40 columns                              |
>>> Line comment before pattern.
if (obj case // c
constant as Type) {;}
<<<
if (obj
    case // c
        constant as Type) {
  ;
}
>>> Line comment before 'as'.
if (obj case constant // c
as Type) {;}
<<<
if (obj
    case constant // c
        as Type) {
  ;
}
>>> Line comment after 'as'.
if (obj case constant as // c
Type) {;}
<<<
if (obj
    case constant
        as // c
        Type) {
  ;
}
>>> Don't split `as` with leading line comment before first operand.
if (obj case
  // comment
  constant as Type) {;}
<<<
if (obj
    case
        // comment
        constant as Type) {
  ;
}