diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 96fb168581b21..b0db3b75029fb 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -206,7 +206,7 @@ declare_lint! {
 
 declare_lint! {
     pub EXTRA_REQUIREMENT_IN_IMPL,
-    Warn,
+    Deny,
     "detects extra requirements in impls that were erroneously allowed"
 }
 
diff --git a/src/test/compile-fail/issue-18937.rs b/src/test/compile-fail/issue-18937.rs
index 8ac66bb44d20a..f57f3477a8a86 100644
--- a/src/test/compile-fail/issue-18937.rs
+++ b/src/test/compile-fail/issue-18937.rs
@@ -10,8 +10,6 @@
 
 // Regression test for #18937.
 
-#![deny(extra_requirement_in_impl)]
-
 use std::fmt;
 
 #[derive(Debug)]