unreachable_switch_default

This default clause is covered by the previous cases.

The analyzer produces this diagnostic when a default clause in a switch statement doesn't match anything because all of the matchable values are matched by an earlier case clause.

The following code produces this diagnostic because the values E.e1 and E.e2 were matched in the preceding cases:

enum E { e1, e2 }

void f(E x) {
  switch (x) {
    case E.e1:
      print('one');
    case E.e2:
      print('two');
    default:
      print('other');
  }
}

Remove the unnecessary default clause:

enum E { e1, e2 }
void f(E x) {
  switch (x) {
    case E.e1:
      print('one');
    case E.e2:
      print('two');
  }
}