XO0171: `..` used more than once or not last in pattern fields

In variant and struct patterns, .. ignores the remaining fields and must come last: Db(msg: m, ..). A list pattern may contain .. once, anywhere: [first, .., last]. .. is not allowed outside list, variant, and struct patterns. See core 3.5.

Example

enum E { Db(msg: Str, code: Int) }

fn f(e: E) -> Int {
  match e {
    Db(.., code: c) => c
  }
}

Fix

enum E { Db(msg: Str, code: Int) }

fn f(e: E) -> Int {
  match e {
    Db(code: c, ..) => c
  }
}

Run xo explain XO0171 for this text in a terminal, or see section 10.6 of the specification.