Allow `case` condition in return statement

[alex-medinsh]

Trying to refactor a simple function that validates a Uri:

bool _validateUri(Uri uri) {
      return uri.path == '/path' &&
          uri.queryParameters['param1'] == 'param1' &&
          uri.queryParameters['param2'] == 'param2' &&
          uri.queryParameters['param3'] != null &&
          uri.queryParameters['param4'] != null;
}

I have followed my instincts and wrote this code using patters:

bool _validateUri(Uri uri) {
     return uri.path == '/path' && uri.queryParameters case {
         'param1': 'param1',
         'param2': 'param2',
         'param3': String _,
         'param4': String _,
     };
}

and found out that I can't use case conditions anywhere outside an if. Furthermore, when I changed the code to use an if condition I found out that I can only use a single case condition in the if.

I got this to work with a switch and a single pattern:

bool _validateUrl(Uri uri) {
    return switch (uri) {
      Uri(
        path: '/path',
        queryParameters: {
         'param1': 'param1',
          'param2': 'param2',
          'param3': String _,
          'param4': String _,
        },
      ) => true,
      _ => false,
   };
}

But this approach requires me to explicitly return true and have a default false case, when all I want is to just return a bool result of "this variable did(n't) match this pattern".

In my opinion it would be useful and intuitive to be able to use case conditions outside of if and to chain multiple conditions with case. This might be two separate issues, but this was my thought process when trying to refactor this function.

[mateusfccp]

Seems like a duplicate of (or directly related to) #3059. If we have case expressions that evaluate to bool, you can achieve this (and much more, like using them in ternary, while, for, negating etc.)

[alex-medinsh]

Sorry, I tried searching for already opened issues, but didn't stumble upon that one. There is a comment describing exactly what I wanted to do. So I guess this is a duplicate, but that issue didn't have any activity for some time.

[mateusfccp]

If you feel like #3059 solves your problem, please, close this issue. Any relevant discussion can be kept in there.