diff --git a/lib/Slic3r/Polyline.pm b/lib/Slic3r/Polyline.pm
index d8b5e3e1d..6a60b0d0f 100644
--- a/lib/Slic3r/Polyline.pm
+++ b/lib/Slic3r/Polyline.pm
@@ -113,7 +113,7 @@ sub clip_start {
     my ($distance) = @_;
     
     my @my_points = @$self;
-    my $points = [ $my_points[0] ];
+    my $points = [ $my_points[0]->clone ];
     
     for (my $i = 1; $distance > 0 && $i <= $#my_points; $i++) {
         my $point = $my_points[$i];
@@ -140,7 +140,7 @@ sub regular_points {
     my ($distance) = @_;
     
     my @my_points = @$self;
-    my @points = ($my_points[0]);
+    my @points = ($my_points[0]->clone);
     my $len = 0;
     
     for (my $i = 1; $i <= $#my_points; $i++) {
diff --git a/lib/Slic3r/Print/SupportMaterial.pm b/lib/Slic3r/Print/SupportMaterial.pm
index 02644fbf1..350611232 100644
--- a/lib/Slic3r/Print/SupportMaterial.pm
+++ b/lib/Slic3r/Print/SupportMaterial.pm
@@ -396,7 +396,7 @@ sub generate_toolpaths {
             push @$base, @$contact;
         } elsif (@$contact && $contact_loops > 0) {
             # generate the outermost loop
-            my @loops0;
+            my @loops0 = ();
             {
                 # find centerline of the external loop of the contours
                 my @external_loops = @{offset($contact, -$flow->scaled_width/2)};