diff --git a/CMakeLists.txt b/CMakeLists.txt
index f16fe57..206bec2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,6 +7,7 @@ add_compile_options(
     -Wpedantic
     -Waliasing
     -Wconversion-extra
+    -Wimplicit-interface
     -Wsurprising
     -Werror)