no branching allowed

src/layout/painter.rs

@@ -291,12 +291,12 @@ impl<'a, 'c> Painter<'a, 'c> {
         self.ctx.text
     }
 
-    pub fn child_layer(&mut self) -> usize {
-        self.ctx.layers.child(self.layer)
+    pub fn child_layer(&mut self) {
+        self.layer = self.ctx.layers.child(self.layer);
     }
 
-    pub fn next_layer(&mut self) -> usize {
-        self.ctx.layers.next(self.layer)
+    pub fn next_layer(&mut self) {
+        self.layer = self.ctx.layers.next(self.layer);
     }
 }