diff --git a/src/ui/widget/ink-spin-button.cpp b/src/ui/widget/ink-spin-button.cpp
index 53c52de78fe3f9685992bc9f33c8a5605ab81d90..8ed514dc7a37ea9a15b52bbdb01a539a02f035f0 100644
--- a/src/ui/widget/ink-spin-button.cpp
+++ b/src/ui/widget/ink-spin-button.cpp
@@ -5,7 +5,8 @@
 //
 
 #include "ink-spin-button.h"
-#include <assert.h>
+
+#include <cassert>
 #include <iomanip>
 
 #include "ui/containerize.h"