Error in using keywords while using moor in Flutter

Issue

In moor flutter, keywords select, into, update, delete show error as below-

error: Couldn’t infer type parameter ‘R’. Tried to infer ‘Lists’ for
‘R’ which doesn’t work: Type parameter ‘R’ declared to extend
‘DataClass’. The type ‘Lists’ was inferred from: Parameter ‘table’
declared as ‘TableInfo’but argument is ‘$ListsTable’. Consider
passing explicit type argument(s) to the generic.

import 'package:moor_flutter/moor_flutter.dart';
import 'package:moor/moor.dart';

part 'List.g.dart';    
@DataClassName('Lists')    
class Lists extends Table{    
  IntColumn get id => integer().autoIncrement()();    
  TextColumn get name => text().withLength(min:1, max: 50)();    
  DateTimeColumn get date => dateTime().nullable()();     
 BoolColumn get strikeThrough => boolean().withDefault(Constant(false))();    
}

@UseMoor(tables: [Lists])    
class AppDatabase extends _$AppDatabase {   
AppDatabase(): super((FlutterQueryExecutor.inDatabaseFolder(path:'db.sqlite',logStatements:true)));

@override    
int get schemaVersion => 1;    
 Future<List<Lists>> getAllLists() => select(lists).get();    
  Stream<List<Lists>> watchAllLists() => select(lists).watch();    
  Future insertLists(Lists list) => into(lists).insert(list);    
  Future updateLists(Lists list) => update(lists).replace(list);    
  Future deleteLists(Lists list) => delete(lists).delete(list);    
}

Solution

You are using Lists class in these functions

Future<List<Lists>> getAllLists() => select(lists).get();    
Stream<List<Lists>> watchAllLists() => select(lists).watch();    
Future insertLists(Lists list) => into(lists).insert(list);    
Future updateLists(Lists list) => update(lists).replace(list);    
Future deleteLists(Lists list) => delete(lists).delete(list);    

which is the moor tables related class. You should be using List class. However I would suggest to rename your table because Dart already have a List class.

From the docs, you can see that Todos getter comes with a Todo (singular) class :

// inside the database class, the `todos` getter has been created by moor.
@UseMoor(tables: [Todos, Categories])                           // Todos getter
class MyDatabase extends _$MyDatabase {  

  Future<List<Todo>> get allTodoEntries => select(todos).get(); // Todo class
  //             ^ no "s" here
  Stream<List<TodoEntry>> watchEntriesInCategory(Category c) {
    return (select(todos)..where((t) => t.category.equals(c.id))).watch();
  }
}

Answered By – Augustin R

Answer Checked By – Robin (FlutterFixes Admin)