diff --git a/xs/src/libslic3r/Flow.cpp b/xs/src/libslic3r/Flow.cpp
index c3346e82b..d34a07472 100644
--- a/xs/src/libslic3r/Flow.cpp
+++ b/xs/src/libslic3r/Flow.cpp
@@ -90,7 +90,7 @@ Flow::_bridge_width(float nozzle_diameter, float bridge_flow_ratio) {
 
 /* This static method returns a sane extrusion width default. */
 float
-Flow::_auto_width(FlowRole role, float nozzle_diameter, float height) const {
+Flow::_auto_width(FlowRole role, float nozzle_diameter, float height) {
     // here we calculate a sane default by matching the flow speed (at the nozzle) and the feed rate
     // shape: rectangle with semicircles at the ends
     float width = ((nozzle_diameter*nozzle_diameter) * PI + (height*height) * (4.0 - PI)) / (4.0 * height);
diff --git a/xs/src/libslic3r/Flow.hpp b/xs/src/libslic3r/Flow.hpp
index 85fa5be85..fb4d8e237 100644
--- a/xs/src/libslic3r/Flow.hpp
+++ b/xs/src/libslic3r/Flow.hpp
@@ -70,7 +70,7 @@ class Flow
     /// Calculate a relatively sane extrusion width, based on height and nozzle diameter.
     /// Algorithm used does not play nice with layer heights < 0.1mm. 
     /// To avoid extra headaches, min and max are capped at 105% and 125% of nozzle diameter.
-    static float _auto_width(FlowRole role, float nozzle_diameter, float height) const;
+    static float _auto_width(FlowRole role, float nozzle_diameter, float height);
     static float _width_from_spacing(float spacing, float nozzle_diameter, float height, bool bridge);
 };