From b9116f4d5dd14cdda85ef5173a97f4d54c3e1dc9 Mon Sep 17 00:00:00 2001
From: supermerill <merill@fr.fr>
Date: Thu, 29 Nov 2018 17:39:30 +0100
Subject: [PATCH] bugfix

---
 xs/src/libslic3r/SurfaceCollection.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xs/src/libslic3r/SurfaceCollection.cpp b/xs/src/libslic3r/SurfaceCollection.cpp
index cb58afaca..8d9a01744 100644
--- a/xs/src/libslic3r/SurfaceCollection.cpp
+++ b/xs/src/libslic3r/SurfaceCollection.cpp
@@ -107,7 +107,7 @@ SurfacesConstPtr
 SurfaceCollection::filter_by_type(std::initializer_list<SurfaceType> types) const
 {
     SurfacesConstPtr ss;
-    for (Surface& s : this->surfaces)
+    for (const Surface& s : this->surfaces)
         for (const SurfaceType& t : types)
             if (s.surface_type == t) {
                 ss.push_back(&s);