en/src/RTIC.svg"
 )]
+//deny_warnings_placeholder_for_ci
 
 use cortex_m::{interrupt::InterruptNumber, peripheral::NVIC};
 pub use cortex_m_rtic_macros::app;