diff --git a/src/Mod/Sketcher/App/SketchObject.cpp b/src/Mod/Sketcher/App/SketchObject.cpp
index bd8e4a7878..768fc1ef99 100644
--- a/src/Mod/Sketcher/App/SketchObject.cpp
+++ b/src/Mod/Sketcher/App/SketchObject.cpp
@@ -5839,7 +5839,7 @@ int SketchObject::changeConstraintsLocking(bool bLock)
     return cntSuccess;
 }
 
-bool SketchObject::constraintHasExpression(int constrid)
+bool SketchObject::constraintHasExpression(int constrid) const
 {
     App::ObjectIdentifier spath = this->Constraints.createPath(constrid);
 
diff --git a/src/Mod/Sketcher/App/SketchObject.h b/src/Mod/Sketcher/App/SketchObject.h
index 13ad9f4058..e1ccb241e6 100644
--- a/src/Mod/Sketcher/App/SketchObject.h
+++ b/src/Mod/Sketcher/App/SketchObject.h
@@ -266,7 +266,7 @@ public:
     double calculateConstraintError(int ConstrId);
     int changeConstraintsLocking(bool bLock);
     /// returns whether a given constraint has an associated expression or not
-    bool constraintHasExpression(int constrid);
+    bool constraintHasExpression(int constrid) const;
 
     ///porting functions
     int port_reversedExternalArcs(bool justAnalyze);