diff --git a/contributing.md b/contributing.md
index 08ae384..8867fb8 100644
--- a/contributing.md
+++ b/contributing.md
@@ -116,6 +116,9 @@
  * Declare internal-only functions as `static`, declare read-only data
    as `const` where possble.
 
+ * Ensure that your code compiles without warnings, especially for changes
+   to the kernel.
+
 
 Developer's Certificate of Origin 1.1
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