Error: A value of type 'Iterable<Transaction>' can't be returned from a function with return type 'List<Transaction>?'. showing this error

The where function in Dart return you an Iterable<T> and not a List<T>.

But since you have the return type of your function as List<Transaction>, you have to convert the Iterable<Transaction> that you are getting from the where function.

For this use the, toList function on the Iterable.

List<Transaction>? get _recentTransactions {    return _userTransactions.where((tx) {        assert(tx != null);        return tx.date.isAfter(DateTime.now().subtract(Duration(days: 7),),);    }).toList(); }

Make a list by .toList

  List<Transaction> get _recentTransactions {        return _userTransactions.where((tx) {                       return tx.date.isAfter(DateTime.now().subtract(Duration(days: 7),),);        }).toList();     }

I had a similar issue with Iterable<String>

A value of type 'Iterable<String?>' can't be returned from a function with return type 'Iterable'. I used .cast like that

customerNames.where((String? option) {          return option!              .toLowerCase()              .contains(textEditingValue.text.toLowerCase());        }).cast()