diff --git a/src/libslic3r/ArcFitter.cpp b/src/libslic3r/ArcFitter.cpp
index bfc95d0b7..cdfd708b1 100644
--- a/src/libslic3r/ArcFitter.cpp
+++ b/src/libslic3r/ArcFitter.cpp
@@ -1,4 +1,5 @@
 #include "ArcFitter.hpp"
+#include "Polyline.hpp"
 
 #include <cmath>
 #include <cassert>