### What it does Checks for unnecessary '..' pattern binding on struct when all fields are explicitly matched. ### Why is this bad? Correctness and readability. It's like having a wildcard pattern after matching all enum variants explicitly. ### Example ``` let a = A { a: 5 }; match a { A { a: 5, .. } => {}, _ => {}, } ``` Use instead: ``` match a { A { a: 5 } => {}, _ => {}, } ```