diff --git a/CMakeLists.txt b/CMakeLists.txt
index 44ddf144c..6cf6b37b6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -398,6 +398,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 
     if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 9.0)
         list(APPEND warning_flags -Wshadow)
+        list(APPEND warning_flags -Wshorten-64-to-32)
     endif()
 
     if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0 AND NOT APPLE)