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unnecessary-flutter-imports

Group: Correctness
Path: lint/correctness/unnecessary-flutter-imports
Default: On (recommended)
Origin: Falcon
Domain: flutter
Rule: 455 of 512

recommendedflutter

Disallow unused Flutter framework and dart:async imports.

Usage is based on resolved symbol identity and import combinators. Unknown unprefixed names conservatively keep an unrestricted import, avoiding guesses from capitalization or substrings.

Invalid

example.dartdart

import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'dart:async';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter/material.dart' as flutter show Text;

void main() {
  print('Hello World');
}

class MyApp {
  void doSomething() {
    print('No Flutter symbols used');
  }
}

Remove this unnecessary Flutter import.

1import 'package:flutter/material.dart';

∙

Remove this unnecessary Flutter import.

1import 'package:flutter/material.dart';

2import 'package:flutter/foundation.dart';

∙

Remove this unnecessary Flutter import.

2import 'package:flutter/foundation.dart';

3import 'dart:async';

∙

Remove this unnecessary Flutter import.

3import 'dart:async';

4import 'package:flutter/services.dart';

∙

Remove this unnecessary Flutter import.

4import 'package:flutter/services.dart';

5import 'package:flutter/widgets.dart';

∙

Remove this unnecessary Flutter import.

5import 'package:flutter/widgets.dart';

6import 'package:flutter/material.dart' as flutter show Text;

∙

Valid

example.dartdart

import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'dart:async';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'My App',
      home: Scaffold(
        appBar: AppBar(title: const Text('Home')),
        body: const Center(
          child: Text('Hello'),
        ),
      ),
    );
  }
}

Future<void> asyncExample() async {
  await Future.delayed(const Duration(seconds: 1));
  debugPrint('Done');
}

// Uses Stream from dart:async
Stream<int> createStream() {
  return Stream.fromIterable([1, 2, 3]);
}

// Uses widgets
Widget createButton() {
  return ElevatedButton(
    onPressed: () {},
    child: const Text('Click me'),
  );
}

// Uses Color from Flutter
void styleContainer() {
  final container = Container(
    color: Color.fromARGB(255, 100, 150, 200),
  );
}

Configure unnecessary-flutter-imports

Set its severity in falcon.json. See the configuration guide.

falcon.jsonjson

{
  "linter": {
    "rules": {
      "correctness": {
        "unnecessary-flutter-imports": "error"
      }
    }
  }
}

Or silence one occurrence with a suppression comment; the reason is required.

example.dartdart

// falcon-ignore lint/correctness/unnecessary-flutter-imports: <reason>

unnecessary-nullablecheck-unnecessary-nullablecross-file
Flags private function or method parameters whose nullable type is unnecessary.
unnecessary-nullable-return-typeunnecessary_nullable_return_type
Disallow nullable return types on functions that never return null.
unnecessary-statementsunnecessary_statementsrecommended
Flags expression statements whose expression has no clear effect.
unrelated-type-equality-checksunrelated_type_equality_checksrecommended
Reports ==/!= comparisons and relational ==/!= patterns whose operand types are unrelated.
unused-codecheck-unused-codecross-file
Report public top-level declarations that nothing references.
unused-dependenciescross-file
Report regular pubspec dependencies with no Dart import or export in the analyzed package.
unused-filescheck-unused-filescross-file
Report lib/ files that no project entrypoint can reach.
use-build-context-synchronouslyuse_build_context_synchronouslyrecommendedflutter
Flags BuildContext use after an asynchronous gap without a mounted guard.