diff --git a/include/swift/Basic/DiverseList.h b/include/swift/Basic/DiverseList.h
index a63b23f90b3..9318518d190 100644
--- a/include/swift/Basic/DiverseList.h
+++ b/include/swift/Basic/DiverseList.h
@@ -192,7 +192,7 @@ public:
       return *this;
     }
     iterator operator++(int _) {
-      iterator copy = *this;
+      auto copy = *this;
       operator++();
       return copy;
     }
@@ -235,7 +235,7 @@ public:
       return *this;
     }
     const_iterator operator++(int _) {
-      const_iterator copy = *this;
+      auto copy = *this;
       operator++();
       return copy;
     }