Assist for merging single-body swicth cases with a logical-or pattern

[FMorschel]

I'd like to ask for an assist for merging single-body swicth cases with a logical-or pattern

So cases like:

int a(int x) {
  switch (x) {
    case 0:
      return 0;
    case 2:
    case 1:
      return 1;
    default:
      return throw UnimplementedError();
  }
}

Can become:

switch (x) {
  case 0:
    return 0;
  case 1 || 2: // or swapped I'm not sure what to put first here (not sure it matters, just an UX question)
    return 1;
  default:
    return throw UnimplementedError();
}

Originally posted by @FMorschel in #55861 (comment)

[dart-github-bot]

Summary: The user proposes a syntax change to Dart's switch statement, allowing multiple case values to be combined using logical OR (||) for more concise code. They specifically want to merge cases with single-body statements.

[FMorschel]

Now that #55861 is closed, a workaround is to do both conversions to and from switch expression. It will give the same result asked above.

But it obviously just works when the switch statement can be converted.

[FMorschel]

If dart-lang/linter#5078 is accepted it would work great with this as well.

[FMorschel]

Also, dart-lang/linter#5079 (if accepted) would help ensure duplicates are removed as well as unreachable_switch_case.