[gnome-nibbles/ricotz/vala] Don't alter or try to write [GtkChild] fields

[Rico Tzschichholz <ricotz src gnome org>]

commit 1b48446068608aff9b5edf1fdbd4b8c0d9f0be94
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Sat Jan 16 13:56:10 2021 +0100

    Don't alter or try to write [GtkChild] fields
    
    See https://gitlab.gnome.org/GNOME/vala/issues/1121

 src/controls.vala | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)
---
diff --git a/src/controls.vala b/src/controls.vala
index 4f073586..584c9ff0 100644
--- a/src/controls.vala
+++ b/src/controls.vala
@@ -140,25 +140,25 @@ private class ControlsGrid : Button
         arrow_left.set_from_pixbuf  (arrow.rotate_simple (Gdk.PixbufRotation.COUNTERCLOCKWISE));
         arrow_right.set_from_pixbuf (arrow.rotate_simple (Gdk.PixbufRotation.CLOCKWISE));
 
-           up_handler = worm_props.notify ["up"].connect    (() => configure_label (worm_props.up,    ref 
move_up_label));
-         down_handler = worm_props.notify ["down"].connect  (() => configure_label (worm_props.down,  ref 
move_down_label));
-         left_handler = worm_props.notify ["left"].connect  (() => configure_label (worm_props.left,  ref 
move_left_label));
-        right_handler = worm_props.notify ["right"].connect (() => configure_label (worm_props.right, ref 
move_right_label));
-
-        configure_label (worm_props.up,    ref move_up_label);
-        configure_label (worm_props.down,  ref move_down_label);
-        configure_label (worm_props.left,  ref move_left_label);
-        configure_label (worm_props.right, ref move_right_label);
+           up_handler = worm_props.notify ["up"].connect    (() => configure_label (worm_props.up,    
move_up_label));
+         down_handler = worm_props.notify ["down"].connect  (() => configure_label (worm_props.down,  
move_down_label));
+         left_handler = worm_props.notify ["left"].connect  (() => configure_label (worm_props.left,  
move_left_label));
+        right_handler = worm_props.notify ["right"].connect (() => configure_label (worm_props.right, 
move_right_label));
+
+        configure_label (worm_props.up,    move_up_label);
+        configure_label (worm_props.down,  move_down_label);
+        configure_label (worm_props.left,  move_left_label);
+        configure_label (worm_props.right, move_right_label);
     }
 
     internal void mark_duplicated_keys (GenericSet<uint> duplicate_keys)
     {
-        set_duplicate_class (worm_props.up    in duplicate_keys, ref move_up_label);
-        set_duplicate_class (worm_props.down  in duplicate_keys, ref move_down_label);
-        set_duplicate_class (worm_props.left  in duplicate_keys, ref move_left_label);
-        set_duplicate_class (worm_props.right in duplicate_keys, ref move_right_label);
+        set_duplicate_class (worm_props.up    in duplicate_keys, move_up_label);
+        set_duplicate_class (worm_props.down  in duplicate_keys, move_down_label);
+        set_duplicate_class (worm_props.left  in duplicate_keys, move_left_label);
+        set_duplicate_class (worm_props.right in duplicate_keys, move_right_label);
     }
-    private static void set_duplicate_class (bool new_value, ref Label label)
+    private static void set_duplicate_class (bool new_value, Label label)
     {
         if (new_value)
             label.get_style_context ().add_class ("duplicate");
@@ -175,7 +175,7 @@ private class ControlsGrid : Button
         worm_props.disconnect (color_handler);
     }
 
-    private static void configure_label (uint key_value, ref Label label)
+    private static void configure_label (uint key_value, Label label)
     {
         string? key_name = Gdk.keyval_name (key_value);
         if (key_name == "Up")