diff --git a/iOS/GBHorizontalLayout.m b/iOS/GBHorizontalLayout.m
index 1cefcc72d..e58a91bda 100644
--- a/iOS/GBHorizontalLayout.m
+++ b/iOS/GBHorizontalLayout.m
@@ -112,6 +112,7 @@ - (instancetype)initWithTheme:(GBTheme *)theme cutoutOnRight:(bool)cutoutOnRight
 - (instancetype)initWithTheme:(GBTheme *)theme
 {
     assert(false);
+    __builtin_unreachable();
 }
 
 - (CGRect)viewRectForOrientation:(UIInterfaceOrientation)orientation