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, |