falconGitHub

unnecessary-late

Same as unnecessary_late in Dart lints

Group
Style
Path
lint/style/unnecessary-late
Default
On (recommended)
Origin
Dart lints
Rule
458 of 512
recommended

Flags a redundant late modifier on an initialized static or top-level variable.

Static fields and top-level variables in Dart are already initialized lazily: their initializer does not run until the variable is first read. Marking such a declaration late therefore buys nothing, and it misleads readers into thinking deferred initialization is significant here. The rule only fires when the declarator actually has an initializer, since late on an uninitialized static or top-level variable does carry meaning. Drop the late keyword.

Invalid

example.dartdart
// `late` on already-lazy static / top-level variables with initializers.
late String banner = 'hello';
late int total = compute();

// `late final` with an initializer is equally redundant: static / top-level
// finals are already lazily initialized, so `late` still adds nothing.
late final int cachedTotal = compute();

int compute() => 42;

class Service {
  static late Service instance = Service._();
  static late int counter = 0;
  static late final int cached = 0;
  Service._();
}

class Cache {
  static late String key = 'k';
  static late bool ready = true;
}
Remove `late` from this already-lazy static or top-level variable.
1// `late` on already-lazy static / top-level variables with initializers.
2late String banner = 'hello';
Remove `late` from this already-lazy static or top-level variable.
2late String banner = 'hello';
3late int total = compute();
Remove `late` from this already-lazy static or top-level variable.
6// finals are already lazily initialized, so `late` still adds nothing.
7late final int cachedTotal = compute();
Remove `late` from this already-lazy static or top-level variable.
11class Service {
12 static late Service instance = Service._();
Remove `late` from this already-lazy static or top-level variable.
12 static late Service instance = Service._();
13 static late int counter = 0;
Remove `late` from this already-lazy static or top-level variable.
13 static late int counter = 0;
14 static late final int cached = 0;
Remove `late` from this already-lazy static or top-level variable.
18class Cache {
19 static late String key = 'k';
Remove `late` from this already-lazy static or top-level variable.
19 static late String key = 'k';
20 static late bool ready = true;

Valid

example.dartdart
// `late` that is genuinely needed, or plain declarations.
late final String deferred;

String loadConfig() => 'cfg';

class Service {
  late final Service instance;
  static final ready = true;
  static int counter = 0;
  late int lazyInstanceField = 1;
  Service();
}

final topLevel = loadConfig();
String plain = 'x';

Configure unnecessary-late

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

falcon.jsonjson
{
  "linter": {
    "rules": {
      "style": {
        "unnecessary-late": "error"
      }
    }
  }
}

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

example.dartdart
// falcon-ignore lint/style/unnecessary-late: <reason>