error[E0499]: cannot borrow `scan` as mutable more than once at a time
  --> tests/ui/dca_ltdc_paint_then_present.rs:27:5
   |
22 |     let pixels = scan.paint_full();
   |                  ---- first mutable borrow occurs here
...
27 |     scan.present(&mut ctx);
   |     ^^^^ second mutable borrow occurs here
28 |     let _ = pixels[0];
   |             --------- first borrow later used here
