diff --git a/tests/dogfood.rs b/tests/dogfood.rs
index 540040a5ed5..83b2acf7d81 100644
--- a/tests/dogfood.rs
+++ b/tests/dogfood.rs
@@ -24,7 +24,7 @@ fn dogfood() {
     let mut s = String::new();
     s.push_str(" -L target/debug/");
     s.push_str(" -L target/debug/deps");
-    s.push_str(" -Zextra-plugins=clippy -Ltarget_recur/debug -Dclippy_pedantic -Dclippy -Dclippy_internal");
+    s.push_str(" -Zextra-plugins=clippy -Ltarget_recur/debug -Dwarnings -Dclippy_pedantic -Dclippy -Dclippy_internal");
     config.target_rustcflags = Some(s);
     if let Ok(name) = var("TESTNAME") {
         config.filter = Some(name.to_owned())