diff --git a/nac3core/build.rs b/nac3core/build.rs
index 38e3382f..1f37121f 100644
--- a/nac3core/build.rs
+++ b/nac3core/build.rs
@@ -31,6 +31,7 @@ fn main() {
         "-S",
         "-Wall",
         "-Wextra",
+        "-Werror=return-type",
         "-o",
         "-",
     ];