error[E0308]: mismatched types
 --> $DIR/derive-invalid-strategy.rs:8:24
  |
8 |       #[merge(strategy = my_custom_merge_strategy)]
  |  ________________________^
9 | |     field1: u8,
  | |__________^ expected `u8`, found `&mut u8`
  |
help: consider removing the borrow
  |
8 |     #[merge(strategy = my_custom_merge_strategy)]
9 |     field1: u8,
  |