diff --git a/src/test/run-pass/type-sizes.rs b/src/test/run-pass/type-sizes.rs
index 8c58ec3e526c6..359f825bb63e0 100644
--- a/src/test/run-pass/type-sizes.rs
+++ b/src/test/run-pass/type-sizes.rs
@@ -26,6 +26,7 @@ enum e2 {
     a(u32), b
 }
 
+#[repr(u8)]
 enum e3 {
     a([u16; 0], u8), b
 }
@@ -52,5 +53,5 @@ pub fn main() {
 
     assert_eq!(size_of::<e1>(), 8 as usize);
     assert_eq!(size_of::<e2>(), 8 as usize);
-    assert_eq!(size_of::<e3>(), 2 as usize);
+    assert_eq!(size_of::<e3>(), 4 as usize);
 }