avoid-cascade-after-if-null

Warns when a cascade expression is used after if null (??) binary expression without parentheses.

Not adding parentheses might lead to unexpected results since cascade will be executed after if null expression.

Additional resources:

• https://github.com/dart-lang/sdk/issues/45667

Example

Bad:

class Cow {
  void moo() {}
}

class Ranch {
  final Cow? _cow;

  Ranch([Cow? cow])
      : _cow = cow ?? Cow()
          ..moo(); // LINT
}

void main() {
  final Cow? nullableCow;

  final cow = nullableCow ?? Cow()
    ..moo(); // LINT
}

Good:

void main() {
  final Cow? nullableCow;

  final cow = (nullableCow ?? Cow())..moo();
  final cow = nullableCow ?? (Cow()..moo());
}