diff --git a/src/test/ui/lint/lint-missing-doc.rs b/src/test/ui/lint/lint-missing-doc.rs
index a2466d28fb0..77f9a3770a3 100644
--- a/src/test/ui/lint/lint-missing-doc.rs
+++ b/src/test/ui/lint/lint-missing-doc.rs
@@ -60,7 +60,7 @@ pub trait D {
 }
 
 /// dox
-pub trait E {
+pub trait E: Sized {
     type AssociatedType; //~ ERROR: missing documentation for an associated type
     type AssociatedTypeDef = Self; //~ ERROR: missing documentation for an associated type